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5E3 - Excessive Bass - *Almost there*

10/30/2004 7:54 PM
JP5E3 - Excessive Bass - *Almost there*
Just switched out all the .1uf Coupling Caps w/ .047s and the 22uf Cathode Bypass caps w/ 4.7uf caps.  
 
Results were lots more sparkle and significantly better clarity when distorted. One problem still remains however - the low E string still shakes the walls and gets more into bass guitar territory than I'd like.  
 
I'm running it through a Celestion Greenback in a 2x12 cab (with only the one speaker connected at the moment). I realize throwing the speaker in the narrow panel cab by itself will affect the frequency response but I've got another amp that doesn't exhibit the same "problem" through the same speaker/cab.  
 
I'd rather go lower on bypass caps because 1.) there are less of them 2.) they're less expensive and 3.) they're easier to come by.  
 
My understanding is that...  
 
Coupling caps form a high pass filter with the resistor/s that follow them resulting in the attenuation of progressively lower bass frequencies with lower value caps.  
 
Bypass caps work to keep the current flowing through the tubes steady, keeping the gain consistent and lowering the value of those caps will increase your treble response (more gain at higher frequencies) but doesn't really have an effect on the lowest frequencies that pass on through - in other words, you may get more or less treble but your bass is going to stay the same.  
 
By that logic (and someone please correct me if I'm off base here) I should really be concentrating on the coupling caps (trying yet lower values) versus the bypass caps if I'm happy with the treble response but simple want to raise the low frequency cutoff point.  
 
Yes, no, maybe?  
 
Where would you go if you were me? Coupling caps, bypass caps, try the speaker in the smaller cab, all of the above?  
 
If Coupling Caps - .022? .01? Just replace the 1st one or all 4?  
 
Thanks!!!  
 
John

 
Replies:
Bruce /Mission Amps Try this mod:Remove the shi... -- 10/31/2004 11:52 AM
23 IMHO it is better to go with .022s ... -- 10/31/2004 12:55 PM