Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: LooseChange on July 24, 2010, 10:29:41 am
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I don't know enough history on these things... Is this a replacement or some kind of factory job? Does it seem appropriate for this amp? Seems a bit small for 2 x 5881's cooking at 475v. Right now it's got some issues and I read the Plates at 350v. (Yup,needs work).
Thanks!
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That can't be stock. Yeah, it isn't rated for 40+ Watts but I would not worry about it. It will play mids and highs fine at 40 Watts but make ugly-waves in the bottom octave of guitar; that's very common for guitar amps.
Your low voltage is probably not here.
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Weber sells a OPT for the 1484 if your are interested in replacing that 18w.
Punky
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Did a cap job and all the voltages popped right back up to where they are supposed to be.
The reverb on this one seems to be gone. I'm leaning toward the tank. The circuits all seem okay.
One question... Should there be any voltage on pin 7 of the phase inverter (6CG7)?? I'm reading 0.5v dc. The amp seems a bit "farty" and this may be why.
Thanks!
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If you have DC voltage on pin 7, C12 coupling cap is probably leaky.
Punky
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Yup. Changed that out and sounds a bit better. Thanks!
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That OT is not stock for sure. It sounds like you're getting the amp to behave though so no big deal there. The reverb sux...don't bother with it honestly. I have a completely stock 1484 here that everything works.....when I got it it was in pieces from a couple different amps, one of which had water damage. Well when I got it all together in one working chassis, I didn't even care if the reverb was going to work or not......it does, but it doesn't really matter much in the grand scheme of things. An EH Holy Grail reverb sounds better unless you're going specifically for the cheesy effect nature that this reverb can do.
On my brother's 1484, I modded the piss out of the amp and I added a Fender reverb tank and circuit. Had to build a new head box and completely modify the amp otherwise.....and it sounds great now, but was a ton of work. I learned a lot so I won't say I wouldn't do it again, but it was a PITA to do and took a long time. Who's to say I might not have worked on something else and learned more? Anyway, the summary is the reverb sux...don't bother if it doesn't want to work. :)
greg