Joule Electra preamps and amps. What is your impression?

^^Any amplifier using 6C33 power tubes will need the power tube sockets replaced on a regular basis. When the tube was used by the Soviet military, the recommended service life included replacement of the socket along with the tube.

The socket was originally designed in the US for a Sylvania tube called the 3C33 which was an RF transmitting dual triode. In that service it ran fine for decades. The Soviet design doubled the filament current and the result is that the connections fail. The best sockets we have seen were made by EF Johnson in the US, and there are some vintage Russian sockets that hold up fairly well too.

Rich Brkich just listed an LA150 line stage for $1500, considering your comment, quite a deal for you @Inna.
When you get to the amp upgrade, perhaps  @atmasphere 's OTLs using the 6AS7 will be a better fit for you. M60s, MA2s are long-standing fixtures in more than one friend's system. I enjoyed my MA1s as well. All use the 6AS7 which is reliable and affordable.
Cheers,
Spencer

It seems Joule Electra is not in business anymore:
http://www.joule-electra.com/

If someone is interested on OTL preamps or AMPs, perhaps it is wise to choose a company which offers reliable customer service like Atma-Sphere.

enjoy the music...

Sbank, yes I saw it too. Atma-Sphere are expensive. Did I hear right that OTL amps require a very careful match with speakers ? In what sense? I read that some use them with big Sound Labs, Classic Audio's modern vintage speakers are apparently excellent match too. But that's big unusual speakers. How about common dynamic speakers ?

OTL amps tend to have a high output impedance.  That means that, if they are matched with low impedance speakers, particularly ones with an impedance curve with wide swings up and down, the frequency response of the speaker could vary quite a bit.  The ideal speaker for all tube amps, particularly OTLs and SETs (which also tend to have highish output impedance), would be one with a high nominal impedance and a curve that is relatively flat.  

Theory aside, all speakers require careful matching of amps.  I haven't noticed, in the setups I've heard using OTLs, any particular sensitivity of the OTL type; they tend to sound very good with a wide variety of speakers.