Aleph Phase Inverting / non inverting

macka · 22nd February 2006, 10:37 AM

It may see an odd question but can anyone confirm if the Aleph has an inverting or non inverting output referenced to the input signal?

Macka

Stefano · 22nd February 2006, 10:59 AM

Hi!
Since his output stage isn't a follower it must be non-inverting (I think).

Bobken · 22nd February 2006, 12:04 PM

Hi,

Surely this is governed by the number of gain stages in the amp, each one providing a nominal 180 Deg. shift or 'reversal'.

If so, Aleph 30 with 2 stages is non-inverting, but some of the earlier Alephs (IIRC, but I cannot access the schematics now to check) had 3 stages, in which case they would be inverting.

jh6you · 22nd February 2006, 12:40 PM

Arr . . .
Aleph is too complicate for me . . .
Anyhow, if I see the feedback line from the output, it is the non-inverting feedback. The output signal has the same sign with the input signal applied to the non-inverting input.

jh

GRollins · 22nd February 2006, 01:14 PM

The amp, taken as a whole, is non-inverting.
The output stage is inverting. The front end, being a differential, can be hooked up to be either inverting or non-inverting. In this case Nelson chose the inverting hookup.
The signal comes in, inverts going through the front end. Now it's "upside-down." Then it goes through the output stage and gets flipped once more, making it "rightside-up."

Grey

Bobken · 22nd February 2006, 01:56 PM

Hi Grey,

Is my above recollection right that one (some?) of the earliest Alephs had 3 amplifying stages, and were accordingly inverting?

I had only downloaded the A30 details, and, of course, Nelson has needed to remove the other circuits from prying eyes.

Regards,

MikeW · 22nd February 2006, 02:33 PM

http://www.passdiy.com/pdf/mos.pdf

Blues · 22nd February 2006, 03:02 PM

Quote:

Originally posted by Bobken
Hi Grey,

Is my above recollection right that one (some?) of the earliest Alephs had 3 amplifying stages, and were accordingly inverting?
Regards,

Bob,

His 1st gen Alephs like the 0 and 1, although having three gain stages is also non-inverting as the 3rd stage is a bunch of paralleled followers and does not invert the output of the 2nd stage. The input is a diff pair with output taken from the drain inverts then the 2nd is a voltage gain stage will revert back to the same phase as the input signal.

Allan

Bobken · 22nd February 2006, 03:32 PM

Hi Allan,

Thanks a lot for this clarification. I was right about the 3 stages then, but my memory let me down on the topology details.

Tries hard, could do better, only 5/10!

Nelson spoilt us all, maybe for too long, and I guess I took it for granted that these details would always be available on his site.

It was a really sad day when I saw that Nelson was forced to remove his schematics, but I fully understand why he did this.

I just wish I had downloaded them all ages ago, when they were available.

Regards,

macka · 22nd February 2006, 07:01 PM

Thanks guys for all your replies.

Macka

22nd February 2006, 10:37 AM	#1
macka diyAudio Member Join Date: Dec 2001 Location: Australia	Aleph Phase Inverting / non inverting It may see an odd question but can anyone confirm if the Aleph has an inverting or non inverting output referenced to the input signal? Macka

22nd February 2006, 10:59 AM	#2
Stefano diyAudio Member Join Date: Jun 2002 Location: Cagliari, Sardinia	Hi! Since his output stage isn't a follower it must be non-inverting (I think). __________________ Let's make something special

22nd February 2006, 12:04 PM	#3
Bobken diyAudio Member Join Date: Dec 2002 Location: UK	Hi, Surely this is governed by the number of gain stages in the amp, each one providing a nominal 180 Deg. shift or 'reversal'. If so, Aleph 30 with 2 stages is non-inverting, but some of the earlier Alephs (IIRC, but I cannot access the schematics now to check) had 3 stages, in which case they would be inverting. __________________ Bob

22nd February 2006, 01:56 PM	#6
Bobken diyAudio Member Join Date: Dec 2002 Location: UK	Grey's the man who will know! Hi Grey, Is my above recollection right that one (some?) of the earliest Alephs had 3 amplifying stages, and were accordingly inverting? I had only downloaded the A30 details, and, of course, Nelson has needed to remove the other circuits from prying eyes. Regards, __________________ Bob

22nd February 2006, 02:33 PM	#7
MikeW diyAudio Member Join Date: Sep 2002 Location: North of Boston	Insight http://www.passdiy.com/pdf/mos.pdf __________________ MikeW


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22nd February 2006, 12:40 PM	#4
jh6you Account Disabled Join Date: Aug 2002 Location: Near to the Pacific Ocean	Arr . . . Aleph is too complicate for me . . . Anyhow, if I see the feedback line from the output, it is the non-inverting feedback. The output signal has the same sign with the input signal applied to the non-inverting input. jh

22nd February 2006, 01:14 PM	#5
GRollins diyAudio Member Join Date: Feb 2001 Location: Columbia, SC	The amp, taken as a whole, is non-inverting. The output stage is inverting. The front end, being a differential, can be hooked up to be either inverting or non-inverting. In this case Nelson chose the inverting hookup. The signal comes in, inverts going through the front end. Now it's "upside-down." Then it goes through the output stage and gets flipped once more, making it "rightside-up." Grey

22nd February 2006, 03:32 PM	#9
Bobken diyAudio Member Join Date: Dec 2002 Location: UK	Hi Allan, Thanks a lot for this clarification. I was right about the 3 stages then, but my memory let me down on the topology details. Tries hard, could do better, only 5/10! Nelson spoilt us all, maybe for too long, and I guess I took it for granted that these details would always be available on his site. It was a really sad day when I saw that Nelson was forced to remove his schematics, but I fully understand why he did this. I just wish I had downloaded them all ages ago, when they were available. Regards, __________________ Bob

22nd February 2006, 07:01 PM	#10
macka diyAudio Member Join Date: Dec 2001 Location: Australia	Thanks guys for all your replies. Macka

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