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Pimp my A-119?
MUFF WIGGLER Forum Index -> Music Tech DIY  
Author Pimp my A-119?
Reptil
hai guys,
eeehmmm Doepfer A-119
not so good (sonically)
to put it mildly

how can I pimp this module for better sound quality and more headroom?
the ICs they are TL062cn (Texas Instruments)
but looking at the datasheet of a TL062CN (or CP) these are 8 pin and not 16 like used in the A-119
I guess that's where it starts.. better IC?
different resistor values?

I don't care much for the mic level input
the line in (unbalanced) is what I use

thanks!
astroschnautzer
This is something I would like to know too.
Reptil
e-grad
This was discussed on German list a while ago. IIRC it'll help to use the big jack input only.

edit: Just checked the postings on the forum mentioned above: You should change the TL064 for an TL074 (I GUESS they have the same pin out but pls CHECK before swapping) and use the Symm. In.
Reptil
where was this discussed? (german language no problem for pirate)

the symmetrical input has the wrong impedance (it's for mics)
change the resistors?

ah ok the TL072 is the quad version of the TL074 (figures)
here it says the TLC072 is even better
http://www.me.umn.edu/labs/hmd/lab/electronics/ic.html

Dankeschön
Chewbacca
Reptil
yes they are pin and voltage compatible
e-grad
Bitteschön, gern geschehen.

These should be the direct links. Author is serenadi whom I think a reliable source:
http://www.sequencer.de/synthesizer/viewtopic.php?p=253557&highlight=a 119#253557

http://www.sequencer.de/synthesizer/viewtopic.php?p=252422&highlight=a 119#252422
Reptil
interessant!
Marge Simpson w00t
Reptil
Guinness ftw!
So, I'll have to change the resistors for the symmetrical input, and will also change the caps for something better..
Reptil
21" rims

http://www.vishay.com/company/press/releases/2008/080507foil/
haven
once you have done this could you post a summary of all the mods? It would be great to have it all in one place for the english only crowd (like me).

My A119 would like to be pimped as well... I wonder if the A138D Insert module can have an IC swap as well?
wetterberg
very cool.
I'd start with the IC replacement, and perhaps report on the sound change?
fonik
the TL064 is just a low power version of the TL074 ant it is 3 times noisier. channel separation and noise is almost the same for TL074 and TL084.
i would use a TL06x only for battery powered devices...
consumed
i just babelfished serenadi's posts and still could understand only half of it.
i know that the tl074 is a direct and superior substitution.
are there any mods (resistor or cap changes) that will work best with the tl074?
consumed
good news--ive tested using the TL074 and it is definitely an improvement.
found that signal level was lower AND the noise higher with the TL064.
i set up an A/B test swapping the TL074 with the TL064 and all else equal.
the TL064 was socketed so the swap was really quick.
here's the results:

606 through TL074 16/44.1 wav
606 through TL064 16/44.1 wav

i set up the test using the TL074, turning the 606 volume all the way up, and the 119 gain knob set to where the overload light was just barely flickering on one 16th note only. i used the asym input (the sym input introduces ground hum in this case). these recordings are completely dry, no compression or eq, and gain set carefully along the signal path.

EDIT: i performed this test using the ASYM in, which ive learned/discovered is the BAD input, and therefore much easier to notice the noise as in these recordings. make sure you always use the SYM in to keep the noise to signal lowest.
Reptil
that sounds much better!

I also posted here

maybe there's something out there better than the TLC07x and compatible???
Reptil
the National LME49740 seems totally compatible!
now let's have a look at how many are needed
quantities from 100.. maybe a group buy?
http://www.national.com/pf/LM/LME49740.html
e-grad
Why you've choosen the LME49740?

The typical OPAmp for the audio path within synth cicuits is the TL072 while MOTM uses OP275GP IIRC.
Reptil
e-grad wrote:
Why you've choosen the LME49740?

The typical OPAmp for the audio path within synth cicuits is the TL072 while MOTM uses OP275GP IIRC.


AFAIK pin and voltage compatible (have to check thouroughly but everything looks fine)
recommended by Jim Williams (the uncrowned king of clean) hihi

Quote:
072's are problematic for me in EQ's. There is too much noise to use them for HF boost. They have only 40 db open loop gain at 10k hz, add + 15 db of HF boost and that opamp has 25 db of loop gain left to push down distortion. That creates high THD.

Better choices (if housecleaning work like phase compensation and power supply decoupling is done) are the National LME49720NA or the Analog Devices AD8599, the LT1358, the OP-275, the BB OPA2134, AD8512, etc.

Some of those have 80 db open loop gain at 10k hz, 40 db less dirt. Compare the AD8599 .9 nv/hz/sq noise to the 072's 22 nv noise.

Jim Williams
Audio Upgrades


so the OP275 is also an option. MOTM sounds good IMHO.
Funky40
OP275 or 2604 are the choices you find everywhere.
Go for these if you like to exchange and don't know things.
For CV circuitry LT1013

all same pinlayout as TL072
doctorvague
Funky40 wrote:
OP275 or 2604 are the choices you find everywhere.
Go for these if you like to exchange and don't know things.
For CV circuitry LT1013

all same pinlayout as TL072


yep the OP's are a common upgrade
I agree this module don't sound so good as it maybe could
better opamps couldn't hurt

thanks for the clips
Reptil
Funky40 wrote:
OP275 or 2604 are the choices you find everywhere.
Go for these if you like to exchange and don't know things.
For CV circuitry LT1013

all same pinlayout as TL072


hey I'm all ears Band
trying to gather nice info about upgrading some workhorses
throwing ideas around
why not OP285
POW!

I want to know


please note this is also about quad opamps (2x2 in one package)
which ones?
why?
I'm trying to match the specs of the 275 to the quad ones (??!)

