@Aleph5 You are absolutely right! That is what I thought too! But instead of using oscilloscope for I am still trying to buy some vintage old signal generator and oscilloscope, I could play fixed frequency (I once checked and they are available on YouTube) and measure it with ordinary multimeter.
Trying hard to look for the beast! Where are they?Hello NE WAY,
my amp came out of the 'F4 beast builders thread'
https://www.diyaudio.com/community/threads/f4-beast-builders.300233/
and the Babelfish XA252 thread (Zen Mod)
https://www.diyaudio.com/community/...belfish-xa252-sit-babelfish-xa252-set.373443/.
I used the bias mechanism of Zen Mod and paired it with a pair (N-ch / P-ch) 'Hockeypuck'-MosFets from IXYS.
As the driver board I made something similar like Sony V-Fet -driverboard from Mr. Pass (see pic below).
Something like a cascoded BA-3-frontend.
If you want to build something crazy like this, I would use ZEn Mods boards (Babelfish XA252 full Mos).
Cheers
Dirk
p.s.: and be sure, that you need a lot of aluminum / heatsink for the IXYS-Mosfets biased to 2.7 A!
if that means 16 pairs in regular Aleph OS (so no bridged amp, as X series), that means 16 pairs, means 16pcs per rail, means 16pcs matched up and 16pcs matched down
going double, everything is double
though, even with 16 pairs, I'm not sure what result can be , if using common Aleph schematic......... that's Helluva capacitance
lazy right now to check what was greatest number of mosfets per stage used in PL products ........
If you want some IRF244 I probably could sell a few. I got them for my Aleph5, but turns out I just blew the zener and my outputs were fine.
I've intended to match some, but have not done so.
I've intended to match some, but have not done so.
Dear Papa, Haven't talked to you for a while.
Now I would like to ask a simple question:
What should be an appropriate complementary pair for IXYS IXTN40P50P.
I have a dozen. 😉
Now I would like to ask a simple question:
What should be an appropriate complementary pair for IXYS IXTN40P50P.
I have a dozen. 😉
not Papa, but to help him chill and enjoy in nice cup of brew..
fact - in XA25, IXFN140N30P and IXTN40P50P
fact - in XA25, IXFN140N30P and IXTN40P50P
Hello Aleph5,
also the INT-25 uses complementary IXYS-Mosfets (the hockeypucks). On the pic in the
'6moons'-review you can see the 4 screws through the outputpcb to the IXYS -Mosfet.
https://6moons.com/audioreview_articles/passlabs6/3/.
But the INT-25 is the integrated amp version of the XA-25.
Greets
Dirk
also the INT-25 uses complementary IXYS-Mosfets (the hockeypucks). On the pic in the
'6moons'-review you can see the 4 screws through the outputpcb to the IXYS -Mosfet.
https://6moons.com/audioreview_articles/passlabs6/3/.
But the INT-25 is the integrated amp version of the XA-25.
Greets
Dirk
That is a good start, the XA25 was developed 8-10 years ago, IXYS have introduced a few more pucks since, I believed that the latest is the IXTN500N15X4 announced 3 months ago, though it may not be suitable for audio amps. Perhaps there may be others newer ones that may be suitable?
Hello NE WAY,
you have to check the datasheets of the IXYS-Mosfets. Check for low Ciss, SOA (safe operating area) and
more. Not so easy to handle. Most of them intended for switching high voltage / high amperes. Most of them are not really suitable for use in an amplifier.
Cheers
Dirk
you have to check the datasheets of the IXYS-Mosfets. Check for low Ciss, SOA (safe operating area) and
more. Not so easy to handle. Most of them intended for switching high voltage / high amperes. Most of them are not really suitable for use in an amplifier.
Cheers
Dirk
Thank you very much to you and others for all the helpful and kind advices， I shall be careful, probably start experimenting with the proven IXFN140N30P/20P, and move from there, although I have the suspicions that IXFN140N30P/20P were chosen in order to find the matching P version for push pull circuit. In any case, this should keep a 60 year old man happy and busy to tinker around for a while 😊
Hi Dirk
Thanks for the SOA reminder. Do I use the DC curve in the SOA since the other curves are for single pulse.
For Aleph 5 with VCC +-35, with the intent to drive speakers with low impedance of 1 ohm, sonic quality aside, from SOA, would the IXFN210N30P3 (SOA 3rd pic) be a better candidate than IXFN140N30P (SOA 4th pic) electrically?
IXFN210N30P3’s:
RDS is 14.5mOhm (vs. 24mOhm)
dV/dt is 35 V/ns (vs. 20 V/ns)
Ciss is worse at 16.2 nF (vs. 14.8 nF)
Qg is worse at 268 nC (vs. 185 nC)
Attachments
existence of DC curve in SOA is condition that part can be even considered
if yes, then look at interelectrode capacitance as next criteria
you'll not find any guidance for pairing by xconductance, simply by lacking proper info for area of our interest
but, they're so wild in xconductance department, that info is hardly of any practical importance
edit: regarding SOA graph DC values, matter of perspective - think about conditions in circuit - in moment of greatest current through part, what is voltage across the same?
suddenly, part is much more potent than looking blindly at numbers
I've wondered the same thing. After hearing XA252, I decided that this was the best amp I have built and there have been a high percentage of the First Watt clones. They are all wonderful, but the transparency and dampening factor are glorious. I wonder not only why more amps havent utilized them, or the equally stunning square law design used in XA 25 and XA 252.
so impressed am I that I am searching and figuring on possibility of commercial XA25. I want to build one more XA 252, (was after two more, but I think P of P amp will fill one of those slots. Hopefully two things, repair of existing XA 252, for one, and two, that Zenmods XA 252 boards get out of customs jail so I can build on!
In my not so important opinion, these mosfet puck and Square Law output sections are the wave of the future....why more havent glommed on to this is beyond me!
Zen mod, any movement on the customs situation and the XA 252 boards? I sure hope so!
Russellc