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previous: Fj on my HOMEBREW 5E3 there are 3 1 ME... -- 10/22/1999 11:05 AM

Re: pots in 5E3 ...

10/23/1999 4:45 AM
Bruce	Re: pots in 5E3 ... Frank, loose the .005uF cap for a second re think the treble cap part of the tweed tone control. It is just like a brite cap over a volume control but it has a 1M variable resistor in series with it. As you move the tone control's wiper closer to the volume control wiper, there is more of the previous stage's signal exposed to the 500pF cap and consequently to the volume control wiper too. That makes it sound brighter and brighter, as long as the volume control is NOT on full blast. When you move the tone control wiper further away from the volume control pot's wiper, (towards what you think of as more bass), you are attenuating more and more of the previous stage's signal by going through more of the tone control's pot on it's way to that same 500pF cap. That attenuates what AC can get to and through the 500pF cap on it's way to the volume control wiper so that makes it sound less bright, or duller, which starts fooling your brain into thinking it's getting more bassier. The signal is now starting to split in the tone control pot and some is going to the other side. When the tone pot wiper is turned even further from the volume control wiper, more of the signal is shunted to ground by the .005uF cap. That .005uF cap is a mid-treble cap too, only this time it is sending the brighter signal to ground so the amp sounds even less bright! Again fooling your brain into thinking less bright must mean more bass! Smoke and mirrors tone control! You can start by lessening the value of the 500pF cap to 360pF and seeing if you like that. Most guys I tweak these amps for, like them brighter not more bassy! These thing suffer form way too much bass fart. I have used a 680pF cap with good results. Messing with the values will change the response curve quite a bit but there really is NO easy way to make it have more bass by changing the tone stack cap values. That's a different trick. Bruce

10/23/1999 4:45 AM

Bruce

Re: pots in 5E3 ...

Frank, loose the .005uF cap for a second re think the treble cap part of the tweed tone control.
It is just like a brite cap over a volume control but it has a 1M variable resistor in series with it.
As you move the tone control's wiper closer to the volume control wiper, there is more of the previous stage's signal exposed to the 500pF cap and consequently to the volume control wiper too.
That makes it sound brighter and brighter, as long as the volume control is NOT on full blast.
When you move the tone control wiper further away from the volume control pot's wiper, (towards what you think of as more bass), you are attenuating more and more of the previous stage's signal by going through more of the tone control's pot on it's way to that same 500pF cap.
That attenuates what AC can get to and through the 500pF cap on it's way to the volume control wiper so that makes it sound less bright, or duller, which starts fooling your brain into thinking it's getting more bassier.
The signal is now starting to split in the tone control pot and some is going to the other side.
When the tone pot wiper is turned even further from the volume control wiper, more of the signal is shunted to ground by the .005uF cap.
That .005uF cap is a mid-treble cap too, only this time it is sending the brighter signal to ground so the amp sounds even less bright! Again fooling your brain into thinking less bright must mean more bass!
Smoke and mirrors tone control!
You can start by lessening the value of the 500pF cap to 360pF and seeing if you like that.
Most guys I tweak these amps for, like them brighter not more bassy! These thing suffer form way too much bass fart.
I have used a 680pF cap with good results.
Messing with the values will change the response curve quite a bit but there really is NO easy way to make it have more bass by changing the tone stack cap values.
That's a different trick.

Bruce

Replies:

Fj thanx Bruce, for now, I've employed... -- 10/23/1999 12:55 PM
Jim S. Reducing excessive bass in 5E3 -- 10/23/1999 3:54 PM