Angry Andy Plus - Bug or feature?

MichaelW

Well-known member
Hey guys,

I just finished building an Angry Andy and not sure if the boost is working correctly.

In non-boost mode, everything works fine.

In Boost mode, it works as its supposed to when the gain knob is 12 o'clock or less.

But if I turn the gain up any higher it starts squealing like a stuck pig. Not "good" feedback mind you, but uncontrollable squealing when there's no note being played. If I play through the squeal it works but as soon as I mute the strings its starts squealing.

If I put my finger on the boost stompswitch the squealing stops. I'm wondering if there's a ground issue?

But then why would it work fine when the gain is dialed back to noon? I searched and found a couple of old threads describing the same issue with no apparent resolution. Does this pedal just really need a noise gate after it at the highest gain settings?

Thanks in advance!

M-



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MichaelW

Well-known member
Revisiting this issue, I checked the boost stomp grounding and it all looks ok.
I was reading a different troubleshooting thread about a similar issue and it was suggested to use a shielded cable for the output cable. I thought I might try that next. Can I just use a regular guitar efx patch cable? I have some thin Mogami lying about. Would I need to connect the ground shielding to a ground pad? TIA
 

MichaelW

Well-known member
Even thin guitar cable is going to be pretty thick, but yes it will work. Ground the shield at one end
I tried it without grounding and it didn't make a difference, I'll try grounding the shielding. I have a feeling it might be the BS170 but not sure how to verify without replacing it. I have a second pcb, I may just build a second one. I think I need to build a probe and step up my trouble shooting skills.
 
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PJS

Active member
A probe will definitely tell you which part of the circuit is generating the noise. Won't necessarily tell you why, but if you can narrow down where then that will help with the why.
 

MichaelW

Well-known member
Ok, I re-did the I/O cables with shielded cables. (Mogami W2314) and grounded both sides to the jack tab. No joy, still squeals like a pig in boost mode when the gain is higher than noon. Something else going on besides EM interference or ground. There's probably a bad component in there some where.

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PJS

Active member
There is possibility of bad solder too. We haven't seen the solder side of the board. It would be pretty normal for a double sided board for the solder to have wicked through the holes so you can see a bit on the non-solder side. There are a lot of joints there where you can't see any solder on the component side. No saying it's impossible to get a good joint without it wicking through, but definitely check all your solder - especially for the boost part.
 

MichaelW

Well-known member
There is possibility of bad solder too. We haven't seen the solder side of the board. It would be pretty normal for a double sided board for the solder to have wicked through the holes so you can see a bit on the non-solder side. There are a lot of joints there where you can't see any solder on the component side. No saying it's impossible to get a good joint without it wicking through, but definitely check all your solder - especially for the boost part.
I'll pull the board out next and check the back solder joints. I'm gonna need to do that anyway to try swapping Q1. Waiting for a red 125b to arrive to build the second pcb I have. I also ordered some RG174 from Amazon. That Mogami W2314 looks a little ridiculous in the pedal :).
(Although I had to buy 17ft feet of the RG174......probably a lifetime supply hahah).
 

MichaelW

Well-known member
Ok, couldn't sleep, was up early and decided to futz around some more with this pedal.
I unboxed it, reflowed every solder joint. Cleaned the pcb as best I could with IPA in it's completed state.
I removed the BS170, socketed Q1 and put a new BS170 in.
No joy, still has the same issue.

One thing I didn't think to try before buttoning it all back up is to replace the Boost 3PDT.
Or possibly replace the B1M Boost pot. Before I do either of those, I'm going to build a new one first.

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matt3310

Active member
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music6000

Well-known member
Ok, I re-did the I/O cables with shielded cables. (Mogami W2314) and grounded both sides to the jack tab. No joy, still squeals like a pig in boost mode when the gain is higher than noon. Something else going on besides EM interference or ground. There's probably a bad component in there some where.
1. Definitely a lack of solder penetration!
2. BS170 is prone to damage from static electricity????

You wouldn't be the First if it's the Tayda Pot causing the issue, I wont use them!
 
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