Ive been wanting to tune the resonance knob on my amp. My amp has a 47k nfb resistor hooked up to the 8 ohm impedance selector switch. Right know im running a 1M pot with a .0068uf cap. Its a little too boomy, i think the frequencies its giving me are too low. How can i raise those?
Smaller or bigger cap? I believe bigger would work because its the opposite since its in the feedback loop am i correct? I always seem to get mixed up dealing with the feedback loops.
Resonance or depth pot capacitor values
Moderators: pompeiisneaks, Colossal
Re: Resonance or depth pot capacitor values
Larger is correct to pass more low end. Selecting feedback components for control of parasitics (in a poor design), or high end response works well. Low frequencies are perhaps better controlled with lower values of coupling and cathode bypass caps. Reducing overall feedback at the same time can benefit tone.
Tube junkie that aspires to become a tri-state bidirectional buss driver.
Re: Resonance or depth pot capacitor values
Thanks, i want to try a .0047uf but dont have one at the moment. I will try the .0022 i have. I think that will boost less lows which is what im looking for. Thanks
Re: Resonance or depth pot capacitor values
How does the amp sound without the resonance and presence circuits, just flat NFB, or no NFB? How's the low frequency response? Sometimes it helps to cut bass earlier in the signal and use the 'resonance' to fill the sound back out. Many high gain amps seem to do this to prevent bass flub, without thinning the sound out too much.
It's true i've lost my marbles and i cant remember where i put them
Re: Resonance or depth pot capacitor values
I changed it to the .0022 which i like a lot better, more percussive and less boomy.. The .0068 was just too much for this particular amp I believe. It already has a good amount of low end with out it.
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Xander8280
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- Joined: Wed Apr 30, 2014 8:18 am
Re: Resonance or depth pot capacitor values
In a 50W head I recently built with quite a bit of feedback (typical Marshall output stage with 33k from 16Ohm tap). With a DPDT (ON/ON/ON) switch I've got the resonance cap value switchable: 14.3nF/4.3nF/1nF.
1nF - starts to exit the resonance range (midrange boost)
4.3nF - where I tend to leave it
14.3nF - very much just sub lows
NOTE: The preamp in this head has a lot of low end shelved off between each gain stage, with the resonance control minimized the amp sounds weak.
1nF - starts to exit the resonance range (midrange boost)
4.3nF - where I tend to leave it
14.3nF - very much just sub lows
NOTE: The preamp in this head has a lot of low end shelved off between each gain stage, with the resonance control minimized the amp sounds weak.