Analog Devices OP482 orrr???
that National LME49740 again? -- slew rate is near the OP275
Reptil
Consumed can you please post an unprocessed recording of that 606
(straight into the converters?) it can then be used as reference to try and find differences.
null test and the noise differences are appearant. w00t
thanks!!
Tim Stinchcombe
Hi folks,
Saw this in passing, and couldn't resist running a few simulations. Looks to me like the main problem with the TL064 is both its limited open-loop gain, and its bandwidth. For the 'asym in' at max gain (about x20 = 26dB), the thing essentially acts as a low-pass filter with a cut-off somewhere around the 1kHz region, so it could well sound pretty 'muddy' - see attached traces. (The low down high-pass effect is almost certainly due to the large back-to-back electrolytic caps at the input, but I didn't look at it in any detail.)

Replacing the '64 with a TL074 increases the bandwidth quite a bit, and using either a OP275 or an LME49720 looks like it will give the same sort of improvement again (the trace for the 49720 is ambiguously labelled as the SPICE model at the product page was actually for the LME49680, but I assume they know what they are doing, and hence that it is equivalent...). The datasheets for both the OP275 and LME49720 show a much higher unity-gain bandwidth than the TI chips, which I assume should help considerably in improving the overall quality of the amplified signal.

Tim

Edit: CAUTION! The OP275 is only a dual op amp package, so is not a 'drop in' replacement! (I originally did this chart before anybody realised that it wasn't a quad part!)
Funky40
uhhh, OP275 is dual, all i mentiioned is dual.
I have no idea about quad OP amps. Interested too to know


i had a A-119 by myself. was very dissapointed by this module.
What you describe Tim fits good how it sounded.
e-grad
consumed wrote:
i just babelfished serenadi's posts and still could understand only half of it.


I squeezed my personal babelfish:

hopefullywelltranslatedserenadi wrote:
Q: Due to the high gain the module is of limited use because it’s noisy?

A: Wwwellllll. „Due to“ is the most important part.

Noise is necessarily dependent on the gain. Not just the inherent noise of the circuit itself but also the noise coming from your audio source (not the module's fault ).

Actually the Audio Level Pot should read Gain since it determines the amplification of the pre-amp.

As stated the Balanced Input is very highl amplified but depends on the Audio Level pot. Furthermore the Balanced Input is NOT configured as a typical microphone pre amp due to it’s relatively high input capacitance (47k Ohm). Thus it is equally configured for line level signals.
Don’t get fooled by the label “Balanced Input” it can be used with any common mono plug. Inevitably you’ll have to lower the audio level to avoid clipping. However, at the time this reduces gain and (inherent) noise.
I would say the module is definately of use as long as one ignores the badly configured Line Input.
In simple words: Connect your drum machine to Balanced-Input and noise won’t be a big issues.

hopefullywelltranslatedserenadi wrote:
My A119 came with a TL064 which is noisier than a TL064. No idea, why Doepfer have choosen this chip as microphone amp since this quad OPAmp is used for the highly amplified microphone input as well as for the line level input. I swapped it immediately for an TL074.

No sign of high cut, though. The line input is linear except for the AC-coupling. There is a lowpass at the microphone input which is configured as differential amplifier using a common 220pf value cap.
Reptil
thanks modular buddies! w00t
opamp sorted Guinness ftw!
now... for those caps and resistors!
maybe put some small fast caps in parallel with the big ones.
(another recommendation of Jim Williams)
I'll try to get that schematic.
haven
I have swapped the TL064 in my A119 with a TL074. super quick with a chip puller. I think it sounds better - the 1/4 input sounds much clearer than the 1/8" input. I still think the A138d Cross Fader/Insert sounds a bit better than the modded A119 though. The A138d also uses TL074


I have not done extensive AB - I mostly just jammed and recorded Rockin' Banana!
Reptil
I think next is the carbon resistors. probably on the A-119 they muck it up.
Can you please point me towards that chip puller? Sounds like something I need. ambulance

PS: happy with the OSC! that was so smooth.... we're not worthy
e-grad
Reptil wrote:
I think next is the carbon resistors. probably on the A-119 they muck it up.

Don't think it worth the effort.
haven
Reptil wrote:

Can you please point me towards that chip puller? Sounds like something I need. ambulance

PS: happy with the OSC! that was so smooth.... we're not worthy


Glad you like the oscillator!

the chip puller I am referring to is also referred to as an IC Extractor. I got mine with an EPROM upgrade for a Mackie Universal Control, but they are cheap to buy. looks like this

fonik
Reptil wrote:
maybe put some small fast caps in parallel with the big ones.
(another recommendation of Jim Williams)

what caps? what for?
haven
Another possible candidate is the A134 VC Panner/Crossfader. It has a TL064 and a TL062 in it. In a few days I will be able to pick up some TL074 and TL072 to try swapping them and see if I can hear a difference.

If I can get rid of the slight fuzzy sound I get with the A134 I will get a second. I almost only use them as VC cross faders for filters and oscillators.
felix
I replaced the 064 on my A-119 with a 074 yesterday and there was certainly a noticeable difference. I almost want to say that the Gate Threshold was easier to dial in, but it might have just been my source material.

FWIW, I didn't even need a chip puller. I just used one of the smaller blades on my swiss army knife to every so gently lift each end up a little bit; enough for me to pull it straight out the rest of the way with my fingers. I wouldn't recommend lifting each end all the way up as you could bend the pins that way, but you could carefully bend them back. Just some advice if you don't want to wait around for a chip puller (like me).
criticalmonkey
i just made the swap too
i noticed a change almost instantly - i re tracked a about 10 minutes worth of stuff cause of it - thanks much
Reptil
fonik wrote:
Reptil wrote:
maybe put some small fast caps in parallel with the big ones.
(another recommendation of Jim Williams)

what caps? what for?


