Icarus Stereo 2A3 -- all parts on hand...almost!

[Erik Mandaville]

Just a short note on this amplifier project:

I've received virtually all the parts for this parallel-feed stereo amp project, based on Jean-Francois Lessard's Horus amplifier. I am provisionally calling it the 'Icarus Stereo 2A3.' I am doing a few rather minor changes in the power supply to hopefully facilitate better stereo separation (including dual vacuum tube rectifiers: 5Y3,5AR4,GZ37...haven't decided yet), and just a couple of value changes of capacitors and resistors in the amp circuit. These are mainly associated with the power supply, and are partly dependent on what rectifier is chosen. I had planned just a single rectifier, but remembered a few amplifiers I had seen (in Glass Audio, I think) that use two rectifiers coming off a single power transformer; in fact, my AES AE-1 preamp uses the same approach, but uses silicon diodes rather than tube rectification. J.F.L. has also shared part of his SRPP preamp schematic, which may become a project later in the summer and early Fall. I'm curious to compare it with the cathode follower, which although famous for characteristically low output impedance, is said to be maybe not so quick on its feet as some other designs.

Anyway...I can start measuring out the chassis tomorrow, and will begin punching holes for tube sockets etc., on Monday.

Oh! I also tried to cut a corner with purchasing a less expensive power transformer -- Jeff informed me he used the same one on a couple of other projects and hated it! Too much noise, hum, mechanical vibration; in short, not good for serious audio use. So I consider myself fortunate to have had his input on this -- as well as other aspects of the project. He has done is homework, for sure!

So that's the scoop!

Erik

...I can't help but say it's nice things have settled down in here a bit.

[NOSValves]

Erik,

I'm not clear on which amp your building there. Is this going to be similar to what Sunny purchased from jeff PP 2A3 stereo or something else ? Sounds like fun

Enjoy Craig

[Erik Mandaville]

No. It's basically a stereo version of the Horus -- with some minor changes here and there. As much as I really wanted to, I simply could not afford all of the parts (in terms of quality), especially the cobalt OPTs, that Jeff L. uses in those he builds. I have chosen very carefully to preserve as much of the quality as I can. I am using a variety of Solen capacitors, and Jensens in coupling positions.

Speaking of Solen capacitors, I have heard them referred to on this forum (not by you)as 'lousy' or 'cheapo' capacitors. This is very simply totally incorrect. They are outstanding capacitors, and are made extremely well. The fact that they are priced fairly should not be used as a measure of their quality and construction. Sorry, I just had to say that! The prices some companies charge is ludicrous, and the same goes for such things as power cords, isolation devices, etc.

But no, this isn't a PP amplifier.

Erik

[NOSValves]

Erik,

I agree nothing wrong with Solens at all. I have only used them building a pair of ALK Xovers but my expereince with them was positive they seemed very well built. I really think most of the geared for Audio type caps are the best choice for audio gear. I pretty much switch to Auricaps on all my rebuilds and I'm really liking them you should give them a try there not all that expensive. Very nice caps ! But this is in the amplications I do they could easily sound bad on a SET amp for all I know. Most of the SET crowd rave about Jensons I put them in a ST-70 and found they really did not do anything for the amps at all.

Craig