Simulcast (latest version) semi working

[innerlight]

Hey all
just finished the new version of the simulcast. When engaged all knobs affect the sound, however the sound is weak in all three modes, a tiny bit of drive, not much increase in volume.
When I first plug it in to the power it sounds how it is meant to for two seconds then it fades back to that quiet/ weak state. if I really dig into the strings it sputters here and there like a gated fuzz.
I’ve built a duo cast in the past and it worked great.
Im pretty confident the problem lies with the ge transistor. I have an OC 71 in it right now. If I wiggle it about it has splutters here and there. I know the transistor works because it was in a functional duocast and it worked fine (a little weak but pretty good).
I have a bunch of MP20 transistors coming so I’ll try them when they arrive. Does anyone have any advice in the mean time? Many thanks.

 

[innerlight]

 

[eh là bas ma]

Hi,

I would start by trying an other PNP transistor to make sure that's the issue.

Are you sure your electrolytic caps are all rated at 35 V or above ?

Is the Tone pot (Low Cut) insulated ?

 

[innerlight]

Hi,

I would start by trying an other PNP transistor to make sure that's the issue.

Are you sure your electrolytic caps are all rated at 35 V or above ?

Is the Tone pot (Low Cut) insulated ?

Hi thanks for your reply! I made sure that all caps were 35 (I think most of mine were 50v or so.)
All pots are insulated. I don’t have any other transistors on hand except some 2N2222s. They had the same issue. I’ll also order some more charge pump ICs in case that’s the issue.

 

[eh là bas ma]

...and your transformer is oriented opposite than in this exemple :

Simulcast - spot the mistake I just noticed while writing this up...

Well, not 100% complete yet but I was taking some other photos and did this one while I was at it. The drive sounds absolutely superb at all three gain settings. I was a bit off-put at first by the control choices. I labeled the Gain Trim knob "Gain" which, if you are familiar with the pedal...

forum.pedalpcb.com

 

[eh là bas ma]

according to this datasheet, the dot is above pin 1 :

TY-141P Datasheet by Triad Magnetics | Digi-Key Electronics

View datasheets for TY-141P Datasheet by Triad Magnetics and other related components here.

www.digikey.com

So a simple way to check this, is to do a continuity test between transformer's pin1 and R10 or R11, according to schematics.

https://docs.pedalpcb.com/project/Simulcast-PedalPCB.pdf

If, as I suspect, that's your issue, it's going to be a bit tricky to unsolder this thing...

Let us know if it's the case, so we can assist you.

 

[jhaneyzz]

...and your transformer is oriented opposite than in this exemple :

Simulcast - spot the mistake I just noticed while writing this up...

Well, not 100% complete yet but I was taking some other photos and did this one while I was at it. The drive sounds absolutely superb at all three gain settings. I was a bit off-put at first by the control choices. I labeled the Gain Trim knob "Gain" which, if you are familiar with the pedal...

forum.pedalpcb.com

I'm pretty sure the transformer is ambidextrous, or whatever the proper term is for "orientation doesn't matter." I've also heard others say that they remove the transformer from the circuit and can't hear any difference for whatever that's worth.

 

[jhaneyzz]

I'm pretty sure the transformer is ambidextrous, or whatever the proper term is for "orientation doesn't matter." I've also heard others say that they remove the transformer from the circuit and can't hear any difference for whatever that's worth.

FYI, that's my functional Simulcast in the photo eh lá bas ma posted.

 

[jhaneyzz]

according to this datasheet, the dot is above pin 1 :

TY-141P Datasheet by Triad Magnetics | Digi-Key Electronics

View datasheets for TY-141P Datasheet by Triad Magnetics and other related components here.

www.digikey.com

So a simple way to check this, is to do a continuity test between transformer's pin1 and R10 or R11, according to schematics.

https://docs.pedalpcb.com/project/Simulcast-PedalPCB.pdf

If, as I suspect, that's your issue, it's going to be a bit tricky to unsolder this thing...

Let us know if it's the case, so we can assist you.

Or... maybe, just this once, i cluelessly got lucky and oriented the thing correctly.

