Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: smackoj on August 05, 2013, 07:21:26 am
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Greetings; one of the local 'junk' antique dealers has a Magnatone M10 he's trying to sell for 3 hundred. His ad says it's making noise and the speakers probably shot? Picture of the front looks like it's been cared for physically? Anybody know more about these amps and if it's worth a go for me to fix 'er up?
thanks, smacko jack
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I have a fully functional M10A that I would not sell for $300. I paid $200 five years ago. It needed a lot of work.
The M10 has an 8" and 3" speaker and uses a transistor for reverb recovery. M10A has a 12" speaker and is all tube (except for rectifier diodes). Do you know which amp the dealer has?
The ptp wiring is not easy to work on. Expect to replace a lot of drifted CC resistors and spend some time doing so if neatness counts. The 7189 tubes are expensive. Hopefully the four varistors are good.
If the amp is actually a M10A I can provide a lot of info. Here are a couple links for some good info...
http://www.magnatoneamps.com/M10.html (http://www.magnatoneamps.com/M10.html)
http://www.vibroworld.com/magnatone/archive.html (http://www.vibroworld.com/magnatone/archive.html)
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First time I visited the magnatoneamps.com site. Thank you Slucky for posting. I do know of a forum where you can ask questions and get info from their archives.
http://launch.dir.groups.yahoo.com/group/Magnatone-Valco?v=1&t=directory&ch=web&pub=groups&sec=dir&slk=5 (http://launch.dir.groups.yahoo.com/group/Magnatone-Valco?v=1&t=directory&ch=web&pub=groups&sec=dir&slk=5)
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I'm not sure if it's a 10 or 10A? The picture he posted only shows the front and I can't tell what spkr(s) it has? I'm gonna go over to his shop and have a look see. I will update later today or tomorrow.
thanks mucho, :icon_biggrin:
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I'm not sure if it's a 10 or 10A? The picture he posted only shows the front and I can't tell what spkr(s) it has? I'm gonna go over to his shop and have a look see. I will update later today or tomorrow.
The M10 has three control knobs per channel (vol,tone,contour switch), the M10A has four control knobs (vol,treb,bass,contour switch). Both have 2 vib. knobs, 1 reverb, and 1 power switch. So M10=10 knobs, M10A=12 knobs. Note that the M10 knobs are all in a single row, the M10A has a little diamond layout for each channel. See the pics on those site and it'll ring clear.
Also, the M10 has a gold motif (faceplate and grille-cloth, although the grille-cloth can be faded to a wheat like color), and M10A is usually, if not always, silver.
If you go check it out, bring an assortment of allen wrenches with you. there are two allen head screws on either side of the top. remove these and you can 'open the hood' revealing tubes, and circuit. on the circuit side, make sure the little circuit board isn't broken, and there should be a good assortment of caps including ceramics, chiefs, and blue molded caps Iif all the 'nice' caps have been replaced with cheap yellow mallory 150's, watch out. on the tube side, the original 7189As were GEs. make sure someone didn't just stick EL84s in it. all the preamp tubes are mullard (and maybe some GE or RCAs), and might have "Estey" screened on them.
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Wow, that's a bunch of good info guys! thanks
your description of the differences made it easy to figure out it is the M10 model.
here is a link:
http://lincoln.craigslist.org/msg/3911741335.html (http://lincoln.craigslist.org/msg/3911741335.html)
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If it is still available you best grab it fast if you can. It's worth $350.00 blown up and in pieces