That's why I think it's probably some sought of Source Follower Output.
Maybe it's push pull source follower combined with a healthy amount of single ended bias like the other XA amps but without the supersymmetry circuit.
clever cheapskate can always joggle with approach to and difference between balanced , symmetrical and differential .......
When I was a boy, I was bloody hopeless with Christmas Presents. Hahahaha
The suspense is killing me.
What do you think of the possibility of old school White cathode follower, could that be defined as single ended?
Last edited:
From Xs manual: The original Aleph 0 from 1991 used an output stage which consisted of a push-pull Class A output stage operated in parallel with a high constant current output stage. The bias currents were high enough to operate to rated power in single-ended Class A, giving it a second harmonic signature, and as a push-pull topology at higher power levels.
Is this what you guys guess?
Is this what you guys guess?
Yes this is what I have been guessing, if not, then some more Papa genius.
Good chance it might be half of a regular XA.8 amp but biased higher than normal with a large share of single ended bias.
Thank you very much Jon, can't wait to learn more about it.
When should we expect to see these for sale?
If push-pull are you able to confirm that it is a complementary pair of N and P channel mosfets at the output, or is it a quasi-complementary push-pull output stage?
Yes I've read that a dozen times.
The problem is single ended can mean quite a few different things.
I would put my faith in Jon Ver Halen since he has a very good relationship with Papa and actually sells Firstwatt products.
ZM knows Station
inputs are RCA , so there is no doubt
but , from rest of text ...... there are so many choices
SE or not
, figures in A/8R , A/4R, A/AB/2R ....... not so many choices for OS
are there any complementary pucks ?
I tried to find complementaries for my thyristors , but nada ....... it seems I'm doomed on mosfets
inputs are RCA , so there is no doubt
but , from rest of text ...... there are so many choices
SE or not
, figures in A/8R , A/4R, A/AB/2R ....... not so many choices for OSare there any complementary pucks ?
I tried to find complementaries for my thyristors , but nada ....... it seems I'm doomed on mosfets
ZM knows Station
inputs are RCA , so there is no doubt
but , from rest of text ...... there are so many choices
SE or not
are there any complementary pucks ?
I tried to find complementaries for my thyristors , but nada ....... it seems I'm doomed on mosfets
There are P Channel Pucks but not true complements, having said that there is no such thing as true complementary p channel parts, and if papa intentionally creates asymmetry by adding single ended biasing in parallel, then probably no need to have complementary parts in the first place, just find the closest match with regards to current, transconductance and power rating and Bob's your uncle.
Some quasi complementary set up wouldn't be out of the question either.
Last edited:
My guess is quasi-complementary since there don't seem to be any decently matching N-P hockey pucks (at least from IXYS) and the article talks about using a new CCS which "compensate(s) for temperature drift." Although a mismatched N-P complementary pair might give a more "single-ended" sound from increased second harmonic.
Altogether, it kind of rings like a BA3 with some sort of mu-follower output to me...
Last edited:
I am in bed with the flu.
Mostly you are wrong. The Villars photo showed a mock up of the circuit
I used as an illustration of cascoded performance that I showed at BAF,
and is not related to the XA25.
The XA25 has an RCA input and not balanced outputs. It is a very simple
amp that had surprising performance, however it is the intellectual property
of Pass Labs, and so remains under wrap.
I will tell you this so that you can reverse engineer it:
Three stages, DF is about 700, high current, high slew, .00x% distortion,
40 uV output noise, big Class A envelope, 25 watts into 8, 100 watts into 2.
And it sounds great.
Now back to bed.
Mostly you are wrong. The Villars photo showed a mock up of the circuit
I used as an illustration of cascoded performance that I showed at BAF,
and is not related to the XA25.
The XA25 has an RCA input and not balanced outputs. It is a very simple
amp that had surprising performance, however it is the intellectual property
of Pass Labs, and so remains under wrap.
I will tell you this so that you can reverse engineer it:
Three stages, DF is about 700, high current, high slew, .00x% distortion,
40 uV output noise, big Class A envelope, 25 watts into 8, 100 watts into 2.
And it sounds great.
Now back to bed.
I will tell you this so that you can reverse engineer it:
Three stages, DF is about 700, high current, high slew, .00x% distortion,
40 uV output noise, big Class A envelope, 25 watts into 8, 100 watts into 2.
And it sounds great.
Now back to bed.
Thank you papa and get well soon.
I will tell you this so that you can reverse engineer it:
Three stages, DF is about 700, high current, high slew, .00x% distortion,
40 uV output noise, big Class A envelope, 25 watts into 8, 100 watts into 2.
Wish you fast recovery Mr.Pass.
Attachments
I will tell you this so that you can reverse engineer it .......
Can't resist.
First guess IXFN 44N80P / IXTN 40P50P.
On track ?
Cheers,
Patrick
Definitely 40P50P but I was thinking 48N60P instead of 44N80P.
http://ixapps.ixys.com/DataSheet/99337.pdf