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Buchla 100 clones: 158, 180, 140, 156, 106, etc. DEMOS
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page Previous  1, 2, 3 ... 29, 30, 31, 32, 33  Next [all]
Author Buchla 100 clones: 158, 180, 140, 156, 106, etc. DEMOS
lasesentaysiete
jersupereq wrote:
Any update on the 112a calibration. I’m seeing a constant 15V on the gate out and am wondering if calibration might be the solution. Thanks!


The trimmers are for C « Pressure » output and « trigger » output. The R1 trimmers have a cumulative effect on all the keys at once.

-R1, etc. (nearest the edge of the PCB) can be set completely CW. The important thing to check is that the Pressure out is 0v without pressing any keys. If you turn 1 or 2 of these trimmers CCW, you will notice the Pressure out rise without pressing any keys.


-R2, etc. (nearest the centre o the PCB) should be set almost completely CCW. If the trimmer is set too far CW, the trigger output will latch and not release when you release the key. The trigger output is ~3v when no key is pressed, and rise the ~15v when a key is pressed.
rosch
diophantine wrote:



Damn alright this is a dream of a project. There are many great clone projects out there now but this is outstanding coolness.

How about current draw, will that 1.5 A PSU you mentioned earlier in the thread be enough for such a cabinet or should I take the 3.0A one?
I hope these PCBs will be available for some time as I will make one or two at a time.

Feels just like 2009 again, finally a thread like that to dig through cool

Btw I'll probably hand saw and screen print my panels, just got a basic screen printing set for beginners this summer. Is there some general overview somewhere about the buchla dimensions?
lasesentaysiete
rosch wrote:

How about current draw, will that 1.5 A PSU you mentioned earlier in the thread be enough for such a cabinet or should I take the 3.0A one?


I think 1.5A is safe for anything up to 15u.

rosch wrote:
Is there some general overview somewhere about the buchla dimensions?


See the attached PDF. Its a from Eardrill.
jersupereq
Thanks for posting the calibration procedure I’ve got everything looking good except the pressure sits around 4v when nothing is pressed and gate remains high at 15. I think I have an incorrect resistor value somewhere. Is there any chance you post a scan of the 112a PCB. I can’t really read all the reference numbers with everything soldered in place.


guitarfool
Scans for most of the La67 PCBs (including the 112) can be found HERE
jersupereq
guitarfool wrote:
Scans for most of the La67 PCBs (including the 112) can be found HERE


Hey guitarfool, that site is super helpful, thanks for doing that!

Upon further inspection it looks like three of the 12 sections are outputting a higher pressure off value (over 1.5V while the other channel's are < 1). These three channel maintain a high gate after depressed while the other keys work well. Is it possible the gain on the transistors have something to do with it? Mine came in a bag but not on a strip so could be different batches. hmmm.....
lasesentaysiete
jersupereq wrote:
guitarfool wrote:
Scans for most of the La67 PCBs (including the 112) can be found HERE


Hey guitarfool, that site is super helpful, thanks for doing that!


Yes, guitarfool's website is a gem thumbs up

jersupereq wrote:
Upon further inspection it looks like three of the 12 sections are outputting a higher pressure off value (over 1.5V while the other channel's are < 1). These three channel maintain a high gate after depressed while the other keys work well. Is it possible the gain on the transistors have something to do with it? Mine came in a bag but not on a strip so could be different batches. hmmm.....


I have built a few of these modules now and have never paid attention to transistor gain. Trimming was always able to resolve the gate hold issue for me. It is possible that the trimmers are faulty. That did happen to me on a build. Do the trimmers on those 3 channels have any effect at all?
jersupereq
They all have a similar effect to the other trimmers they just start at a much higher voltage before being trimmed down. I believe the trimmers looked good when I checked them but I'll double check when I get home and get back to you.
lasesentaysiete
jersupereq wrote:
They all have a similar effect to the other trimmers they just start at a much higher voltage before being trimmed down. I believe the trimmers looked good when I checked them but I'll double check when I get home and get back to you.


Otherwise I suggest checking component values. The problem is likely to be found on the channels themselves.
jersupereq
lasesentaysiete wrote:
jersupereq wrote:
They all have a similar effect to the other trimmers they just start at a much higher voltage before being trimmed down. I believe the trimmers looked good when I checked them but I'll double check when I get home and get back to you.


Otherwise I suggest checking component values. The problem is likely to be found on the channels themselves.


Just compared a broken channel vs a good one (12 /11)Went over all the component values, verified resistors, trimmers, caps and transistors. Compared resistance between channels across each component everything matched. Also tested voltage drop on all transistors matched. I’m really stumped and I feel like it’s going to be something dumb. hmmm..... Dead Banana

Ignore the bad soldering I pulled quite a few legs up to test the caps.

lasesentaysiete
jersupereq
It may still be a calibration issue. I may not have explained it clearly, but the trimmers for Pressure out all have a simultaneous effect. They are not "independent" from one another, so all of them need to be set correctly in order for the output to drop to 0v with no keys pressed.

I will have another look at my 112 regarding the gate output.
jersupereq
lasesentaysiete
First off thanks for all your help!

