gain and mid circuits

emosms · 18th July 2011, 04:00 PM

HI
any suggestions how to modify an amplifier and introduce a midtone and gain chains (knobs)?
The circuit itself, taken from old russian radio:

I am using it as electric guitar amp, has a pretty decent clean tone but want to overdrive it and add some crunch drive

nightanole · 18th July 2011, 04:46 PM

http://home.comcast.net/~machrone/bjr/bjtone.htm

Hammond AO-44 Reverb Amp to Hi-Fi Amp Conversion

Not really the guitar type tone stacks but its a start.

http://amps.zugster.net/articles/ton...TweedPrinceton

razorrick1293 · 18th July 2011, 07:22 PM

anychance of uploading the schematic again? doesnt seem to want to work, but id check for anywhere you can add a cathode cap and reduce attenuation, maybe even increase plate load and adjust cathode resistor accordingly?

emosms · 18th July 2011, 10:35 PM

Here it comes the shematics (i hope):
View image: Rigonda 102 small

I can implement the modification, but i don't know if I would manage to understand and calculate the chains, especially for the gain.
(I cannot even recognize which filter is for the low and which one for the highs now

)

Looking for a brigth crunch, like SRV sound, little wing, e.t.c.
Possibly with a capability for a bit more gain, lets say like ibanez ts808
Overdriving the preamp tube? Or the EL84 twin?

emosms · 18th July 2011, 10:41 PM

View image: Rigonda 102 small
View image: Rigonda 102 small

ruffrecords · 19th July 2011, 11:17 AM

The part you have labelled 'what are these for' looks to me like a loudness control.

Cheers

Ian

payitforwardeddie · 11:42 AM

Quote:

Originally Posted by ruffrecords

The part you have labelled 'what are these for' looks to me like a loudness control.

Cheers

Ian

Definitely a Loudness control.

R3 is Treble.
R4 is Bass.

flatheadmurre · 19th July 2011, 11:47 AM

The potentiometer has bass taps for compensating the bass at different listening levels to fit the human ear. Popular at older amps.The marked components are for this.

emosms · 19th July 2011, 11:53 AM

ok, so I just omit the chain and change the pot with an ordinary one

?

emosms · 19th July 2011, 11:58 AM

what about replacing the power supply with some impulse supply or just a resistor shunt?
View image: Rigonda 102 supply
View image: Rigonda 102 supply
too much of a hardware weight for 2-3watts amp

18th July 2011, 04:00 PM	#1
emosms diyAudio Member Join Date: Sep 2010	gain and mid circuits HI any suggestions how to modify an amplifier and introduce a midtone and gain chains (knobs)? The circuit itself, taken from old russian radio: I am using it as electric guitar amp, has a pretty decent clean tone but want to overdrive it and add some crunch drive

18th July 2011, 10:41 PM	#5
emosms diyAudio Member Join Date: Sep 2010	schematics View image: Rigonda 102 small View image: Rigonda 102 small

19th July 2011, 11:17 AM	#6
ruffrecords diyAudio Member Join Date: Jun 2007 Location: Holt, Norfolk	The part you have labelled 'what are these for' looks to me like a loudness control. Cheers Ian __________________ Ian

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18th July 2011, 04:46 PM	#2
nightanole diyAudio Member Join Date: Feb 2009	http://home.comcast.net/~machrone/bjr/bjtone.htm Hammond AO-44 Reverb Amp to Hi-Fi Amp Conversion Not really the guitar type tone stacks but its a start. http://amps.zugster.net/articles/ton...TweedPrinceton

18th July 2011, 07:22 PM	#3
razorrick1293 diyAudio Member Join Date: Nov 2010 Location: England Hertfordshire	anychance of uploading the schematic again? doesnt seem to want to work, but id check for anywhere you can add a cathode cap and reduce attenuation, maybe even increase plate load and adjust cathode resistor accordingly?

18th July 2011, 10:35 PM	#4
emosms diyAudio Member Join Date: Sep 2010	Here it comes the shematics (i hope): View image: Rigonda 102 small I can implement the modification, but i don't know if I would manage to understand and calculate the chains, especially for the gain. (I cannot even recognize which filter is for the low and which one for the highs now ) Looking for a brigth crunch, like SRV sound, little wing, e.t.c. Possibly with a capability for a bit more gain, lets say like ibanez ts808 Overdriving the preamp tube? Or the EL84 twin?

19th July 2011, 11:47 AM	#8
flatheadmurre diyAudio Member Join Date: Mar 2011 Location: Jarna	The potentiometer has bass taps for compensating the bass at different listening levels to fit the human ear. Popular at older amps.The marked components are for this.

19th July 2011, 11:53 AM	#9
emosms diyAudio Member Join Date: Sep 2010	ok, so I just omit the chain and change the pot with an ordinary one ?

19th July 2011, 11:58 AM	#10
emosms diyAudio Member Join Date: Sep 2010	what about replacing the power supply with some impulse supply or just a resistor shunt? View image: Rigonda 102 supply View image: Rigonda 102 supply too much of a hardware weight for 2-3watts amp

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