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You should audio probe it before you go chasing down dead ends. Wouldn't want you to have to replace things unnecessary.


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YES! I've never used an audio probe and I was a little intimidated by trying to read the schematic and follow it on the board, but I found the problem pretty much immediately.

The .22u cap at C12 was dead for some reason. Appearance wise it looked fine, but it wasn't passing any signal. Replaced that and now the circuit works as expected.

Thanks for your help!

New update:

I realized that the out pad on the effect board was grounded because the level pot was turned all the way down.  I then desoldered the pots, double checked all the solder joints underneath them, and reattached them temporarily on leads. If I crank every setting, I get a slightly compressed signal that's roughly the same volume as no effect.  The bass setting is the only one that seems to work as expected, every other control seems to just mute the signal if backed off.

HOWEVER, If I decrease the pre-gain trimmer, it does this crazy oscillating stuff when you move the other controls.  You can hear it in the video linked below.  My best (uneducated) guess is that I fried the TLE2074 when I soldered it in. I know I should have used a socket but I forgot to order them and didn't want to wait, haste makes waste I suppose.  I ordered another from Mouser (and some sockets this time), but if anyone can confirm my suspicions are at least logical before I go through the trouble of desoldering it, I would be very grateful.

https://i.imgur.com/pmQcm7z.mp4

Update: Disconnected the White Horse output from the switching board. The out pad on the switching board is no longer grounded, but the output from the effect is going to ground somewhere. I can't find any obvious shorts on the white horse board, could a bad component cause this?

Another question. Going through everything trying to double check stuff, including the switching board. Everything works fine in bypass mode, and the relay clicks when I use the switch, lighting the led. When the effect is bypassed, the "IN" pad is grounded as stated in the build doc. However, the "OUT" pad is grounded in either state. Is this supposed to be like that? I'm examining my soldering for shorts and whatnot but I'm not seeing any.

I can't tell from the pic but (I think) if you are using regular diodes rather than the bs170 you need to jump the middle pin hole over to the other that goes to ground . I believe the bs170 does that internally as part of the body diode.

Yep, the middle holes are empty, still reading voltage on those empty pads though.

Hello all.

I've built a white horse, and it is not working. The bypass board seems to be working properly, and is outputting the correct + and - voltages, but when I turn the effect on the whole signal cuts out. If I crank all of the knobs I do get a very quiet distorted signal coming through, but that's it. 

I have a version 4.2 board, and am using the version 5 clipping, with the 1N914 diodes stacked. I was worried I might overheat one of those when soldering them together, could that cause problems with the whole circuit?

Going through and testing the voltages, I seem to have mV readings in a few places where I'm not supposed to have any, and the voltages to the clipping diodes are wildly different from whats shown in the build doc.  I also soldered in the big chip in the TLE 2074, would overheating it cause these problems?

All voltage readings were taken with the LED in place, pre-gain cranked, and all other knobs all the way down.

Any help is much appreciated.

Also idk  why the photo got all stretched like that but hopefully y'all can see things well enough.

Yeah Mouser in particular really confuses me when I try to use their search tools.

Ok cool. I swear, sourcing and buying the parts is harder than building the dang things! At least that one's cheaper on mouser and I've got other stuff coming from there so I'll give it a go.

The EA2-5TNJ is non-latching. You need the latching version EA2-5SNJ. I think Mouser has it in stock

https://www.mouser.com/ProductDetail/KEMET/EA2-5SNJ?qs=%2Fha2pyFaduiqW6ONdq9hGqQ67RxYZJNtzdsxQdp7A8c%3D

If anyone knows of any others that work I'd be interested to know as well

Interesting, Mouser has them both listed as latching, is there something I'm missing there?

Hi all! Trying to get the parts together for a couple of these builds. Unfortunately the relay required for the switching board (both the 5v and the 4.5v versions) are out of stock at Mouser until September of next year. Anybody know an alternate source for these? Alternatively, will this NEC EA2-5TNJ http://smallbear-electronics.mybigcommerce.com/relay-dpdt-5-volt-double-coil-latching/ from Small Bear work? It looks to have the same form factor and specs as the Panasonic piece, but I'm far from an expert at this so if anyone can confirm it should work that would be super helpful.  Thanks!

Yay, it works!  In all my bumbling around and soldering/desoldering I had lifted the solder pad for lug 3 of the balance control.  Fixed that and it's nice and loud. 

Thanks for all your help, you guys rock!

So, a check with my meter shows no voltage to Q3 still, regardless of knob position.  I'm wondering if the balance pot is bad, since it seems to do nothing?
I also forgot to mention that when I first completed the build I had the transistors backwards, could that have killed any components?

Wow I feel silly.  Flipped the caps around and it sounds much better, less gated and whatnot. 
However the balance control doesn't seem to do anything, and there is still a volume drop compared to my clean signal.  Is that normal for this circuit?

I'm getting the -9v from a battery.  It also works off an isolated output from my voodoo labs pedal power using their 9v clip adapter.
Thanks for the help guys

Hey guys.  So I built this yesterday, it's my first build.  I used oc75 transistors, and substituted a 25kb pot for the balance control.  It makes fuzz, but there's a drastic volume drop when engaged, and the fuzz is very gated and scratchy sounding.
I've checked continuity everywhere and it all seems fine, except I have no voltage at Q3.  Does this mean I have a dead transistor? I know I should have used sockets, but I was quick with the iron but do you guys think I killed it?

Voltages:
Q1
C -3.5 v
B -1.6 v
E -1.5 v

Q2
C -3.3 v
B -1.5 v
E -1.4 v

Q3
No voltage