Here is what I have done so far:
For calibration checked the voltage on the pressure out and pressed each key then let go, then starting with trimmers top CW and bottom CCW I calibrated them to get the lowest possible voltage out. This usually required very slightly moving them both inwards. Each key has a different lowest value it could reach. One channel went as low as .07V but most were near .6V and some over 1V. The keys that also had the gate staying high issue all had a low value of over 1V. I noticed if I turned the power supply up slightly > 15V, more keys had the gate issue and higher pressure off value, and if I turned it down they had a lower pressure off value and this fixed some of the ones that latched gate on. No matter what I calibrated though I could not get the pressure off to drop to 0.
sines
Hi Dan / et al,

I am 2 56uF tantalum capacitors shy of completion of my 158A; can I temporarily [or hopefully, long term] substitute 47uF electrolytics for a couple of days to at least hear it, or will this do some damage elsewhere in the mix? It is for C5, C4 are already correctly installed as tantalum caps, I didn't order enough. d'oh!

Also — the DC converter for the 100 series power supply is 9-36V, 4.9A. My supply [used successfully in the 211 Power Supply] is 12V, 5A. I want to use it for this for a bit, is that extra .1 A going to fry the 100 series supply? It's a pretty simple circuit with zero fuses, don't want to start torching modules.

Thanks,

Todd
Leverkusen
Ampere settings state how much current a PSU can deliver at best - not what it pumps into a circuit. That would be voltage. So a higher ampere rated PSU will not be a problem, only higher voltage can and probably will fry your modules. Lower current would let your modules starve.
lasesentaysiete
sines
Electrolytics should be fine as a replacement, but you will miss out on the tantalum TONE razz
lasesentaysiete
jersupereq
Did you perform the modification of R10 as suggested by diopantine?
sines
Leverkusen wrote:
Ampere settings state how much current a PSU can deliver at best - not what it pumps into a circuit. That would be voltage. So a higher ampere rated PSU will not be a problem, only higher voltage can and probably will fry your modules. Lower current would let your modules starve.


Thank you! Welp, there's no magic smoke, but I put together the Power PCB [with both the +15V and 24V regulators] and I'm getting ~30V on the 15V Rail.

I'm using this:
https://modularaddict.com/manufacturer/la-sesenta-y-siete/l67-psu-pcb
and this is the 15V DC:DC converter I'm using [was for Kijimi] but looks like the pinouts are wrong for this application.

S24DE15001PDFA
https://www.mouser.com/ProductDetail/Delta-Electronics/S24DE15001PDFA? qs=%2FW4LtXOBxKuNpgFiDsSj4g%3D%3D

lasesentaysiete
Come to think of it, I am not sure I ever found the correct 15V DC:DC listed anywhere. is it on the LA67 or ModularAddict sites... anywhere? Last check it just said "BOM Coming Soon". And you have me paranoid, so I ordered the correct tantalums after all. razz
lasesentaysiete
sines wrote:

lasesentaysiete
Come to think of it, I am not sure I ever found the correct 15V DC:DC listed anywhere. is it on the LA67 or ModularAddict sites... anywhere? Last check it just said "BOM Coming Soon". And you have me paranoid, so I ordered the correct tantalums after all. razz


I had not realized that the BOM was not published anywhere. It is on my website now. Sorry for the delay. The 15v DC-DC is a Meanwell SKM10A-15.

I was mostly kidding about the tantalums, but some swear that Neve preamps get their sound from the old tantalum caps in the signal path seriously, i just don't get it
rosch
Is that 15V Regulator for people who power just a few? With the big 15V psu I only need the 24v for the reverb etc, right?
lasesentaysiete
rosch wrote:
Is that 15V Regulator for people who power just a few? With the big 15V psu I only need the 24v for the reverb etc, right?


Correct on both accounts.

Modular Addict stocks a smaller PCB that has both 15v and 24v regulators.
sines
lasesentaysiete wrote:
rosch wrote:
Is that 15V Regulator for people who power just a few? With the big 15V psu I only need the 24v for the reverb etc, right?


Correct on both accounts.

Modular Addict stocks a smaller PCB that has both 15v and 24v regulators.


Rosch what "big" 15V PSU are you using? I have healthy number of modules, definitely need more amps [although, I have no idea what draw I'm currently using: 106, 110, 111, 123, 140, 144, 158, 172, 180, 191 and planned on 5-6 more. Would be great to run all this off a solid supply. I'm powering it off a 12V, 5A laptop [actually, it's for camera / photo gear] style brick, and fear I need to run some more juice than I am now.
lasesentaysiete
sines
I use the 1.5A version of this to power 20u worth of modules:

https://www.mouser.es/ProductDetail/Bel-Power-Solutions/HC15-3-AG?qs=s GAEpiMZZMtl%252B%2Ft8G5TWgOwb%2Fg65SZxkC5ezCISNKQ8%3D
rosch
Yes planning to use the 1.5A one mentioned earlier in the thread if that's enough for a 5 rows cupboard with 24V stuff inside too.

https://www.mouser.de/ProductDetail/597-B15-1.5
diophantine
I went with 3A per 5-row cabinet. Based on my calculations, as well as experience with a smaller Blacet PSU while testing, I felt that a 1.5A PSU might not be sufficient & didn't want to risk it.

The amplitude of the 160 starts to drop off dramatically if you don't have enough power. This is the first module affected.
rosch
diophantine wrote:
I went with 3A per 5-row cabinet. Based on my calculations, as well as experience with a smaller Blacet PSU while testing, I felt that a 1.5A PSU might not be sufficient & didn't want to risk it.

The amplitude of the 160 starts to drop off dramatically if you don't have enough power. This is the first module affected.


I think that's a reasonable approach. I'll do that too. The 3A PSU is just 10 or 20 bucks more and it's always good to have some room to the limit. I'll start with the PSU and the cabinet. Decided to go all diy with that and the panels. Might be a bit of a learning curve with my beginner screen printing set, and a reason to finally get a small circular saw. Those pics and sound bites in this thread are very inspiring. The best surprise for me in 2019
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