It's supposedly to allow fast transients through, gives a more even frequency response. While still blocking high freq trash.
The guy (Jim Williams) posts over at Gearslutz, he's been involved in mixer designs for a long time, and his mods are nothing short of fantastic I have heard from guys who upgraded their old Soundcraft desks.
Why not bring these pro audio ideas into the modular (DIY) world.
here's a couple of threads
http://www.gearslutz.com/board/geekslutz-forum/363128-d-r-orion-mode.h tml
http://www.gearslutz.com/board/geekslutz-forum/344943-foil-caps-micpre -inputs.html
and here's his company webpage
http://www.audioupgrades.com/default.htm

I'll get that IC puller, and leave the resistors on the a-119 alone.
Bigger fish to fry. Thanks!!!
I got a-134 too. I guess all doepfer modules passing audio will have to be modded. lol
nanners
DGTom
I noticed when I was inside my case a couple of weeks ago that the Doepfer LPG uses a lowly LM324... I wonder if that would be worth swapping out for a 074 hmmm.....
astroschnautzer
changed to the tl074 too, instant betterness notified. It wouldn`t be that expensive for döpfer to make this a standard feature. Have to check out on those caps too...
e-grad
Doepfer has choosen the LM324 intentionally. IIRC it improves the response to incoming CVs. There was a thread on that on the Doepfer-Yahoo group.

I've changed the OPAmps on my LPG which gave it's sound a MS10-ish touch.
Tim Stinchcombe
e-grad wrote:
Doepfer has choosen the LM324 intentionally. IIRC it improves the response to incoming CVs. There was a thread on that on the Doepfer-Yahoo group.

I've changed the OPAmps on my LPG which gave it's sound a MS10-ish touch.
Over the last several days I have seen a few mentions of the hidden pitfalls of swapping opamps (one being the modding the Plan B Model 9 thread here; the other was Synth DIY or Electro-Music, don't remember which) so I went looking for that thread, and I think I found it: the question of the LM324 was half-way through it, at the end of message #13182, and Dieter's response was #13195 (The search facility didn't find it searching on 'LM324' - had to go with '101-2' in the end...). So if this is the one you remember, it seems the LM324 use was as an extra precaution against it bursting into oscillation (which will be in the several hundred kHz region I would expect, i.e. you won't hear it directly, but will see lots of nasty mush on a scope if you have one!).

Yet again we are reminded that as simple as it may seem, swapping a chip for an apparently higher-specd part might bring other undesired side-effects with it, like increased noise, or nasty oscillations etc. Dang, this electronics lark can be particularly tricky sometimes!

Tim

Edit: the 'other' was Synth DIY, a 'BTW' type comment to a completely unrelated topic.
e-grad
Yes, that is the thread I was referring to.
wyrtti
I too changed the TL064 on my A-119. Since my local store was out of TL074's, I tried a TL084. Seems to work fine and, like many have reported with the TL074, was an improvement in sound quality. I am very happy with the mod.

Thank you all for you input and ideas. This was such a simple and inexpensive "fix"! we're not worthy

Now for some knob tweaking and... Guinness ftw! (had to try that smiley for the first time, sorry hihi )

wyrtti
thelizard
Sorry for the necropost, but I did a search for TL074 on DigiKey, and it provided me with hundreds of parts. I was already putting together a large order, so I thought I would throw a few of these in with it. Can someone guide me to the correct part?
Tim Stinchcombe
thelizard wrote:
Sorry for the necropost, but I did a search for TL074 on DigiKey, and it provided me with hundreds of parts. I was already putting together a large order, so I thought I would throw a few of these in with it. Can someone guide me to the correct part?
Just limit the search to '14 DIP' and just about any of those left (and in stock) will do, e.g. 497-2205-5-ND, but make sure you can order individually, so you don't end up with a whole tube of 25! (but then the total price will be rather high!).

Tim
thelizard
Thanks for your help!
consumed
has anyone used the OP275 in the a-119? its an 8-pin DIP. the TL074 is 14 pin, so some funky rigging would have to take place.
Reptil
consumed wrote:
has anyone used the OP275 in the a-119? its an 8-pin DIP. the TL074 is 14 pin, so some funky rigging would have to take place.

that would be correct. For a TL062 or even TL072 It would be perfect replacement.

Funky40 wrote:
uhhh, OP275 is dual, all i mentiioned is dual.
I have no idea about quad OP amps. Interested too to know
........


looking at the ADA4692..... hmmmmmmmmmmmmmmmmmmmmmmmmmm hmmm.....
http://www.analog.com/en/amplifiers-and-comparators/operational-amplif iers-op-amps/ada4692-4/products/product.html
going to order some caps and parts and also ICs tonight It's peanut butter jelly time!

hihi
consumed
silly me. i ordered the op275 before i realized its a dual package
note to self - ALWAYS CHECK THE DATASHEET FIRST

ok, fuck it. here's a silly cheap little project im going to try.
ill use a tiny single sided protoboard with headers mounted in the TL074 position
im going to socket the op275 on the protoboard as well
this pic is the top view so i have to remember it will be reversed if the headers are on the top
(the headers will plug directly into the onboard 14 pin socket)

consumed
re ^ that up there

aint gonna do it. i was going to work up a little protoboard circuit with .100 headers to mount into the socket but it looks like it wont work out very easily with the limited space available. im going to be happy with my TL074 replacement.
D/A A/D
God dammit, I also bought a op275 after seeing Tim's chart... Anyone care to trade me a TL074 for my op275??? seriously, i just don't get it

Also, I ordered it on the 18th... So no, I am not a complete nimrod...
Tim Stinchcombe
D/A A/D wrote:
God dammit, I also bought a op275 after seeing Tim's chart...
Sorry about that! I suspect I did it before anybody spotted that the OP275 was only a dual part - in any case I have added a warning now to hopefully stop anyone else falling into that trap...

Tim
D/A A/D
Tim Stinchcombe wrote:
D/A A/D wrote:
God dammit, I also bought a op275 after seeing Tim's chart...
Sorry about that! I suspect I did it before anybody spotted that the OP275 was only a dual part - in any case I have added a warning now to hopefully stop anyone else falling into that trap...

