# Transformer builds?



## Dan0h (Mar 12, 2021)

Is there a way to view all pedalPCBs that use transformers? I’m really into wanting to build more pedals with them. My Duocast is so epic.


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## fig (Mar 12, 2021)

GoogleFu

siteedalpcb.com/Docs/ transformer

EDIT: love how it displayed the link (it still works). The top of the results will give some lame notice about no good results, but look below that. It searched the build docs and found all with the term "transformer".


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## Dan0h (Mar 12, 2021)

fig said:


> GoogleFu
> 
> siteedalpcb.com/Docs/ transformer


Hiya! Thanks grasshopper.


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## Betty Wont (Mar 12, 2021)

I'm curious what it is about the transformer that has you excited? There are many pedal applications for transformers. Pickup simulators, inductors, wave rectifier for octave up, ring mod...


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## Dan0h (Mar 12, 2021)

Torgoslayer said:


> I'm curious what it is about the transformer that has you excited? There are many pedal applications for transformers. Pickup simulators, inductors, wave rectifier for octave up, ring mod...


I think it’s part of the magic of audio for the signal to travel across the transformer. In my mind and what I (think) I hear is similar to that amazing tube saturation sound (warmth). Not the same but along the same lines. I feel like it’s a noticeable difference that gives life to the sound. My Duocast just does something to the sound that is indescribable, and I think it’s due to the transformer and Ge trans combo. Just wanting to build some more pedals with transformers to see if my thoughts are right.


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## Betty Wont (Mar 12, 2021)

Dan0h said:


> I think it’s part of the magic of audio for the signal to travel across the transformer. In my mind and what I (think) I hear is similar to that amazing tube saturation sound (warmth). Not the same but along the same lines. I feel like it’s a noticeable difference that gives life to the sound. My Duocast just does something to the sound that is indescribable, and I think it’s due to the transformer and Ge trans combo. Just wanting to build some more pedals with transformers to see if my thoughts are right.


Right on. I love my Duocast too. It has some kind of magic going on. My other favorite builds with transformers are the Spaceman Geminis and Sputniks, and the Brassmaster,


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## caiofilipini (Mar 12, 2021)

I really wanted to love my Duocast, but I didn't connect that much with it, to be honest. I don't think it's something wrong with my build, but I've been meaning to build a second one just to scratch that itch.


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## Dan0h (Mar 12, 2021)

caiofilipini said:


> I really wanted to love my Duocast, but I didn't connect that much with it, to be honest. I don't think it's something wrong with my build, but I've been meaning to build a second one just to scratch that itch.


It's really a love hate thing going on for me. My build sounds AMAZING as a clean boost, literally breathes life into my signal that I have never felt before. But my drive/fuzz side of it sounds great until the CRACKLE shit starts creeping in, I have searched and searched for the issues and can not seem to find it. Its very random, a true gremlin. I might just have to build a second Duocast. A member suggested it might be in the FS itself but I havn't swapped in a new one.


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## caiofilipini (Mar 12, 2021)

Yeah, hope you figure that one out!

I'm moving houses today and it might take a while before I'm able to build anything again. 😭


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## Dan0h (Mar 12, 2021)

caiofilipini said:


> Yeah, hope you figure that one out!
> 
> I'm moving houses today and it might take a while before I'm able to build anything again. 😭


Good luck on the move. One of the least favorite activities in life, but also one of the best ways to have a nice reset.


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## caiofilipini (Mar 12, 2021)

Haha exactly! Thanks, man.


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## jjjimi84 (Mar 12, 2021)

Dan0h said:


> It's really a love hate thing going on for me. My build sounds AMAZING as a clean boost, literally breathes life into my signal that I have never felt before. But my drive/fuzz side of it sounds great until the CRACKLE shit starts creeping in, I have searched and searched for the issues and can not seem to find it. Its very random, a true gremlin. I might just have to build a second Duocast. A member suggested it might be in the FS itself but I havn't swapped in a new one.


Check the foot switch, I had a few of those gremlins and a new FS or soft bypass rig fixed it right up.


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## caiofilipini (Apr 12, 2021)

caiofilipini said:


> I really wanted to love my Duocast, but I didn't connect that much with it, to be honest. I don't think it's something wrong with my build, but I've been meaning to build a second one just to scratch that itch.



Welllllllll.... turns out there might be something wrong with my build. I got ahold of a real Broadcast Dual last week, so I did some close inspection on it, measured voltage references, transistor biases, etc, and I'm fairly sure my BC549C is backwards! I got some fancy BC549C from Pedal Hacker a while back their pinout is reverse compared to regular BC549Cs (which is reverse compared to other silicon transistors).

Everything else seems correct with my build. I actually *really* like the original pedal, so hopefully I'll be able to get much closer after fixing this. I'll post and update here later!


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## Dan0h (Apr 12, 2021)

caiofilipini said:


> Welllllllll.... turns out there might be something wrong with my build. I got ahold of a real Broadcast Dual last week, so I did some close inspection on it, measured voltage references, transistor biases, etc, and I'm fairly sure my BC549C is backwards! I got some fancy BC549C from Pedal Hacker a while back their pinout is reverse compared to regular BC549Cs (which is reverse compared to other silicon transistors).
> 
> Everything else seems correct with my build. I actually *really* like the original pedal, so hopefully I'll be able to get much closer after fixing this. I'll post and update here later!


