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Question for dem folks who know about dem maplifiers
http://maplifiers.net/forum/viewtopic.php?f=7&t=2680		 Page 1 of 1
Author:  Unstrung [ Tue Nov 27, 2012 11:25 pm ]
Post subject:  Question for dem folks who know about dem maplifiers
Chris, teh Bleeding, Zozobora...

I have an old combo amp, basically a Vibro Champ clone. It sounded lovely. However it now hums... very loudly, when the amp is fully powered up. I think it is probably the filter cap, but I'm not sure yet. If it is, would the filters caps they use in Vibro Champs be suitable? This amp has the one 6V6, a 12ax7 in the preamp and a 12ax7, but unlike the Fender it has a solid state rectifier.
Author:  chris_d [ Thu Nov 29, 2012 4:56 pm ]
Post subject:  Re: Question for dem folks who know about dem maplifiers
Yarr, should be good with vibrochamp type caps.

If you want, you could measure the B+ voltage(with care, it is prolly 300+ VDC) and simply buy caps rated for more volts than what you measure.

But i suspect that vibrochamp ones would be a proper volt spec. As a guess, you probably need at least 450v, possibly 500v, caps. If it is an exact copy of the vibrochamp, then the PT voltage can maybe run a bit higher than what in the modern era we might expect for a single ended 6V6 amp. :idk:
Author:  Zozobra [ Mon Dec 03, 2012 1:38 pm ]
Post subject:  Re: Question for dem folks who know about dem maplifiers
As said Chris said, make sure the caps are rated for the job. From the official ye olde schematic it specifies 450V rated caps for the filters so that would be the minimum. It uses fairly low capacitance anyway so 500V rated caps wouldn't hurt and should be cheap enough in those values. The SS recto also will result in higher voltages than a tube recto so if it uses the same PT it will be a bit higher. It also wont sag anywhere near as much but that can be modded in pretty easily.
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