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Musical Power Supplies, Inc.

Columbia TN, 38401






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MPS New Projects

Updates 17-MAR-2024

I've been catching business from Shop ( the Morgan Amp local HQ.  Joe picked up my small PT190.1 and the OT5PP and OT8SE early last year and has restarted his low power "5" amps.  He's been using the PT285M, OT12PP and OT20PP on his custom projects & he's trying out the OT45PP-JTM/OT50PP-JCM.  Must be doing something right here.  

The OT15SE-HF-5K-UL  got tested recently by SKUNKIE DESIGNS Skunkie Designs | Tube Audio Electronics .  Stef ordered more sets and found a lower distortion on the MPS part than what was being seen in the competitive part.  I believe this is the 300B project.. but I have not been thru all of the YouTubes out there to find the specifics.  I'm building a pair now with Z11 lams which allows for a tighter wind with fewer turns than 29M6.  On the bench the Bass response isequivalent and the Leakage Inductance losses are down a third.  On paper... that's all good.

I have some PT winding assemblies on order for PT190M, 275M, 285M, 330M and 350M.  I expect samples this month for approval.  We will laminate, complete and test here - this will get us back into having a regular stock of 120 to 150mA PT's.  Sorry- still no Laydown types.  That just does not seem to work well with the 2-section bobbin I use for Safety.

OT19PP-DYN35 update- I've got a couple of pairs done using the current recipe.  They test out at full pretty solidily 24Hz to 40KHz at 17.5W+.  About 15W at 20Hz.  I have one more version to try and get the full 20Hz.  It's been intersting working with the HiFi gurus on a full load test cycle.  At the more typical 1V testing transformer companies use to rate performance 20-20Khz would have been accomplished about 15 versions ago ;-)   This coming week we'll put together "version 22" and make a final production decision between v20 + v22.  Of course results on the test stand still need to be compared to the ears of some good end users!

So a pretty good mix of Guitar Amp and HiFi activity going on now hee in Columbia TN!!!


Prior Update23-FEB-2024

Added an Instagram link to the landing page-   The thought is that we'll share ongoing stories on custom parts, things related to the shop, and perhaps some customer stories in that format.  A good local Amp customer has snagged my 50W JCM OT/PT transformers - I'm interested to see how that turns out.

Notes on Sales- Just a reminder that while there is an EBay Store, there is no direct MPS webstore, you can always contact us by email for a PayPal Invoice and save money on fees and US Sales Tax (except FL & TN).  Anything in stock (EBay) is available directly too.  Many of the standard guitar OT parts are on the shelf in TN in larger quantities than we keep active in EBay.

HiFi Transformers:

OT19PP-DYN35 is our Dynaco ST-35 type PP output transformer.  We have had good results with the Z11 Lam and a bobbin wound version of the original 2400Turn input winding that covers 17.5W at full load from 20Hz to 20KHz (-1dB).  We have limited lamination stock currently but should have plenty in the 2nd half of February.  It can be built with shallow covers for kit and OEM use on Dynaco chassis or with more conventional Full Mount Bells if size does not matter to your project.

There are also (2) Versions of the Dynaco 35W Power Transformer. 
1- PT325.2_DYN35 is the same size as the original Dynaco PT and weighs in just over 4LB. 
Since I use a modern 2-section bobbin for PT safety the lead exits for the mains will have the Hi Voltage or Heater leads as well - we will leave 12IN of lead wire on each PT to help with routing.
The covers are shallow to acheive the original equipment footprint and height.

2- PT330M_DYN35 is on the next larger bobbin (EI-1-1/8) and weighs in a 4.5LB.  Standard covers will be Bahrs HC200 so that the PT core is 180 degrees opposed to the OT's.  It can be ordered in FM100 vertical bells if preferred.  


Other recent New Stuff 

Working on several HiFi projects & now have an assortment of better looking covers for HiFi projects including painted and a polished plated version.


PT330M in the HC200 covers.  Replacing a laydown PT in a Deluxe type amp.


The main shop is now heated/cooled and provisioned!  We are looking forward to more great projects.