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previous: frankenstein Bruce: I was under the impression t... -- 3/19/2002 5:19 AM view thread

Re: need more headroom

3/19/2002 6:09 AM
Bruce /Mission Amps
Re: need more headroom
If you are happy with the way it sounds, then leave it that way.  
Improvement? Well, the large value dropping resistor is there to isolate the plate and screen/preamp filter caps and lower the voltage to the screens and lower the plate voltages of the preamp tubes.  
Your choke does make for a better filtered supply but IMHO, it's overkill in this little amp and it could make the amp sounds and play differently.  
It's obvious that the power tubes idle hotter because of the extra screen voltage and the preamp tubes are probably running higher voltages too.  
None of that is bad, just different.  
If you take the lead that feeds your 470 ohm screen resistors with B+, (from the second filter cap and the B+ return from the choke), and insert a 2W, 2K to 5K resistor there, you'll drop the screen voltage a little more and the tubes will run cooler.  
Will it sound different? Maybe, maybe not much.  
Your 470 ohm screen resistors are mildly needed with your circuit (choke) but not with the single 5k resistor in the stock 5E3.  
 
Bruce

 
Replies:
frankenstein Bruce: Understood. Why not just pu... -- 3/19/2002 3:07 PM
woodyc Bruce,Re: "sound different,... -- 3/19/2002 9:01 PM