Pass Labs B1 preamp build

[blackraven]

That's great. I had once or twice considered building a B1, and I'll be looking forward to your updates for sure

I was daunted mainly by the volume control issue, (since I insist on remote control), and the need to buy or build a suitable case/cabinet to house it. I'll be very interested in your solutions to these problems.

Here is a link to a DIY store for a chassis with a remote Alps pot-

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I am going to buy the chassis in silver

[Feanor]

Here is a link to a DIY store for a chassis with a remote Alps pot-

DIYCLUB

DIYCLUB

I am going to buy the chassis in silver

Those look like good choices. Also that Hong Kong site looks a bit more confidence inspiring that some.

Are you going to need an input selector?

What are you doing about a power supply for the B1 and also for the remote control. The former needs an 19-24 VDC supply while the latter needs 9 or 12 VDC.

[blackraven]

I am going to go with the recommended wall wart for the B1 which is 18 to 24v. I will have to use a step down voltage converter. You can find them for about $5. I will have my Electrical Engineer friend help me with that.

EPS240025-P5P CUI Inc. | Power Supplies - External/Internal (Off-Board) | DigiKey

Here is the actual part list for the B1. It's about $150 for the stock parts, but I will be using better Caps and some boutique resistors, about $250 in parts.

Nelson Pass B-1 preamp kit

[Feanor]

I am going to go with the recommended wall wart for the B1 which is 18 to 24v. I will have to use a step down voltage converter. You can find them for about $5. I will have my Electrical Engineer friend help me with that.

EPS240025-P5P CUI Inc. | Power Supplies - External/Internal (Off-Board) | DigiKey

Here is the actual part list for the B1. It's about $150 for the stock parts, but I will be using better Caps and some boutique resistors, about $250 in parts.

Nelson Pass B-1 preamp kit

Yep, a wall wart will work fine. Come to that, I have a draw full of wall warts from defunct electronic equipment, including an 18.5 VDC power supply from long-gone HP laptop, plus enumerable 9 and 12 VDC units.

As I discovered after posing the question, there are also slightly up-market linear power supplies that are available for about $60. E.g. ...

15W DC18V Linear Power Supply PSU With Digital Display 110V OR 220V Available | eBay



Set-down devices are available and cheap, e.g. ...

DC DC Converter Step Down Regulator LM2596 Power Supply 3 30V TO 1 21 18V EA | eBay

[blackraven]

I started my build of the B1 the other day. My soldering skills are coming back to me. I am going to teach my son how to solder and let him help build it. I will post pic's as the build progresses.

I went with Mundorf MCap supreme and Clarity ESA caps for the 1uF and 10uF caps.

In addition to the Riken Carbon (output stage) and Tx 2575 resistors (input stage) I am using Audio Note Tantalum resistors through out.

I have settled on an Alps Blue Velvet volume pot 50K. And I will eventually add a remote volume pot if I like the sound.

I am using 24g stranded copper hook up wire and Cardas Silver Solder for its low melting temperature.

[Feanor]

Thanks for the update. I'll continue to follow you progress with interest.

Do you intend to use the B1 with your Pass amp? The B1 is single-ended obviously. It seems one could use TWO B1's to make a fully balance preamp; have you heard of anyone doing this?

[blackraven]

Thanks for the update. I'll continue to follow you progress with interest.

Do you intend to use the B1 with your Pass amp? The B1 is single-ended obviously. It seems one could use TWO B1's to make a fully balance preamp; have you heard of anyone doing this?

Bill, I am building this for my son to use with the Parasound A21 that I gave him. He is currently using my AVA hybrid tube preamp. It will be interesting to see how the 2 compare. The B1 is supposed to have a lot of air and transparency. I will try the B1 with the Pass but I doubt that it would better the BAT. I could use the B1 as a buffer between the Pass and BAT to fix the slight impedance mismatch.

I have thought about buying 2 boards and making a balanced unit. It would be fun to try.

I have ordered this chassis in silver-

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Lite A28 A Series Preamplifier General Chassis Amp Box Preamp Case | eBay