A30 verses A60

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#21
Dennis Hui said:
Mr Pass wrote about some mods to the Aleph a few years ago. It might be worth
having a look:

https://www.diyaudio.com/forums/pass-labs/267857-aleph-design-reloaded.html#post4184920

Your transformer (Antek AN-7240) seems no longer available, but by Antek's
part naming convention, looks to be 700VA with 2 x 40VAC secondaries. If
that's the case, the rail voltage will be near +/-50 volt, putting you in the
Aleph 2 range (and somewhat higher than an A60)
Click to expand...


That Antek transformer is 40V center tapped for 20V for 2 rectifiers. Should be good for an A30 I assuming.


Which transformer is recommended for an A60 these days? If not a model, perhaps VA rating and secondaries. Should this be 28VAC at 800VA?
 
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#23
Aleph 60 Mosfet Options

Curious what experimentation over the years has demonstrated as sonic differences between Vishay IRPF150/140/244 in TO-47AC packaging? I know Papa went with 244's. I noticed the input capacitance of the 150's is much higher than the 240/244 specs. Not sure of the impact of higher capacitance.

I like the idea 6 IRFP150 devices instead of 12 240/244's per A60 channel.


The help is very much appreciated from the form so far!
 

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#24
as I said - Aleph is an concept, which is much more than just one amp of which we have schematic, with damn big Title - "Carved in Stone! Use Just These Special Parts or it'll be Utter Drek!"

decide how much power you need, then everything ie easy

you can read some of About possible Babelfish J interest, to get an idea about versatility

as long output mosfets are chosen in a way that there is no BigBadaBoom, differences in sound between various types are smaller than people usually claim ...... under condition that FE is having enough Cojones to feed them all :rofl:
 
#25
The input capacitance is higher with the IRFP150 but you will probably use fewer
of them compared to IRFP240, so no biggie.

Members have built Alephs using many different devices and power levels from headphone
amps to big Aleph 2 using the same topology. Within reason, many parts will work fine.

Here's an old post where Mr Pass commented on parts:

Power Mosfet Choices

Cheers,
Dennis
 
#26
Dennis Hui said:
The input capacitance is higher with the IRFP150 but you will probably use fewer
of them compared to IRFP240, so no biggie.

Members have built Alephs using many different devices and power levels from headphone
amps to big Aleph 2 using the same topology. Within reason, many parts will work fine.

Here's an old post where Mr Pass commented on parts:

Power Mosfet Choices

Cheers,
Dennis
Click to expand...

Great thread to bring back up.

I've very interested in experimenting with 6 IRF150's per side for an A60. I'm listening to a Volksamp 30 right now with my Magnepan 1.6QR's and just love it; however curious to hear the effect of greater power in driving the speakers. In a past life I was an electronics technician with mad soldering and fabrication skills and am enamored with DIY.

I'll need a little coaching on the engineering side adjusting the Aleph 60 schematic to accommodate the component replacements for 6 IRFP-150's per channel then 12 IRFP-244's.

I'm assuming the A60 schematic and PSU requirements remain the same, and wondering which resistor values change to accommodate the IRPF150's?

Thank you for help with this journey!
 
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