Diode Clipping Level Drop Compensation

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Mr. Lime
Posts: 123
Joined: Sun Mar 05, 2017 12:57 am

Diode Clipping Level Drop Compensation

Post by Mr. Lime »

Hi!

Distortion from diodes like Jose has used always drops the signal level especially when 5V Zeners are used. I would like to do something like a level compensation after the tone stack where the signal is padded down for the effects loop.
Pretty much like a third channel I would like to have the option to boost the signal when the diodes are switched to ground. My first idea is a simple 100k pot parallel to the 1M resistor which creates an interstage divider with the 56k to ground.
Have you guys already made something like that or could give me advice if there's a better way to compensate the volume drop in my current amp situation with the MV after the effects loop?
diode boost channel.png
Thanks a lot
best regards
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romberg
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Re: Diode Clipping Level Drop Compensation

Post by romberg »

The way your schematic is setup, you could potentially have just 56k to ground after the tone stack. I'm not exactly sure what effect (if any this may have on the tone stack). But 56k is alot lower than 1M.

Why not just wire in a switchable master into or as part of the effects loop? A 1M audio taper pot with the ground connection switched ought to do it. I've used such an arrangement in an effects loop before to give a lead volume "boost" from a footswitch. You could wire it up and either leave the switch for the FX loop MV independent or tied to the diode clipper.

Mike
Cameron
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Joined: Sat Aug 05, 2006 4:38 am

Re: Diode Clipping Level Drop Compensation

Post by Cameron »

I've tried all sorts of things ...it always added something I didn't like to the tone. The only thing that worked good was using the loop to pad or boost the signal as needed at the send to keep an even level at the send then boost the return a little more to balance everything out. Something I've done for years ..and worked better.....is to have a solo boost and it has the 5volt zeners the normal master without any or a higher voltage zener. So you basically have to masters and you can even out both volumes or turn up the solo boost for a lead boost..... There is still enough signal getting to the PI so I wouldn't really worry about that...I've never had a problem using the amp live with a band cranked up loud....it will still be very loud ....
Mr. Lime
Posts: 123
Joined: Sun Mar 05, 2017 12:57 am

Re: Diode Clipping Level Drop Compensation

Post by Mr. Lime »

romberg wrote: Sun Nov 05, 2017 11:53 pm The way your schematic is setup, you could potentially have just 56k to ground after the tone stack. I'm not exactly sure what effect (if any this may have on the tone stack). But 56k is alot lower than 1M.

Why not just wire in a switchable master into or as part of the effects loop? A 1M audio taper pot with the ground connection switched ought to do it. I've used such an arrangement in an effects loop before to give a lead volume "boost" from a footswitch. You could wire it up and either leave the switch for the FX loop MV independent or tied to the diode clipper.

Mike
KOC has some similar switching on the LPSP schematic.

Well, you are probably right, the 56k parallel to the tone stack could cause some weird things going on, so it's better to raise the resistance when the diodes are in the Signal path and the 100k boost pot is on. For that I would use the second half of the switch which is bound to the diodes.
A second switchable MV / send pot isn't an elegant solution here imo. The signal would be very low after the effects loop pad and the additional volume drop from the diodes.
The 56k/1M combination is the -20dB pad from the Naylor SD60 which would be predestined for the volume compensation while keeping the tone somewhat consistent I guess.
I just need the right ratio for an insterstage divider when the diodes are on. It's more or less a MV switch with one pot basically fixed.
The true MV is wired to the PI and bootstrapped.
Diode Boost.png
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