Problems with Glam Chorus & Vorg Warp Sound

[kesakko]

Hi,

So I've built a few pedals before – a few fuzzes including a Warp Sound and a Fuzz Factory. Just having problems with these two.


First up is a Glam Chorus from Fuzzdog. With this one, I have found the live wire from the power input gives a 0-volt reading. However, when I desolder the wire from the power input and then test the input directly, it reads as 9 volts.




The Warp Sound is also from Fuzzdog. It works, kinda. I can play it and get a good sound, but there's a buzz in the background at all times. And also this happens – a tone when I touch my guitar strings and stops when I stop touching it.

Video here – https://streamable.com/onro18




Any ideas?

[GibsonGM]

0V and then 9V when connected sounds to me like something is causing a short from  your power supply to ground on the board.  A solder bridge, mis-placed component or so on.  Using an ohmmeter or 'beep' continuity tester from + input to ground might show you something.

2nd problem, sounds like something is oscillating.  What is your power supply, is it meant for audio use? Does it do this just with a battery?    If yes to both, might be time to dig out the audio probe! Most of these issues end up being 'user error'...we build them wrong, LOL.   So going over all connections VERY closely can give the answer...a non-connected ground...a cap that's the wrong value in the wrong place...

See if you can fill this out: https://www.diystompboxes.com/smfforum/index.php?topic=29816.0      welcome to the forum!  We'll probably be able to get you some answers, just gotta go thru the process

Also, do be sure the ICs are installed 'right way around' in their sockets!

[kesakko]

Thanks.

Have tried both Tone City Pedalstation and a 9v power supply from a Big Muff for the power. ICs are all the correct way round according to the PDF instructions.

How can I test the Glam Chorus with my multimeter when there's no voltage going into the pedal? Everything just reads 0.00.


Here's the Warp Sound readings.

1. Buzzing and string touching sound as seen here - https://streamable.com/onro18
2. Warp Sound
3. http://pedalparts.co.uk/docs/WarpSound.pdf
4. N
5. N
6. N
7. No battery??

C1: 0.00 & 3.64
C2: 4.71 & 0.00
C3: 4.57 & 4.66
C4: 4.63 & 0.00
C5: 4.98 & 0.00
C6: 4.66 & 0.00

D1: A 4.99, K 4.68

D2: A 4.68, K 4.99

IC1:
4.26
4.26
4.21
9.24
3.5
4.53
4.53
0.00

IC2:
4.24
4.6
4.54
9.24
4.54
4.54
4.62
0.00

[GibsonGM]

Hi, internet went down overnight, sorry.

How you looking at your ICs?  What is the number on the IC?   Should be this way, from the top. Measure power on, of course:

*
1   8
2   7
3   6
4   5

* = dot to orient you

Pin 4 should be 0, pin 8 should read ~9v.  Is something backwards?  Sure of which power wire is + and - ?

-----------------------------------------
Glam chorus:   To test 'continuity' (connection) from + to -, set your meter to "Ohms" (omega sign) OR to 'beeper', and test between 2 points. The internal battery provides its own power to see if there is a connection between 2 things.    In this case we're testing the power supply for a short, so put red probe on + of battery, - on ground ( - terminal), and make sure a plug is inserted in input jack to complete the circuit.    DON'T use ohms/beep with power on! Will toast your fuse in meter.

If you use beep, a short = beep, or you may see a low resistance reading - write it down if so.

If there is a short to gnd, the resistance will be zero/very low.    If no short, expect it to be high and drop as caps charge up (high moving lower).

[kesakko]

Yep I get 9v on the 4s and 0v on the 8s. Same when I take the IC out and test the socket.

I have the red cable from multimeter on the red live wire to power and testing with black multimeter cable.


What ohms should I set multimeter to? Have 2000k, 200k, 20k, 2000, 200.
And where should I put red/black probe to test the circuit away from the live/ground power inputs?

[GibsonGM]

Probably 200 ohms will suffice...to drag your power supply right to nothing either means the power isn't getting there, or that there is a hard short, which should be 0 ohms.  (You say you get 9V on the actual wires disconnected so I am going with a short...I am going with your 'assessment' that the power supply is fine and any other common sense stuff like plugged in and so on).   

