After half a bottle of Bordeaux, I am probably not entire in sane.
So I hope Nelson would forgive me for messing around with his creations.
Following the ideas published in :
http://www.diyaudio.com/forums/showthread.php?s=&threadid=128571
Here are a couple of equivalents which could be applied to an Aleph-X or Zen-2 like circuit.
Values are approximate, only to demonstrate principle.
Only output stage shown.
I hope there are no grave mistakes.
Patrick
So I hope Nelson would forgive me for messing around with his creations.
Following the ideas published in :
http://www.diyaudio.com/forums/showthread.php?s=&threadid=128571
Here are a couple of equivalents which could be applied to an Aleph-X or Zen-2 like circuit.
Values are approximate, only to demonstrate principle.
Only output stage shown.
I hope there are no grave mistakes.
Patrick
Added a third variant which is sort of hybrid of the Taylor Current Source and the CSA Current Source, removing the current sensing resistor from the output signal path. AND no loop feedback.
Patrick
Patrick
PS
This current source can be easily adapted to allow the use of LU1014 as the power device in the current source. Just reduce the current source above the 2SK170V by about 4mA.
Hannes !!
Patrick
This current source can be easily adapted to allow the use of LU1014 as the power device in the current source. Just reduce the current source above the 2SK170V by about 4mA.
Hannes !!
Patrick
Thanks for sharing, Patrick (also the other thread, too).
This Taylor source was new to me...
BTW: I reattached the last document as a PDF instead of zipped .DOC, and without blanks in the filename (both might cause problems -- with my system the latter does).
- Klaus
This Taylor source was new to me...
BTW: I reattached the last document as a PDF instead of zipped .DOC, and without blanks in the filename (both might cause problems -- with my system the latter does).
- Klaus
Hi Patrick,
thanks for the hint!!
A very cute thing, such an all jfet "Aleph" (if one ignores the cascodes for a moment).
It's a pity, I just have the wrong speakers for that beauty. Some high impedance, high SPL speakers would be best, due to low damping factor and way lower distortion at high impedances.
To get the output impedance down, you can just crank up negative feedback, which was not the point of the exercise 😀
Also the stupid resonances in the frequency response should be taken care of by a more sophisticated mind, I can't imagine that adding a Zobel is the last word on that.
Anyway, that amp will be stored and revived when the right speakers come 😀
Have fun, Hannes
thanks for the hint!!
A very cute thing, such an all jfet "Aleph" (if one ignores the cascodes for a moment).
It's a pity, I just have the wrong speakers for that beauty. Some high impedance, high SPL speakers would be best, due to low damping factor and way lower distortion at high impedances.
To get the output impedance down, you can just crank up negative feedback, which was not the point of the exercise 😀
Also the stupid resonances in the frequency response should be taken care of by a more sophisticated mind, I can't imagine that adding a Zobel is the last word on that.
Anyway, that amp will be stored and revived when the right speakers come 😀
Have fun, Hannes
2 sets of 8 matched jfets 😱
times 2 for the other channel...
Yes this is something to dream about 😀
Keeps you warm in winter.
Have fun, Hannes
PS: I'm toying with a ClassB amp at the moment - I know, I know close to blasphemy here 😀
times 2 for the other channel...
Yes this is something to dream about 😀
Keeps you warm in winter.
Have fun, Hannes
PS: I'm toying with a ClassB amp at the moment - I know, I know close to blasphemy here 😀
> Yes this is something to dream about
What's the problem?
They are still available in Germany.
There are enough people who have built 100W AX's.
16x LU1014 will just fit the bill.
Patrick
What's the problem?
They are still available in Germany.
There are enough people who have built 100W AX's.
16x LU1014 will just fit the bill.
Patrick
You're perfectly right, Patrick. I forgot about that online shop!
Oh dear. I think I could heat my whole flat with that.
For sure these guys have my respect.
Have fun, Hannes
Oh dear. I think I could heat my whole flat with that.
For sure these guys have my respect.
Have fun, Hannes
You would be pushing it with 4 LU1014s per channel, at 8 ohms.
If your speaker is 4 ohms, then you certainly need 8.
So I would start with 8, biased at 1.3A each.
Probably +/-22-24V rails, total bias per channel 5.2A.
Power will peak at 6 ohm, about 80W.
About 50W at 4 & 8 ohm.
And of course you need equal number of cascode devices, such as IRFP240s or FQA19N20C.
Patrick
If your speaker is 4 ohms, then you certainly need 8.
So I would start with 8, biased at 1.3A each.
Probably +/-22-24V rails, total bias per channel 5.2A.
Power will peak at 6 ohm, about 80W.
About 50W at 4 & 8 ohm.
And of course you need equal number of cascode devices, such as IRFP240s or FQA19N20C.
Patrick
Thanx Patrick for the very fast
reply !
So 4 Pieces for the Mangers are
just enought , can you give me
please the data for the 4 pieces
version ?
Jürgen
reply !
So 4 Pieces for the Mangers are
just enought , can you give me
please the data for the 4 pieces
version ?
Jürgen
Jürgen,
We discussed this before.
Why not take my advice and just build the standard Aleph-X using the PCBs available first?
Schönen Gruss,
Patrick
We discussed this before.
Why not take my advice and just build the standard Aleph-X using the PCBs available first?
Schönen Gruss,
Patrick
> My own favourite is the third one, which is not Taylor.
Well, I like this third one so much that I decided to build a quick prototype to test the principle and see whether I made any mistakes in the design.
The Zip file shows the test circuit built, based on the standard Rollins AX with 4 IRFP044s, with the modified current source AND a JFET frontend (matched 2SJ74BLs cascoded by J174s) diffpair with 1.2k drain resistors.
The frequency response shown is without any optimisation and with a reactive load. The small hump can be flattened by increasing the feedback cap to 8p or so. But I did not bother, as I could not stop listening to it for some 3 hours even with an iPOD as source and not with my reference speaker, though I initially just wanted to have a quick test.
A proper A-B test against the original Rollins AX and an equivalent Lindsley-Hood Xed MOSFET with almost identical layout and component choice is planned in October.
I would encourage the experimentally minded to try this for yourself.
Patrick
Well, I like this third one so much that I decided to build a quick prototype to test the principle and see whether I made any mistakes in the design.
The Zip file shows the test circuit built, based on the standard Rollins AX with 4 IRFP044s, with the modified current source AND a JFET frontend (matched 2SJ74BLs cascoded by J174s) diffpair with 1.2k drain resistors.
The frequency response shown is without any optimisation and with a reactive load. The small hump can be flattened by increasing the feedback cap to 8p or so. But I did not bother, as I could not stop listening to it for some 3 hours even with an iPOD as source and not with my reference speaker, though I initially just wanted to have a quick test.
A proper A-B test against the original Rollins AX and an equivalent Lindsley-Hood Xed MOSFET with almost identical layout and component choice is planned in October.
I would encourage the experimentally minded to try this for yourself.
Patrick
hi patrick,
is there any reason why your mods wouldn t work with standard unbalanced alephs with only a pair of output devices?
since i converted my dao to taylored version and recently built the f5, i thought my aleph j could benefit from a something like this.
regards,
-py
is there any reason why your mods wouldn t work with standard unbalanced alephs with only a pair of output devices?
since i converted my dao to taylored version and recently built the f5, i thought my aleph j could benefit from a something like this.
regards,
-py
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