Class A for home use

[jacco vermeulen]

Are you willing to mention the kind of bipolars before we are sitting under the Christmas tree ?

[DRC]

andrew (anli),
you rejected single ended OP's due to their low efficiency. Did you consider the case of single ended with active current sources (aleph / aleph-x) and their improved efficiency ?

dave

[anli]

Originally posted by DRC
andrew (anli),
you rejected single ended OP's due to their low efficiency. Did you consider the case of single ended with active current sources (aleph / aleph-x) and their improved efficiency ?

dave

Dave,

Is it possible to point to the schematics variant you are talking about?

Andrew

[DRC]

Andrew,
All of the aleph series amplifiers use a 'load current sensing' active current sinks (ie they are not constant current) - I think that is what 'aleph' is intended to refer to.

As you asked about bridge load amps :

Aleph-X

If I recall correctly (?), the gain of the 'current source(s)' is ~x1.5 so the peak load current is somewhat higher the standing current would suggest (and the current in the other CS decreases at the same time).

As I see it - it is more efficient than a true bridge load, constant current, single ended amp.

dave

[anli]

Originally posted by DRC

...
As I see it - it is more efficient than a true bridge load, constant current, single ended amp.
...
dave

Agree. But I prefer:

- to exclude capacitors from signal chains,
- use a push-pull topology to reduce demands to power supplier.

There are different shcools (is this word appropriate here? :-) how to
design. One of them - to use fewer (but expensive) parts. At this case
audio quality depends on, as example, concrete capacitors models
at very high degree. And I go to by a next capacitor to replace the old one,
then - next, and so on. One day, I see the last capacitor cost is about the
whole amplifier cost :-) You see, I overdraw the reality :-) I just want to say,
it is more interesting to me to resolve the problems schematically.

Both ways are good: each scool has nice realisation examples.
It's matter of taste, I think.

Andrew

[DRC]

Andrew, I agree with you on the issue of expensive components - I do not think it is money well spent and prefer to use low cost parts myself (preferable the ones in my junkbox)


Slightly off topic (sorry, no MOSFET's and not even a complete / tested design !!!), here is my own take on an "aleph-X like" amp using very low cost components :

Daves amp !

I went for a SE design as I could see no benefit in the complexity of push-pull, when using a bridge-load design, as source & sink are fully symmetric. BTW, my current source works like a differential current generator (i hope !) and should produce 'optimum' efficiency.

I am interested in why you made push-pull and bridge-load a requirement ???

dave

[anli]

Originally posted by DRC

...
Daves amp !
...
I am interested in why you made push-pull and bridge-load a requirement ???

dave

I need some time to understand your project and to read that thread.

As for push-pull - the topology seem to be much more tolerant of PS pulsation,
I think.

Andrew