Red probe on the + terminal of the PCB, black on - of the PCB, no power on, wall wart unplugged.  A reading of about 0 ohms tells a lot.  A high-ish reading that gradually goes down would be expected.   Is your meter a digital multimeter, or 'needle movement' type?

I am also assuming that you get the 9V AFTER the jack you plug the wall wart into?  Because those are often wired incorrectly, so checking the 'barrel' of the wall wart isn't enough...power thru that jack should be rock-solid, too, of course.  Remember, that thing is a switch and thus can be set up wrong...gotta check the most simple things first, they are where we (all) make mistakes!


Warp Sound sounds really strange to me...not connected ground somewhere or wrong component value, all things otherwise working ok (?) 
Just me, I'd make an audio probe and try to determine where in the circuit it starts doing that, which may narrow it down to one opamp, and so give a place to look in.    Solder bridge short is a possibility....

[duck_arse]

also welcome.

I think, from looking your pics, you have miswired your jacks. you seem to have sleeve and tip confused. sleeve is ALWAYS ground for our purposes.

[ManicStrat1982]

On the glam chorus.....it sounds like you have a defective 9v jack. I had a pedal with the same issue and after hours of pulling my hair out I switched jacks.....and bingo. Unless I misunderstood your issue....try a different jack.

[GibsonGM]

On the glam chorus.....it sounds like you have a defective 9v jack. I had a pedal with the same issue and after hours of pulling my hair out I switched jacks.....and bingo. Unless I misunderstood your issue....try a different jack.

Tho he says no battery...Duck arse pointed out the 'intricacy' of the ground switching using an input jack, as I was working around to find out "why no power" and looking at the power supply input jack, which normally would switch out battery for wall wart (pulling hair).  Somewhere in the offboard wiring will lie the culprit, UNLESS there is a bridge somewhere.   Hence my attempt to get the dude to remove his power leads and just test the board with a DMM etc.
He'll be happy if he finds he shorted something 'offboard', LOL.

[kesakko]

Have rewired the jacks on both. Now there is no sound at all from the Warp Sound and the Glam Chorus still has the same problem.

Have tried different input jacks with the Glam Chorus but the problem is the same.

When I plug Glam Chorus into my Tone City Substation I get a red light, which obviously indicates some power problem.

Probably 200 ohms will suffice...to drag your power supply right to nothing either means the power isn't getting there, or that there is a hard short, which should be 0 ohms.  (You say you get 9V on the actual wires disconnected so I am going with a short...I am going with your 'assessment' that the power supply is fine and any other common sense stuff like plugged in and so on).   

Red probe on the + terminal of the PCB, black on - of the PCB, no power on, wall wart unplugged.  A reading of about 0 ohms tells a lot.  A high-ish reading that gradually goes down would be expected.   Is your meter a digital multimeter, or 'needle movement' type?

It's a digital multimeter.

Red on live and black on ground of the main board and I get a reading of 0.3 ohms.

I am also assuming that you get the 9V AFTER the jack you plug the wall wart into?  Because those are often wired incorrectly, so checking the 'barrel' of the wall wart isn't enough...power thru that jack should be rock-solid, too, of course.  Remember, that thing is a switch and thus can be set up wrong...gotta check the most simple things first, they are where we (all) make mistakes!

If I detach the live wire from the 9v input jack and then test the power, it records 9v. With the live wire soldered on it records 0v.

Have tried multiple plugs that work with all my other pedals and the outcome is the same.

Warp Sound sounds really strange to me...not connected ground somewhere or wrong component value, all things otherwise working ok (?) 
Just me, I'd make an audio probe and try to determine where in the circuit it starts doing that, which may narrow it down to one opamp, and so give a place to look in.    Solder bridge short is a possibility....

I have some capacitors now so I'll make an audio probe to try this tomorrow.

