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Old 16th April 2004, 07:35 PM   #1
cowanrg is offline cowanrg  United States
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Default aleph3 transformer advice

hey everyone, its been awhile!

i have some free time lately, so ive been trying to finish up some of the many projects in my basement! im finally gonna finish off the aleph2;s i have down there. but in the meantime, i want to do a test run by throwing together some aleph3's. i already have the boards and all the parts (and heatsinks). the only thing i need is a transformer. i want to keep this pretty cheap, as finishing up the aleph2's will be very costly still.

i saw a thread awhile back about using avel lindbergs from partsexpress, but they have 25v secondaries... someone suggested using a CRC filter. i was unable to find that PSU software that you could calculate values...

if i could get by with this transformer, i would save some cash. they are only $60 each, whereas VM or other would be $80 and up each...

also, i will be driving a 4ohm (max) load. i have magnepans. so, would the higher voltage be beneficial? they will be well heatsinked, and i have a BOX of 26,000uf caps, so i can give them ample cap banks as well.

thanks guys! i hope to have new pictures soon.
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Old 16th April 2004, 08:36 PM   #2
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Not being an expert, here goes (I am sure the experts will correct me if I am wrong). The Aleph 3 is designed for +/-25v rails. At 25VAC with a CLC filter (assuming you are using a Hammond 159ZL choke) you will get approximately +/- 31 to 32Vdc rails. I am pretty sure the 2 sets of IRFP244's can handle that, but I would add one more set of IRFP244's just to be sure.
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Old 16th April 2004, 08:46 PM   #3
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Avel Lindberg sells direct as well. Check their prices. They were very nice to deal with.
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Old 16th April 2004, 09:02 PM   #4
cowanrg is offline cowanrg  United States
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any ideas on how i would go about contacting them?

that seems like the best solution.
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Old 16th April 2004, 09:09 PM   #5
MikeW is offline MikeW  United States
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Old 16th April 2004, 09:11 PM   #6
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Default Check Again at VM

I just recieved a couple of transformers from VM. A 320 watt was 65.00 and a 250 watt was 58.00. But you will have a two week wait.
They appear very well made.

George
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Old 16th April 2004, 09:35 PM   #7
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Since you're driving a 4 ohm load, you might consider
lowering the rail voltage while cranking up the bias current.

BTW, I used a 500VA 2x20VAC transformer for my A30
and the rails were around 25VDC.

Cheers,
Dennis
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Old 16th April 2004, 09:45 PM   #8
cowanrg is offline cowanrg  United States
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Quote:
Originally posted by MikeW
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mike,

i got your email, but unfortunately, i need two. i am doing two monos. (in separate cases too, so i cant do a common xformer.) thanks though.
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Old 16th April 2004, 09:48 PM   #9
cowanrg is offline cowanrg  United States
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Quote:
Originally posted by Dennis Hui
Since you're driving a 4 ohm load, you might consider
lowering the rail voltage while cranking up the bias current.

BTW, I used a 500VA 2x20VAC transformer for my A30
and the rails were around 25VDC.

Cheers,
Dennis
any threads i can look at for examples? im still a beginner when it comes to the actual circuits of an amp. the extra bias would help im sure though... keep in mind, these are going to be JUST driving the tweeters (quasi-ribbon), where the aleph2's will be driving the bass panel.
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Old 16th April 2004, 09:54 PM   #10
MikeW is offline MikeW  United States
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Default Mono

You can use the 18-0-18 230 VA from Avel for mono's. I used the 15-0-15 for my mini-a and they sound great.
http://avellindberg.com/transformers...ange_specs.htm
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