Synergy Diezel Herbert in MTS problem solved !

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Active member
Apr 12, 2023
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Hi again,
I was able to find out what's missing, and I thought it's better to start a new thread with a new headline for folks who search for a fix for this.
As I mentioned before, the problem is not the recessed pin "C" that carries the anode voltage.
The issue is that the Herbert module makes use of the two pins "H" and "J" and these pins are not uses my any other module.
So far, so good, but what are these pins for ?


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Here is the solution !

The "Herbert" uses an OpAmp, probably for some active filtering, that needs a bipolar voltage, usually +/- 15 Volts to work.

Here is the way the current flows:
1.) Voltage input at pins "J" (positive) and "H" (negative)
2.) 22 Ohm resistors R30 (positive) and R32 (negative)
3.) regulators "IC1" (78L12 / positive)and "IC2" (79L12 / negative)
4.) OpAmp pin "8" (positive) and pin "4" (negative)

So all you need is to built a tiny +/- 15 Volt (+/- 13,7 Volt in theory) power supply and connect it to pin "J" (positive) and pin "H" negative




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I don't have a mini PSU at hand, but I got a bigger one to test my findings, and guess what ... It's working !


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One correction please !
I said "connectors H and G" in the video, but it's "connectors H and J" !


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No problem, I am into Synergy-MTS for about three months now, and I've drawn a lot of information from this forum.
So being a technician myself, I thought it's time to give something back to the community. :cool:
By the way ...
Is here a technician in this forum who is able to measure the exact voltages used by Synergy ?
One would have to measure the 5th and 6th contact of the lower row, counting from left to right against ground (housing, etc.).
I am just curious what's exactly going on ... ;)
Last update about this "Herbert-Bipolar-Supply-Voltage-Thing", for the folks who want to know it.

I was able to get my hands on a SYN-1 unit, and what was the first thing I did ?
RIGHT ! I used it with my modular synth to emulate the behavior of a tube Trautonium and ...

Okay, okay, it was not the first thing I did, but at least it was the second (after some weeks ...).
YESSS ! I measured the supply voltages, you need to get the Herbert-Module running in an MTS-amp.

So here it comes.
Positive: +18,4 Volt with no load / +17,6 Volt with Herbert-Module
Negative: - 19 Volt with no load / - 18,3 Volt with Herbert-Module
As it turned out, it's an unstabilized voltage.
Mission accomplished, case closed, thanks for tuning in !
Sorry, this is a little difficult for me to track, would you be willing to summarize? I have both Egnater and Randall module chassis and am trying to sort of what, if anything, can be done to accommodate the Synergy Herbert module. Can power be tapped or added to those amps to work with the Herbert and no negative effects on the amp or other modules? Thanks for all your experimentation.