[GibsonGM]

Ok, so for Glam my suspicion is that you have a short somewhere on the board.  This can be caused by a solder blob touching another solder blob and making a bridge, or a blown component that failed as a short (tho not that common, my experience has always been things fail open).    Examine each contact on the PCB for solder bridging.  Check anywhere else power goes (stomp switch board?  Wire 'hairs' could be a problem there)  Check each part, that it's the right value and in the right place.   Check the electrolytic cap that it has the "Minus" sign, usually with black arrow, oriented to ground (ok, that's reaching, but while we're doing this).    Let's make sure the board is ok first.     Can you post a good-quality picture of the board rear, where it's soldered?  many, like Duck, are good at spotting buggy connections!!

Yes, an audio probe is something you'll use often in this hobby.  Glad you want to keep trying, this is how you learn.  We all have this happen at times.   Might take 50 times looking at it, but generally something is spotted that is the cause!

* make sure those grounds on the jacks have continuity with board " - " before you mess around more, just for the heck of it.  If any of them are accidentally " + ", you got problems...

[kesakko]

Some photos of the Glam Chorus board








The audio probe makes 'scratching' noises but nothing else really. Pedal is plugged into 9v, ground to ground and using capacitor on the board...

[GibsonGM]

Yeah, because we suspect a short, there will be no sound when you probe and play something into FX - tho you SHOULD have sound up to Q1.  After that, the (not working) active device would take over, too low a signal to 'punch thru' so no sound, in theory.  Regardless, you have some issue with power supply being shorted, so that's irrelevant.
------------------------------------

Ok - I'm kind of awake this morning. Here is the build doc. for Glam Chorus:  http://pedalparts.co.uk/docs/Glam2.pdf

I'll assume you KNOW that you have 9V right at the wire that attaches to the PC board at "+" input terminal, and you read this against the ground from the same location....

I see a protection diode D1, which I should've clued to before but didn't have the schematic at hand...this MUST be installed with the cathode - banded end - facing the + power supply.  If it's backwards, that could account for a short!  Looks like top picture, right hand side by electro cap, standing up...the cathode goes to the left-hand pad so would be on top in the pic.    If it is NOT oriented wrong, then perhaps the voltage regulator IC is installed wrong (pins to wrong terminals)?  (is the flat on the IC facing us in the pic? Can't tell w/my bifocals).   Is the center pin on the regulator connected to gnd, and NOT connected to +?

If the above looks ok, You'll have to go thru and check some things....I'd carefully (!) remove the ICs, put them aside carefully (!).  Re-apply power, see if it is 'normal' without the chips in.  If not, I'd suspect the JFET or regulator is toasted, but not sure about how it would fail if overheated (or hit with reverse polarity...).  Anyone?

Did you follow the build notes? They say not to put the CLR resistor on the main board, but at the switch...and tell how to test for power etc, BEFORE hooking up jacks, switch, and so on, LOL.  I'm tempted to say remove all that for now.  I wonder if Q1 or U1 was overheated during soldering - did you use a clip heatsink to protect them?

I know, it's a crappy process, and it's far easier to do in person once you know how   Keep at it...

[ElectricDruid]

Yep I get 9v on the 4s and 0v on the 8s. Same when I take the IC out and test the socket.

Welcome Kesakko!

Why has no-one pointed out this is back to front?!? It looks like you'Ve got the power wires reversed somewhere - on the power input jack possibly, since you were having trouble with that.

[GibsonGM]

I've been asking just that...he seemed to have 'been good' with it - but maybe not...that what I mean when I say "I assume you have 9V to the board..." and so on.       Perhaps that was taken for granted....?  Polarity is kinda important after all.   That problem was for the Warp drive, this stuff here is glam chorus, but the issue may well be the same in both.  So:

Kesakko...Glam - when you test just the power wires going to the board AFTER the jack ('open', not connected)...do you get " 9V " with the meter set one way, and " -9" if you reverse your meter probes??      This is partly why I've been asking if you're testing power AFTER the jack, BEFORE the PCB...in which case....when the meter reads " 9V" (meaning 'plus 9V') - all things being proper (black wire plugged into common terminal on meter, red wire on the one marked 'volts' or some such things) the red probe indicates your " + " wire, which goes to " + " on the PCB, and vice versa for the black to gnd...

