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Jürgen Haible Krautrock phaser BUILD THREAD
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page Previous  1, 2, 3, 4, 5, 6, 7, 8, 9  Next [all]
Author Jürgen Haible Krautrock phaser BUILD THREAD
LektroiD
muckmires wrote:
Yes, and I find out now, one of them is kind of unreliable. I agree that a torroidal might be the way to go. Where did you source yours?


This one works fine in mine:
http://uk.farnell.com/multicomp/mcta015-18/transformer-toroidal-2-x-18 v-15va/dp/9530274?CMP=i-ddd7-00001003

Still can't find the cabinets slo was asking about, all I know is it is by Hammond, I got one that fitted the dimensions of the PCB with a little extra space each side
donaldharper
What value of potentiometer should be used for the resonance pot?
fragletrollet
Ok, mine is built up, and I just applied power for the first time.

It seems the two bulbs on the pcb won`t light up. The front panel (third) bulb lights up fine. So no phasing unless I apply light to the LDR`s with a flashlight or so, and then it seems to work as it should. Any idea why my modulation bulbs won`t light up?


Sounds gorgeous tough, can`t wait to get it working totally right!
fragletrollet
donaldharper wrote:
What value of potentiometer should be used for the resonance pot?



I used a B500K, works fine!
fragletrollet


So, what are these for? I`ve left them unjumped...


I`ve also not installed any of the SMD-caps on the back, as I thought these are just to be installed if some form of high frequency oscillation is heard?
fragletrollet
So I jumped the points in question, and jumped the wiper of the osc period with the CW-end, and it all works beautifully, all lamps lighting up and phasing in all its glory. Great great sound.

However, the L/Stereo output is much lower in volume compared to the R/Mono output. Normal? Not really a problem tough, as I am feeding into a couple of lundahl di`s into a couple of (c)API vp312`s, and can adjust the gain there. Sounds so good This is fun!
fragletrollet
So.... It seems it went through some phases (pun intended) before "settling in". Now both outputs are the same volume. Modulation knob only works on the L/Mono output, but I think that is normal. What an absolutely gorgeous sounding thing. Using the mono output and no resonance but cranking the modulation knob results in some very beefy vibrato like sound. Awesome. The phasing goes from totally invisible to over the top scifi sweeps. The overdrive/saturation you get when overdriving the inputs is just gorgeous, can see myself using this for alot other than just synth-phasing.

I did exchange the OSC period with a 100k log, so the sweep time is doubled at the max setting. Nice, loving the long sweeps. I also put the resonance as a knob on the front panel. This only briefly affects the "sharpness" of the feedback. I like it in the upper area of the knob.

Anybody have a link to a preferred rotary switch so I can wire up the different stages aswell? Preferrably from Mouser or Tayda. Only been trying it in the middle (4stage) position so far. I know this was talked about earlier in the thread, but it`s still a little mystic to me.

I`m so much looking forward to the rest of the resurrection of the Haible designs, as this is plainly awesome.
ElSmurf
Anybody know what kind of pots the pedal inputs for Rate and Depth want to see? I'm thinking of just putting a pot on the front panel for Rate, instead of using jacks.

As for the rotary switch, after doing a quick search on Mouser it seems they only have one single 2P3T switch with solder lugs : http://www.mouser.be/ProductDetail/CK-Components/A20315RNZQK/?qs=MrZKd %2funjJ1Xt1ww1pBs4Q%3d%3d

*edit* so I realised that the Rate and Depth input are just switched jacks that bypass the onboard Period and Depth pots, so I'll just leave them out. Anyone pondered on the idea to use vactrols there instead, so they can take CV to control these parameters?
Cablebasher
It would be great to see some photos of finished or partly finished boards from the new pcb run.

I will be starting mine soon and the photos and advice on this forum, as always, is a great help.

Cheers,
donaldharper
Hi,

I've just finished populating the board, but I having never built a standalone unit with AC before I need a bit of advice about powering/grounding it

My intention is to use a DC-style socket such as this one:

http://www.maplin.co.uk/p/21-x-55mm-single-hole-fixing-dc-socket-jk09k

And also this wall wart, which I believe should give the correct output (please correct me if I'm wrong):

http://images.esellerpro.com/2131/I/124/62/DCP_2614.JPG

My questions are, how would I correctly wire the socket to the board? And also, what should I use as a source for ground?

I've had some experience with mains power, but I'd rather not guess this one. I'm UK-based if this is relevant

Thanks in advance!

Donald
magman
You actually need two 18v windings for the Krautrock, so one of these transformers won't be good enough.

Theoretically, you could buy two of these, but you would then have the issue of making sure both are plugged in before you switch on the phaser, plus using two mains sockets.

If you are looking to go the external transformer route, you might do better to look at the Yamaha PA-20 line lump. You can get these from Studiospares, Thomann and eBay, and the connectors from CPC, Farnell and ESR. They are rated at 2x17.5V AC, which should be good enough for this job.

