Randall RG100ES. Layout inside.

Started by fishbone_vet, January 02, 2015, 05:16:37 PM

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jarrodthebobo

Completely rebuild the board and still have a lack of gain; the volume appears to be a bit better, but the gain is still very weak.

Have tried all different combinations of jfets to no avail;  I'm so confused as to what could be causing this.

I mean, I can't have made the same error twice, could I?

Does anyone have a sound clip without a boost pedal in front of it so I can hear what it sounds like?

Thanks!

slashandburn

#61
Hard to tell man, depends on what your perception of high-gain is and what you run it into.

It's not gonna turn a crystal clean amp into a dual rectifier. With these preamp circuits my philosophy is basically boost the @#$% out the front end (and in this case if the volume drop is ruining your fun then also run a buffer after).

Bias those trannies. Turn it up. Also check Marcos correction to the pcb earlier in this thread. Seems you've used a different layout but worth checking the pot wiring is correct as per Marcos correction.


Bennett99

Ive just build this circuit for the second time and i cannot get it to work. I can turn it on and hear a quiet pop but nothing else happens. Im running it qt 24.6 volts and im reading about 22-23 volts at the output and im getting voltage through all transistors.

duck_arse

welcome to the forum, Bennett99.

you will need to show us the stuff. photos of what you have built, component side so we can see what's there, copper side and off board wirings. and you need to post your voltage measures on all transistors. and post your circuit diagram and the layout you used [please don't make us chase the stuff you have in front of you].
don't make me draw another line.

Share

Are any of you aware of someone selling a board for this circuit, say, made on JLCPCB or similar manufacturer?

glops

Quote from: Share on July 28, 2021, 03:29:49 PM
Are any of you aware of someone selling a board for this circuit, say, made on JLCPCB or similar manufacturer?

This?

https://pcbguitarmania.com/product/vandal-from-hell/