Good to hear, I thought it was strange that you were not loving it as much as the rest of us seem to. Makes sense that something was off. Good luck.


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## caiofilipini (Apr 12, 2021)

I was right, my BC549C was in backwards. I fixed it and now it sounds *really* close to the Hudson! I'm waiting for a rev3 board to arrive, so I guess I'm gonna build a new one anyway, but it makes a lot more sense now!


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## jcrhee (Apr 12, 2021)

caiofilipini said:


> I was right, my BC549C was in backwards. I fixed it and now it sounds *really* close to the Hudson! I'm waiting for a rev3 board to arrive, so I guess I'm gonna build a new one anyway, but it makes a lot more sense now!


curious, which BC549C did you get from PedalHackers? I bought this one. Curious if mine is backward as well. 









						5 Pack BC549C High Gain NPN Fuzz Silicon Transistor
					

BC549C high gain transistor Original



					www.pedalhackerelectronics.com


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## caiofilipini (Apr 12, 2021)

jcrhee said:


> curious, which BC549C did you get from PedalHackers? I bought this one. Curious if mine is backward as well.
> 
> 
> 
> ...



I got these a while back (they're out of stock now):









						BC549C Ferranti High Gain NPN Fuzz Silicon Transistor
					

BC549C Ferranti High Gain NPN Fuzz Silicon Transistor



					www.pedalhackerelectronics.com
				




Yours are different, you should be fine!


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## ntuncer (Nov 19, 2021)

caiofilipini said:


> Welllllllll.... turns out there might be something wrong with my build. I got ahold of a real Broadcast Dual last week, so I did some close inspection on it, measured voltage references, transistor biases, etc, and I'm fairly sure my BC549C is backwards! I got some fancy BC549C from Pedal Hacker a while back their pinout is reverse compared to regular BC549Cs (which is reverse compared to other silicon transistors).
> 
> Everything else seems correct with my build. I actually *really* like the original pedal, so hopefully I'll be able to get much closer after fixing this. I'll post and update here later!


Hello, @caiofilipini, could you please share voltage references for the real Broadcast? I will build soon a simulcast and I 'd like to use those reference values.

Cheers!


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## caiofilipini (Nov 19, 2021)

ntuncer said:


> Hello, @caiofilipini, could you please share voltage references for the real Broadcast? I will build soon a simulcast and I 'd like to use those reference values.
> 
> Cheers!



Sure thing! Here's what I got:

VCC = 9.25V
VREF = 3.21V
VDD  = 8.76V

Q1 (BC549C)
Vb = 2.976V
Ve = 2.42V
Vc = 6.64V

Q2 (2N404A NTE)
Vb = 6.64V
Ve = 6.77V
Vc = 2.86V

VCC, VREF and VDD are reference voltages as you see in the Duocast schematic, so I'm assuming they should be the same in the Simulcast schematic.

Hope that helps!


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## ntuncer (Nov 19, 2021)

caiofilipini said:


> Sure thing! Here's what I got:
> 
> VCC = 9.25V
> VREF = 3.21V
> ...


Thanks a lot! Those numbers will be my reference. By the way I expect to have OC71 in Q2, does Hudson replace it with 2N404A in current production?

Cheers!


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## caiofilipini (Nov 19, 2021)

ntuncer said:


> Thanks a lot! Those numbers will be my reference. By the way I expect to have OC71 in Q2, does Hudson replace it with 2N404A in current production?
> 
> Cheers!


Yeah, and I believe they use some Russian germanium transistors as well.


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## mdc (Nov 21, 2021)

It's interesting, I've been reading a bunch of accounts of folks who've built broadcast clones, left the transformer out completely (iirc there was a period last year where that TYP-somethingsomething was unobtanium?), and they sound identical to the originals. There's probably a FSB or DIYS thread about it somewhere, but the scuttlebutt seems to be that the transformer does little to nothing in that circuit.


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## Chuck D. Bones (Nov 22, 2021)

I have not built a Broadcast, yet, but my experience with that transformer in other circuits is it has shitty bandwidth and cuts off some of the bass and treble.


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## mdc (Nov 22, 2021)

I've meaning to breadboard one of these 




__
		https://www.reddit.com/r/diypedals/comments/gh40xv


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## Chuck D. Bones (Nov 22, 2021)

Looks like that guy does not know how to stabilize a feedback loop.

"optional, causes oscillation"
"optional, can prevent oscillation"
"trim for low resistance without oscillation"

Proceed at your own risk.


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## caiofilipini (Nov 29, 2021)

I haven't seen a schematic for it, but the Greer Royal Velvet also uses a transformer. In fact, the same transformer used in the Broadcast.


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## Chuck D. Bones (Nov 29, 2021)

mdc said:


> ...but the scuttlebutt seems to be that the transformer does little to nothing in that circuit.



That transformer could be used for isolation if the secondary side is disconnected from ground.  Seems like a missed opportunity.


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## jubal81 (Nov 29, 2021)

Chuck D. Bones said:


> That transformer could be used for isolation if the secondary side is disconnected from ground.  Seems like a missed opportunity.


I'm surprised I've never seen anyone do a dedicated isolated pedalboard output module.


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## Preverb (Nov 29, 2021)

caiofilipini said:


> I haven't seen a schematic for it, but the Greer Royal Velvet also uses a transformer. In fact, the same transformer used in the Broadcast.


This was one I was interested in too.


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