Yes, most AB amps are class-A up to perhaps a watt or two. Very few are more, and many are less.
That said, the Aleph J is not a Push-Pull amp, it's single ended. It cannot pass more current than it's bias, and therefore it must operate in class-A all the time. Push Pull can be Class -B, -AB, and -A. Single ended can only be -A or better, but that's a discussion for another day and applies to tube amps.
It depends how close to the rails your signal is swinging.
In the case of ACA you had 19V pk to pk so increasing the voltage gave further improvements even at low power output.
With your Aleph J you have 40V pk to pk. So unless you're swinging more than 15W rms you won't notice any improvement.
If you are then it might be worthwhile.
In the case of ACA you had 19V pk to pk so increasing the voltage gave further improvements even at low power output.
With your Aleph J you have 40V pk to pk. So unless you're swinging more than 15W rms you won't notice any improvement.
If you are then it might be worthwhile.
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I actually had done something similar last fall.
I have an Aleph J (converted from mini-Aleph on Brian GT boards) with a single set of IRFP140's per side. I had been running it on 19V-ish rails from a 16V transformer (our wall AC is a bit low here). I was running it at 2.2 amps per side (big heatsinks) and liked the sound very much.
However, I had been itching to try an M2
.As a first step I switched the power transformer to 20V secondaries and had rails with 24V-ish voltage, still with the Aleph J. Set bias to 2.0 amps, so roughly 48W per MOSFET, which still worked with my heatsinks.
Too my ears, the sound of the Aleph J with higher rail voltage moved into the direction of more sterile, more sober. Certainly strong and clean bass, but that I did have before as well.
My speakers are 100db/W efficient Jericho Horns with the original Fostex 208 Sigma (not -EZ) drivers. They don't need much damping, and the higher voltage of the Aleph J might have brought on more damping and changed the sound into a direction that I didn't like.
I'm conjecturing here, but a changing in damping factor might happen if you raise the rail voltage.
For the M2 I put into the case then (built on JPS64 boards, running 2SJ201/2SK1530 at 1.81 amps and 24V), the rail voltage seems perfect.
But if I would put my Aleph J back into the case at one time, for my speakers, I definitely would go with the 19V rails and higher bias current again.
Hope this can give some perspective,
best regards,
Claas
when I'm craving for direct energy , I just put my knitting needles directly in the mains
post photos please!
Well, I have heard Class-D amps compared to the Aleph J, though not specifically amps that use Pioneer's nifty marketing buzzwords, and my general impression and opinion is that they are fast, clean, powerful, dynamic, and suck the soul completely out of the music.
The Aleph J has the most beautiful presentation of any amplifier I've ever heard, it's simply amazing. It is so much better than any mass-market mass-produced amp it's hard to make a meaningful comparison.
The Aleph J has the most beautiful presentation of any amplifier I've ever heard, it's simply amazing. It is so much better than any mass-market mass-produced amp it's hard to make a meaningful comparison.