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Tweaking has begun


 
9/24/2003 4:42 PM
Clint B
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Tweaking has begun
Hi all,  
 
I have begun tweaking my Tweady.  
 
I plan to only do one tweak at a time to be able to know what each tweak changes. My first and only tweak so far has been to change the 6v6's cathode bias cap from the 22uf to 4.7 uf. I'm pleased with this tweak. Results: The low e string farts much less than it did on the bottom few frets. This is the main reason for my tweaking. Another effect has been a better balance between the volume of the high e string and the b string. Before this mod the e string was noticeably lower volume than the b string. I at first thought the difference was in the guitar but other amps did not have this problem with this guitar.  
 
Results... It's a keeper. It tamed the wild farting bass AND balanced the top two strings volume. The amp doesn't overdrive as easily. Cost: A dollar or so. That's much cheaper than a new speaker.  
 
While in the amp I found and fixed another problem. The problem was a sharp humm that didn't respond to chopstickery. I finally traced it to an input jack which was not closing to ground with the plug out. A little careful bending and the problem is solved. Cost: $0  
 
Clint
 
9/24/2003 4:57 PM
Mike G.
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I changed my preamp tubes' cathode bypass caps to 4.7ufd, but left the output tubes' stock. Hmmm...perhaps I'll give it a try and see if I like it. I also changed out all my coupling caps as well to smaller values to get rid of what my ear told me was way too much bass response. That was a keeper in my opinion.  
Keep us posted on any other tweaks.
 
 
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9/24/2003 5:00 PM
Bruce /Mission Amps
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For what it's worth Clint, I like no more then 10uF anywhere on the eyelet board and .047uF caps to the volume pots.  
Bruce
 
9/24/2003 5:06 PM
Aaron
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weird! i noticed the same thing - my high e was WAY lower than the b. i also wondered if it was the pickup. i havent had any farting problems on low strings tho. still, this is definitely a mod i'm gonna do. thanks for the news. keep it coming :)  
 
-Aaron
 
9/24/2003 8:23 PM
Clint B
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Suggestions for the next tweak?  
 
My origional plan was to work any tweaks from the output end to the input. This may be just plain silly!  
I have a two more 4.7 uf caps I had planned to use for the preamp cathode resistor bypass caps. I also have three .047uf 630 v caps for the coupling caps and one of the volume caps.  
 
For my next tweak I'm thinking either the coupling caps or the preamp cathode bypass caps. Any recommendations?  
 
Clint
 
9/24/2003 6:37 PM
Aaron
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yup :)  
 
preamp cathode bypass caps! it's only the next logical step ;)  
 
-Aaron
 
9/25/2003 1:06 PM
Mike G.
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I replaced my caps as follows, and highly recommend it:  
Bright channel coupling cap to 0.022ufd.  
Normal channel coupling cap to 0.01ufd.  
Pre amp tube cathode bypass caps to 4.7ufd.  
6V6 coupling caps to 0.047ufd.  
 
I originally had the 0.01ufd on the Bright channel, but it took TOO much of the bass and lower midrange out. So I swapped the Bright and Normal channel caps.  
 
Mike G.
 
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