TwentyTrees
Well-known member
For sale is this two channel set of Samuel Groner’s ultra-clean, ultra-quiet “Monte Generoso” transformerless mic preamp PCBs. The Monte Generoso is a double-balanced Cohen-type mic preamp (as found in Millenia or Earthworks designs) with no electrolytic capacitors or servos in the direct audio signal path, pushing the theoretical limits of low noise design in a mic preamp - no surprise, as Samuel used to design for Weiss. Frequency response is nearly independent of gain setting, and low frequency response in particular is very impressive.
Full design details and documentation on Samuel’s website here:
Analog Circuit Design · Samuel Groner · Resources · Microphone Preamplifiers
See Samuel's photos below for what’s included. I bought this set direct from him in 2023, intending to build it up as a main preamp for orchestral & ensemble recording, but my 2024 plans have changed so it makes more sense to offer it up for someone who will get better value from it. Samuel built and tested one channel, the other channel and PSU PCBs are untouched (all I've done is open the box to check everything's there, bundle in the MAT02s, and pack it up again). All the hardest-to-find parts are here, including two additional MAT-02 dual transistors that I tracked down for the second channel - you’d just need to get an OPA627 plus the remaining parts.
The set includes:
I’m not looking to make a profit on this - all-in, I paid around £400 including sourcing the additional pair of MAT-02, so I’m asking £350 plus P&P in the first instance. Payment via PayPal Friends & Family, or regular PayPal if you cover the fees. It’ll be posted from the UK fully tracked and insured, with UPS (likely around £18 within the UK, £30 to Europe, £100 to the US).
Full design details and documentation on Samuel’s website here:
Analog Circuit Design · Samuel Groner · Resources · Microphone Preamplifiers
See Samuel's photos below for what’s included. I bought this set direct from him in 2023, intending to build it up as a main preamp for orchestral & ensemble recording, but my 2024 plans have changed so it makes more sense to offer it up for someone who will get better value from it. Samuel built and tested one channel, the other channel and PSU PCBs are untouched (all I've done is open the box to check everything's there, bundle in the MAT02s, and pack it up again). All the hardest-to-find parts are here, including two additional MAT-02 dual transistors that I tracked down for the second channel - you’d just need to get an OPA627 plus the remaining parts.
The set includes:
- one finished preamp (tested by Samuel when built);
- PCBs for another preamp channel and a suitable linear power supply;
- Elma gold-plated 24 position rotary switches;
- gold-plated switches for phantom power and polarity;
- Haufe custom-made power transformer with Mu-metal magnetic shield;
- two MAT-02 dual transistors;
- three OPA627 opamps (you'll need to get a fourth one);
- a few capacitors and a common-mode choke;
- a partially drilled cased with custom front-panel, line voltage selector switch, and power switch;
- printed schematics and overlay prints.
I’m not looking to make a profit on this - all-in, I paid around £400 including sourcing the additional pair of MAT-02, so I’m asking £350 plus P&P in the first instance. Payment via PayPal Friends & Family, or regular PayPal if you cover the fees. It’ll be posted from the UK fully tracked and insured, with UPS (likely around £18 within the UK, £30 to Europe, £100 to the US).
