I will try them in lower part as suggested. I can always switch to the IRFP parts. May as well try to do something with the parts.to clarify what I meant
as long they are SJEP120R[*] you're good...... whatever numbers you have as [*] , who cares .... ZM is happy with any of them
so, if you have them (any), you're good and use them as lower one in OS
if you don't have them, be perfectly happy with both IRFP in OS
magic of F8 isn't in Semisouth part (it is just partially) but in everything (else)
heh, it's almost good as M2
didn't you show pic of 2 SJEP quartets, somewhere around?
These devices are very dangerous. Known to cause addiction to sound. That's why they aren't produced anymore. A few of these got into wrong hands, but at least the damage has been contained and not widespread. If in doubt, send a pair to me immedately
Hi! I would like to build this beautiful beast. Not sure, which version.
This thread does not really tell a lot about the relationship of bias and sound.
I understand that there was a successful build with a bias of only 1A3.
This would allow smaller heatsinks, which would be perfect for me as I do
not want to exceed 4U x 30cm.
This thread does not really tell a lot about the relationship of bias and sound.
I understand that there was a successful build with a bias of only 1A3.
This would allow smaller heatsinks, which would be perfect for me as I do
not want to exceed 4U x 30cm.
for my ears, all 3 amp iterations are practically the same amp
preferably with Semisouth down, but there is no huge difference if using IRFP in both positions
yes, it'll sound same nice with decreased Iq, but with slightly less power
I have limited number of 2SJ74 now, that limiting amount of available kits of basic version
F8b and F8m are available in practically unlimited quantity
preferably with Semisouth down, but there is no huge difference if using IRFP in both positions
yes, it'll sound same nice with decreased Iq, but with slightly less power
I have limited number of 2SJ74 now, that limiting amount of available kits of basic version
F8b and F8m are available in practically unlimited quantity
That was my amp. I built the standard version with tightly matched Toshiba 2SJ74BL (8.00mAIdss) and Semisouth down. I built it with a chassis I had repurposed and set the Iq to 1.3A to give a 50 deg C heatsink temp. For me as it is, this is the best sounding of the Pass amps I have built all with the same type of power output. I also built it with dual SMPS PSU rather than the normal type supply. It has clarity and finesse in spades on my Yamaha NS1000M speakers.
You wont be disappointed. So contact ZM sooner rather than later to get hold of the F8 boards, I already had the J74's.
... aaaand if you ever get bigger chassis, you can turn it up to 2A which I did, and than you get the amp with the sound which makes multiverse collide 🙂
Simple, adjust the Iq level to suit the heat sinks in your chassis. Shoot for 50 deg C at the warmest point on the heat sink - or if you are brave and have good ventilation around the amp go for 55 deg C. It will take a good hour or more to get the temp to stabilize so do it in steps and with the chassis lid sitting in place, as you monitor the bias and temps.
ZM fighting with Plethora of e-mails and PM-s
at least half of them are regarding something I don't have a slightest clue about ......
I believe tonight will catch up present time
at least half of them are regarding something I don't have a slightest clue about ......
I believe tonight will catch up present time
Order is in. Now patiently wait and plan the conversion. Taking Aleph J boards out of the 4U/400 and will retrofit BF8 with SJES that have sat idle since the gracious giveaway.
Still have J2 boards that may need to be tried at some point but I think this F8 build will hold me over.
And to no end, already planning what's next. Any suggestions what to do with big hulking Tokin SIT? How much power could I get with two channels inside a 4U chassis?
Eager to hear from anyone who has spent time with Aleph J (mine has been in system 2 for 5 years) and made the move to F8.
Still have J2 boards that may need to be tried at some point but I think this F8 build will hold me over.
And to no end, already planning what's next. Any suggestions what to do with big hulking Tokin SIT? How much power could I get with two channels inside a 4U chassis?
Eager to hear from anyone who has spent time with Aleph J (mine has been in system 2 for 5 years) and made the move to F8.
Quick question regarding substituting this into my Aleph J. If I remember correct, for reasons unknown, I went with 20V secondary transformer. Maybe cause I thought I'd drop some voltage on CLC.
I think my rails loaded down might be 27 volts. Is there anything I need to worry about regarding cap ratings that may be worth swapping? 2 volts over on a 25V cap no big deal?
I think my rails loaded down might be 27 volts. Is there anything I need to worry about regarding cap ratings that may be worth swapping? 2 volts over on a 25V cap no big deal?
if you go with 20Vac secs, instead of 18Vac, if everything is as usual, you'll end up with appr. 24V5dc rails
for that, you need PSU caps with 35Vdc rating
now, nothing to change in channel pcbs, except to take care how much Iq you're going to set, keeping palm on heatsinks
but, that's normal routine, even when nuttin' is changed
for that, you need PSU caps with 35Vdc rating
now, nothing to change in channel pcbs, except to take care how much Iq you're going to set, keeping palm on heatsinks
but, that's normal routine, even when nuttin' is changed