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Transformer availability


michael kaus
Posted on Sunday, January 23, 2005 - 04:57 pm:   

In our continuing saga of MM tranny's, this was just posted on the Weber board::::

Just in case anyone's interested... I got a flyer from Mojo Musical Supply (www.mojotone.com) advertising Music Man replacement transformers; 4 OT models (3-65, 5-75, 8-50, 4-130), 2 PT's (100-65-120 and 200-130-120), and 4 NOS PT's (7-50-120, 9-80-120, 9-80-250, 100-65-250). Prices range from $40 to $100.
John Drexler
Posted on Sunday, January 23, 2005 - 07:29 pm:   

Yes. I just bought a new 3-65 from them (still have not received the one ordered from Handwound) and paid $75 for it. I installed it and it is GREAT! What a difference it made in my amp! Heyboer is the winder on these...I talked to Phil there, and he has specs on almost all of the OT's used by MM. Good news indeed! By the way, Mojo Music Supply's contact is Andy Turner, and he had my unit on the shelf and it shipped the same day. Got it 3 days later, UPS ground. $7 for shipping 5 lbs.
Steve Kennedy (admin)
Posted on Monday, February 14, 2005 - 05:06 pm:   

Very Cool! Mojo had purchased a bunch of NOS MM transformers from someone who bought them at the final bankruptcy sale in 1985, but they were gone in a very short period of time. Perhaps that spurred them on to having copies made?


Posted on Tuesday, February 15, 2005 - 10:15 am:   

Can someone help with a correct output tranny ID? I have a MM 112-RP 100Watts! The schematic shows two numbers which I assume one is for the 65 watt version and the other for the 100 watt version. The numbers are 5-75 and then 4-130 respectively. Now I think the 4-130 is what I need right (if MOJO can find/make me one)? Check out the MM schematic link, page 5 of 7 http://www.ernieball.com/mmonline/techin fo/old_amps/2165-rp_&_2100-rp.pdf
any help?
Ted from Ohio
John Drexler
Posted on Wednesday, February 16, 2005 - 03:41 pm:   

For Steve: Cool, indeed! Andy told me that when he ran out of the OT's, he saved one of each and had Heyboer spec them for future windings. Smart man. As I said, mine is terrific and Andy said they are even better than the original MM OT's made mostly by Schumacher or someone. He said he still has some NOS parts for MM amps, but didn't specify which ones...but it'd be a good "first stop" when looking for something for an MM amp...especially chassis stuff. By the way, a nice fellow in Canada named Don Hunka bought the 5-75 and put it in a down MM amp. I took it out of my 65-112 and I assume it has worked perfectly for him as I haven't heard anything contrariwise and he posted a good rating for me on Ebay...so another MM is resurrected from the dead!
Ed Goforth (ed_goforth)
Username: ed_goforth

Registered: 06-2006
Posted on Monday, October 12, 2009 - 11:29 am:   

Hi, anyone have a HD-150 power transformer for sale? Or know where I can get one? I checked the Mojotone site, but they did not list a HD-150, only 130, 100, 75. 65, and 50 watt models. Any help appreciated! I am getting very low "Hi" voltage readings, 450 in Hi mode, 250 vdc in Low mode, with "NO power tubes installed". The voltage drops further to 350-"Hi" and 150 "low" with the tubes loaded... Power supply caps replaced about a year ago.
Ed Goforth
Daniel Hall (dan_hall)
Username: dan_hall

Registered: 01-2009
Posted on Tuesday, October 20, 2009 - 10:47 am:   

I know you know your stuff, Ed, but are you sure it's the trafo? Just thinking out loud here: could it be simply a shorted HV power supply diode in the voltage doubler? I simulated the MM tranny voltages in Duncan's PSUD2 w/ simple half wave rectification (a single diode), and they look alot like yours. Now, I'm not sure that's likely or even possible, but might be worth a look.

Good luck,