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PRODUCTS - With over forty years of electronic design and manufacturing experience, mostly in the audio industry, I still love taking on challenges and winning! For me, designing something and seeing it through to a commercial product, is as creative as writing and producing in the studio. Under this category,  you can browse through the things I make to help musicians, producers and engineers, along the way. 🙂

SERVICES (Technical) - Don't let the fact that you're unable to install one of my systems into your beloved piece of vintage equipment scare you off! I'm more than happy to do that for you. I also repair and  service studio and live performance gear as well as renovate vintage synthesisers, signal processors and guitar amps.

SERVICES (Creative) - I've been involved with studio and live music production, since 1985. It's my passion and I have a huge wealth of knowledge and experience. Being a musician myself, I'm able to connect with my clients while I make magic things happen. I'm also a keen photographer, website and graphics designer. If you think I can be of assistance, please do check out this category.

UPCYCLED AUDIO - My project for 2023, Upcycled Audio offers vintage equipment that's been renovated and / or upgraded with a view to deliver classic quality performance with modern convenience. You can read more about it here.

MARSHALL JMP-1 STUFF - Putting all my bits 'n' pieces for the Marshall JMP-1 into one place will hopefully make things a little easier for fans of this legendary MIDI valve pre-amp.

PML-TX01 Transformer for the Marshall JMP-1

Product Details


The PML-TX01 isn't just a replacement transformer for the Marshall JMP-1. It's an upgraded design featuring laminates that are made from a much higher quality material than the original, thereby reducing laminate oscillation (hum) and heat.

Made in the same factory as the original, the PML-TX01 is pin-for-pin compatible with the Marshall (Dagnall) TXMA-00014 transformer, so it's pretty straight-forward swapping out the old one.

Fully detailed, illustrated and printable installation instructions are available after purchase. If you miss the link, please don't hesitate to contact me and I'll send them out to you.


I regularly receive two questions from those interested in my PML-TX01. Both are about the Marshall JMP-1 input voltage selection:

  1. Is the PML-TX01 replacement transformer for the Marshall JMP-1, 230V or 115V?
  2. Are the voltage selector components diodes, ferrite beads or just fancy wire links?

The answer to the first question is, just like the original TXMA-00014, my PML-TX01 has two separate primary windings, each rated at 115V. So…

  • EUOPEAN / UK VOLTAGE SELECTION. Wired in series, the primary becomes a single 230V winding. To wire in series, connect ONLY LK2.
  • USA / CANADA / JAPAN VOLTAGE SELECTION. Wired in parallel, the primary becomes a single 115V winding. To wire in parallel, connect LK1 and LK3.

The Marshall JMP-1 input voltage selection is quite easy to change. The use of those eighties style wire links makes some people think that they are devices like diodes or something but the original links were JUST WIRE LINKS and nothing else, so you can use wire. I would however, recommend that you use covered wire as these connections carry mains voltage!

PML-TX01 replacement transformer for the Marshall JMP-1

The image below shows a schematic representation of the transformer windings. On the left are the two primaries which connect to domestic a.c. power via the fuse and ON / OFF switch. Jumpers LK1 and LK3 are installed for 115V operation. For 230V operation, ONLY LK2 is installed.

JMP-1 Input Voltage Selection Schematic


The above is a simple schematic REPRESENTATION of how the links are connected to configure the primaries for either 230V or 115V operation. The physical configuration of the voltage selector links however, is a bit unconventional and suggests that the transformer's primary windings are mirrored with START and FINISH for each winding not being where one might expect! The STARTs, for example could be the the two middle pins and the FINISHes, the two outside pins. Normally, transformer windings would be laid out START - FINISH, START - FINISH. I thought it might therefore be helpful to provide an illustration of the actual (physical) layout of the power input in the Marshall JMP-1 (below).


Annoyingly, my shopping cart software displays shipping information after you’ve confirmed your payment option. I’m trying to get this changed as I believe that customers should always know exactly what they’re paying. Of course, I have no control over import duties but I try my best to give clear, concise information.

I therefore maintain a ‘Shipping Prices’ page and visitors to my website who are interested in buying stuff, have the opportunity to check shipping costs to their country / region.

My shipping costs are calculated on item value and not weight as everything is insured.

UPDATE - August 2023

I'm offering my CR2032 adapter for the JMP-1 at a discounted price when purchased with the PML-TX01. Hey, you gotta take the board anyway, right?

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