Tim


Sokay brother, I should have double checked the data sheet... At least I ordered a bunch of stuff from small bear that day.
D/A A/D
TL74 is installed, and I couldn't be happier...
HeWhoWantsJeans
D/A A/D wrote:
TL74 is installed, and I couldn't be happier...

I just received a bunch of TL74's the other day. Ideally I'll be throwing up an A/B test video between a stock 119 and a 119 with a 74.
attacksustain
I switched out one of the TL062's in the A112 ring mod for a TL082 last night. Noticably different sound, and worth doing if you want some variation between both halves. The 82 sounds louder, and brighter to me.
attacksustain
well that's curious. perceivable difference on headphones, but not when I try to record it.
terrafractyl
Whilst stumbling around this DIY section I found this thread, and well I'm interested.

I popped open my case and checked out my a-119 and saw that its now sporting a TL084 IC in there.
To be honest I was a little dissapointed by this, as from the moment I plugged this module in, I was dissapointed in the sound quality.
So my question is, after looking at the graph posted by tim in the last page, would replacing the TL084 with a LME49720 make a significant / noticable increase in sound quality? or is it not worth the effort?

I'd really love to be able to thow a whole mix or a buss though a modular filter every now and again, but at the moment the loss of sound quality really is ruining this possiblity for me.


consumed
@terrafractyl: you are using only the quarter inch input as well?
The_Crooked_Man
I just got a A-119 and it is completely and utterly useless. Doepfer should be ashamed of himself for releasing this thing!

Anyway, is the TL074 still the consensus replacement for the TL064n in there? I've never done any DIYing at all, but this seems simple enough, so I figure I'll give it a go.
The_Crooked_Man
Sorry for the double post, but I delved a little deeper, and saw that the LME49740 was also recommended as a much better replacement, but that it might draw too much current.

Has anyone used that chip in an A119?

Are the same ones useable to replace the LM324n found in the A119 (my A119 has a LM324n and a TL064CN) and A138b?

Would replacing BOTH in the A119 make much of a difference, or is the LM324 used in the CV path?

What about the A199 reverb module? That has a TL084 and I've found it to be quite noisy, though the noise could be coming from the tank. . .
tortug
some info and tip here:

http://wiki.muffwiggler.com/wiki/A119
The_Crooked_Man
tortug wrote:
some info and tip here:

http://wiki.muffwiggler.com/wiki/A119


Gotcha, but that's what I already know. I'm more interested in how much the LME would be an improvement over the TL074. The reason that I'm looking into that is that no one has said that the 119 sounds "good" after replacing the TL064, it just sounds less awful.

Also, I took my A119 out of the case, and it's NOT socketed. Guess I have an early one very frustrating
negativspace
I've found the LME49470s to be a nice improvement on the TL074s in my A-132-3s. I have a pair and ended up swapping all 4 chips. Better definition in the low end and up high.

I haven't tried one my A-119, which I threw an 074 into instead. I usually run it in a 'satellite' minicase with some other modules for my bass player, and power consumption is a consideration. It's in my 9U case right now, though... I'll dig out one of my 49470s and see if I can make out a difference.
terrafractyl
Please do!

I would be very interested to know how that goes. As The Crooked Man said, even with tl074 I still feel like my a-119 could sound a lot better.
The_Crooked_Man
Well, I just ordered a few LME49740's and I'm going to try them in my A119 and A199. I'll post before and afters as soon as I get them thumbs up
Reptil
yes, please do!! applause
The_Crooked_Man
Well, I'm ashamed to admit this, but I can't remove the damned solder on the tl064 on my A119! My solder sucker is too big to get between the tiny soldering points, and there's so little solder that a wick isn't working, either. Anyone have any suggestions?
negativspace
Standard advice for removing an unsocketed and expendable chip is to snip all of the legs with a pair of clippers and remove each one individually. That should make it a lot easier.
The_Crooked_Man
Yeah, I got to that point and then couldn't find my damned snips. I'll pick up a new set tomorrow and get this taken care of. By the way, I switched out the TL084 in my Doepfer spring reverb and A-138b (they were socketed) and the difference is unbelievable applause
negativspace
Yeah, I have one in my 138b as well, it was the first one I did. Maybe 2 minutes after I tried the swap, I ordered 6 more chips...

I found my last 3, but I haven't worked up the gumption to untangle the 119 (it's deeply patched right now) and test it out. You may yet beat me to it. Dead Banana
daverj
Cutting the leads and removing them one at a time is often the best way, and causes less damage to the traces.

But, a tip for when using a sucker or wick and there is too little solder: Add more solder.

Often a sucker or wick works best with lots of solder. Adding more solder gives you that, plus gets fresh flux in there to help things flow better.
Tim Stinchcombe
The_Crooked_Man wrote:
I switched out the TL084 in my Doepfer spring reverb and A-138b (they were socketed) and the difference is unbelievable applause
A quick comparison of simulation runs of the 'recovery' amp on the output of the spring gives an indication why. This amp, as well as giving lots of gain, is a bandpass filter, and the 'emphasis' control boosts the mid-range frequencies (presumably to help compensate for the fact that the amp driving the spring doesn't attempt to allow for the natural 6dB/octave drop-off with increasing frequency due to the spring input transducer being an inductor). The plots are effectively for 6 settings of the pot, from '0' round to '1' (= max emphasis).

The extra bandwidth due to the LME amp is quite startling!

(Note that National link to the LME49860 SPICE model when you ask for the SPICE model of the LME49740, so I imagine they are much of a muchness in terms of frequency response etc.)

Tim
thelizard
Just did the replacement today and added a TL074.

