B1 preamp build thread

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I couldn't hear any difference between a well implemented LM317 and a Salas Reg PSU.

Try comparing your 317 or Salas unit to a laptop PS. You will hear a difference.
Also against battery based supply. For whatever reason, the B-1 (to me at least) MUCH prefers a regulated PS of decent quality. Again, make no mistake, the difference was not subtle in the least between the laptop supply....batteries were also superior to laptop dreck I used.

The Power supply outlined in this build thread that 6L6 used is not earth shattering design or anything and is based on 317 device. The B-1 loved it in my system(s)...far better than laptop, and to a lesser degree the batteries. I did not try a capacitor as suggested by 2picodumbs above, so cant comment.

The Unit just likes a regulated supply it seems. Never tried a Salas unit, maybe it provides no extra help than the 317 in this particular simple circuit. While I have mostly assembled Hypnotize and Mezmorize kits around here, I have never completed or listened to, I understand it makes a difference with them. Others will have to comment to that, and I guess you did...as far as the basic B-1 here is concerned.

Russellc
 
... VISION 12V 5Ah in serie; erternally charger is Meanwell PA/PB-120...
 

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I was going to let someone else teach you but since no one has Pappa can do it.

Class A amplifiers (the "pure" kind) all draw an average constant
current from the supply, but this is not necessarily the case at any
given instant.

Your typical PP Class A will draw AC current from the supply, but the
average is a constant.

Your typical single-ended Class A will draw a constant value at all
times from the rail if it is biased with a constant current source -
See the first Zen amp as the example.

Balanced single-ended and push pull designs tend to draw constant
current, Son of Zen being a simple example.

:cool:
 
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Mine is full B1 clone, not the minaturised version.

The Salas reg. is a very highly acclaimed shunt reg.

No doubt the laptop supply was appalling, the original B1 was supplied with a wall brick (not SMPS).

That's not original B-1, that appears to be DCB1? With no coupling caps? Your B-1 board appears to be a diy effort of the original B-1? Seems I do see the coupling caps, and not the circuit of the DCB1 type units...

Here's Pass B-1: FIRST WATT B1 This is "Full B-1" from Papa. No Salas power supply, like you said, wall wart.

Mine is built from this set:
B1 PCB and matched J fets https://www.passdiy.com/store

The version you are showing isn't a Pass item per se, but a no coupling cap version, hot-rodded inspired by Pass B-1. Or did you just graft partial Salas power supply to a standard B-1 circuit? I have assembled boards for Mezmorize and Hypnotize with the Salas power supply. Lost interest when need for gain arose and BA-3 pre sounded so much better for those purposes, in my systems. Did think about using power supply part on a BA-3 pre....others said it was no improvement in that particular application than 317 based regulator. For the DCB1 I have no doubt, but I wanted the gain...

Russellc
 
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Hi, I am new here. I would like to build a B1 for my son. I gave him my Parasound A21 amp several years ago after upgrading to a Pass X250 amp and X1 preamp.

I am using TX2575 1K resistors in the input section and Riken 1K carbons in the output section. I have a budget of about $175-$150 set aside for caps. I would appreciate any recommendations. I would like a slightly warmer, tube like sound with excellent air and transparency.

I am planning on using an 18v 330mA regulated wall wart as a power supply.

Any recommendations on a volume pot in the $25-50 range or a remote volume pot for a little more.

I want to keep this pretty simple.

Much Thanks,

Larry
 
I have a few more questions.

I am considering an Alps volume pot. Has any one used a Valab pot like this-

Valab 23 Step Attenuator Potentiometer 50K Log Stereo

I have built a 25k using Dale RN55D and a 50k using Takman and used both in my B1. Both worked great but I did not compare them and have not tried the alps pot. It was a lot of work but this is diy:D

Amplifier valve kits, HIFI pre-amplifiers, speaker kits, AMP Parts, upgrade components - Hifi Collective have a large range of ready made and diy. I used the cheap blue/white switch to make shunt attenuators.

I used Clarity Cap SA caps on Pass pcb with Pass supplied Jfets. RN55D resistors and external 24v wall wart, so pretty standard. It is a nice buffer but not in the same league as an Aleph P1.7.

Good luck with your build.
 
I have built a 25k using Dale RN55D and a 50k using Takman and used both in my B1. Both worked great but I did not compare them and have not tried the alps pot. It was a lot of work but this is diy:D

Amplifier valve kits, HIFI pre-amplifiers, speaker kits, AMP Parts, upgrade components - Hifi Collective have a large range of ready made and diy. I used the cheap blue/white switch to make shunt attenuators.

I used Clarity Cap SA caps on Pass pcb with Pass supplied Jfets. RN55D resistors and external 24v wall wart, so pretty standard. It is a nice buffer but not in the same league as an Aleph P1.7.

Good luck with your build.


Thanks, I will look into those pots. I bought the Pass kit with the JFets.

I am thinking about using Obliggato Premium Gold Caps or a combinstion of Mundorf Mcap Evo Silver/Gold-oil caps 1uF 450v and 10uF 630v Obbligato caps.

Any thought on this?
 
There are no "filter" capacitors in a B1 build. They are signal coupling capacitors. As such they pass all the audio signal.

If you choose the correct size and type to suit the duty, then there will be no measurable distortion and no other degradation of the signal.

It is when one adopts the wrong size/type, or a faulty, capacitor that one hears degradation of the signal.