Wanted ReQuest parts needed

[electronicsmusicisme]

I'm looking for an entire rear panel with crossover and power supply. If you can help in anyway, even with just a few of the necessary parts, please reach out to me on here! Thanks!!!
The power supply I have is MPLS103 rev-h

 

[Jazzman53]

I'm looking for an entire rear panel with crossover and power supply. If you can help in anyway, even with just a few of the necessary parts, please reach out to me on here! Thanks!!!
The power supply I have is MPLS103 rev-h

Your best outcome would be finding used/original replacement parts, or new/original replacement parts, at a decent price.

However; if original replacement parts are unavailable, there is a third option:

If you can solder components onto a circuit board, you could build your own power supplies, and then bi-amp the system using an active crossover. This would require replacing the power supplies in both speakers.

You would need four amp channels (two stereo amps) and an aftermarket active crossover-- preferably a digital unit with a mic for tuning.

It's not so hard, really.

If this is feasible for you; PM me and I will send you a parts list, and I may even have a spare pair of circuit boards to donate.

I haven't priced components recently but I'm guessing the power supplies (HV bias supplies + transformers) for both speakers would run about $325.

A DBX Driverack PA2 DSP/Crossover with a tuning mic would probably run you about $700 new, or used on Ebay for around $400. This unit even has auto-EQ functionality and a super cool smart phone or tablet interface.

The power supplies would be identical to the one shown below, consisting of a 3.25kV DC bias supply & tandem toroidal step-up transformers (76:1 ratio):

Just a thought....

 

[electronicsmusicisme]

Your best outcome would be finding used/original replacement parts, or new/original replacement parts, at a decent price.

However; if original replacement parts are unavailable, there is a third option:

If you can solder components onto a circuit board, you could build your own power supplies, and then bi-amp the system using an active crossover. This would require replacing the power supplies in both speakers.

You would need four amp channels (two stereo amps) and an aftermarket active crossover-- preferably a digital unit with a mic for tuning.

It's not so hard, really.

If this is feasible for you; PM me and I will send you a parts list, and I may even have a spare pair of circuit boards to donate.

I haven't priced components recently but I'm guessing the power supplies (HV bias supplies + transformers) for both speakers would run about $325.

A DBX Driverack PA2 DSP/Crossover with a tuning mic would probably run you about $700 new, or used on Ebay for around $400. This unit even has auto-EQ functionality and a super cool smart phone or tablet interface.

The power supplies would be identical to the one shown below, consisting of a 3.25kV DC bias supply & tandem toroidal step-up transformers (76:1 ratio):

View attachment 25859

Just a thought....

As you can probably guess used or new replacement parts are not out there. ML quoted me $491 for the power supply board, and $140 for the step-up transformer.
Since I already have one transformer, is it better to just buy another matching one, or are the toroids much better? I welcome any and all info you're willing to share. I am fairly competent in electronics repair
Also I have plenty of Amplifier channels, and an 8 channel MiniDSP and a measurement MIC for it. Adequate?

 

[Jazzman53]

As you can probably guess used or new replacement parts are not out there. ML quoted me $491 for the power supply board, and $140 for the step-up transformer.
Since I already have one transformer, is it better to just buy another matching one, or are the toroids much better? I welcome any and all info you're willing to share. I am fairly competent in electronics repair
Also I have plenty of Amplifier channels, and an 8 channel MiniDSP and a measurement MIC for it. Adequate?

The 230V/6V toroids are an inexpensive and popular choice among DIY ESL builders, but are almost always used with active/adjustible crossovers with EQ functionality.

Whereas; the fixed passive crossovers in your ML speakers were designed to work in synergy with a specific ML transformer, which may be have a different winding ratio, or capacitance or inductance-- all of which affect output and frequency response.

 

[electronicsmusicisme]

The 230V/6V toroids are an inexpensive and popular choice among DIY ESL builders, but are almost always used with active/adjustible crossovers with EQ functionality.

Whereas; the fixed passive crossovers in your ML speakers were designed to work in synergy with a specific ML transformer, which may be have a different winding ratio, or capacitance or inductance-- all of which affect the frequency response.

You are a wealth of knowledge and I thank you!

 

[Jazzman53]

As you can probably guess used or new replacement parts are not out there. ML quoted me $491 for the power supply board, and $140 for the step-up transformer.
Since I already have one transformer, is it better to just buy another matching one, or are the toroids much better? I welcome any and all info you're willing to share. I am fairly competent in electronics repair
Also I have plenty of Amplifier channels, and an 8 channel MiniDSP and a measurement MIC for it. Adequate?

I haven't answered all of your questions.

The 50VA 230V/6V toroids are cheap power transformers designed to step down the 230 volt mains voltage used in Europe to 6V, for powering small appliances. They were not designed as audio transformers but a tandem pair wired in reverse (they don't care which side is the primary or secondary) sounds really good-- providing a 76:1 step-up ratio which is great for a hybrid ESL operating above 200Hz.

If you bypass the [evil/nasty] passive crossovers and use a mini-DSP with at least 4 channels, and EQ functionality (you will definitely need EQ capability to tune the response), then the tandem toroids will work fine.

You would need four of these (two per speaker), with ground side of the bias supply center-tapped between their 230V windings:

https://www.rapidonline.com/vigortr...sformer-230v-single-primary-50va-0-6v-88-5190