Looking to confirm the differences between the A30 and A60.
Looks like both amps have 6 output devices per channel, but biased higher for the A60. I acquired a set of Brian GT boards, and have the schematics and parts list with the component differences between the two.
Couple of questions:
Looks like both amps have 6 output devices per channel, but biased higher for the A60. I acquired a set of Brian GT boards, and have the schematics and parts list with the component differences between the two.
Couple of questions:
- Could someone confirm the voltage rails for each amp? I think the Aleph 30 is +- 25vdc.
- On an appropriately sized large rectangular heatsink with long side front to back and shorter side vertical, where is the best place to mount the TO-220 Mosfets? At the vertical mid-point for 2/3 the way towards the top?
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Aleph 30 : +/-25Vdc rails , consumption 100W per channel
Aleph 60 : +/-35Vdc rails , consumption 100W per channel
thumb of rule - position your output device at 33% of height, starting from bottom
Aleph 60 : +/-35Vdc rails , consumption 100W per channel
thumb of rule - position your output device at 33% of height, starting from bottom
Thanks Zen Mod. Interesting, I would have thought the A60 would require larger heatsinks over the A30.
I have an Antek AN-7240 with +-40VAC output, and heard that's a great A30 stereo Transformer. Any recommendations for a stereo A60 transformer for a CRC power supply?
I have an Antek AN-7240 with +-40VAC output, and heard that's a great A30 stereo Transformer. Any recommendations for a stereo A60 transformer for a CRC power supply?
for 35 rail , loaded ....... that calls for 28Vac secondaries
which type exactly - boyz from your side of Pond need to chime in
I would use 250-300VA for single channel or 500-600VA for common supply
which type exactly - boyz from your side of Pond need to chime in
I would use 250-300VA for single channel or 500-600VA for common supply
Sorry for the newbie questions...
What are builders recommending for number of output Mosfets for an A30 and A60? Looks like most are using matched IFR244 for both amps.
Looks like everyone is using 6 Mosfets per channel for A30, would this mean A60 requires 12 Mosfets per channel?
What are builders recommending for number of output Mosfets for an A30 and A60? Looks like most are using matched IFR244 for both amps.
Looks like everyone is using 6 Mosfets per channel for A30, would this mean A60 requires 12 Mosfets per channel?
Miss-typed on a conference call. Meant IRF240 in TO-220 packaging as Mosfet output devices.
are 6 devices per channel enough to dissipate the heat for an A60? Though the original had 12. Just curious what builders have had success with.
are 6 devices per channel enough to dissipate the heat for an A60? Though the original had 12. Just curious what builders have had success with.
original A30 had 3 pairs , sum Iq around 1A6
original A60 had 6 pairs, sum Iq around 2A2
so , as I previously wrote - both declared having around 100W of heat per channel, pretty common things that Pa is copy-pasting parts of his Service Manuals, later forgetting to check irrelevant numbers
so, let's trust later ones, which is logical, you can't get 60W of A class from air
anyhow, first thing for making an amp is schematic; make one you have schematic for
or ask actual questions, without beating around the bush too much
and yes, you can use one piece of IRFP150 instead of 2pcs of IRFP240, under condition that you cool them properly, do not go above 40(max 50)W of heat per piece and use half of Rs value
so, post your schematics here, then we can talk about details - adequate case. heatsinks,xformer,caps
also, weight your needs for power -carefully .......
original A60 had 6 pairs, sum Iq around 2A2
so , as I previously wrote - both declared having around 100W of heat per channel, pretty common things that Pa is copy-pasting parts of his Service Manuals, later forgetting to check irrelevant numbers
so, let's trust later ones, which is logical, you can't get 60W of A class from air
anyhow, first thing for making an amp is schematic; make one you have schematic for
or ask actual questions, without beating around the bush too much
and yes, you can use one piece of IRFP150 instead of 2pcs of IRFP240, under condition that you cool them properly, do not go above 40(max 50)W of heat per piece and use half of Rs value
so, post your schematics here, then we can talk about details - adequate case. heatsinks,xformer,caps
also, weight your needs for power -carefully .......
I'm using the attached schematic and BOM. My heatsinks are massive 350mmx151mm with a thermal resistance
C/Watt for 80 °C rise of .21 Conrad Heatsinks - Products MF35-151.5
I have 2 matched sets of 6 IRFP240's in TO-240 package for a total of 12. Also an Antek AN-7240 with +/-40VAC center-tapped transformer, which should good for an A30. Since I'm driving a pair of Magnepan 106QR's the additional power of the A60 might be helpful.
You're awesome for helping!
-David
C/Watt for 80 °C rise of .21 Conrad Heatsinks - Products MF35-151.5
I have 2 matched sets of 6 IRFP240's in TO-240 package for a total of 12. Also an Antek AN-7240 with +/-40VAC center-tapped transformer, which should good for an A30. Since I'm driving a pair of Magnepan 106QR's the additional power of the A60 might be helpful.
You're awesome for helping!
