Aleph circuit is Single, SEPP ,SRPP or other ?

[SkyChu]

I always thought the Aleph circuit is SRPP liked circuit. But, someone said it is Single class-A circuit and someone said it is SEPP.
What's it ? Single class-A ? SEPP ? SRPP ? or who ?

[Fuling]

What about SE with an active current source?

[Nelson Pass]

I would call it a Common Source Single-ended gain stage
biased at DC by a constant current source and biased at
AC with a negative impedance converter. In this case, the
impedance converter "ghosts" a negative image of the load,
usually -2X.

What the tube equivalent is, I leave for someone else to
figure out.

[SkyChu]

Thanks ! Master !

[Fuling]

What the tube equivalent is, I leave for someone else to figure out

Then I´d say SRPP, but it´s only a wild guess.

[Nelson Pass]

What do you think the definition of SRPP is, just out of
curiosity.

[Fuling]

Shunt (or is it series?) Regulated Push... Wait a minute, I see your point

[rif]

Maybe along with his great ideas and patents, Mr. Pass should coin and copyright some acronyms

That would be a fun contest/thread, I'll leave it to otehrs to initiate if interested.

[Bigun]

I was thinking about this question today and a search lead to this thread. Not sure I got the answer I was looking for but my thinking is that the Aleph is not an SRPP, but that it may be set up to behave like one. And it seems that an extended form of an SRPP can be set up to behave like an Aleph.

see attached:


Aleph: as I understand it, the current through the speaker load is 'measured' across a resistor in series with the load and used to modulate the top current source. In the Aleph amplifier this modulation is adjustable, which I've shown conceptually, so that the modulation amplitude can be varied, with the possibility that the amplitude of modulation in both the top and bottom sources can be the same.

SRPP: I've drawn this topology with the output taken from mid-point of a resistor to represent the concept that the ratio of resistance between the output take-off point and the top device verses the resistance between the output take-off point and the bottom device, can be varied. In the traditional SRPP the output take-off point would be set at the upper end of this adjustment so that there was no resistance between it and the top device. With this adjustability one might argue it's no longer SRPP.The current flowing through the resistor is 'measured' and is used to modulate the top device so that the amplitude of both the top and bottom sources. The amplitude of current modulation through the top device can be adjusted, as shown, with the possibility that the amplitude of modulation in both the top and bottom sources can be the same.

So......... it would seem that with respect to current modulation, I can make an SRPP behave like an Aleph and I can make an Aleph behave like an SRPP. Doesn't mean they sound the same and phase differences between the current modulation of top & bottom devices maybe different over frequency between the Aleph and the SRPP version.