I guess I'm asking if you know how to use your meter and what the various voltages and polarity signs indicate?  Sorry for taking that for granted.

[duck_arse]

the glam -



your jacks are miswired in this pic. this WILL kill sound. it's most likely that that D1 Gibson mentioned is backwards. we've had NO voltage measures from that build yet - if supply reads 0V7 and the diode gets hot, it is one of the culprits.

the more information you provide us - photos, circuit diagrams, voltage readings, problem descriptions - the less scratching at dark corners of the interwebs we have to do, the more likely we are going to stick around and help.

[kesakko]

The jacks have been rewired and the issue is still there. Now the ground goes to sleeve and the in/output goes to tip.

I will focus on the Glam Chorus for now because I think we're mixing up various issues and instructions.


From the power jack, the red live wire goes to V, the black ground wire goes to G.
From the daughterboard to the main board, the red live wire goes from V to V. The black ground wire goes from G to G.
From the in/out jacks, the black ground wire goes to G, the red live wire goes to V.
The blue input/output wires go to the correct JI/JO/IN/OUT.

All the wiring is completely correct by the instructions.


Here is a video overview of the Glam Chorus if that shows any better how it's wired – https://streamable.com/dic6qc

Here is a video of me testing the power at the power input (multimeter is set to 20V) – https://streamable.com/o1282q
When I test the same red live/black ground connections on the daughterboard and on the main board, there is the same reading of not even half a volt.
When I take the red live wire away and directly test the jack I get 9V reading.

[ElectricDruid]

I will focus on the Glam Chorus for now because I think we're mixing up various issues and instructions.

I think so too, so good idea. Keep it simple.

When I test the same red live/black ground connections on the daughterboard and on the main board, there is the same reading of not even half a volt.
When I take the red live wire away and directly test the jack I get 9V reading.

This suggests a short on the board that drags the power down when the board is connected. Other people have suggested that you can test for this by doing a continuity check between the PCB's power wires. This will test for a "low" resistance (exactly how low depends on he meter, but generally "low" is too low, so it doesn't matter). You shouldn't get a continuity beep across the power wires, but with these symptoms, we'd suspect that you will.

[GibsonGM]

I see a protection diode D1, which I should've clued to before but didn't have the schematic at hand...this MUST be installed with the cathode - banded end - facing the + power supply.  If it's backwards, that could account for a short!  Looks like top picture, right hand side by electro cap, standing up...the cathode goes to the left-hand pad so would be on top in the pic.    If it is NOT oriented wrong, then perhaps the voltage regulator IC is installed wrong (pins to wrong terminals)?  (is the flat on the IC facing us in the pic? Can't tell w/my bifocals).   Is the center pin on the regulator connected to gnd, and NOT connected to +?

If the above looks ok, You'll have to go thru and check some things....I'd carefully (!) remove the ICs, put them aside carefully (!).  Re-apply power, see if it is 'normal' without the chips in.  If not, I'd suspect the JFET or regulator is toasted, but not sure about how it would fail if overheated (or hit with reverse polarity...).  Anyone?

Did you follow the build notes? They say not to put the CLR resistor on the main board, but at the switch...and tell how to test for power etc, BEFORE hooking up jacks, switch, and so on, LOL.  I'm tempted to say remove all that for now.  I wonder if Q1 or U1 was overheated during soldering - did you use a clip heatsink to protect them?

I know, it's a crappy process, and it's far easier to do in person once you know how   Keep at it...

  You have found some things, corrected others - so now on to the PCB.  I think either a solder bridge we haven't found, or a component is fried and shorting.    I suggest checking that diode FIRST (if backwards, that may well be the trouble) and then a VERY good look w/magnifying glass under both boards for solder bridging or bad connections.

If nothing, then gently remove the ICs without bending the legs (!), etc etc as above.   Any thoughts on failure mode of the JFET/regulator, folks?  Can they die shorting??