-David
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use this one as reference
Aleph is concept; how big/how much scaled up - depends simply of your ambitions and needs
finding original Aleph 30 and Aleph 60 schmtcs is easy
proceed with purchasing parts only when you decide what you're going to build, hopefully understanding differences
Aleph is concept; how big/how much scaled up - depends simply of your ambitions and needs
finding original Aleph 30 and Aleph 60 schmtcs is easy
proceed with purchasing parts only when you decide what you're going to build, hopefully understanding differences
I posted the schematics and BOM in post #10. https://www.diyaudio.com/forums/pass-labs/353152-a30-verses-a60.html#post6171005
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I was typing while you posted that post and later I didn't spot it
you have 6+6 pcs of IRFP240 ; perfect for one channel - one sextet for lower group, second sextet for upper group (that's how matched groups needs to be used)
obtain two sextets more, find Aleph 60 original schematic ( cry here if you can't find it) and proceed making proper one , with values shown in original schematic
rails with your xformer will be just little higher than for A30, but A60 arrangement will give you greater current capacity, perfect for your Maggies
you have 6+6 pcs of IRFP240 ; perfect for one channel - one sextet for lower group, second sextet for upper group (that's how matched groups needs to be used)
obtain two sextets more, find Aleph 60 original schematic ( cry here if you can't find it) and proceed making proper one , with values shown in original schematic
rails with your xformer will be just little higher than for A30, but A60 arrangement will give you greater current capacity, perfect for your Maggies
Thank you Zen Mod for your kind assistance as we cross-posted yesterday!
Attached below is an Aleph60 & KK's schematic for common reference. Looks like per stereo channel; 6 IRF-240's are needed for A30 and 12 IRF-240's for A60. The KK A60 schematic shows 6 IRF-244's or maybe IRF-240's per channel. I'd prefer to to 6 Mosfets per channel if this is a safe approach. Appreciate any thoughts on 6 verses 12 devices per channel and which schematic is better.
KK Aleph5 Schematic:
Aleph60 Schematic:
BrianGT Schematic:
Attached below is an Aleph60 & KK's schematic for common reference. Looks like per stereo channel; 6 IRF-240's are needed for A30 and 12 IRF-240's for A60. The KK A60 schematic shows 6 IRF-244's or maybe IRF-240's per channel. I'd prefer to to 6 Mosfets per channel if this is a safe approach. Appreciate any thoughts on 6 verses 12 devices per channel and which schematic is better.
KK Aleph5 Schematic:
An externally hosted image should be here but it was not working when we last tested it.
Aleph60 Schematic:
BrianGT Schematic:
Attachments
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ignore KK schematic
considering your Maggies, I would go with two mosfet sextets per channel , following Aleph 60 schm up to last dot
only - you can put 500R multiturn trimpot in place of R14, and 100K multiturn trimpot in place of R19 , all ref. original Aleph 60 schematic
additional cost for two mosfet sextets is peanuts , considering final quality of intended amp
considering your Maggies, I would go with two mosfet sextets per channel , following Aleph 60 schm up to last dot
only - you can put 500R multiturn trimpot in place of R14, and 100K multiturn trimpot in place of R19 , all ref. original Aleph 60 schematic
additional cost for two mosfet sextets is peanuts , considering final quality of intended amp
Attachments
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As usual Choky (ZM 🙂 ) is right.
The 60 with more fets is probably the better amp.
I prefer the A5 with IRFP140, but not with the Brian GT boards as the fets are too close together for my comfort. The IRFP140 because they take more of a beating with only six per channel than the 240.
Your best bet is probably to do up a A60 as spec'd.
I have a couple of channels worth of BrianGT 3x fet board snap-offs in the drawer I have been shoving around for years. You can have them for the cost of a flat rate envelope. You can then cleanly do your 12 x fet per channel A60.
Up to you ....
The 60 with more fets is probably the better amp.
I prefer the A5 with IRFP140, but not with the Brian GT boards as the fets are too close together for my comfort. The IRFP140 because they take more of a beating with only six per channel than the 240.
Your best bet is probably to do up a A60 as spec'd.
I have a couple of channels worth of BrianGT 3x fet board snap-offs in the drawer I have been shoving around for years. You can have them for the cost of a flat rate envelope. You can then cleanly do your 12 x fet per channel A60.
Up to you ....
Attachments
I'm assuming the Mosfets are matched per each sextet for an A60?
How many Mosfets are needed to get a matched set of 6?
I'm guessing the IRF9610's and ZTX540's need to be matched as well respectively?
How many Mosfets are needed to get a matched set of 6?
I'm guessing the IRF9610's and ZTX540's need to be matched as well respectively?
I wrote up how output mosfets need to be grouped/matched
say that you need to buy 50pcs (2 bars, same batch) to easily get at least 2 sextets plus plenty of more -matched smaller groups
input LTP mosfets need to be matched, so you need 2 pairs
anything else ( CCS mosfet, bjts) , just grab them from the bag
say that you need to buy 50pcs (2 bars, same batch) to easily get at least 2 sextets plus plenty of more -matched smaller groups
input LTP mosfets need to be matched, so you need 2 pairs
anything else ( CCS mosfet, bjts) , just grab them from the bag
Mr Pass wrote about some mods to the Aleph a few years ago. It might be worth
having a look:
https://www.diyaudio.com/forums/pass-labs/267857-aleph-design-reloaded.html#post4184920
Your transformer (Antek AN-7240) seems no longer available, but by Antek's
part naming convention, looks to be 700VA with 2 x 40VAC secondaries. If
that's the case, the rail voltage will be near +/-50 volt, putting you in the
Aleph 2 range (and somewhat higher than an A60)
having a look:
https://www.diyaudio.com/forums/pass-labs/267857-aleph-design-reloaded.html#post4184920
Your transformer (Antek AN-7240) seems no longer available, but by Antek's
part naming convention, looks to be 700VA with 2 x 40VAC secondaries. If
that's the case, the rail voltage will be near +/-50 volt, putting you in the
Aleph 2 range (and somewhat higher than an A60)