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Musical Power Supplies, Inc.

Columbia TN, 38401

 

Email: matt@musicalpowersupplies.com

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

MPS New Projects

Updates 30-JAN-2022-

1- The OT20SE winding from the Mexico plant is on order. We will laminate, varnish and test here and offer it from stock shortly.

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.  We've been using USPS Priority again for non-eBay shipments

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:

OT60PP-DYN-USA- Dynaco 60W scaled up to EI 1-1/4 x 1.75IN iron (4K3: 4/8 ohm)
OT43PP-DYN-M: scaled the Dynaco OT up to 85VA using EI 1-1/8 Lams (4K3: 4/8 ohm)
OT22PP-DYN-USA - Dynaco35 OT scaled up a size using EI 1-1/8 Lams (8K: 4/8 ohm)
OT50PP-HF-USA- 50VA  EI 1-1/4 x 1.75IN iron (7K6: 4/8 ohm)
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
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
PT250.1-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.