First Watt Aleph J

I intend to operate mine via a Pass B-1 unity gain buffer, but can't find info on gain being sufficient for this or for a passive controller.
 
The gain may be a bit low with the Aleph unless you have a source that puts out a healthy 2Vrms or more. I ran mine with a B1 that I built for a period of time. I had a CAL CL-25 that I used as a source and its close to 2V out. To me it lacked dynamics compared to my active pre's.
 
That's not encouraging, the B-1 is about the only compromise I'm willing to make to a good passive controller, a very simple active pre notwithstanding.
 
You should build it and try it for sure. Its such a simple design that you can breadboard it to see if you like it. Just buy one of those inexpensive LM337/317 Dual rail PS boards off of Ebay to power it they come in handy even if you don't use it permanently in the B1. Because you're running an Aleph J versus my classic Aleph that may make a big difference as well.
 
Iirc, the sensitivity of the J is higher than other Alephs, but I cannot find that chart.
Btw, I already have a working example, I just haven't put it in yet since it arrived last August, flipping other amps thru to establish a baseline.
 
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When using the Aleph J and B1 with inefficient vintage speakers, I get enough gain when using a CD player, Chromecast, etc. When using a turntable and preamp it's borderline ok.
 
Pio1980 said:
Iirc, the sensitivity of the J is higher than other Alephs, but I cannot find that chart.
Btw, I already have a working example, I just haven't put it in yet since it arrived last August, flipping other amps thru to establish a baseline.
Click to expand...

The gain shows to be 20dB for both J & standard versions on unbalanced inputs.

Just give it a try!
 
mondialfan said:
The gain shows to be 20dB for both J & standard versions on unbalanced inputs.

Just give it a try!
Click to expand...
I shall. I have the option of a Conrad Johnson Motif MC-9 line stage if necessary from another system, but I'd rather keep the B-1 in this one.
 
1108 said:
When using the Aleph J and B1 with inefficient vintage speakers, I get enough gain when using a CD player, Chromecast, etc. When using a turntable and preamp it's borderline ok.
Click to expand...
My mag phono has adjustable gain, so, like with varying CD levels, it may be sufficient on most if not all source material.
 
I'm using an F5 I built with 32V rails. The 15.5dB of gain needs a little help to drive my Focal 936's at 90dB sensitive. If for whatever reason you're not getting the gain you need, just drop a BAGS on the B1 output. 6L6 has a good guide on using the BAGS stages in pre-amps.
 
ReactiveLoad said:
I'm using an F5 I built with 32V rails. The 15.5dB of gain needs a little help to drive my Focal 936's at 90dB sensitive. If for whatever reason you're not getting the gain you need, just drop a BAGS on the B1 output. 6L6 has a good guide on using the BAGS stages in pre-amps.
Click to expand...
Dunno what that is, the Motif MC-9 is about as simple as a FET line stage with gain gets as an alternative to the B-1.
 
There are 2 types of BAGS (Burning Amp Gain Stage). One is complimentary. One is differential. The complimentary BAGS is like a scaled down version of an F5 topology; a voltage gain stage with a buffer stage. The differential is sort of like the Aleph J topology. Neither have feedback by themselves. They're all designed by Nelson Pass as the voltage gain stages for the modular Burning Amp variations of amps.
 
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