Pass ALEPH HYBRID!!!!! (ECC88 in the first stage)

[atom]

Generoso Cozza has transform an Aleph in a Hybrid amplifier.It looks fantastic .A person of taiwan who have built it found it sound better than Pass Aleph 2.
It can be built in 30W, 60W, or 100W (Single ended, Class A, Mosfets..).In His web page you will found all detail (Shématics, componants etc)

http://digilander.iol.it/essentialaudio/index.htm

[Asen]

In this site (see the address) there is more info about that hybrid amp. You have to speak russian though. The autor pretends there are a few problems solved.
http://www.zeuslab.newmail.ru/ha.htm

[Edited by Asen on 01-22-2001 at 05:54 PM]

[Jon T.]

That looks like a really nice design, but there is one important difference from the Aleph.

The Aleph uses a dynamic current source that adjusts itself based on feedback from the output. This allows it to achieve a near 50% efficiency.

The hybrid design uses a more conventional current source loaded single ended design and will thus only be about 25% efficient.

Not a big deal for the DIYer; it only means you'll need more heatsinks, but it'd be more difficult for a manufacturer.

The design actually looks more like a tube differential input stage connected to a Zen amp used as the output.

-Jon

[promitheus]

I agree with jon t. it isnt different, but it´s a good idea.
It´s interesting.

[hifi]

Sorry to bring up such an old thread but have there been any recent work in this arena?

[moamps]

Hybrid Amp

Regards,
Milan

[GRollins]

This circuit is one of a half-dozen that pop up at intervals. The concept is interesting, but the execution is poor. Direct connection of tubes to solid state devices can be done, but it's difficult to do reliably and tends not to sound very good. Most hybrid circuits seem to show the weaknesses of solid state and tubes, not their strengths. You'll be better off going all solid state or all tubes, depending on what you're trying to accomplish.
The people who come up with these circuits tend to feel that they're the greatest thing since sliced bread, but then that's human nature.
For the record, I've got one or two hybrid circuits that I keep meaning to try, but that doesn't mean I've got very high expectations for them--just something I'll putter around with some rainy day when I don't have anything better to do. No one would be more surprised than me if they ended up sounding any better than mid-fi.

Grey

[Upupa Epops]

Driving cca 3 nF of input capacity of Mosfets by a few mA give really amazing sound and surpraisly low distortion . Stupidity is blooming, halelujah !

[SY]

Originally posted by GRollins
Direct connection of tubes to solid state devices can be done, but it's difficult to do reliably and tends not to sound very good. Most hybrid circuits seem to show the weaknesses of solid state and tubes, not their strengths. You'll be better off going all solid state or all tubes, depending on what you're trying to accomplish.

Grey

That's probably true in this case (IMO), but not as a general rule. It depends on what the nature of the hybridization is. For example, a couple of bipolar transistors configured as a CCS cathode load in a tube diff amp can result in a much better circuit than one can get with tubes alone.

[GRollins]

For the life of me, I can't think of a single classic circuit that's been hybrid. They're all either pure tube or pure solid state. Can you make a hybrid circuit that works? Of course. But it's usually just a mediocre circuit when you're done. Perhaps an interesting technical exercise--gee, look what I can do--but a great-sounding piece of gear? I ain't holding my breath.

Grey