 

[innerlight]

I'm pretty sure the transformer is ambidextrous, or whatever the proper term is for "orientation doesn't matter." I've also heard others say that they remove the transformer from the circuit and can't hear any difference for whatever that's worth.

I had also read this and was operating under this assumption
can someone confirm?

 

[innerlight]

...and your transformer is oriented opposite than in this exemple :

Simulcast - spot the mistake I just noticed while writing this up...

Well, not 100% complete yet but I was taking some other photos and did this one while I was at it. The drive sounds absolutely superb at all three gain settings. I was a bit off-put at first by the control choices. I labeled the Gain Trim knob "Gain" which, if you are familiar with the pedal...

forum.pedalpcb.com

Ps thank you for looking this over. I appreciate it!

 

[eh là bas ma]

I'm pretty sure the transformer is ambidextrous, or whatever the proper term is for "orientation doesn't matter." I've also heard others say that they remove the transformer from the circuit and can't hear any difference for whatever that's worth.

can someone confirm?

I'd humbly suggest that the honorable Mr Haney unsolder his transformer and put it back in the opposite orientation, to confirm ? For Innerlight, and for science's sake ?

Edit : You may be right, but why bother with a marker if these things aren't polarized ? The dot is probably there for a reason... Maybe both sides are doing the same thing, but if you put pin 4 instead of pin 1 and pin 3 instead of pin 6...

Innerlight, did you check if theres's continuity between the dotted pin and R10/R11 ? So we can at least confirm if yours is backward and not Jhaneyzz's ?

 

[eh là bas ma]

On schematics, the dots below 1 and 6 make me wonder if you really can just flip it without consequencies :


I mean you can probably use pin 6 instead of pin 1, as if you soldered the part on the other side of the pcb, but using 3 and 4 instead of 1 and 6, really ?

 

[benny_profane]

Don’t remove the transformer—it is oriented correctly. Pin 1 is on the primary. The transformer used here happens to have equal impedance on each side. That isn’t the case for all transformers; with those, orientation will matter.

Can you ensure that the transistor is maintaining good electrical contact in the sockets? Have you inspected your values and your soldering?

 

[innerlight]

Don’t remove the transformer—it is oriented correctly. Pin 1 is on the primary. The transformer used here happens to have equal impedance on each side. That isn’t the case for all transformers; with those, orientation will matter.

Can you ensure that the transistor is maintaining good electrical contact in the sockets? Have you inspected your values and your soldering?

Oh fantastic! I didn’t want to remove the transformer.
I’m going to go over the values asap. How might I ensure contact on the transistor?

 

[innerlight]

Don’t remove the transformer—it is oriented correctly. Pin 1 is on the primary. The transformer used here happens to have equal impedance on each side. That isn’t the case for all transformers; with those, orientation will matter.

Can you ensure that the transistor is maintaining good electrical contact in the sockets? Have you inspected your values and your soldering?

This theory holds water because when I jiggle the transistor about the signal cuts in and out. But it really seems like it’s making contact, I’m not sure how it wouldn’t be

 

[jhaneyzz]

I'd humbly suggest that the honorable Mr Haney unsolder his transformer and put it back in the opposite orientation, to confirm ? For Innerlight, and for science's sake ?

Edit : You may be right, but why bother with a marker if these things aren't polarized ? The dot is probably there for a reason... Maybe both sides are doing the same thing, but if you put pin 4 instead of pin 1 and pin 3 instead of pin 6...

Innerlight, did you check if theres's continuity between the dotted pin and R10/R11 ? So we can at least confirm if yours is backward and not Jhaneyzz's ?

Not gonna happen... I tried to unsolder one of those things in a past build.... about as hard as unsoldering a 3PDT from a PCB...

 

[Harry Klippton]

Not gonna happen... I tried to unsolder one of those things in a past build.... about as hard as unsoldering a 3PDT from a PCB...

I completely stripped one recently and put all the parts in a new board

 

[jhaneyzz]

I completely stripped one recently and put all the parts in a new board

I need to learn your desoldering ninja skills.

 

[Harry Klippton]

I need to learn your desoldering ninja skills.

Hot iron, good solder sucker, a good rotating PCB holder, some probes, patience, and magnification works for me