Aion Refractor Help?

[oldlefty]

Hey guys- first post here, I'm usually over at BYOC where I've cut my teeth building 7 or 8 of their kits.  I bought the Refractor (Klon clone) board from Aion as my first adventure in sourcing my own parts.  Some of the caps were, um "a little bigger than I expected"  but all in all it didn't go too bad.  Here's the problem-

Light lights up, I get sound at a reduced volume with the effect engaged, very low volume on bypass (I had to lean into the speaker to be sure anything was coming through). All three pots do what they should, just everything at reduced volume. This has the Klon dual gain pot that both adds gain and blends clean and dirty signal. If I back it all the way off I get almost nothing, so I'm guessing that it should be taking the bypassed signal and blending it in, but since I'm getting almost no bypass I'm missing what should be being blended in?

I think all the componants are correct, but- "this was my first time" 

The germanium diodes are socketed.

See anything obvious, or do the symptoms point to something? Thanks!

The build documentation is here:

[https://www.dropbox.com/s/nu4bbm7ezrpijkj/aion-refractor-centaur-documentation.pdf

[aion]

Can you post the pin voltages from each of the three ICs? I'm particularly wondering about IC1 in this case, since the signal is split right after IC1A into drive, clean blend and bypass. The drive path has its own op amp which might compensate somewhat for a weak signal coming out of IC1A, but the clean blend and bypass signals would remain weak.

The next thing I'd look at is IC3, the charge pump, to make sure it's generating -9V and +18V properly. Neither of these will affect IC1 since it runs off of +9V, but it would be the next most likely issue if IC1 isn't the problem.

[Gus]

Have you asked Aion about the problem?

[oldlefty]

Thanks Kevin!

Pedal powered, switch on, dummy plug in "in" jack:

IC1:

1 4.64     8  9.33
2 4.67     7  4.65
3 3.57     6  4.65
4  0.00    5  4.64

IC2:

1  9.25   8  9.33
2  4.76   7  4.65
3  0.00   6  4.38
4  4.36   5  8.90


IC3:

1  4.84   8  16.89
2  4.66   7  4.49
3  4.65   6  4.66
4  8.90   5  4.65

Gus- the Aion website suggests asking for help here first, Kevin jumped right in.

[nate77]

I've sourced and built well over a dozen projects from Kevin at aion electronics and despite the fact that it posts that there is no direct support, Kevin has walked through a ton of issues. His PCBs are laid out unusually well and whatever the issue was for me, was always some error I had made and Kevin has always been great and concise when it comes to debugging. In the world of DIY effects that is contagious (thankfully!!) he has se of the most well thought out and moddable  boards I've ever used. If you shoot Kevin an email with some pin readings, etc., I assume he'll help you out. I've put together 3 of these refractor boards in the past week and they are spot on with both the gold centaur and silver (my friend has both, and incidentally a boatload of cash....). I know that this seems obvious but if you don't have any solder bridges, or ground out components, Then the wiring is the only thing that really stands out (faulty components are possible but wildly unlikely unless you've applied too much heat to sensitive components). Good luck. This circuit sounds great, although I prefer a true bypass pedal. But FWIW, this is one of the best buffers I've come across,
Andy signal chain is getting long enough to need a good buffer! Good luck man!

[duck_arse]

is there a ground wire connected to the jack on the right of your pic?

[oldlefty]

Nate- I underestand- I just did as the page suggested.  I sent Kevin a message through his page and he was back to me in minutes.  Glad to hear you think the pedal is spot on!  Usually my soldering is passable, I'm betting on a wrong componant since this was my first time buying parts.  I measured each resisitor before soldering in.  Did those IC pin values look similar to what you have on your builds?

duck- No, there's no ground wire on the out jack- as per the directions.  It grounds on the case.  First time on that for me!

[aion]

Yep, as long as the in/out jacks have ground continuity through the enclosure then there's no need to use the ground lug on both of them. Can be a problem with powdercoating sometimes if there's overspray, but it looks fine to me.

Here are some working voltages I found for reference - they aren't mine, but just subtract about 10% from everything (since his supply voltage was 10.24V and yours is 9.3) and that should be close.

IC 1: TLO72
Pin 1, +5.11V
Pin 2, +5.12V
Pin 3, +3.89V
Pin 4, 0V (ground)
Pin 5, +5.13V
Pin 6, +5.14V
Pin 7, +5.13V
Pin 8, +10.24V

IC 2: TLO72
Pin 1, +5.10V
Pin 2, +5.13V
Pin 3, +5.13V
Pin 4, -9.65V
Pin 5, +5.13V
Pin 6, +5.13V
Pin 7, +5.13V
Pin 8, +18.70V

IC 3: TC1044
Pin 1, +10.27V
Pin 2, +5.23V
Pin 3, 0V (ground)
Pin 4, -4.79V
Pin 5, -9.66V
Pin 6, +5.20V
Pin 7, +8.20V
Pin 8, +10.17V

So, your IC1 looks spot on but IC2 and IC3 are off.

Can you double-check your voltages on pin 4 of IC2 and pins 4 & 5 of IC3? These should all be negative rather than positive, but it's sometimes easy to miss the "-" since most pedals only use positive voltages.

[oldlefty]

My Bad!     I had IC2 and IC3 reversed- the values for 2 are for 3 and visa versa.  And yes, those three are negative.

[nate77]

I'll open up the refractor on my board and measure the voltages, but they look pretty accurate to me from memory and experience. This build has a pretty high part count and its worth stating the obvious, but it's worth checking and reflowing some of the solder joints. The soldering looks pretty good but from what I can see, it looks as if the solder may have been applied hastily on some of the components. Maybe a cold joint somewhere? Kevin used star grounding through the enclosure so that shouldn't cause any issues. It's tough to see the board with some of those larger red caps (which I love BTW) but I'll take a closer look when I've got a bit of time tomorrow. FWIW, I'm a true bypass fanatic, but the buffer on this bad boy is unique and punchy. I love it.

[aion]

My Bad!     I had IC2 and IC3 reversed- the values for 2 are for 3 and visa versa.  And yes, those three are negative.

Oh, awesome - looks like the voltages are all spot-on then.

I'm with Nate in thinking it could just be a solder joint someplace. When I first built the OD-820 (which is a vaguely similar circuit to the Centaur), it was doing all kinds of weird things including the charge pump getting really hot. I doublechecked all the components and all the values were correct. But I went through and touched all the solder joints and added just a dab more solder to each one (the extra flux helps the new solder melt and bond more easily with the old). I plugged it back in and it worked perfectly.

I like to think my soldering skills are pretty good after doing this for a few years, but if there's nothing obviously wrong then I usually do that first and it still fixes the problem once in awhile.

[oldlefty]

I reflowed all the joints and checked over the cap values, all look good.  (in HAL voice) "Wait a minuite, wait a minute..."  In checking over the resistors I just noticed that it looks like in R4 and R25 I have 560Ks in place of the 560Rs (I have green/blue/black/orange/brown).  That "might make a difference"  .  Off to the Rat Shack to see if they have them.  Thanks again for the help.

[oldlefty]

Bingo!  Amazing what a million extra ohms floating around a circuit can do....    Radio Shack only had 1/2 watters so I had to stand them up, but they fit.  Just gave it a quick run through, everything works and it's quiet.  Have to spend more time with it, but it does sort of remind me of my Hotcake- the "transparent boost" thing, just makes the tone "more there".

THANK YOU Kevin and Nate for the help.

[aion]

Awesome! Glad to hear it's working. The new resistors match the caps now... if anyone asks what the deal is, just say the parts were "carefully selected and audited for their tonal characteristics" ;)