Effects loop for SV20ish clone

audiosalvage

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Hello. I have a newly built 1987 plexi circuit which is cathode biased. I'm very pleased with the sound, but I'd really love to add my reverb and delay pedals. Using them in front sounds terrible. I'm currently using an attenuator and experimented with running the LINE out into the reverb and then into a second amp. Sounds okay with reverb but the delay sound like crap. I dug into the secret sv20 schematic and am attempting to replicate their FX loop section. It does however require a 9v source, how do I get that from my amp? I have the 275-0-275 PT with 6.3v heater taps.
Does anyone have ideas or suggestions?
 

Gene Ballzz

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Hello. I have a newly built 1987 plexi circuit which is cathode biased. I'm very pleased with the sound, but I'd really love to add my reverb and delay pedals. Using them in front sounds terrible. I'm currently using an attenuator and experimented with running the LINE out into the reverb and then into a second amp. Sounds okay with reverb but the delay sound like crap. I dug into the secret sv20 schematic and am attempting to replicate their FX loop section. It does however require a 9v source, how do I get that from my amp? I have the 275-0-275 PT with 6.3v heater taps.
Does anyone have ideas or suggestions?

Look into an Ultimate Effects Loop from Granger amps. I'd suggest a Metro Zero Loss, but I believe the Granger will run well on lower voltage than the Metro. I've read comments from techs that the worst part of the Studio Series amps is the low voltage powered effects loop! The Granger works well, with some nice features.


Just Loopin'
Gene
 

Jason deBroux

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where did you find the SV20 schematic!?
Hello. I have a newly built 1987 plexi circuit which is cathode biased. I'm very pleased with the sound, but I'd really love to add my reverb and delay pedals. Using them in front sounds terrible. I'm currently using an attenuator and experimented with running the LINE out into the reverb and then into a second amp. Sounds okay with reverb but the delay sound like crap. I dug into the secret sv20 schematic and am attempting to replicate their FX loop section. It does however require a 9v source, how do I get that from my amp? I have the 275-0-275 PT with 6.3v heater taps.
Does anyone have ideas or suggestions?
f
 

Gene Ballzz

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where did you find the SV20 schematic!?

f


That is NOT a real SV20 schematic! It is a re-draw from a Super Lead that has had values, etc. changed and it was done by a guy who called himself and labeled them as drawn by Hugh Jorgan (Huge Organ) :rolleyes: and there are errors galore. The real Marshall drawings are available in pdf format, in post #1 of this thread:


If you want them, you should download and save them quickly, as Marshall will likely make the forum take them down, sometime soon!
Just Sayin'
Gene
 

Dixierocker

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Take a look at Trinity Amps Tube Effects Loop.
This series Fx Loop utilizes a 6N17B sub-miniature military-grade, dual-triode vacuum tube with Dumble style Local Negative Feedback for low distortion, flat frequency response and tonal transparency. It employs high voltage, has zero-loss, is built on a PCB and includes an optional true-bypass switch.
You an Find it here: Its an easy install as well!
 

jackfalbo

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i just added two normally closed 1/4" jacks in between the phase inverter and the output section. it is not buffered but so far has worked fine with
my effects pedals and tube reverb unit. the amp is a 2203 clone
 

audiosalvage

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i just added two normally closed 1/4" jacks in between the phase inverter and the output section. it is not buffered but so far has worked fine with
my effects pedals and tube reverb unit. the amp is a 2203 clone
Worth a try I guess
 

audiosalvage

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I'm looking at the lnd150 based effects loop and wondering why some have zeners and some don't. Why is this
 
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