That is exactly what the Aleph J excels at. Dynamic and detailed without sounding too bright. Midway between forward and laid back presentation. Yes, it is single ended Class A, as is the ACA, but better all around. While you had a pair of ACA monos, you were getting a taste of how separate power supplies per channel can improve an amp.
The F6 (as I built it) is also dynamic and detailed, but with a more forward sound. If anything a bit on the clean sounding side; very neutral. I use the different output transistors for their higher transconductance, as well as their power handling ability. I actually tweaked mine to give it a little more H2 ('dirty' it up), but that is a lot of work. Maybe best to leave it as an example of a cleaner sounding amp.
The F6 (as I built it) is also dynamic and detailed, but with a more forward sound. If anything a bit on the clean sounding side; very neutral. I use the different output transistors for their higher transconductance, as well as their power handling ability. I actually tweaked mine to give it a little more H2 ('dirty' it up), but that is a lot of work. Maybe best to leave it as an example of a cleaner sounding amp.
Alea iacta est. Thank you very much, I am not absolutely convinced I am going to build an Aleph J! Waiting for the boards to arrive now. Will also make a dual power supply. Thanks for all the help!
Yes, it would certainly be fun to hear a well done F8. Meanwhile I am working (slowly) on ZM's LuDEF. Still putting together a Mouser shopping cart for that one. Also have a LuFo on deck to try with a couple different choke loads. The boards for the LuFo are already built; I'm still working on the PSU for that one. Not completely done with my VFET amp either, though still enjoying it immensely with various FE cards. Have a couple custom FE cards of my own to finish.
Yes, it is an illness. 😉
Yes, it is an illness. 😉
I think “punch” might have more to do with combination of peak power and output impedance (low output impedance is same as high damping factor). Many of the SE Class A amps have a smooth sweet sound but tend to have not the lowest output impedance needed to provide the “grip” on the bass. Push pull Class A amps tend to have better grip. I have found that Class A amps in balanced bridge tied load (BTL) configuration can have very good bass punch. My one anecdotal evidence is the bass grip of the SuSyLu was as good if not better than most Class AB amps I have heard in the same 100w class range. For background, I have built the following Class A amps: ACA, F5, M2, M2X, Aleph J, BabelfishJ, DIYA VFET, MoFo, Alpha 20, Alpha BB, Alpha Nirvana, JLH, DLH, Omega 35, Glass Harmony, LuFo, and SuSyLu.
Sometimes the output stage topology can have an impact simply by having the MOSFETs of the push pull oriented with either the source facing the load or the drain facing the load. I think source facing the load (N channel on top and P channel on bottom of a schematic with +ve rail on top and -ve rail on bottom) has better grip because the output is more directly related to gate voltage.
Sometimes the output stage topology can have an impact simply by having the MOSFETs of the push pull oriented with either the source facing the load or the drain facing the load. I think source facing the load (N channel on top and P channel on bottom of a schematic with +ve rail on top and -ve rail on bottom) has better grip because the output is more directly related to gate voltage.
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I've noticed that having a good preamp seems to make a big difference as well. I have the Korg new tube B1, the BA 2018 and recently picked up a dual mono BOSOZ. Korg is very sweet but I think some would consider a little light in the bass, BA2018 is in the middle but very dynamic, BOSOZ dual mono will straight up take your head off if you're listening to something like Private investigations by Dire Straits. Quite a different sound between all three using the same amp.
Interesting. So with SE normally I get a sweeter sound with airy highs and not so much grip on the bass and PP reduces 2nd harmonic distortion and gives over all a cleaner and more accurate sound with more punch. Did I get this right? Of all the amps you built, which one is the best compromise between these two worlds? I am still planning on building an Aleph J as soon as the boards are available again. Any other suggestions?
