The second channel just doesn't work, so I've ordered all new parts to re-wire the entire board.
A question about heatsinking --just how much watts of heat does one channel produce from a 16V transformer? My rather small .75 C/W heatsink gets too hot for my liking. Is one channel just producing excess power because of the missing 2nd channel?
I think that I might have to use one .75 C/W heatsink per FET if I don't use a fan.
A question about heatsinking --just how much watts of heat does one channel produce from a 16V transformer? My rather small .75 C/W heatsink gets too hot for my liking. Is one channel just producing excess power because of the missing 2nd channel?
I think that I might have to use one .75 C/W heatsink per FET if I don't use a fan.
Hi Applebook,
Assuming 16VAC secondaries, I would guess
the final rail voltages to be around +/- 21V DC.
If you're using the basic 1A bias then you
can expect som 40+ watts of dissipation per
channel.
Naturally cooler is better as far as heatsinks
go. Can you touch the heatsink for at least
a few seconds. If so, then the heatsinks
are acceptable warm.
Cheers,
Dennis
Assuming 16VAC secondaries, I would guess
the final rail voltages to be around +/- 21V DC.
If you're using the basic 1A bias then you
can expect som 40+ watts of dissipation per
channel.
Naturally cooler is better as far as heatsinks
go. Can you touch the heatsink for at least
a few seconds. If so, then the heatsinks
are acceptable warm.
Cheers,
Dennis
Thanks, Dennis, I can touch them for at least 3 seconds before feeling too uncomfortable. I guess I'll use a low-powered fan for now.
An externally hosted image should be here but it was not working when we last tested it.
Hi Applebook,
Have you been running that channel with the heatsink
facing down as shown in the picture and you can still
touch it for a few seconds?
For maximal efficiency, the heatsink should be vertical,
with the fins going in the up/down direction. Also,
it looks like you have the output mosfets mounted in
the direction of the fins. Please consider remounting
them in the other direction (rotate setup 90 degrees)
and have them a little further up from the bottom
of the heatsink; about 1/3 of the way is ideal.
Cheers,
Dennis
Have you been running that channel with the heatsink
facing down as shown in the picture and you can still
touch it for a few seconds?
For maximal efficiency, the heatsink should be vertical,
with the fins going in the up/down direction. Also,
it looks like you have the output mosfets mounted in
the direction of the fins. Please consider remounting
them in the other direction (rotate setup 90 degrees)
and have them a little further up from the bottom
of the heatsink; about 1/3 of the way is ideal.
Cheers,
Dennis
Hello APPLE
im back online now. did you ever send me your address?
do you need any parts? i have surplus of alot of the required parts. id gladly pack some freebies for you if needed?
im still looking for some parts to finish my miniA if anybody would like to swap parts etc. i cant order anymore parts until after the new year.
here is what i have coming up.......sinks pulled from a dumpster dive!http://www.diyaudio.com/forums/showthread.php?s=&threadid=86756
im back online now. did you ever send me your address?
do you need any parts? i have surplus of alot of the required parts. id gladly pack some freebies for you if needed?
im still looking for some parts to finish my miniA if anybody would like to swap parts etc. i cant order anymore parts until after the new year.
here is what i have coming up.......sinks pulled from a dumpster dive!http://www.diyaudio.com/forums/showthread.php?s=&threadid=86756
Attachments
im new but i jumped into the diy spirit when i first joined this forum. i wanted to build everything i see on this site so ifigured id buy in bulk..... 100's of source resistors -100's of wirewounds for CRC - 100's of mpsa18, 9volt zener , 1000's of stacked films for bypass-100's of dale rh-50 for SOZ -100's of 220uf panny caps for gainclone ALEPH etc.
well now im unable to spend alot of money on my hobbies., and i still dont have a working PASS clone. That has really bummed me out
i still need: C4,C5,C6 and R0
i have some fets to use as test dummies, but plan to buy matched fets later.
i have alot of oddball stuff i have sourced from other electronics. Ultrafast soft recovery 600v diodes? 60amp 3phase filters, massive fan cooled heatsinks, HUGE inductors? i have become a complete DIYAUDIO JUNKIE
well now im unable to spend alot of money on my hobbies., and i still dont have a working PASS clone. That has really bummed me out
i still need: C4,C5,C6 and R0
i have some fets to use as test dummies, but plan to buy matched fets later.
i have alot of oddball stuff i have sourced from other electronics. Ultrafast soft recovery 600v diodes? 60amp 3phase filters, massive fan cooled heatsinks, HUGE inductors? i have become a complete DIYAUDIO JUNKIE
i have several hundred of panasonic 220uf NHG, ECQ-V 270nf, and riedon UT-2B 0.75R 3W 5%.
im going to run 2 miniA's for my mids/highs. I figured i could use a little extra bias for my BG neo8/neo3 @4ohms
i planned to use matched fets, because when i get time ill prolly step up to a Aleph30 for the neo8.
i still have a AlephX in the plans, and matched fets are a must!
i have some PSU caps 12000uf 50v nichicons snap ins. i dont have the budget for computer grades so ill just CRCRCRCRC the crap out off my supply!
im going to run 2 miniA's for my mids/highs. I figured i could use a little extra bias for my BG neo8/neo3 @4ohms
i planned to use matched fets, because when i get time ill prolly step up to a Aleph30 for the neo8.
i still have a AlephX in the plans, and matched fets are a must!
i have some PSU caps 12000uf 50v nichicons snap ins. i dont have the budget for computer grades so ill just CRCRCRCRC the crap out off my supply!
Banned
Joined 2002
HIPCHECK said:
You only have to match the input fet's The output fets on a mini a ( 2 fets ) do not have to be matched it will not makea difference at all in sound.
I'm moving into a house in amonth so i will be starting projects again speaker enclosures and building my amplifier chassis's.
Excited to build my aleph stereo blocks.
this was posted over in the chipamp forum, i figured some people might want to look at this.
if i guess right 117vac input 44v ct would be 30volt rectified, lose 3-4 v drop under load, and then a healthy CRCRC filter = a nice regulated 25v. perfect for a A30.
with UPS i got a shipping estimate of $11.00 + $33.50 seems to be a good deal for me. can i get a better deal ($44.50) for a 500va+ toroid shipped anywhere else?
i had been looking at the Antek transformers on ebay.....
just looking into my options.... right now i have some 12v 17ah batteries to run my miniA amps.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=93133
if i guess right 117vac input 44v ct would be 30volt rectified, lose 3-4 v drop under load, and then a healthy CRCRC filter = a nice regulated 25v. perfect for a A30.
with UPS i got a shipping estimate of $11.00 + $33.50 seems to be a good deal for me. can i get a better deal ($44.50) for a 500va+ toroid shipped anywhere else?
i had been looking at the Antek transformers on ebay.....
just looking into my options.... right now i have some 12v 17ah batteries to run my miniA amps.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=93133
Banned
Joined 2002
CALLING APPLEBOOK
Applebook (Derek)
hey i have sent you some emails regarding the shipping of the pcb's , and i see you havnt been to diyaudio for a few days. reply to my email with correct shipping address and ill get your package sent off asap! (its all packed up and ready)
as promised i threw in some freebies to help you get started on this and other projects.
Applebook (Derek)
hey i have sent you some emails regarding the shipping of the pcb's , and i see you havnt been to diyaudio for a few days. reply to my email with correct shipping address and ill get your package sent off asap! (its all packed up and ready)
as promised i threw in some freebies to help you get started on this and other projects.
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