Marvel Posted December 2, 2004 Share Posted December 2, 2004 Thanks Craig. It figures they would be different. Quote Link to comment Share on other sites More sharing options...
sunnysal Posted December 2, 2004 Share Posted December 2, 2004 you can find new output trannies but not power trannies out there. you have to, as craig said, find a parts mkIV to get power trannies. if the power trannie is blown send it back. MHO, tony Quote Link to comment Share on other sites More sharing options...
sunnysal Posted December 2, 2004 Share Posted December 2, 2004 Fini, you may like this one...a st-35 with el84 tubes...yummy... if it goes for less than $250 I think you would love it... http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=5735716447&fromMakeTrack=true regards, tony Quote Link to comment Share on other sites More sharing options...
fini Posted December 2, 2004 Author Share Posted December 2, 2004 Amp #1 with cage Quote Link to comment Share on other sites More sharing options...
fini Posted December 2, 2004 Author Share Posted December 2, 2004 Amp #2 with cage Quote Link to comment Share on other sites More sharing options...
fini Posted December 2, 2004 Author Share Posted December 2, 2004 Top of chassis: Good one on top Quote Link to comment Share on other sites More sharing options...
fini Posted December 2, 2004 Author Share Posted December 2, 2004 Driver boards close-up. Good one on top Quote Link to comment Share on other sites More sharing options...
fini Posted December 2, 2004 Author Share Posted December 2, 2004 Tangled mess underneath . Good one on top. Notice bad choke in bad amp. Quote Link to comment Share on other sites More sharing options...
fini Posted December 2, 2004 Author Share Posted December 2, 2004 Another shot underneath. Good one on left. Quote Link to comment Share on other sites More sharing options...
sfogg Posted December 2, 2004 Share Posted December 2, 2004 For the power transformer it may be possible to get it rewound if needed. There are companies that do that. Shawn Quote Link to comment Share on other sites More sharing options...
fini Posted December 2, 2004 Author Share Posted December 2, 2004 Shawn, Do you have links, or recommendations? Any idea of the cost of rewinding a transformer? I am suspecting that might push the project out of the "bargain" range... Quote Link to comment Share on other sites More sharing options...
NOSValves Posted December 2, 2004 Share Posted December 2, 2004 Fini, Well there in descent cosmetic shape ! Really those are not tangle messes I've seen much worse. You may be able to get the power transformers rewound but it will probably be just as cheap to have 2 new ones made just send them both to Heybour trasnformer here in Michigan and plan on spending about $200 of so. The power transformer in the "good" amp looks like its had some excess stress put on it also. The choke is no big deal $10 for Triode. What you need to do before you go any further is to determain that the output iron is in good shape. I would proceed as follows mess with the so called working amplifier and get it working. Then switch out the output transformer from the bad amplifier into the working amplifier and see if it indeed works properly. You can do basic tests with a common meter to output transformers but nothing is 100% until the full voltage and load is present. I know this all sounds like a pain but no sense doing a thing until you know what you have. Craig Quote Link to comment Share on other sites More sharing options...
sfogg Posted December 2, 2004 Share Posted December 2, 2004 You might also want to check with this guy: http://www.tubes4hifi.com/MK34.htm He sells a MKIV modded clone. The power transformers he uses might be suitable though I'd probably replace both of them to make sure the voltages matched. You could probably sell your good one pretty easily on ebay if needed. Shawn (Note: This guys site has some pretty inexpensive kits available but it rubs me the wrong way. He reviewed a bunch of St-70 modifications boards back in Glass Audio and of course prefered his own version... but never mentioned it was his version in the article....) Quote Link to comment Share on other sites More sharing options...
NOSValves Posted December 2, 2004 Share Posted December 2, 2004 His boards are just fine but he told me he sources his transformers from the "Handwound transformer" trust me these transformers are complete junk. I had the place make me a set for Mark III's over a year ago. I still have them here if some one wants them they can have them for free !! I'm out $300 bucks on that deal completely worthless junk the power transformers vibrated like my wife favortie toy and the outputs had horrible frequecy response. Do a search on AA and you will find some comments about the Handwound garbage. I can't believe Roy uses the garbage myself. Craig Quote Link to comment Share on other sites More sharing options...
fini Posted December 2, 2004 Author Share Posted December 2, 2004 I took the bad amp over to a local gee-tar amp builder (K&M Analog Designs, here's their website: http://www.two-rock.com/), and they were kind enough to test it, and yup, bad trannie. This is beginning to seem like a bigger can of worms than I'd hoped to open. I am leaning toward taking them back. Quote Link to comment Share on other sites More sharing options...
Painful Reality Posted December 2, 2004 Share Posted December 2, 2004 ---------------- On 12/2/2004 5:21:20 PM fini wrote: I took the bad amp over to a local gee-tar amp builder (K&M Analog Designs, here's their website: http://www.two-rock.com/), and they were kind enough to test it, and yup, bad trannie. This is beginning to seem like a bigger can of worms than I'd hoped to open. I am leaning toward taking them back. ---------------- Wait a bit before taking this decision. I'm looking for a link to a transformer winder that do sell copies of old transformers design. I now I have it somewhere and I'll find it. He sells copies of output transformers and power transformers from Eico, Ampeg, Fender, Dyna, etc. His price are surprisingly good and apparently his work his top notch. For exemple, I was quoted 80 USD for a Eico HF-81 power transformer replacement unit. Quote Link to comment Share on other sites More sharing options...
fini Posted December 2, 2004 Author Share Posted December 2, 2004 Okie-dokie. I'm in a holding pattern... So, if I were to get a couple of matching power transformers, I wonder what I could get for the good one? Actually, I am not 100% positive the other IS good. It doesn't blow a 2a fuse, anyway. Quote Link to comment Share on other sites More sharing options...
Painful Reality Posted December 2, 2004 Share Posted December 2, 2004 ...still looking... ...Hold on! Quote Link to comment Share on other sites More sharing options...
NOSValves Posted December 2, 2004 Share Posted December 2, 2004 Its Heybour transformer here in Michigan but still the the output transformers should be tested before he starts spending cash! Take a look at the so called "good" amps power transformer in his pictures. Looks like its gotten pretty hot to me. Craig Quote Link to comment Share on other sites More sharing options...
binkt Posted December 2, 2004 Share Posted December 2, 2004 When you find out what you can get for your good trans, I have a spare MKIV power thransformer and would be pleased to share. Also See Curcio for sure he provides the BEST design and sound performance with truth and service. I could not resist trying to help with your struggle, so I registered. binkt Quote Link to comment Share on other sites More sharing options...
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