FS : Nelson Pass Labs B1 Buffer Class A Pre-amp (Clone)

[swampy]

Nelson Pass Labs B1 Buffer Pre-amp (Clone)

I am think of selling my Nelson Pass Class A B1 buffer (pre-amp) clone. I am switching back to headphone listening and will no longer need this. I used this to drive my Pass Labs F5.
This is a unity gain buffer with 1:1 gain.
It is a self / DIY build by me and it has been tweaked and upgraded over the period I have used it.

Note : The internal photo shows yellow caps on the input, these have been replaced with Black SCR Premium Tin Foil Caps.

There is 1 input, 1 pass-thru (record out) and the output. It originally had 2 inputs switch-able by a mini silver toggle on the rear but since I only used 1 source I eventually converted it to the single input for a more direct signal path with a pass-thru rec out on 2. I can rewire it back for switch-able dual inputs if required. Note that the rear photo shows the labelling for the original 2 inputs which I will relabel.

Case is really nice thick solid aluminium and not the usual junk.


Single Cast top and sides Thick Solid Aluminium Chassis
7mm brushed Aluminium faceplate
50VA Potted Mains Transformer
44,000uF Smoothing (More than some power amps !!)
Matched JFets
Halco Grid and Output Resistors on the signal path
SCR Premium Tin Foil Input Caps
MKP 10uF output cap with bypass
Solid Core Silver Wire on all audio paths
OFC on all audio ground paths separated from mains earth
CMC Sandy Gold Phono Sockets
Gold Plated Audio Earthing post
Alps Pot
Solid Aluminium Knob
All Silver soldered


I'll warranty it myself for 6 months. My job is an electronic engineer so no problems if anything goes wrong (which is very unlikely). Sound is transparent, neutral and clean without being clinical, probably the best solid state pre I have had so far. I used to switch between this and my now sold Kondo M77 clone depending on mood and speakers in use at the time. If I ever go back to speakers I'll probably make another anyway !!

£295 ono + Post by UPS at cost or pick-up very much preferred. I don't have any 'proper' speakers now so can't really demo this to its full potential but check the net for reviews of the B1 in general.

http://www.enjoythemusic.com/magazine/equipment/0708/first_watt_b1_preamplifier.htm

Picture 1 (http://www.dms-audio.webspace.virginmedia.com/photos/b1-1.jpg)
Picture 2 (http://www.dms-audio.webspace.virginmedia.com/photos/b1-2.jpg)
Picture 3 (http://www.dms-audio.webspace.virginmedia.com/photos/b1-3.jpg)

I'll try and get some more internal photos as its neatly made, I'm a bit OTT at times and like it all to look perfect inside and not just a nice box. It means pulling the case apart due to it being single cast !!

[Spectral Morn]

How many inputs has yours ?

if only two could you add a few more?


Regards D S D L

[swampy]

2 when using a mini toggle on the back for shortest signal path.

If any more then it would likely need a rotary selector switch fitting on the front meaning routing all the wires from the inputs on the back to the front of the pre. I built it in mind for simplest and cleanest signal routing. There are fittings for 4 rca inputs on the back of the case but the pre would need to be modified somewhat. I also would need to buy 4 more matching cmc sockets and another matching aluminium knob. It could be done with a little more effort.

[Spectral Morn]

Thank you for the answer, I was curious as I would require more inputs and at least one output for tape.

PM me how much extra that would cost and we can discuss it further. However if you get an offer for it as is then just take it...ok.


Regards D S D L

[swampy]

I might give ebay a try this weekend since its a free listing day and it saves me work modifying it. I don't have much time ATM as my Dad is in Hospital and with visiting daily. I guess the only other way is an external switching box in front or after the buffer stage if you need lots of inputs.

I have put some better photos 1 and 2 up now but no up to date internal shot.

I'd take £250 for it. It stands me about 180 in parts so a small profit just to cover my build time over 2 days which I am sure many engineers who custom build amps would charge much more for.

[swampy]

Provisionally Sold to Ali