Tone stack caps in C+

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Henz

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Greetings. I have a1984 DRG C+ and have been tweaking the tone stack caps. Haven't replaced any yet although i have two micas for the treble and treble shift and the other 715P's drops . Question: when inside, i removed the old silicone that bound the two 250pf and 750pf's and straightened them upright. With that little thing, the amps tone has changed for the better. Was that silicone that important? I know that it was put there to help reduce vibrations and microphonics. Will the new micas make a big difference?And O drops? A little undecided. Thanks for your time, Jim
 
Interesting! Maybe a loose connection fixed itself when you straightened them upright. I doubt the silicone wouldn't do anything it's there for vibration reasons as you mentioned. It would indicate that the tone stack area is a good place to look into as I know you had a bit of a voltage spark around that area. Maybe clean up the solder joints first with fresh LEAD solder (NOT Lead Free) and investigate further. If it sounds great, then leave it! But you can swap the 2x orange drops and 2x ceramic caps in the tone stack easily enough.

I'm a big fan of micas but others hate them. Did you get any ceramic discs as well just in case? Tone stack is relatively easy to swap out though especially if in any doubt of components. Just be wary of the fragile PCB board.

I know boogiebabies likes putting micas in the Lead Section at the very least. I did this on mine and sounds great.

http://forum.grailtone.com/viewtopic.php?f=9&t=49710

7. Replaced 120pf cap for Lead Drive input- Dipped for lower Microphonic Noise
8. Replaced 1000pf cap for Lead Drive Output- Dipped for lower Microphonic Noise
9. Replaced 1000pf cap for Lead Drive Plate Resistor- Dipped for lower Microphonic Noise

Tone stack micas - this is more debatable...
 
Hello JR32, how are you? Thanks for the reply. I would have sent you an email but I thought that you may have been busy with your studies. Yes, I purchased ceramic discs too. It is relatively easy but that 10meg resistor may be in the way plus the potentiometer side of the drops is really tight. About the solder, I'm using a 60/40 tin lead. That ok? And if you could , can you be more specific on the caps that you replaced in your lead stage? Give me cap numbers that's on your schematic that I have a copy of. I'm a little confused with the caps that BB changed on that link. What you highlighted from BB work, what are those cap numbers? On your schematic there are 5 disc caps in lead stage ( # 22, 24,27,31 and 32) . Which ones should I focus on? I'm assuming that cap 10 is the 10pf that BB changed. I know I'm throwing a lot at you again and I apologize but one more thing. The problem with my verb is that it has way too much decay. If I do that 220k mod with the 1meg, will that help? It looks like that's what BB did to that amp to help reduce decay. Thanks for your time. Hope to hear from you, Jim.
 

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