It sounds wayyyy better. Something else I found out about the A-119: It works wonderfully as a distortion unit.
debriff
I've also pimped my A-199 reverb :

- TL074 (I didn't see sooo much improvment compared to TL084)

- Accutronics tank : THIS is the sound improvement, nothing to see with the Belton ! thumbs up I've chosen the big 42 cm model with 6 springs, much longer decay, more transparent and musical sound. The model is 9BB3C1B and it works perfectly well ! w00t
telegasm
Did anyone test the sound of a LME49740?
negativspace
I found that the LME49740 was good in my A-132-3s and A-138b, but it didn't do much for the A-119. I left a TL074 in mine.
telegasm
Ah, thank you.
nativestate
looks like I'll be picking one of these bad boys up! Although is this the only solution for bringing line level signal back into my modular. Need to run mix through filter. If so, Im ordering mod. Can anyone PM me the link to order the correct mod.
debriff
telegasm wrote:
Did anyone test the sound of a LME49740?


Yes I did

I replaced LM324 with TL074 in A-138 audio mixer, and then with LME49740.

Not as spectacular as I expected... sad banana
Reptil
nativestate wrote:
looks like I'll be picking one of these bad boys up! Although is this the only solution for bringing line level signal back into my modular. Need to run mix through filter. If so, Im ordering mod. Can anyone PM me the link to order the correct mod.


no, you can route line level signals straight into the modular. (unbalanced)
the a-119 allows for more control and an envelope follower (with CV and gate out), very useful!

awesome info on the LME49740, thanks!
Demi Jon
I've got a A-119 and a TL074 in the mail to me now. I've never done any DIY, and just wondering -- is it possible to put the TL074 in the wrong way? Do i just slot it in with the writing on the IC in the same direction as the one I am removing?

There may be an obvious answer to this, but I won't have either the module or the IC in front of me for a week or so.
ndkent
Demi Jon wrote:
I've got a A-119 and a TL074 in the mail to me now. I've never done any DIY, and just wondering -- is it possible to put the TL074 in the wrong way? Do i just slot it in with the writing on the IC in the same direction as the one I am removing?

There may be an obvious answer to this, but I won't have either the module or the IC in front of me for a week or so.


There is a little dot or indent for orientation on or near one of the short sides of the chip. You want the orientation to be the same as the chip you are taking out.
Most sockets will have a little indent too and sometimes it's painted on the pcb. But the direction of the old chip is the most trustable (so long as your new chip is a drop in replacement)
Tim Stinchcombe
Resurrecting this thread as I have made a rather interesting discovery. Just after I made this post in the thread about an oscillating A-119, I was comparing the plots I gave there to those I made further up this thread. The eagle-eyed amongst you will notice that the cut-off frequency shown for the standard TL064 case, 'C5 = 22p' in the former and 'TL064' the latter, are markedly different! For the former I didn't simulate the whole circuit, as I didn't think I needed too - here is a side-by-side comparison:


My assumption that I didn't need to bother with the whole circuit is clearly misplaced, as there is a huge difference in the bandwidths between the two. It seems there is some strange loading affect of the output of the symmetric input stage at the iinput of main gain stage, where it is summed with the 'asym' input. I have been running various simulations all day to try and understand what is going on, but it is very weird indeed. Thus I finally relented and fired up my unit to take some real readings, and sure enough these show exactly the same thing - the red trace is the response from the standard module; the green trace is with the end of the resistor feeding the sym input into the main gain stage lifted:

The increase in bandwidth is enormous, around 4kHz! All this from simply disconnecting the (not being used) symmetric input - I was inputting a 200mV sinewave into the 'asym' in, gain set to max (fully CW, so gain at 20x, and output therefore approx 4V), and nothing into the 'sym' input, and then stepped the frequency.

I am continuing to think about how this happens, and also if there is some sort of 'fix' for it that will liberate the extra bandwidth without the need to disconnect the symmetric in sub-circuit! (I currently think it is connected with the dominant pole of the TL064, as 'idealizing' the OA in the simulation doesn't show the effect, so it must be something my ideal OA leaves off, i.e. the poles maybe...)

Tim
nihilist
All this information will be quite helpful if mine ever shows up, as this was sent to me today...

"Hi Andy,

I wanted to let you know that we made a mistake and instead of send you
the
doepfer A-119 we sent you the doepfer A-189.

My customer who purchased the A-189 already received yours and i was
wondering if i send you a prepaid label would you be so kind and drop it
back in the mail? Your doepfer went to Martin Gore (Depeche Mode). I spoke
to him and he said he will drop your module in the as well.
I really hope for your understanding and i am terribly sorry for the
inconvenience.
Please call us at 818-709-**** or call my cell at 818-325-****
Tanya smile"
Paranormal Patroler
nihilist wrote:
Your doepfer went to Martin Gore (Depeche Mode).


Tell him to sign it before he sends it back! hihi
Paranormal Patroler
Sorry for necroing this thread, but I have to ask: apart from the chip swap is there any other ways to improve the a-119 ? Tim ?
Tim Stinchcombe
Well having seen the thread bumped, I see that back in August I was trying to work out why disconnecting the symmetric input liberated a shed load of bandwidth - it seems I got diverted on to something else and forgot all about this. So I have been looking over my notes, and started thinking about it all again, and I may be making some headway - when I do fathom it out, I will make a couple of recordings to try and show what the difference sounds like, and it is also quite likely that the improvement will carry across to those who have replaced the chip!

Tim
Paranormal Patroler
Glad to have bumped the thread then. Mr. Green
Reptil
That would be great! thumbs up
skipperdean
bump. any news Tim?
Tim Stinchcombe
It is not forgotten, but unfortunately I haven't had too much time to look into it recently, with doing other bits and pieces on a number of different projects for other people. I did manage to spend last weekend on it and thrashed out a load of algebra, but annoyingly just what is going on is still escaping me! I'm sure it has to be staring me in the face, but I just can't see it. It is actually top of my list of things to do, it's just that other poeples' stuff is currently getting in the way!

