have problem with tone control

Ahmad_tbp · 6th February 2006, 06:11 PM

hi ...
i built the tone control that marshall uses in bass and guitar amp ... ( http://users.chariot.net.au/~gmarts/ampbasic.htm )
and used a jfet buffer before it ...
infact i wanted to build a tone control effect pedal , i plugged my bass right into the buffer and then tone control circuit .... but the sound decreased too much and almost dead , and nothin change so much when i turn the knobs ...
so should i use a pre amp ? or the problem s not cuz of i don usin a preamp ?

anatech · 6th February 2006, 06:29 PM

Hi Ahmad_tbp,
The tone circuit is designed to work at line levels. You need to provide gain as a tone control circuit can only drop the signal level. I would expect you to get increased noise doing this.

Can you post the schematic of your buffer?

-Chris

Ahmad_tbp · 6th February 2006, 08:07 PM

here s : http://www.generalguitargadgets.com/...er_jfet_sc.gif

anatech · 7th February 2006, 02:02 AM

Hi Ahmad_tbp,
Okay, the buffer is close to unity gain. You need to have at least as much gain in the buffer as you lose in the network. You need a quiet buffer / amplifier stage to work at those levels. Think dynamic mic level quiet.

-Chris

Ahmad_tbp · 7th February 2006, 07:34 AM

hi Chris

i need a mic preamp befor buffer ?

anatech · 7th February 2006, 01:54 PM

Hi Ahmad,
A preamp would be the buffer. If you design it to just compensate for the loss, you can plug it into the same input. This tone stack is intended to go after amplification and mixing of channels. You may be trading some noise for external tone controls.

-Chris

6th February 2006, 06:11 PM	#1
Ahmad_tbp diyAudio Member Join Date: Jul 2004 Location: Iran/Shiraz	have problem with tone control hi ... i built the tone control that marshall uses in bass and guitar amp ... ( http://users.chariot.net.au/~gmarts/ampbasic.htm ) and used a jfet buffer before it ... infact i wanted to build a tone control effect pedal , i plugged my bass right into the buffer and then tone control circuit .... but the sound decreased too much and almost dead , and nothin change so much when i turn the knobs ... so should i use a pre amp ? or the problem s not cuz of i don usin a preamp ? __________________ Rest my eyes from the world. This dying place, it's so absurd.

6th February 2006, 08:07 PM	#3
Ahmad_tbp diyAudio Member Join Date: Jul 2004 Location: Iran/Shiraz	here s : http://www.generalguitargadgets.com/...er_jfet_sc.gif __________________ Rest my eyes from the world. This dying place, it's so absurd.

7th February 2006, 07:34 AM	#5
Ahmad_tbp diyAudio Member Join Date: Jul 2004 Location: Iran/Shiraz	hi Chris i need a mic preamp befor buffer ? __________________ Rest my eyes from the world. This dying place, it's so absurd.

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6th February 2006, 06:29 PM	#2
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi Ahmad_tbp, The tone circuit is designed to work at line levels. You need to provide gain as a tone control circuit can only drop the signal level. I would expect you to get increased noise doing this. Can you post the schematic of your buffer? -Chris

7th February 2006, 02:02 AM	#4
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi Ahmad_tbp, Okay, the buffer is close to unity gain. You need to have at least as much gain in the buffer as you lose in the network. You need a quiet buffer / amplifier stage to work at those levels. Think dynamic mic level quiet. -Chris

7th February 2006, 01:54 PM	#6
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi Ahmad, A preamp would be the buffer. If you design it to just compensate for the loss, you can plug it into the same input. This tone stack is intended to go after amplification and mixing of channels. You may be trading some noise for external tone controls. -Chris

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