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Pass Aleph P 1.7 preamp builders thread
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Old 16th July 2013, 05:27 AM   #11
FormosaWest is offline FormosaWest  Canada
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Old 16th July 2013, 05:29 AM   #12
sakellogg is offline sakellogg  United States
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relay based attenuator pretty much what you have. ive got to replace the pot on it. its getting flakey.

i put in relays for the db selection too. so basic 3 knob system.

youll like it. very nice sounding.
only thing i dont like is now i know how many crap records i have. if your recording sucks youll know it. but if its a gem youl love it.
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Old 16th July 2013, 05:32 AM   #13
sakellogg is offline sakellogg  United States
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nice.

ive been there with the caps! trying to make them fit.
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Old 16th July 2013, 05:35 AM   #14
FormosaWest is offline FormosaWest  Canada
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Db selection?

Question for you.... The 2k multi turn variable resistors on the Center of the board... Are those for setting gain?
Since this board is running on + dc voltage only i wont need to worry about dc offset will i?
I take it the little keyboard switches are for gain level selection.
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Old 16th July 2013, 05:47 AM   #15
sakellogg is offline sakellogg  United States
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2k pots... yes, they can. i used them to get the output the same for both chan.

it dosent just run on positive. do you mean its not bypolar?
but no that isnt why you dont have to worry. if i remember right..... the 30uf on each leg of the output is why no worrys on offset.
remember to dc caps look like a open, but let ac go through.

keyboards yes you are right. those are what i call db selection.
i did them with relays too.
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Old 16th July 2013, 06:09 AM   #16
FormosaWest is offline FormosaWest  Canada
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Quote:
Originally Posted by sakellogg View Post
2k pots... yes, they can. i used them to get the output the same for both chan.

it dosent just run on positive. do you mean its not bypolar?
but no that isnt why you dont have to worry. if i remember right..... the 30uf on each leg of the output is why no worrys on offset.
remember to dc caps look like a open, but let ac go through.

keyboards yes you are right. those are what i call db selection.
i did them with relays too.
Thats a Good idea doing then db selection like that.. Saves cracking the case open to make the selection.. when running a phono stage sometimes a little extra gain is great, but not otherwise needed/wanted for other modern high gain sources. Any recollection what relays used.. Im guessing you just wired it up off board?... Hmm ill have to think about it how do do that to give the three settings. Two relays per channel (one for each little keyboard key) and one panel mounted switch?

Im thinking of adding a 12 volt trigger out from the power switch to allow me to trigger future components on/off with the alephP

Last edited by FormosaWest; 16th July 2013 at 06:12 AM.
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Old 16th July 2013, 06:23 AM   #17
sakellogg is offline sakellogg  United States
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i did it as a daughter board off of the main. i used some mini signal relays. i dont remember. ill take dome pics tomarrow.
but 2,2pole per chan. is what i think i did. funny thing is you make a 3 point switch. 1 pole picks one relay. next pole dosent do anything... next picks the other relay. it was hard to wrap my mind around a pole on the switch just for the click so to speak. kinda funny to me. but like you said its nice for a l.p. guy.

i haddent thought of a trigger out....which is funny cause i built it into my alephs....woops!

im gunna have to add that to it! thanks for reminding me.
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Old 16th July 2013, 02:57 PM   #18
FormosaWest is offline FormosaWest  Canada
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Im really curious about building a pair of balanced aleph x mono block's at about 100watts. Though for some reason that project appears to be a bigger challenge to me mentally than the pearl or the ap1.7. Seems the amps are expensive to uild and everyone here seems to be using scopes to get them right.... And i dont have a scope, nor do i know how to use one. ... But boy woul dlike to build a pair.

Did you ever build the xbosoz? I wonder how the ap1.7 compares sound wise.
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Old 16th July 2013, 03:01 PM   #19
FormosaWest is offline FormosaWest  Canada
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About the 2k pot. Dpes gain increase as the level of resistance increases, or does it increase as the level of resistance decreases? Before i soldered them in i matched them both to 2.00k and im wondering if that will be its maximum gain or minimum gain (for any given keyboard switch setting)
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Old 16th July 2013, 09:38 PM   #20
generg is offline generg  Germany
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Pass Aleph P 1.7 preamp builders thread
As far as I remember, lower value of the 2k gives more gain and vice versa....
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