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Old 11th September 2006, 10:28 PM   #1
adwsail is offline adwsail  United States
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Default Aleph-L Preamp

Is there ANY chance of getting some info on the Aleph-L preamp? I have searched high and low to no avail, just a lot of intriguing references. I am specifically interested in the passive/active version, v1.2 I believe. How was it done?, crossover issues? It seems pretty idea in theory in this age of hot output CDP's (my Njoe Tjoeb 4000) and so-so tuners (NAD 1700).

I have built the BOZ and like it a lot. It's feeding a Tubelab SE 300B tube amp that gives me a great sound through some single driver Decware HDT's. My intention is to A-B compare the Tubelab with a V9 whenever some boards come available but in the meantime I would like to build an Aleph-L. Any help is GREATLY appreciated.
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Audiosector USB DAC --> NAD 1700 Tuner/Preamp --> Tubelab 300B SET or ZV9 or Mini-Aleph or 41hz Amp6 or Tubelab Simple PP --> Decware HDT's or JBL SR4702X's
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Old 12th September 2006, 05:42 PM   #2
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Halo,

How the passive/active version is done you can see in service manual. If you don't have one drop me an e-mail and I will mail it to you.

I have built BOZ, BSOZ, both Aleph L and Both Aleph P.

The best sounding of them in my opinion are both Aleph P (I like 1.0 better) and the second would be Aleph L all time active version. I didn't like passive/active version and didn't find it interesting.

Aleph L all time active version is a very good sounding pramplifier, where it looses to Alpeh P is some refinement of frequency extremes (bass and highs), but it has much higher gain so if you need a high gain Aleph L is the way to go.

All my observations are based on my copies of those designs, originals or some other's versions may vary. But I must say I used very similar or exactly the same parts (resistors, capacitors..) and enclosures to evaluate the sonic diffrances between them.

Bartek
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Old 13th September 2006, 12:48 PM   #3
adwsail is offline adwsail  United States
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Thanks for the reply, an email is heading your way.
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Old 13th September 2006, 01:04 PM   #4
Formerly "jh6you". R.I.P.
 
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Quote:
Originally posted by zygibajt



I have built BOZ, BSOZ, both Aleph L and Both Aleph P.

The best sounding of them in my opinion are both Aleph P (I like 1.0 better) . . .

Believe or not . . . Love of my ears is P1.0 . . .
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Old 13th September 2006, 01:38 PM   #5
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Quote:
Believe or not . . . Love of my ears is P1.0 . . .


Try to power it from batteries. Makes wonders to the sound.

I power it from ten 6V 2Ah batteries connected in series. Bare circuit, ommiting regulator.

6 Volt batteries becouse a take 18V reference voltage out of first three of them.

What I still haven't tried is instead feeding the bare gain circuit out of 60 Volts trying to feed the circuit with regulator out of bank of 80 Volt batteries.

Bartek
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Old 14th September 2006, 08:48 AM   #6
Buhl is offline Buhl  Denmark
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Whats the fuzz about the P - I really must build it now that you all sing its praises - at least as a project to fill out the time before somebody makes a nice pcb and kit for the UGS-clone...

I see that it uses really big FETs in the gainstage - the irf244 - would the IRFP240 be a good replacement as it is in the powerstages of the alephs ?

And what about the ref. voltage @ 18 volts that charges the mosfets' gates - is this the secret an where the "dog is buried" ?

Cheers !
Buhl
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Old 14th September 2006, 09:29 AM   #7
Formerly "jh6you". R.I.P.
 
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Quote:
Originally posted by Buhl



"dog is buried" ?

Buried? No . . . on our dinner table . . .


We love dogs . . .
We buy special food for dogs . . .
We bring them to beauty shop . . .
We kiss them . . .


4V is used for Vgs and the remaining 14V for 20mA bias . . .
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Old 14th September 2006, 09:56 AM   #8
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Quote:
I see that it uses really big FETs in the gainstage - the irf244 - would the IRFP240 be a good replacement as it is in the powerstages of the alephs ?
IRFP240 works well

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