Tim
jimmyambulance
we'll keep bumping!
skipperdean
bump for Tim progress.
replaced my tl064 for a tl074 and highly recommend it to those who haven't done it yet.
Paranormal Patroler
Is it easy to find a tl074?
skipperdean
yea, tl074cn works.
Reptil
Guinness ftw! hihi
gooooooo Tim! thumbs up
haima
Paranormal Patroler wrote:
Is it easy to find a tl074?


shouldn't be hard... pretty much anywhere that sells ICs should have it - it's a very common chip, probably one of the most common analog ICs, after the TL072 thumbs up
Paranormal Patroler
haima wrote:

shouldn't be hard... pretty much anywhere that sells ICs should have it - it's a very common chip, probably one of the most common analog ICs, after the TL072 thumbs up


Exactly what I wanted to read.
radiokoala
A bit offtopic, but as this is a recent topic, I think it's appropriate to ask.

Could you use audio outs of a-119 for modulating parameters (i.e. as CV)? Or is it only an audio signal - like, for running through filter or reverb? I know exactly that env. out is CV but with audio out I was unable to figure out - nothing about that in manual.

Thanks!
equalpyramid
Afaik, the audio output is a line level audio signal and shouldn't be used for cv.
negativspace
You can use any audio signal to 'CV' anything that has an input... that's half the fun of modular synths!
radiokoala
Now, that's what I wanted to hear!! SlayerBadger! I sure need it for using as a poor man's modulator before I get PEG (and before kits are available). One oscillator is not enough for sterling wiggling, even while it is dual razz
daverj
The audio out of the A-119 is amplified up to full modular levels, so can be used as CV or audio. The same as any audio frequency signals within the modular can be used as CV if you want to.

Depending on what you plug it in to you might need to attenuate it, since some Euro modules use smaller signal levels for modulation than for audio signals.
ersatzplanet
haima wrote:
Paranormal Patroler wrote:
Is it easy to find a tl074?


shouldn't be hard... pretty much anywhere that sells ICs should have it - it's a very common chip, probably one of the most common analog ICs, after the TL072 thumbs up


I just found 9 tubes of TL074CN's in my old stores - we used them on the first generation of the FSR-4 which was through hole. Looks like I might be pulling some modules and swapping some chips soon.

About the dis-connecting the Symm. input on the A-119. Can this somehow be don using the normalizing input of the Asymm. jack - It would make it really more convenient. I guess there is panel space for a small toggle between the LEDs but I would prefer a automatic approach if possible.
Paranormal Patroler
seriously, i just don't get it something weird just happened and I accidentally answered in an older post. Please ignore me while I hide in shame.
Reptil
a switch would be a good idea. but something's wrong with that circuit, if I look at Tim's plot. hmmm.....

equalpyramid wrote:
Afaik, the audio output is a line level audio signal and shouldn't be used for cv.


I cut the connection so the bottom part is seperated, but easily connected
it's an unbuffered mult, a passive "thru". I'd rather mult somwhere else. but if you want to keep it, perhaps a switch there as well? plenty of space.
roglok
I believe this wasn't mentioned before:

Reptil kindly informed me that you can change the timing of the envelope follower by swapping C6 (100nF) for a smaller value cap. He suggested using a 10nF, but there is a tradeoff between envelope speed and smoothness: The faster the envelope, the more 'ripple' in the output. As a compromise I settled for 47nF.

This mod makes a noticeable difference when working with fast-transient input signals (i.e. drum machines). It might be a good idea to add a 'precise/smooth' switch hooked up to two or more different cap values...
Reptil
roglok wrote:
I believe this wasn't mentioned before:

Reptil kindly informed me that you can change the timing of the envelope follower by swapping C6 (100nF) for a smaller value cap. He suggested using a 10nF, but there is a tradeoff between envelope speed and smoothness: The faster the envelope, the more 'ripple' in the output. As a compromise I settled for 47nF.

This mod makes a noticeable difference when working with fast-transient input signals (i.e. drum machines). It might be a good idea to add a 'precise/smooth' switch hooked up to two or more different cap values...


awesome I'll try that, thanks! thumbs up
Jarno
That switch is also on the Polyfusion envelope follower:


Edit:
My apologies for the size, can you somehow zoom this out a little bit?
Reptil
no need I can see it fine hihi
got the knoppies already?
BrotherTheo
My choice is the TI/National LME49740. Very low noise, very very low distortion.

--BT
DanPacific
I'm just about to replace mine with TL074. Just a quick question as I'm a right idiot when it comes to electronics - I spot 2 OPAmps on the back of the A-119 and I was wondering if both should be replaced and if only one, then which?
roglok
DanPacific wrote:
I'm just about to replace mine with TL074. Just a quick question as I'm a right idiot when it comes to electronics - I spot 2 OPAmps on the back of the A-119 and I was wondering if both should be replaced and if only one, then which?


The answer to your question is in this very thread -
https://www.muffwiggler.com/forum/viewtopic.php?p=100858#100858
Jarno
One thing that isn't mentioned in the thread is the option of tacking supply bypassing and a bypass cap in the feedback loop to tame over-enthousiastic opamps.
Anyone do this?

Obviously the use case is important, but in the Soundcraft Delta console, they are using TL07* without the caps in the feedback loop, so you might get away with substituting the opamps in the A-119 as well (because I assume the LM324 doesn't use caps in the feedback loop either).
roglok
Jarno wrote:
One thing that isn't mentioned in the thread is the option of tacking supply bypassing and a bypass cap in the feedback loop to tame over-enthousiastic opamps.
Anyone do this?

Obviously the use case is important, but in the Soundcraft Delta console, they are using TL07* without the caps in the feedback loop, so you might get away with substituting the opamps in the A-119 as well (because I assume the LM324 doesn't use caps in the feedback loop either).


good point! lemme check mine...
roglok
There are two 100nF bypass caps near the TL062 and a 22pF across its pins 15 and 16.

