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Old 1st December 2004, 01:23 PM   #1
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elviukai's Avatar
Join Date: Apr 2003
Location: EU- Electronic Union country
Default basic on aleph p 1.7 preamp

hello guys, in my plans are pass aleph p 1.7. I searched but find a little about parts. only Kilowatsky.. dear kilowatsky and othres I have folowing quastions and plans

I will build this preamp-
1-without relays
2-with discrete volume regulator

questions are
1)what volume pot I should use 2? 10? 100kilo ohm?? or can I redo 100k pot to 2??
2)I cant use 50v elna silmic in power suply stage.?? min 63V panasonic for ex? . seeing from schematic I see that voltage after refricter can be arround 86(!) volts. I am limited on 63v capasitors only..

3) what capasitors are the most important of theese 10uf? c9/c13 or c 10/c14- 3x10uf ?? I planing use audyn zinc folie to c9/13 and audyn zinc folie mixed with simple mundorf ?

also I need pcb layout that I can build myself pcb, prefered single sided. can anybody post it to me. email

thanks for everybody and will wait answer..

Hope I can build this nice preamp. btw it will be mached with aleph5 clone
natural sound reproduction from traditional dynamic drivers?!! come on.. no no, it can be.. it must be!..
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Old 2nd December 2004, 08:02 PM   #2
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Location: Long Island, New York
Your volume pot should be 5K ohms. If you can only get 63 volt caps simply double the capacity and put them in series because unloaded, the voltage out of the transformer can be as high as 80 volts. Simply use the best capacitors you have for all the capacitors. Lastly, I don't know of any artwork floating around the forum.
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Old 2nd December 2004, 09:07 PM   #3
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Location: San Jose

I'm using 10K for my volume pot. It is the Taiwan ladder attuenator that was available a while back. It is a slightly noisy while switching sometimes, but for $50USD it is tough to beat. I'm upgrade to relays later.

Mine sounds great. Is there a down side going with 10K rather than 5K?

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Old 2nd December 2004, 09:43 PM   #4
SteveA is offline SteveA  United States
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Location: St Paul, MN
Default Aleph P1.7

Try this:

The site does not give a component overlay diagram, however, for someone who knows electronics better than I do (which is just about everybody on this site) I would think one could make it work.

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Old 3rd December 2004, 02:15 AM   #5
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I have a 10K in mine too. I think 5K simply matches the output impedance.
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Old 3rd December 2004, 03:01 AM   #6
jleaman is offline jleaman  Belgium
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I got my boards from kristian k. Ill post a pic of the boards soon if any one is insterested.
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Old 3rd December 2004, 04:50 AM   #7
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As far as I understand, P1.7 has output attenuators of ladder circuits. The concept seems to be 8 different attenuators, each of which has varying Ri (= Rih + Ril). Max Ri is seen as about 8K while min Ri about 120.

If so, I interpret that we could use any of 10K output volume or lower.

For me to enjoy diy, I am planning to build the P1.7 output ladder attenuators, using 8 manual toggle switches.
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Old 3rd December 2004, 08:54 AM   #8
JEKYLL is offline JEKYLL  France
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PCB for AP1.7, look here:Aleph1.7
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Old 5th December 2004, 03:10 AM   #9
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1. I'm using 5K stepped attenuators and it works fine. I tried 50K pot but it was no good.

2. Don't use 63V caps after the rectifier, but you can use them after the mosfet regulator (IRF610).

3. I think output caps (3x10uf) are more important. I didn't experiment with these. I've just put BG N type (like kilowattski) all over the place and the sound is awesome.
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