Cool thanks Bill. If I remember correctly, you helped me out on the A60/A5 amp.
I do have a little "room" in the sinks...the chassis was designed by a fellow on this site for an Aleph 2 Monoblock (supposedly able to dissipate around 400+ watts, but I think that may be pushing it)
If I build the AJX exactly with components from a real AJ schematic (8 fets/channel) and get the PS down to +/-22V, the dissipation should be around 180watts, correct? Or will it be double because of the "X"?
I do have a little "room" in the sinks...the chassis was designed by a fellow on this site for an Aleph 2 Monoblock (supposedly able to dissipate around 400+ watts, but I think that may be pushing it)
If I build the AJX exactly with components from a real AJ schematic (8 fets/channel) and get the PS down to +/-22V, the dissipation should be around 180watts, correct? Or will it be double because of the "X"?
I would say 22V is too high unless you adjusted the bias downward, but I would much rather give up a few volts. I think the bias current is much more important. There are a few variables that you will have to balance, but 18V rails would probably give you the best compromise, if it really is a compromise. The Aleph Js I have built have generally run right at 1.1A per fet and at 22V you would be very close to 400 watts.
Compared in what way? The J is a retired commercial design, the JX is an iteration of 2 Js in a bridged configuration originally (or not) conceived by G. Rollins. The JX is push-pull, the J is single ended. The JX is probably 10X more difficult to pull off correctly, but that is just an opinion. The noise and distortion are much lower if done right.
Folks:
This may be a particularly foolish question, but is the Aleph JX as suitable for single-ended sources as it is for balanced sources? If not, which high powered (approx 100 watts into 8 ohms) Pass design would you recommend instead? I'm asking because neither my turntable nor CD player is balanced.
Regards,
Scott
This may be a particularly foolish question, but is the Aleph JX as suitable for single-ended sources as it is for balanced sources? If not, which high powered (approx 100 watts into 8 ohms) Pass design would you recommend instead? I'm asking because neither my turntable nor CD player is balanced.
Regards,
Scott
Fred, Have you reached out to Peter Daniel? He may have some, I vaguely recall he was looking for interest in another production round.
It's probably just a typo but wanted to make sure you realize that the output mosfets get installed 4 at a time - 4, 8, or 12 with these boards.
It's probably just a typo but wanted to make sure you realize that the output mosfets get installed 4 at a time - 4, 8, or 12 with these boards.
Nelson:
Presuming you are responding to the question, as opposed to the personal observation, thank you!
Regards,
Scott
Presuming you are responding to the question, as opposed to the personal observation, thank you!
Regards,
Scott
Am I correct that I will need 8 matched triples of IRFP240's if I utilise all the output locations fot a pair of JX mono blocks?
😀
That is the main reasonn i am building as mono blocks. I hope two Conrad 350 x 150mm will suffice per mono block, I may look at having the base plate sitting slightly lower than the bottom of the fins any use two quiet fans to get some air flow rising over the sink fins.
Hi there guys, just starting to collect a few parts for this project while I wait for the boards to get here (Peters); plus I need to order my TX from sumR so that'll be a bit and my speakers arent done either 😉 but anyway I am building the JX and i'm already in possession of some IRFP240 (need to match them up), some 2SK1530 and some semisouth R550. now i've been doing quite a bit of reading in here and other threads and strangely I havent come across anyone using the SS parts, which for an amp of this name seems a nobrainer someone would at least try. anyone know how feasible it is and perhaps have a link to someone who has built it? I have nothing against the 240's at all, but just want to weigh up my options.
in case you are wondering, I had intended to install the 240's first, but mainly asking out of interest. probably I should go read 1000 pages
bias
when reading the spec of original AJ It says max output current 2.5A
does that mean that the total bias Is 2.5A which Is 1.25 for a vertical output IRF240s
what Is R27 value that relate to this bias
when reading the spec of original AJ It says max output current 2.5A
does that mean that the total bias Is 2.5A which Is 1.25 for a vertical output IRF240s
what Is R27 value that relate to this bias
total bias of original A J is well under 2A/channel
exact value of R27 depends of exact Ugs of upper output mosfet , and exact Ube of current programming bjt
Remember the Aleph J current source is modulated, max output current is higher than the bias.
What value component should I use for RP and P1. About to send of Mouser order and dont have time to read 110 pages. Ill be using the ZTX550.
Cheers
Cheers