However, as you suggested, there are no caps for the LM324. It would be very easy to add a couple of SMD supply bypass caps on the solder side (between pins 4 & 5 and 10 & 11 respectively). Same goes for feedback caps... I might try tonight...
Jarno
roglok wrote:
It would be very easy to add a couple of SMD supply bypass caps on the solder side


+1
On new layouts, they'll often fit underneath a 8-pin DIL, quite convenient


On existing layouts, you need a spot somewhere close to the IC, where the tracks are parallel. Small through-hole ceramic caps with legs allow some "elbow room" to tack to tracks which are spaced further apart.
On my eurorack mic preamp with INA217, I tacked 10uF or so close to the IC to the supply rails, or else it would ring like crazy.
logicgate
another drop in replacement for the tl074 would be the TLE2074, has anyone tested those?
roglok
logicgate wrote:
another drop in replacement for the tl074 would be the TLE2074, has anyone tested those?


yep. what's in mine. works well...
logicgate
roglok wrote:
logicgate wrote:
another drop in replacement for the tl074 would be the TLE2074, has anyone tested those?


yep. what's in mine. works well...



Do you think that there's a drastic "sound improvement" by using this one instead of a tl074?

Do you think that you would notice a difference?

Cheers Guinness ftw!
radiosignaali
Bumping an old thread:

I am using my A-119 solely as distortion nowadays, but it has this nasty high frequency whining that I would like to get rid of.

About this different mods: how does the distortion characteristic change? Or should I just keep using the A-119 unmodded and try to eliminate the whining with EQs?
Bonefish67
I am thinking of experimenting with an OP amp that is equivalent to the 5532. I already need some of these for my 388 pre amp upgrade.

It has been Pooged. Pooge is an expression devised by Walt Jung, the engineer who researched and publicly exposed BOTH of the two most significant bottlenecks in quality audio in the chip age: Slew Rate limits and Dilectric Absorption. In this 388, all the channel op amps have been upgraded to 5532s, which are a fine-sounding audio chip whose imperfections are, for an IC, remarkably tubelike. And every one of these 5532s have been bandlimited (~70 kHz) to maintain closed loop performance to the limits of the chip itself. With expensive mica capacitors. You'd be surprised how seldom this is done, and how often manufacturers allow op amps to go into open-loop operation, which sends all kinds of spurious trash down into the audio.
donpachi
An easy solution would be to send the output through a passive lowpass filter which is a really easy DIY project:
http://www.doepfer.de/DIY/a100_diy.htm
Bonefish67
Thanks for the link.
Stinktier86
radiosignaali wrote:
Bumping an old thread:

I am using my A-119 solely as distortion nowadays, but it has this nasty high frequency whining that I would like to get rid of.

About this different mods: how does the distortion characteristic change? Or should I just keep using the A-119 unmodded and try to eliminate the whining with EQs?


Haven't used my a-119 in a while, but i can't recall it producing a whining sound. Maybe it's coping differently with other power supplies or high power consumption? I'm using a doepfer A-100PSU2, with about half the max load.
Jarno
Is the original opamp still in there? It could be that it is oscillating (especially if the original slow opamp is exchanged by something more high end).
You could try to tack a few caps over the PSU rails, really close to the IC (directly from + pin to ground and from - pin to ground), try 100nF or so, bigger if you want to put something really cranky in there (AD797, or AD825? Dead Banana ).
memes_33
so, maybe a stupid question, but i ordered Texas Instruments TL074s on ebay, but what arrived were STmicroelectronics TL074s. Is this a big deal? Should I send them back? The TIs seem to have slightly better specs than the STs...
negativspace
In the real world I don't think you'd ever notice a difference.
bemushroomed
Would this work for A-119: http://www.electrokit.com/tl074cp.41950

* Wide common-mode (up to Vcc+) and differential voltage range
* Low input bias and offset current
* Low noise en = 15nV/vHz (typ)
* Output short-circuit protection
* High input impedance JFET input stage
* Low harmonic distortion: 0.01% (typ)
* Internal frequency compensation
* Latch-up free operation
* High slew rate: 16V/us (typ)

I use these in my 2 A-138 (mixer) modules and they work fine there..
En_Annan
Yes, that would do!

I think we discussesd this over at 99 some time back too (swedish forum)
En_Annan
As for the thread I was thinking of
http://www.99musik.se/archive/index.php/t-316273.html
Have a nice weekend!
bemushroomed
Great, thanks!
davebot1
BrotherTheo wrote:
My choice is the TI/National LME49740. Very low noise, very very low distortion.

--BT


Sorry, I know this is an ancient ancient thread, but I wanted to report that installing the LME49740 in the a-119 sounds good to me! Ordered it from mouser. It was cheap.
dani
roglok wrote:
DanPacific wrote:
I'm just about to replace mine with TL074. Just a quick question as I'm a right idiot when it comes to electronics - I spot 2 OPAmps on the back of the A-119 and I was wondering if both should be replaced and if only one, then which?


The answer to your question is in this very thread -
https://www.muffwiggler.com/forum/viewtopic.php?p=100858#100858


I'm also not very clear about this question, I think it's the TL064CN.

are there any improvements if instead of TL074 we replace it with a LME49740NA ?

btw why not just give the short answer instead of posting a link? hmmm.....

thanks for your help
roglok
dani wrote:
roglok wrote:
DanPacific wrote:
I'm just about to replace mine with TL074. Just a quick question as I'm a right idiot when it comes to electronics - I spot 2 OPAmps on the back of the A-119 and I was wondering if both should be replaced and if only one, then which?


The answer to your question is in this very thread -
https://www.muffwiggler.com/forum/viewtopic.php?p=100858#100858


I'm also not very clear about this question, I think it's the TL064CN.

are there any improvements if instead of TL074 we replace it with a LME49740NA ?

btw why not just give the short answer instead of posting a link? hmmm.....

thanks for your help



wut?

hanging out in a forum but too lazy to read a post and have others type out what's been written before? tim's post clarifies exactly what the improvements are and which op amp it is that benefits from a swap...

to spare you the effort, yes it's the TL064 meh

EDIT
this is the one:
https://www.muffwiggler.com/forum/viewtopic.php?p=66498#66498
dani
hey Roglok

Thanks for helping me out, yes I was reading the whole thread (and then the others and also on the german board) and it was a bit information overload for me (as somewhere it's suggested to swap the other one), sometimes for beginners it's better to have one clear sentence.


anyway I got the TL074 and the LME49740NA wasn't available, so I'll do the replacement as soon as I have space again in the rack


cheers
loteae
Thought I'd post the issue here too.

