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Musical Power Supplies, Inc.

Lake St Louis, MO 63367

 

 

Email: matt@musicalpowersupplies.com

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To check out our newest projects , click here for New Stuff.

MPS New Projects

Updates 08/08/2021-
We are still in the process of relocation from MO to TN.  Building being what it is these days we now expect to be moving in at the beginning of September and should have our equipment and component parts mid-month.  At that point we'll be able to start taking in custom build work again.  Our apologies for the delay.

A couple of recent updates: 

1- Mexican windings for OT33PP, OT42PP, OT19PP are on their way to us.  So when we can assemble/varnish again these will become another stock offering.  The OT20SE winding from the Mexico plant is being reviewed currently but looks good. 

2- Domestic USPS performance is getting better.  We'll probably remove all the dire warnings we have on EBay listings shortly as the FEDEX Smartpost shipping is typically 25 to 30% more expensive.   I may swap FEDEX back to primary choice in November......

At some point this year I'll see if I can't work up a spreadsheet of custom designs we've worked out in the past 15 years.  It may give some of you ideas for starting points.  I don't always know the applications involved, but where I do I'd drop that in.
Recent custom jobs include:

OT22PP-DYN-USA - Dynaco35 OT scaled up a size using EI 1-1/8 Lams (8K: 4/8ohm)
OT25SE-Special- EI-112 SE at 2K5/3K5/5K/7K to 8 ohms for tube swap amp
PT350M-TWD-USA- a basic 700Vct 130mA Tweed Deluxe PT in upright FM200 end bells
PT315.2-W145- a replacement PT for a Wurlizter 145 piano
OT43PP-DYN-M: scaled the Dynaco OT up to 85VA using EI 1-1/8 Lams (4K3: 4/8/16ohm)
PT260-Special-VJR: created a Valve JR replacement PT (120Vac mains x 260vac no-CT x 6.3A)
PT2R5 & PT7R5- filament PT's 120Vac mains x 2.5Vac(1.75A) & 7.5Vac(1.25A) for radio tubes
PT325P-Special: EI-1-1/4 Power Xfr 120Vac mains x 325-0-325V (180mA) x 6.3v(4A) x 5V(3A)
OT25SE-HiFi Special: A pair at 3K5 ohms (90mADC) x 8 Ohm  18VA- 5X interleaved.
OT10SE-UL-HiFi Special: pair of 4K5 ohm (UL taps) x 4/8 ohm (50mADC, 10VA) oversized core 
OT15SE-Special: Guitar OT at 3K: 4/8/16Ohms 75mADC on oversized EI-7/8 stack
PT250P-Special: EI-1-1/4 Power Xfr 120Vac mains x 250-0-250V (120mA) x 6.3v(4.9A) x 5V(1A
P
T250.1-USA-Special: a Power Xfmr for Pre-amps and 1 or 2 VA Guitar amps.  120Vac mains x        250-0-250(40mA) x 6.3V(1.5A).  Using the EI-7/8 x 1in 2-section bobbin and VC87 bells
L4M35- Small choke for amps 5W or less at 4Henries x 35mADC x 105 ohms in EI-5/8 shielded case
PT030M/PT045M- 30Vct & 45Vct 3A Power transformers for Juke Box motors

PT350M-TWD-USA Tweed Power Xfmr 700Vct(130mA) 6.3Vct(3A) and 5V(2A) heaters.

 

OT8SE STD- 5K/7K ohm 4,8,16 ohm 4-8VA (50mADC) Mexico built shielded Single Output Transformer     <<Coming late JUL 2020>>
Samples approved in June for a production run this Summer.
This is a small economical Single Ended project transformer using the EI-3/4 29M6 Laminations in a 3/4 in square stack.  Think EL84 and 6V6 on a budget with three outputs.  Last ran this version in Asia.

 

OT5PP STD- 22K5 ohm 4,8,16 ohm 1-5VA Mexico built shielded Push Pull Output Transformer     <<Coming AUG 2020>>
Samples approved in June for a production run this Summer.
This is a Low Power project transformer with full range sound using the EI-3/4 29M6 Laminations in a 3/4 in square stack.  Same design we've offered since 2010.  Looking to keep this in EBay Store stock regulary.

 

OT12PP+ STD- 10K/8K ohm 4,8,16 ohm 12 - 18VA Mexico built shielded Push Pull Output Transformer     <<Coming AUG 2020>>
Samples approved in June for a production run this Summer.
This is a "Tweed" or Vintage project transformer using the EI-3/4 29M6 Laminations in an oversized 1in thick stack.

 

OT19PP-DYN-USA- 8K:4,8 ohm USA built OT Dynaco35 HiFi amplifier Kits-  EI-1 size 22VA version

OT22PP-DYN-USA- 8K:4,8 ohm USA built OT Dynaco35 HiFi amplifier Kits-  EI-1-1/8 size 30VA version

OT43PP_DYN70 (USA)- 4K6:4,8 ohm USA built OT fuse in Dynaco 70 HiFi amplifier Kits

OT16PP (USA)- simple 6K6:8 ohm USA built OT for the economically minded Deluxe or 6V6 P-P combo builder

OT17PP (USA)- simple 8K:8 ohm USA built OT for the economically minded Tweed/Princeton/18W builder

PT240.1 (USA)- I've had a nice little 2-section PT Bobbin hanging around for a while & have built a couple of filament transformers with it.  This month I finally got around to building a small HiV PT with it for 12AU7-ish circuits running at 1W to 5W.  It is the same size as the OT20PP USA in VC87 bells & on the bench I dropped it into my 20VA resistive load and it held up a 325Vdc B+ thru my diode bridge (using "120" inputs) and 340Vdc B+ putting 120 actual onto the "115" inputs.  I center-tapped the heater .... just because Hammond doesn't and I can.  I'm not yet seeing why I can't offer this somewhere around the OT20PP USA price level.

PT190.1 (USA)- a small HiV PT with it for 12AU7-ish circuits running at 1W to 5W.  It is the same size as the OT20PP USA in VC87 bells & on the bench I dropped it into my 20VA resistive load and it held up a 260Vdc B+ thru my diode bridge (using "120" inputs) and 285Vdc B+ putting 120 actual onto the "115" inputs.  I center-tapped the heater 

2016 Amp Build Project

It seems like I find time around the holidays each year to build myself an Amp.  This year I built a Classix Audio NSV6B kit with custom OT20PP (5K1:8ohm) and PT290.2  updated Traynor Bassmate 20 6v6 circuit .  My first PCB based kit.  Nice circuit with Basic Traynor Bass input plus a high gain for guitar.  It works OK as a bass practice amp & rocks nicely as a guitar amp.  Got the nice lows with the custom OT I whipped up for this build.  It's good to be the Xfmr guy ;-)
http://classixaudio.com/nsv6b.htm

 

Other Projects 

PT290.2i - smaller 220/240Vac mains int'l type Power Transformers just under 4Lbs shipping.  These will fit in the 4Lb USPS Int'l Flat Rate package and ship for a reasonable cost (~$26USD).  I can tweak the PT275.2i to operate anywhere from 190-0-190 (120MA)  to about 325-0-325 (80mA).  

OT3SE in the EI-62 material set. It's an over-sized 3/4" stack with a gap.
OT18.2PP 8000Ohm :4/8/16 EI100 x 1.4in stack w/5 Layer winding interleave. 4 Lbs of sonic goodness. What do you have inside your amp????
OT18.2PP PLUS- EI112 x 1.7in stack. 5 Lbs of heavy goodness. 8000Ohm: 4/8/16 Ohms and 35VA.