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Post subject: Re: 1978 Twin Reverb - Master Volume-------HELP
Posted: Tue Nov 25, 2014 7:23 pm
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Caps Pix - In my opinion these are new, they read in spec and even above.

http://i7.photobucket.com/albums/y286/6 ... hnhcf3.jpg


Update!! I was reading the pins in the wrong direction on V6!!!!!
Son of a #^$@$..............new readings

Pin 1 - 303
Pin 2 - 60
Pin 3 Tied to pin 8 - 102
Pin 4 Tied to pin 5 - ZERO
Pin 6 - 282
Pin 7 - 63
Pin 8 (again tied to pin 3) 102
Pin 9 - Zero

Also the speaker input jacks are open nice and wide.


Last edited by Ryan41018 on Tue Nov 25, 2014 7:40 pm, edited 1 time in total.

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Post subject: Re: 1978 Twin Reverb - Master Volume-------HELP
Posted: Tue Nov 25, 2014 7:33 pm
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Yeah, caps look fairly new. You can measure voltages at each cap node in the PSU and see if they correspond to the schematic (+/- 10-15%).


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Post subject: Re: 1978 Twin Reverb - Master Volume-------HELP
Posted: Tue Nov 25, 2014 9:26 pm
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Bias was set at 20MA - reset to 38 and now i got more power....is that possible?


:?: :?:


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Post subject: Re: 1978 Twin Reverb - Master Volume-------HELP
Posted: Tue Nov 25, 2014 9:31 pm
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No not more power. But, cleaner power for guitar amp use. At lower mA of idle bias, you force the tube into Class B or Class C operation. Which leads to much more crossover distortion. Very noticeable.

For most Fender blackface & silverface 6L6GC amps... 38-42mA idle bias is in the zone. The plate voltages usually run between 450 and 480VDC --- depending on health of PT and the power supply rectification & filtering.


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Post subject: Re: 1978 Twin Reverb - Master Volume-------HELP
Posted: Tue Nov 25, 2014 9:52 pm
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Definitely more head room but feels LOUDER


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Post subject: Re: 1978 Twin Reverb - Master Volume-------HELP
Posted: Wed Nov 26, 2014 2:36 am
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Rock Star
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Yeah. Cleaner power = more apparent power. When bass is cleaner, the amp tends to have more headroom "feel" to it.

Well, that was an easy fix. :D :mrgreen: :D


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