regarding voltage, you will get 1.2 x V ( on sec. ) under load...at least that's what I get with aleph x...CRC ( 24000uF - 0.2 Ohm - 36000uF )...
so for 21V x 1.2 = 25.2V or 22V x 1.2 = 26.4V
regarding VA...
if aleph 30 drows 100W and Mr. Pass recomend to use factor of 2-3, then I don't see reason to go for 500W...
so for 21V x 1.2 = 25.2V or 22V x 1.2 = 26.4V
regarding VA...
if aleph 30 drows 100W and Mr. Pass recomend to use factor of 2-3, then I don't see reason to go for 500W...
Yoke: your figures for the line voltage are very helpful - I hadn't been sure whether I needed additional compensation beyond "1.2 x" when using CRC. Re-reading Mark Finnis' Aleph 5 webpage [http://www.users.on.net/~mefinnis/passlabs/aleph5_construction.htm] he suggests a absolute minimum of x2 current draw, and up to x3 as desirable, which I guess echos Mr. Pass' recommendation. I suppose more is better but the 2 x 300VA fits the budget 
BrianDonegan: Thanks for the note... I'll most likely use the stacked Panasonic's in that case.
Was there a list of what was included in the parts GB posted anywhere? I'm trying to make sense of the bag of bits I received and they don't seem entirely consistent with the briangt parts list.
Finally is there a specific need to use the CL-60 thermistor? I can source some surplus ntc thermistors with 10ohm/5amp rating but wasn't sure if there was something I was missing, apart from Pass approval of course!!
cheers
Paul
BrianDonegan: Thanks for the note... I'll most likely use the stacked Panasonic's in that case.
Was there a list of what was included in the parts GB posted anywhere? I'm trying to make sense of the bag of bits I received and they don't seem entirely consistent with the briangt parts list.
Finally is there a specific need to use the CL-60 thermistor? I can source some surplus ntc thermistors with 10ohm/5amp rating but wasn't sure if there was something I was missing, apart from Pass approval of course!!
cheers
Paul
Cool. I thought that might be the case so I ordered a few anyway. I could get 6 surplus for the cost of one CL-60 so why not!?
I picked up my heatsinks (4 x ML25-151.5) from Conrad this afternoon. Handy having the manufacturer a 5 minute drive from home The heatsinks are really nicely made - I can see why Conrad have such a good reputation on diyaudio. Don't think I'm going to have cooling issues with these monoblocks.
Unfortunately now I have a 2-3 week wait for the transformers.
I picked up my heatsinks (4 x ML25-151.5) from Conrad this afternoon. Handy having the manufacturer a 5 minute drive from home
The heatsinks are really nicely made - I can see why Conrad have such a good reputation on diyaudio. Don't think I'm going to have cooling issues with these monoblocks.Unfortunately now I have a 2-3 week wait for the transformers.
Assorted A30 questions...
I've got the boards fully stuffed minus the silver mica caps for c6 as I was short one, and the output transistors.
I'm a bit unsure of what needs to be wired where - obviously v+ -> OB v+, etc but I'm wondering what to do with the 2x +/-C,G&V?? Are the two sets simply for convenience in wiring?
By a stroke of luck I've been able to locate 2 500VA/2*22VA transformers for a very small premium over the 300VA txf's I'd ordered.
btw if anyone could pass on a copy of the A30 service manual that would be really helpful.
pj
I've got the boards fully stuffed minus the silver mica caps for c6 as I was short one, and the output transistors.
I'm a bit unsure of what needs to be wired where - obviously v+ -> OB v+, etc but I'm wondering what to do with the 2x +/-C,G&V?? Are the two sets simply for convenience in wiring?
By a stroke of luck I've been able to locate 2 500VA/2*22VA transformers for a very small premium over the 300VA txf's I'd ordered.
btw if anyone could pass on a copy of the A30 service manual that would be really helpful.
pj
spzzzzkt...are you useing those boards http://www.diyamps.com/aleph/aleph.shtml
if so, for Aleph30, you just have to conect + side ( +S,+C,+V,+G ) to + side outpot board ( +S,+C,+V,+G ) and - ( -S,-C,-V,-G ) to - ( -S,-C,-V,-G ) output board...
don't forget to conect 0 from power supllay to pcb
http://www.diyamps.com/aleph/docs/miniAleph-sch.pdf
if so, for Aleph30, you just have to conect + side ( +S,+C,+V,+G ) to + side outpot board ( +S,+C,+V,+G ) and - ( -S,-C,-V,-G ) to - ( -S,-C,-V,-G ) output board...
don't forget to conect 0 from power supllay to pcb
http://www.diyamps.com/aleph/docs/miniAleph-sch.pdf
Yes, I'm using BrianGT's Aleph Mini boards...
