Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: toomanyslurpees on November 11, 2011, 02:12:33 pm
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Greetings, I haven't been playing with tube amps much lately but decided I have to get this YGM-3 I bought last year up and running. It's working fine other than a zap I got while messing around running it in stereo while touching both amps made me think it's time for that three prong cord before I play much more with it.... put a weber Alnico speaker in it which is a huge upgrade to the marsland. I'm getting around to ordering up the electrolytics to re cap it, there's two 64uF, 250V caps in the bias supply which I'm having trouble finding without navigating the increadible non-user friendly electronics supply sites. Thought I'd see what you guys would do? How far can I stray from this value or would it be practical to consider a series or parallel combination to make up for it?
btw; I have an empty hole where the ground switch was, any thoughts on a worthy mod to fill it up? what would an adjustable NFB sound like in this amp? Maybe just a plastic cap and leave it be?
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On schematic , I see C29 , a 64 MFD 64 volts, you can put a 100 MFD 75 volts. Higher cap will keep voltage with less AC on the EL84 grid = less noise. There are only one, not two
The other capacitor is C28, a 8 MFD 250 volts, put a 8 MFD 450 ( Sprague Atom ) volts avalaible at Antiques electronics supply
http://www.tubesandmore.com/ (http://www.tubesandmore.com/)
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Ha, look at that, it pays to look a little closer, the two caps look identical, I read 250V off one, 64uF off the other and never looked close enough to the schematic... Out of all the forums I'm on (bassists, model airplane nerd, aviation buffs) this one has the most members who really know their stuff, so it's not hard to look like a dope, but sometimes I just make it all that much easier.... Thanks!
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Go to the very top-left of this page and click on "Capacitors (http://www.hoffmanamps.com/MyStore/catalog/parts4.htm)".
100uf 100 volt
Replaces the 70uf and 80uf bias caps in later Fenders
Price each = $1.50
8uf 450 volt
sprague atom cap
Price each = $4.10
You will get charged actual shipping (no 4X oversize carton) and it will be delivered really-quick.