What is it?



  • mystery module.jpg
    mystery module.jpg
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Hi all

To end all questions and assumptions: it IS the Thel Musicamp 2000 as anyone could check at Thel's website (link posted within my FIRST answer).

It is a discrete op-amp for audio purposes and can be used (apart from the amp posted by carlmart) for preamps etc. Thel also uses them within their parametric EQ.

The LEDs will almost for sure be used FOR (not AS) the current sources within the circuit.



Do you know where favourable reviews were published for this hybrid amp and what they liked?

The LEDs are probably used for the ccs and perhaps bias the cascodes. What we can't know is what they put as discrete devices (FET or bipolar), but all the other parts seem standard types. I wonder why they charge so much for each, as they do not even use dual transistors.


>Those were either in the magazine "Hobby HiFi" or "Klang & Ton" or both. Most of the reviews were not about the module alone but Thel equipment based on them (preamp, parametric EQ etc).
I can try to find out which issues, but this would take some time.

Are those magazines in English? Besides Spanish and Portuguese I can't read other languages. If you can just comment on what they said.

The reason I asked about the mags is because most reviews nowadays are so vague, and usually more subjective, that it's really very little you can learn from them. I think a good review should include subjective and objective information. Although that doesn't mean reviews will necessarily be good. The former "Audio" magazine did both and still could not be trusted really.

It would be great if we could get hold on one of those hybrids to see what makes them tick.

Hi Carlos

Those mags are in German. Maybe they are even pointing towards the articles on Thel's homepage.

They make some vague description of it's interiors: It is a low open loop design (contrary to most IC op-amps) and the output stage is a cascode. I don't think that it is very complicated at all. It could be quite difficult to analyse one because they are filled with some resin.

One of Nelson Pass' hobbies seems to be taking such things apart, maybe he had done it with one of these as well already ? ;)