I picked up an A-119, and installed the TL074 upgrade. Whilst the sound is noticeably improved, I get this horrible background buzz when I play guitar, even at minimal gain.

The buzz isn't present when I reinstall the TL064. Is this normal? Could it be a power issue? I used multiple TL074, all with the same problem.

Audio:
TL074
TL064
tommiot
Just got my A-119 to use
a) as a decent quality Hi-Z preamp for my guitar as I didn't have any preamp for my RME ADI2 ADC.
b) to process stuff like drums from the computer through the modular and back to the computer.

I tried the stock unit which sounded just AWFUL.

While I replaced the opamp quad with TL074 I also removed the 220pF input caps which form a lowpass filter @ 15kHz with the input resistors. And actually the corner frequency is much lower when using a high impedance source like a guitar.

Now it sounds decent for the stuff I'm using it. A bit noisy when using lots of distortion for the guitar but that might be a power supply issue too. Not noticeably noisy in normal use.

I didn't see any discussion about these input caps? The amount of high cut they do seems excessive to me.

I'm probably going to increase the input impedance (from the 330k?) and decrease the maximum gain (possibly by reducing the 1M pot to something like 100k or 250k) as it's a bit hard to adjust accurately...
Nino
Since the LME49740NA is not being provided anymore, which one is the best available op amp to pimp the a-119?
APETECHNOLOGY
i to would like to know what would be better then LME49740NA?
DJMaytag
APETECHNOLOGY wrote:
i to would like to know what would be better then LME49740NA?

I think these are back now, but is it a worthwhile option here? I bought a 119 last year and finally fired it up last night (along with the rest of the system I've been building), and the stock unit sounded... bad. I had some 074's from Tayda handy, but could hear that background noise that was mentioned above. Would a 074B work/sound better (or have lower noise)? I do have some of those in my Mouser cart for an upcoming project (as well as some LME49740's).
poorness
So... I am in the same situation as everyone else. I'm going to try to do the TL074 swap on my A-119. Just to be clear though, all you have to do is swap the single IC to see an initial benefit, correct? There's a ton of good information here (spanning several years and about a dozen wigglers), but no pics and all the audio clips are now expired links.
The_Crooked_Man
poorness wrote:
So... I am in the same situation as everyone else. I'm going to try to do the TL074 swap on my A-119. Just to be clear though, all you have to do is swap the single IC to see an initial benefit, correct? There's a ton of good information here (spanning several years and about a dozen wigglers), but no pics and all the audio clips are now expired links.


Yup, but early revisions aren't socketed, so you'll have to desolder the chip. Otherwise, it's literally a 3 second swap.
poorness
Mine is a May 2016 model, so we should be good. thumbs up
I'll post pics and opinions once I get a few minutes to sit down and do the mod.
Old Man Euro Module Rockin' Banana!
DJMaytag
poorness wrote:
Mine is a May 2016 model, so we should be good. thumbs up
I'll post pics and opinions once I get a few minutes to sit down and do the mod.
Old Man Euro Module Rockin' Banana!

If it takes you more than a minute, you're doing it wrong. It was a pretty simple swap with an IC puller. I noticed major differences between the two, good and bad. The TL074 sounded better in its sonic range, but might have been noisier. I was using a 074CP, so that might have had something to do with it. I'll be getting some TL074B's in the future, which should sound better.
poorness
For the next guy who comes across this thread. Here is a before and after pic.



Like the others said, it takes about 10 seconds to do the swap. The signal seems a tiny bit quieter after the swap (that could also be in my head), but it has more headroom and an overall smoother tone. Quite honestly, you won't notice any drastic differences. If you like the A-119 pre-swap, you'll probably like it post-swap. If you hate the A-119 before the upgrade, you'll probably still hate it afterwards. It's a subtle change.

All in all, I like it so far, but need to play with it a bit more to give a full assessment. Overall though, I'm not sorry I did it. cool

EDIT: fixed broken image
ebowist
Just bumped to this discussion, after purchasing the A-119 pretty much without prior investigation and being horrified about the sound. seriously, i just don't get it
I decided to make the TL074 swap and got also rid of C1 and C2 (see above) for possible extra bit of crispiness. After some A/B-ing I would say that the sound is improved now, but still not comparable to a high bandwidth/quality original signal.
erwanito12
Tim Stinchcombe wrote:

The increase in bandwidth is enormous, around 4kHz! All this from simply disconnecting the (not being used) symmetric input - I was inputting a 200mV sinewave into the 'asym' in, gain set to max (fully CW, so gain at 20x, and output therefore approx 4V), and nothing into the 'sym' input, and then stepped the frequency.
Tim


Hello,
Can you tell me how you did to disconnect the symmetrical input of the A 119 please.
with a simple schema I have little knowledge in electronics.
thanks in advance
Jarno
If you have little experience in electronics AND you do not have an issue with the module, maybe it doesn't bring a lot of benefits.
Do you have a problem with the module, currently, did you do any of the other mods?
erwanito12
Jarno wrote:
If you have little experience in electronics AND you do not have an issue with the module, maybe it doesn't bring a lot of benefits.
Do you have a problem with the module, currently, did you do any of the other mods?


Hello,
yes I have a bandwidth problem with this module, to connect a bass guitar or a roland d 50.
I change this chip for a TL074 but it does not solve the problem.
the sound lacks clarity.
earning 4khz of bandwidth will be beautiful for me.
thank you for your quick reply.
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