Regards

Magman
Nordcore
Quote:
And also this wall wart, which I believe should give the correct output (please correct me if I'm wrong):

http://images.esellerpro.com/2131/I/124/62/DCP_2614.JPG

That one should work.

Just measured my build with a (somewhat larger) 16V transformer:
transformer idle: 3W
with phaser: 7W max.
... so your 18V/500mA (=9W output) transformer should be OK.

One wire of the jack goes to one AC pin, the other to the GND pin. The other AC pin on the the PCB is not used.
Fuse should be 500mA slow blow. (Only one used/needed!)

(The second AC just gives less ripple. As there is plenty of filtering in the input it is not really needed...)
donaldharper
Thanks for the help!

I just rigged this as per Nordcore's advice, the lamp on the front panel comes on, but nothing else appears to be working.

Please can anyone recommend any key points I should be checking on the board, or advise what the issue here might be?
fragletrollet
remembered to jump the points in question in my picture a few posts up?
donaldharper
Yes, those were installed when I switched on
magman
Nordcore wrote:

That one should work.

Just measured my build with a (somewhat larger) 16V transformer:
transformer idle: 3W
with phaser: 7W max.
... so your 18V/500mA (=9W output) transformer should be OK.

One wire of the jack goes to one AC pin, the other to the GND pin. The other AC pin on the the PCB is not used.
Fuse should be 500mA slow blow. (Only one used/needed!)

(The second AC just gives less ripple. As there is plenty of filtering in the input it is not really needed...)

Apologies to Nordcore, but I don't see how the circuit that Jürgen published will work properly with a single transformer winding.

A single transformer winding will only power one of the regulators in the circuit. If you are lucky, and power the +15V regulator and the circuit may partially work, but most of the op-amps in the circuit need 2 rails and without modifications the circuit won't work as designed (you would have to short the -15V rail to ground, then the front panel lamp wouldn't work and you would have to bias the op-amps to pass a full AC signal, so not a good compromise).

If you are taking the trouble to build a top of the range phaser like this, don't compromise on critical parts like the power supply, use the right parts. In this case, either use a dual winding external transformer like the PA-20 mentioned, or use a dual winding internal transformer and take proper care in setting up the correct safe mains connections and fuses. Other people in this thread have already identified suitable internal transformers.

Just my opinion of course, but I think I am right in this case.

[Edit]
Now I am really confused, as the photo's on Jürgens site only show a single winding connected.
I obviously need to look into this a bit more.

For DonaldHarper, it might be worth checking if your transformer connections are the same as Jürgens photographs.
[\Edit]

Regards

Magman
magman
Apologies to Nordcore again and time to admit my mistake. oops

Just had another look at the circuit and it will work with a single transformer winding.

With a single winding the power will be half wave rectified. With two windings it will be full wave rectified. The two windings version will have lower ripple and potentially less noise, but both will work.

It doesn't matter which pair of connections you use either.

Time to go and do a bit more studying of PSU circuits methinks.

Regards

Magman
LED-man
The Mode Machines KRP works from Factory with a Single AC wandwart.
donaldharper
Thanks for the help Magman, my transformer connections appear to be correct

Can anyone recommend any useful points on the board to measure so I can work out what the issue is?

To recap, the panel-mount bulb is on (constantly, no oscillation), the two bulbs on the pcb are not on
pulsepsycle
Cablebasher wrote:
It would be great to see some photos of finished or partly finished boards from the new pcb run.

I will be starting mine soon and the photos and advice on this forum, as always, is a great help.

Cheers,


I started yesterday with the build. Here are some photo's: https://www.facebook.com/PulsePsycle

Karel.
Nordcore
donaldharper wrote:
Can anyone recommend any useful points on the board to measure so I can work out what the issue is?


Do you have the AMOUNT jack wired *with* normalization?
If not, place a jumper as seen on this image:
http://jhaible.com/legacy/compact_clone/compact_clone_2007_prototype_8 .jpg
donaldharper
Thank you Nordcore, that did the trick! Completely missed that one out

I've also omitted the rate jack, does that need bridging too?

I can now hear and see phasing, but it seems very quiet until the feedback is fully up. Any ideas what might be causing that?
Nordcore
RATE can be left open.

Try to turn the "RESO" trim pot for feedback.
(That can kill the input signal if set to one end ...)
donaldharper
The Reso trimmer is fine, and I also tried changing R54/R58 to 5.1k (as mentioned earlier in this thread), still seems really quiet!

If anyone's got any other suggestions I'd really appreciate it, meanwhile I'm going to take a break and look at this again tomorrow
the bad producer
It's worth mentioning - maybe! - that the two bulbs on the PCB and their associated LDR's should be covered up, or test it in the dark! That got me on my first one!
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