sheltie dave Posted June 18, 2009 Share Posted June 18, 2009 Cos I picked one up, and don't have a solid grasp of what to do with these controls.... It is from 1958, and was reviewed in Audio. Quote Link to comment Share on other sites More sharing options...
JL Sargent Posted June 18, 2009 Share Posted June 18, 2009 What's the tube compliment? Have you tried it? Quote Link to comment Share on other sites More sharing options...
sheltie dave Posted June 18, 2009 Author Share Posted June 18, 2009 It is a push pull 6BQ5, 5AR4 rectifier, 5 12AX7s, and of course I have not tried it. That is the reason for my question [*-)] It is far too nice to fry because I can't have a little patience. There must be some gray haired eminence around - I hope. Quote Link to comment Share on other sites More sharing options...
mike stehr Posted June 18, 2009 Share Posted June 18, 2009 Cos I picked one up, and don't have a solid grasp of what to do with these controls.... It is from 1958, and was reviewed in Audio. Does that make it special? Maybe it's some sort of balance or bias check, and uses the tuning eye for a indicator. I like the left and right mono thing the amp has going. Does it have some decent sized iron? Quote Link to comment Share on other sites More sharing options...
sheltie dave Posted June 18, 2009 Author Share Posted June 18, 2009 Mike, it has Todd transformers, and evidently can be run either as a bridged mono, or stereo at 20 wpc. Interstage Tranny raves about it (and the Todd transformers)on AA, but I have yet to find anyone else who knows about it, and Interstage blocks all e-mail. The rectifier is a metal based Mullard GZ34, and the original outputs were Mullard as well, tho there is only one left. Having a review in Audio put it at a level similar to the Marantz and McIntosh of the day, and also means someone probably still has that issue, and the article would help immensely with the calibration, slector switch, tuning eye, and mono /stereo questions I have, along with the eq settings on the outboard controls. It is nice enough to wait for the EBay Sam's photofac I just picked up. I'm hoping Dr. Bill, Khorn 58, Larry, or one of the more knowledgable folk had one of these going way back. Maron, Bill, CaptnBob and my other local encyclopedias all come up dry for info on this. If it were not so exotic, I would have it on now. The wow! factor is quite high, with the walnut and brass cabinet presenting a stately design. Quote Link to comment Share on other sites More sharing options...
JL Sargent Posted June 18, 2009 Share Posted June 18, 2009 I'm no expert, but if it were mine... It'd be getting a slow wind up on a variac after a careful visual inspection and speaker hookup. Watching one come to life after a long silence is the best part of hunting up old tube gear IMHO. Quote Link to comment Share on other sites More sharing options...
ZAKO Posted June 19, 2009 Share Posted June 19, 2009 Keep a bucket of water ready in case of fire. Quote Link to comment Share on other sites More sharing options...
Moderators dtel Posted June 19, 2009 Moderators Share Posted June 19, 2009 Darn that's old as dirt, I was only 1 when it was made. I don't know about the water but I would tie a string on the power cord to unplug it without getting to close, just to be safe. [li] Quote Link to comment Share on other sites More sharing options...
jacksonbart Posted June 19, 2009 Share Posted June 19, 2009 I have a car you can buy too. Quote Link to comment Share on other sites More sharing options...
sheltie dave Posted June 19, 2009 Author Share Posted June 19, 2009 Is it stereo or mono, JB? Quote Link to comment Share on other sites More sharing options...
jacksonbart Posted June 19, 2009 Share Posted June 19, 2009 Not sure, but it handles very well. It makes so much down force that its glued to the ground, literally. Quote Link to comment Share on other sites More sharing options...
JL Sargent Posted June 19, 2009 Share Posted June 19, 2009 How does it sound? Quote Link to comment Share on other sites More sharing options...
sheltie dave Posted June 19, 2009 Author Share Posted June 19, 2009 It sounds quiet, like without any sound, until I get the tech manual and begin to understand the controls. I have already blown up one McIntosh amplifier from poor advice, and seen a Carver amp blown up previously from boneheaded operators. It will eventually sound great, judging from the sparse information available to be gleaned. I'll test the tubes, try to diagram a one line schematic, and wait for the Sams tech paper. Quote Link to comment Share on other sites More sharing options...
