I agree with Buzz's choices for amps - if planing on using B1, you need normal gain in amp, Aleph J would be my first choice, parts and PCB readily available, lots of completions on the forum, and sounds utterly fantastic.
Can you provide more information on the heatsinks you are using? Just a G5 case (as beautiful as it is) will be woefully too small for the cooling requirements of any of these amplifiers.
Can you provide more information on the heatsinks you are using? Just a G5 case (as beautiful as it is) will be woefully too small for the cooling requirements of any of these amplifiers.
stabender,
I have a pair of these:AN-6218 - 600VA 18V Transformer - AnTek Products Corp
one new and one with very little use. If you are in the States two of them fit in a large flat rate box from usps. $16.85 to ship. One is $12.35 to ship. I would sell them for $50.00 each.
Evan
I have a pair of these:AN-6218 - 600VA 18V Transformer - AnTek Products Corp
one new and one with very little use. If you are in the States two of them fit in a large flat rate box from usps. $16.85 to ship. One is $12.35 to ship. I would sell them for $50.00 each.
Evan
Aleph J pcb's are available at the Diyaudio store. This would be my first choice.
G5 case dimentions are 45cm width, 46cm depth, 22cm height. I can use 46x22cm heatsinks with long fins. Or I can mount a bit higher ones. G5 case is full aluminium, I think it is good for heat dissipation? Or should I get a bigger, longer chassis?
Evan, thanks for your kind offer. Unfortunately I'm too far from states.. Other side of the world
I thought we were still in the dark about exact details of the J2. Did I miss a thread with a circuit?
Alephs like to run hot, a heatsink like that per channel will be great.
Aluminum is good for dissipation, but there's no good way to attach the hot things to the case, nor is the chassis made to be a radiator, whereby much of the case won't have any thermal transfer.
Thanks. So, I'm planning to build Aleph J in this case. Also, I don't need lots of power, all of my speakers are very efficient. After hearing ACA for a month (its not sophisticated like f5 or aleph, but still!) , all my other amps sounds dull, lifeless, less detailed.. We will see where this journey ends..If there is any
After all reading, researching, I decided to build classic F5. Right now I'm gathering parts and designing a chassis. I'll be using NOS fairchild mosfets and ~8mA toshiba jfets.
I build Pass B1 with linear regulated psu year ago.Dead silence, lots of detail! B1 has no gain, F5 has ~15dB gain if I'm not mistaken. As I read, F5 likes a gain stage at preamp. I'm wondering, if B1 and F5 is enough for my FR and old efficient bookshelfs that I have? Or should I follow a different route and build BA-3 gain stage for F5? Is it a good match?
How is BA-3 front end? Is it better than B1? Soundwise?
Thanks!
I build Pass B1 with linear regulated psu year ago.Dead silence, lots of detail! B1 has no gain, F5 has ~15dB gain if I'm not mistaken. As I read, F5 likes a gain stage at preamp. I'm wondering, if B1 and F5 is enough for my FR and old efficient bookshelfs that I have? Or should I follow a different route and build BA-3 gain stage for F5? Is it a good match?
How is BA-3 front end? Is it better than B1? Soundwise?
Thanks!
Well.. Finally I built my f5. Everything went fine until biasing. I had two dmm. I read somewhere, bias should be measured across R3 or R4! So, in my weird logic I thoght either one will fine. So I measured bias across R3 while monitoring dc offset . When I increase bias with one pot -one or two turn- offset increased. I turned other trimpot until dc offset at the output vanishes. While I'm doing this 500va toroid was humming mecanically. Biased other channel with only R3. (I know it was a huge mistake!) Both channel biased to 0.59V across only R3. Whole process took 3-5 min. I knew there is something wrong with this process. I kept going. I measured voltage across R4 to check. One channel has 2V, other channel has 1,8V!!! Turned off completely. I realized my silly mistake. Returned all pots to zero, turned on the amp. No humming transformer.. No dc offset.. Both channel biased to (this time both R3-R4) 0.59V. But dc offset does not change at all this time, constant zero.
Power supply for both channels steady +24/-24V.
I think I shorted outputs? I'm using original FQA mosfets. Did I blew something else at the amp boards by doing this silly bias procedure? Or replacing output mosfets may solve my problem?
Power supply for both channels steady +24/-24V.
I think I shorted outputs? I'm using original FQA mosfets. Did I blew something else at the amp boards by doing this silly bias procedure? Or replacing output mosfets may solve my problem?
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