Harmonic Energiser 2nd attempt - 2nd fail

[Ben79]

Well I had to scrap my previous board because I couldn't work out why it was clipping, so I built another.

I was SUPER careful.  I measured resistors with a DMM before putting them in and double checked everything as I went. 

I made a note of where all the off board wires went and wired the board into the pedal expecting/hoping to hear a nice Harmonic Energiser with no nasty clipping.

Silence.  OK, must be some small error somewhere.  Checked everything again.  Checked all the cuts and jumpers and checked for solder bridges between tracks.  All good.

But something is wrong because look at my voltages on the TL074...

1. 7.75
2. 7.74
3. 8.21
4. 9.03
5. 8.21
6. 8.21
7. 7.75
8. 7.74
9. 7.74
10. 8.21
11. 0
12. 7.76
13. 7.66 (not a typo)
14. 7.76

Last time they were all at 4.5ish

Here's the layout.



Can anyone please offer some idea of what I might have got wrong here?  After a year a half regularly building pedals, usually using my own layouts from schematics and eventually getting them to work with a bit of debugging, this build has got me wondering whether pedal building is for me - it seems no matter what I do, it's just never going to work .  Help?

Thanks

[Kipper4]

Did you put that 8 row long jumper in (from pin 11 to the second row up from bottom)?
Might be a stupid question.

[Ben79]

Yeah that's in there.  No questions are stupid and I would take ideas from a chimp right now!

[Kevin Mitchell]

Get the audio probe out and track down that bugger.

[Kipper4]

It's weird because I would expect every tl074 pin except 11 (0v) and 4 (9v) to be around the 4.5 volt mark.
Some may vary with meter loading but not up so close to the positive voltage rail.
Do you read schematic's?
Have you seen the schematic for it? It's out there.
The reason this chimp asked about the jumper is if it wasn't present it may lead to the voltages your experiencing.
It might be worth checking the biasing network resistors are properly soldered in.
So that's the 10k under pin 7 and the other 10k hanging off pin 4.
Happy hunting.....

Edit
It's a good practice to check the boards work before boxing them too.
At least this way you know the problem happened when you boxed it. Less things to eliminate.

[Ben79]

Sorry, when I said chimp, I wasn't referring to you!  I just meant I'm desperate for help.  Yours is obviously much appreciated and better than anything even the most qualified chimp could offer.

That's what I thought re the bias network.  I'll triple check those joints tomorrow.

This is why I prefer perf - i can twist the leads together and then solder them to each other and the pads and I know I've always got a good joint.  And I get to know the circuit by laying it out as I go from the schematic.

I'm sure the offboard wiring is good as it was all working (save the nasty clipping problem) with the last board and nothing has been altered.

Schem:

[YUPedals]

Is the layout verified on Tagboardeffects?

Verstuurd vanaf mijn ECOO E04 met Tapatalk

[Mojah63]

Took me a while to get vero builds working right the first time.  After you make ur cuts be clean the tracks making sure there is no oxidation. Use as little solder as possible then clean the flux away from the rows. After I became ocd about cleaning I haven't had any vero problems. Before I had all sorts of crazy problems. Bad solder joints and the flux conducting between tracks etc..

[Kipper4]

Quick question.
Does it matter that the 10uf from pin 6 goes to Gnd or Vb?

[TejfolvonDanone]

Quick question.
Does it matter that the 10uf from pin 6 goes to Gnd or Vb?

If you put the cap to Vb you essentially couple in the noise and ripple coming from the power supply. 

[Kipper4]

Thanks for that. I had a feeling but I had to ask.

[TejfolvonDanone]

If you are desperate try to be systematic:
1) Is the power right? Is it arriving everywhere it should? (DMM - Continuity measure between the 9V input and everywhere the power should be connected. Preferably to the actual pin of the component not the strip on the board. Might be broken leg at the case or just the board wasn't clean enough when you started soldering. Always clean it befor you do anything.)
2) Is the bias network good? Is every pin gets the bias as it should? (Again do continuity check.)
3) If that's right follow the signal path from input. If you have a scope it's easier but you can do it with a DMM in AC volt meter.

You won't arrive to point 3 because the bias doesn't arrive where it should. Pin 3 5 and 10 should be on 4.5V. They aren't but they at the same voltage so it looks like jumper from row 10 isn't there. (under the IC)

[whoisalhedges]

Like TejfolvonDanone said, be systematic. And don't give up! My second build was a complex ring modulator of my own design (you can probably count the obvious errors in judgment in that sentence), it sounds amazing and bizarre and utterly mad on breadboard, and I got it to work on vero precisely once. Got it tested, then wired it up for switching and an LED and... silence. I've trashed two boards trying to make it work. My first design & build (a fuzz, of course) was such a success that I got overconfident; my second was such an abject failure - in the finishing move only, I can still breadboard it almost with my eyes closed - that I half wanted to quit. But I've got all this stuff, and I'm still too poor to waste it... 

In any case, keep at it. I've put together some pretty swell pedals since I didn't give up. All drive. I still haven't gotten the trem & delay I so desperately want, despite having a couple PT2399s and some 555s and LDRs and all kinda things for all sorts of attempted LFOs... I'm just not skilled enough for modulation yet. But I'm not giving up. The Harmonic Energizer is a sweet circuit, and once you get it working right your struggles will make your build even more special to you.  And if you don't get it to work - so what? You'll get other stuff to work. Maybe you'll come back to the HE in a year or so and knock it out. If you can't get it to work, maybe you do give up: but only on THIS circuit, and only for NOW. I gave up on my ring mod so that I could move on and build my soldering/cutting/layout skills - so that when I come back to it, I won't be stopped by anything.

Cheers.

[Ben79]

Thanks for the help guys - I'll work my way through this one way or another.

Never had trouble with Vero before, though I've only used it a few times for big circuits that I didn't want to perf.

Working on it today.

UPDATE: the first 10k in the bias network was a 1k!  That should have been my first place to look, I don't know why I was so sure it was correct when those voltages were saying it was most likely not.  I think because my electronics knowledge is so limited I get so overwhelmed by the infinity of possible unknown explanations for a problem that I gloss over the simple ones thinking that would be too easy.  I had used carbon film resistors for the 1ks and blue metal film 10ks so I hadn't thought it possible but a metal film 1k had slipped into my 10k section in my parts box.

So it's working now, but it TOO is doing the nasty clipping thing that the other board did.  This tells me the problem is elsewhere in the pedal.  Could a pot do this perhaps?  More hunting necessary but at last, some progress!  Thanks again and sorry for making a thread that turned out to be about a wrong resistor