JL Sargent Posted June 19, 2009 Share Posted June 19, 2009 WOW, guess I've been lucky. But I haven't tried a Madison Fielding 320 yet. I'm sure some expert advice will be along shortly preventing you from letting the smoke out. Lets see a picture of the blown up Mac. How did that happen? Quote Link to comment Share on other sites More sharing options...
sheltie dave Posted June 19, 2009 Author Share Posted June 19, 2009 Had a freshly rebuilt Mac MC250, which has the mono/stereo switch. The stereo shop owner that rebuilt it told me the left channel was the "mono" channel, when in reality the knife switch is either stereo for both channels, or mono for both channels - it does not bridge in mono. I traded a friend for a Marantz 250 amp, and he sent the Mac to his son for use in driving a passive subwoofer. He went to bridge the Mac, ran it from the left channel only in mono, cranked it, and called his dad four minutes later....magic smoke gone, fuse blown and breaker tripped. Unhappy guts, unhappy output transformer, unhappy son and dad, unhappy me. McIntosh unhappy as well, but they sent out a free output transformer from the goodness of their thirty year out of warranty heart. So I go slow when I don't know. Quote Link to comment Share on other sites More sharing options...
seti Posted June 19, 2009 Share Posted June 19, 2009 Had a freshly rebuilt Mac MC250, which has the mono/stereo switch. The stereo shop owner that rebuilt it told me the left channel was the "mono" channel, when in reality the knife switch is either stereo for both channels, or mono for both channels - it does not bridge in mono. I traded a friend for a Marantz 250 amp, and he sent the Mac to his son for use in driving a passive subwoofer. He went to bridge the Mac, ran it from the left channel only in mono, cranked it, and called his dad four minutes later....magic smoke gone, fuse blown and breaker tripped. Unhappy guts, unhappy output transformer, unhappy son and dad, unhappy me. McIntosh unhappy as well, but they sent out a free output transformer from the goodness of their thirty year out of warranty heart. So I go slow when I don't know. WOW they sent a transformer for a 30yr amp. Amazing. Quote Link to comment Share on other sites More sharing options...
sheltie dave Posted June 19, 2009 Author Share Posted June 19, 2009 I was a little surprised by McIntosh, Seti, but they tend to take a long term view of customer relationships, and and how to keep people happy when an authorized repair facility puts out bad info. I opened the hood on the Madison, and the 51 year old Good Alls look like...51 year old Goodalls. Yuch! All four 400 V Goodalls are covered with sweated wax, and bulging. It wouldn't be long before they went down, possibly cascading through the output tubes. There is good reason these amps should get a thorough inspection and replacement of the out of tolerance parts at a bare minimum. Quote Link to comment Share on other sites More sharing options...
bkrop Posted June 19, 2009 Share Posted June 19, 2009 Those tube positions are all labeled with valve (european) number, maybe try to look for european manufacturers... p.s. get an ABC fire extinguisher, electrical wood and maybe oil will be involved;) Quote Link to comment Share on other sites More sharing options...
JL Sargent Posted June 19, 2009 Share Posted June 19, 2009 The top side is pretty. Like you say, the bottom side certainly needs some attention. Its a neat amp. Interesting how you can choose the equalization standard. Quote Link to comment Share on other sites More sharing options...
Leslie Young Posted August 31, 2011 Share Posted August 31, 2011 Hello Sheltie Dave: I am owner of a Madison Fielding 320 amplifier in great condition. My parents were the original owners. I am attempting to fix a value on it and wondered how much you paid for yours. My understanding from the current Madison Fielding company (different owners than the past), is that the company was in existence only 5 years, til the early 1960s, in Brooklyn. These amps are rare, really hard to find now. I don't know if this is because few were made, or most of them were fried or broken and thrown away, or people just love them and hang onto them. But I can't find any information on what they are selling for. Any help is appreciated! I also have a set of Supersonic wood housing stereo speakers from 1959, gorgeous. Not sure if I want to keep the amp and speakers, depends on the value and if it is destined to go up in the future. Quote Link to comment Share on other sites More sharing options...
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