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Need help w/ Master Volume on 5E3


 
3/18/2000 5:12 PM
joe Z
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Need help w/ Master Volume on 5E3
 
Last night I added a temporary master volume control to my 5E3 clone by connecting a 1meg audio pot to the point where the the pair of 220k resistors meet the .1uf caps that feed the power tubes.  
 
Right off I noticed a problem with the taper of the control- by 3-4 it is fully up. Is this just a bad taper?  
 
Are there any other components I should change. Although I lost the print out of a previous post, I remember Bruce mentioning changing those .1uf caps to .068 for greater clarity. I enjoy playing the deluxe clean, the MV trick was just an attempt to add some flexibilty while home recording. In other words, I don't want to screw up the tone. Thanks. Joe
 
3/18/2000 10:39 PM
Steve A.
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Cross-line MV- Spitfire cloners help out please!
Joe:  
 
    I think that Bruce Collins knows more about the tweed Deluxes than Leo himself so maybe he will jump in here... (I was going to insert a thread I had saved with a lot of tips from him- but it was about the Princetons- sorry!)  
 
    It sounds like you are using a "cross-line" master volume. You might try a linear taper pot. You have it wired up like a variable resistor- right? Which "side" of the pot did you use? I believe that when used as a variable resistor, one side would have a reverse audio taper... Do you have full volume at 0 or 10?  
 
    The Spitfire used a similar MV pot so maybe someone who built one of those can chime in...  
 
Steve Ahola
 
3/18/2000 11:00 PM
Trace
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Re: Need help w/ Master Volume on 5E3
Joe Z;  
 
Did you try using a 250K dual ganged pot in place of those two 220K resistors? This might sound a might better in a 5E3 than the 1meg...or more natural as far as recording in concerned.  
 
Bruce will most likely have some killer input regarding these amps. He's worked on a ton of these! :)  
 
Trace
 
3/19/2000 5:50 AM
joe Z
email

Trace, I added the 1meg pot To the 220k resistors, not in place of, hope I am understanding you correctly. I followed the diagram in the "trainwreck pages" - Master Volume #3. This seems to be the identical circuit used both in the Spitfire and Lightning, not to say your idea won't sound better- "natural sounding" is in fact the operative word here.  
 
Steve, I used both the center and left lug of the pot, looking at it from the back. Thanks for the input thus far. Joe
 
3/19/2000 6:46 AM
Steve A.
email

Joe:  
 
I used both the center and left lug of the pot, looking at it from the back.  
 
    You might check the articles at AMZ and GeoFEX to see if I got this right, but if you were to add a 1M resistor between those terminals it should create a 500k pot with a "super audio" taper (which should work better for you). As pointed out in prior threads here such an arrangement does give the source (namely the PI stages) an impedance which changes as you adjust the pot. Maybe someone else can explain the effects of such changes in impedance... as that stuff is way over my head!  
 
Steve Ahola
 
3/19/2000 1:55 PM
dave rutherford
email

Hi Joe!  
 
Center and left lugs should be correct since thas how it is on my spitfire clone. Maybe it doesn't function the same due to the different type of phase inverter.  
 
Dave Rutherford  
 
3/19/2000 6:18 PM
Trace
email

quote:
"Trace, I added the 1meg pot To the 220k resistors, not in place of, hope I am understanding you correctly."
 
 
The master volume I was refering to is the #2 MV in that book. I've used this for recording and it's really nice. With the MV on "10" the amp is stock.  
 
 
Trace  
 
 
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