Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: gtrbryan on November 30, 2016, 09:54:51 am
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I have an old, 1960's Custom Kraft Model 880 amp. This amp is Valco made (I think) and very similar to the more common Supro Corsicca s6622. It has the cardboard reverb tank that doesn't do the greatest job. I would like to try a new tank. Any suggestions on values? I came across the page on the internet where an accoutronics tank was used, but I have no idea if this is correct. http://www.smpartizan.com/?page_id=989 (http://www.smpartizan.com/?page_id=989) The Supro schematic which I think is very close to the Custom Kraft except for an added tone control is at http://el34world.com/charts/Schematics/files/supro/supro_s6622.pdf. (http://el34world.com/charts/Schematics/files/supro/supro_s6622.pdf)
Is there any way to test primary/secondary impedance? I would think I just need to get close. Thanks for any assistance.
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I have no idea if this is correct
That tank will work in that Supro amp. Can't say about your amp yet.
Is there any way to test primary/secondary impedance?
Disconnect the tank. Measure the input resistance. Measure the output resistance. Compare to the table on page 4 of the attached pdf...
I would suggest you use a long tank (4xxxxxxx) rather than a short tank (8xxxxxxxx) if it will fit your cab.
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When I measure, should I measure resistance from tip to ground on each side of reverb tank?
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There are two wires that come from the input transducer. Same with the output transducer. You want to measure resistance between these wires. If they connect to an RCA jack just measure from the tip to the shell of the jack. The shell may or may not be isolated from the chassis.