Gotta love Nelson Pass

I’m new to Nelson Pass stuff, being a tube guy i decided to try something different for my Zu Audio Druid speakers. I bought First Watt F2J current source power amp this month (only 100 made), then i quickly ordered the original First Watt B1 buffer preamp by Nelson’s advice. Pass Labs Aleph L and Aleph P were competitive, but for a much higher price, so i’m happy i ended up with First Watt B1. I bought everything used, but Nelson Pass was very helpful by email. So i joined the "club", hello

Everything explained on firstwatt.com , even about discontinued models. For example my F2J current source power amp is designed for crossover-less, high sensitive speakers (full range drivers) and not suitable for the speakers with crossover. For traditional speakers he has different amps. 

Right, current source amps vs. volage source amps is a big difference. 

Active gain preamps vs. passive preamps with no gain at all is a big difference too. He has passive preamps which became active after the volume turned up to 9 o'clock (the aleph L series). 

But if you know what you need for your particular speakers then it's a benefit. For example i don't need much power for my full range crossover-less speakers with 101db sensitivity. Nelson said he use Zu Audio speakers himself (among others). So for my need current source F2J power amp of 5w per channel is enough. And absolutely neutral First Watt B1 buffer preamp (pretty small box) is good match for F2J power amp. 

Everyone should learn more about FW or Pass Labs products, but Nelson can help with a great support for his products. 

 

@whoopycat i guess so, but my source is analog only, no digital. Phono preamps will be connected to First Watt B1 buffer and it would be nice to judge the actual quality of the cartridge+phonopreamp. 

@georgehifi 

There was 2 versions of Aleph L preamps and only one of them works as you have described above. 

Versions distinguishable by how many wires go up tothe volume control – 6 wires = early version, more than 6 = later version.

   

@georgehifi 

I ended up with original First Watt B1 buffer preamp instead of the old and more expensive Aleph L preamp for a double price. Hope it was the right move, my speakers are 101db. Gonna get it tomorrow from the postman. Can't wait to check it out with my First Watt F2J power amp. 

Hi George
Actually i have F2 upgraded to F2J by Nelson Pass for previous owner.
MOSFETs replaced with JFETs

Input impedance is 50k Ohms which is stated in the original manual that i have on hands. But this is F2 manual, not F2J.

I realized that F2J input impedance is lower ( approximately 25 Kohm )
"So the F2J is recommended for use with preamps with ordinary to low output resistance – tube preamps without cathode followers will work but will not reap as much benefit at high frequencies. "

As Nelson said the F2J has a bit lower input impedance than most are used to, so having a preamp that can provide more current is a good idea. But there is no current production in my B1.

He said the Aleph L in my system would be fine!

P.S. What i don’t want is a tube preamp, i sold all my tube gear before i bought First Watt. Still have nice mega rare vintage tubes, but i want to sell them too. No more tubes at least in the near future.

Seems like it become addictive when someone buying First Watt stuff. I decided to buy another preamp for my FW F2J power amp. 

Soon i will be able to compare my FW B1 Buffer Preamp and Pass Aleph L. 

After 7 month of using my B1 i realized that i need at least 4 inputs to switch between different phono stages. The B1 has only two inputs, the Aleph L has 4 inputs. 

Another reason to buy Aleph L was the second output which can be used for an active SUB if i will buy Zu Undertone sub for my Druid speakers. 

It was not easy to find the latest version of Aleph L which is passive if the volume control knob position is not higher than 3 o'clock. I'm sure that i don't need an active gain in my system, because even with B1 buffer preamp i only use 10-20% of the volume control. It was hard to imagine that less than 5 watt Power Amp (F2J) is more than enough for 101db speakers in my big room. 

if someone compared the same preamps (First Watt B1 and Pass Labs Aleph L mkII) please share your experience. 

thanks