I was half suspecting that I needed double runs of hookup wire to the output boards. I wasn't sure if I'd missed something with the two sets of holes on the output board.
have schematic but the reasoning behind the [v,c,g]2+ and [v,c,g]2- on the output boards was unclear.
Paul
I was half suspecting that I needed double runs of hookup wire to the output boards. I wasn't sure if I'd missed something with the two sets of holes on the output board.
have schematic but the reasoning behind the [v,c,g]2+ and [v,c,g]2- on the output boards was unclear.
Paul
One step closer...
Had a minor victory today - powered up one of the PSU's without any dramas. I followed the forum advice and put together a light bulb limiter but the whole process was uneventful. I've gone with a 1ohm 50W resistor in the CRC filter, for 30,000uF - 1R - 15,000uf. With the 2*22 secondaries I'm getting +30.9/-30.8 unloaded and I'm interested to see what that will sag to under load.
Is the .1V difference between +/- something to be concerned about? I suspect this is primarily due to the 5% tolerance on the alu bodied resistors.
pj
Had a minor victory today - powered up one of the PSU's without any dramas. I followed the forum advice and put together a light bulb limiter but the whole process was uneventful. I've gone with a 1ohm 50W resistor in the CRC filter, for 30,000uF - 1R - 15,000uf. With the 2*22 secondaries I'm getting +30.9/-30.8 unloaded and I'm interested to see what that will sag to under load.
Is the .1V difference between +/- something to be concerned about? I suspect this is primarily due to the 5% tolerance on the alu bodied resistors.
pj
Nope, thats next to nothing so dont worry. I finished an Aleph 5 today, using BrianGT's small and nice boards. The amp isnt small though, it weighs in at just under 40kg. Dual mono, 2 500VA 2x25v trafos and 6x22000uF per channel. It can deliver the current needed to really rock my Proac Response clones
The sound? simply terrific. Just what I likeHave a look.
Steen
Attachments
Here is another one of the internals. The chunky heatsinks doesnt get warmer than its still possible to hold your hands on them after 3 hours (thats what the amp has been playing right now). They weigh just over 8 kg a piece. The psu sags about 2,5 volts. I had around just under 37V at no load and just over 34V under load. By the way, the amp worked from first turn on! I just love it, when that happens
Steen
Steen
Attachments
steenoe said:
powered up the second psu and that's sitting on +/- 30.8 both rails unloaded. I might take another look at the "high" rail but won't stress too much
Proac Response clones!? Nice - I was going to ask which DIY speaker design you had builtIt can deliver the current needed to really rock my Proac Response clones
Nice looking Aleph 5 btw. In fact your whole Pass "rack" is very very impressive
I'm sure I haven't thought my Chassis through very well - it is my first diy amp - and I'm pressed for space. I'm having to go for an arrangement as illustrated in attachment. The main board is going to be pretty close to the trafo so I think I'm going need a shield of some kind?
pj
steenoe said:Here is another one of the internals. The chunky heatsinks doesnt get warmer than its still possible to hold your hands on them after 3 hours (thats what the amp has been playing right now). They weigh just over 8 kg a piece. The psu sags about 2,5 volts. I had around just under 37V at no load and just over 34V under load. By the way, the amp worked from first turn on! I just love it, when that happens
Steen
Steen,
Very nice works.
Seems that you get very efficient heat sinks. I'm looking for such heat sinks for reasonable price. Care to tell us where did you get them, dimensions and the cost?
Thanks. Them stickers look cool
I didnt put one on the Zen headphone amp, since the sticker would take over the whole faceplate Well, maybe I will. Mr. Pass rocks Any chance to stack the mainboard on top of the psu?
If yes, you could place it in the most opposite corner.
They measure 400mmx200mmx85mm. The bodyplate is 16mm thick. I havent seen them for sale anywhere. A friend of mine had 4 of those and I managed to pursuade him to trade 2 of them with me
Would you believe that he wanted to cut then to smaller pieces to be used for gainclones? That must top the list of crazy things you can do to nice fat heatsinks. I had to tell him he was mad He still has the other set, he wants to use them for a Krell KSA50. Pheeew, glad he reconsidered the cutting Yeah, I agree. The amp doesnt look too sexy.
Steen
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