B1 builders thread

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#681
richluvsound said:
I think I have a problem with the selector .... can't get any continuity with the DMM
Click to expand...

You are measuring it incorrectly. Grayhill switches are Mil-spec, the likelihood of you having a bad switch is about the same as finding an honest politician... 🙂 🙂 🙂

If I recall, Grayhill switches have many contacts (solder lugs) on the same plane, these are the "input" connections.

You have a 2-pole switch, so there will be 2 lugs (likely opposite of each other) that are on a different plane, probably closer to the shaft. Those lugs are the output connections. (common) Set the DMM to continuity beep. Put one lead of your meter on one of the output lugs and now touch each of the input lugs until you get a beep. That will show that in and out for that particular switch position, on that half of the switch. Move the switch and repeat. After messing with that for a bit you will see which lugs on the input connect with the output lugs.
 
#685
Yes thank you Sir 6 !

Used 9v batteries . Bit of a hum ,but thats not a suprise considering its gator clipped together .

PSU ? If you remember , you helped me build it last year . The batteries do sound crisp though ,but I have the PSU board made up all ready , the IEC and the switch sitting here .

What are my options ?

Rich
 
#686
So you just need a transformer? 14-20v secondary voltage, 50VA or so is all you need. Let me look at Farnell for something appropriate.

A DC wall-wart at 20-24v or so would be fine, just remove the rectifier on the regulator board.

A laptop PSU would also work, they are usually 19v. You wouldn't need the regulator, however.
 
#690
B1 Sound

Hi all,
I’ve recently built a B1 using a Pass DIY PCB and have been listening and experimenting with different capacitors. I have tried some audio grade MKP types from Maplin on their own and with low value (100nF) bypass caps and also some Mundorf aluminium – oil types from Hifi Collective wih and without the bypass capacitors. All combinations sound different with the ally – oil types on their own sounding nicest.
The B1 is powered using a simple linear regulator circuit with a John Linsley Hood shunt regulator across it giving about 18.6 volts. I am quite a fan of these shunt regulators and have been using a pair on the supply to a Linsley Hood discrete component shunt feedback phono stage for nearly 20 years and they made an impressive improvement to the sound (using a low output moving coil cartridge) when I added them.
Anyhow, I have to agree with KatieandDad’s opinion that the sound lacks excitement. It’s as if the “attack” and dynamic impact of the music is diminished. Also the stereo soundstage has somehow shrunk. I had a long listen last Sunday afternoon and eventually re-connected my 26 year old (it’s older than I was when I bought it!) Audiolab 8000C preamp and WOW excitement, dynamics and attack have returned and the stereo soundstage is now huge, 3 dimensional and well out of the speakers again. I’m using 2 Pass A40 monoblocks which I finished earlier this year. I was wondering if anyone may be able to shed any light on this or if KatieandDad managed to cure their B1 and make it sound as good as it should? I have included a photo with the Mundorfs fitted.
 

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#692
B1 BUFFER

Hi
this is my B1 Buffer .
Pcb its from gerber fille .
2sk 170 matched to 7.8 ma at 640 mv vgs
10mf-1mf Audiophiller
JLH Shunt Reg at 22V
LM 317 at 22.10 V
Two separate pots 25kΩ
 

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#694
Earthloop said:
Hi all,
I’ve recently built a B1 using a Pass DIY PCB and have been listening and experimenting with different capacitors. I have tried some audio grade MKP types from Maplin on their own and with low value (100nF) bypass caps and also some Mundorf aluminium – oil types from Hifi Collective wih and without the bypass capacitors. All combinations sound different with the ally – oil types on their own sounding nicest.
The B1 is powered using a simple linear regulator circuit with a John Linsley Hood shunt regulator across it giving about 18.6 volts. I am quite a fan of these shunt regulators and have been using a pair on the supply to a Linsley Hood discrete component shunt feedback phono stage for nearly 20 years and they made an impressive improvement to the sound (using a low output moving coil cartridge) when I added them.
Anyhow, I have to agree with KatieandDad’s opinion that the sound lacks excitement. It’s as if the “attack” and dynamic impact of the music is diminished. Also the stereo soundstage has somehow shrunk. I had a long listen last Sunday afternoon and eventually re-connected my 26 year old (it’s older than I was when I bought it!) Audiolab 8000C preamp and WOW excitement, dynamics and attack have returned and the stereo soundstage is now huge, 3 dimensional and well out of the speakers again. I’m using 2 Pass A40 monoblocks which I finished earlier this year. I was wondering if anyone may be able to shed any light on this or if KatieandDad managed to cure their B1 and make it sound as good as it should? I have included a photo with the Mundorfs fitted.
Click to expand...

I had the same impression…..

and I decided to look at Nelsons commercial product well reviewed.

That means the classic circuit but the caps Nelson recommends in the B1 pdf himself

- the Vishay metallized polyester 1uF caps for the input

- the Axon 10uF for the output

This combination was the only one that had magic to my ears.
They but the B1 a bit on the dark side, blow up the stage….so if your system is already on the dark side this might be too much, if not highly recommended.

🙂

for me the most convincing example that caps form sometimes a better sound.

and these caps are cheap!
 
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#697
Earthloop, have you tried lifting the voltage, above 20 volts?

And those Mundorf caps take ages to start sounding good - well over 100 hours of signal use - sound quite dull and lifeless for first 50 odd hours.

The B1 is so simple that anything/everything connected has some effect on it's sound quality - the supply, the resistors, those caps, even the connecting wires, the interconnects - everything - a great opportunity to 'tweak' it any way you want.
 
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