Pass B1

[sachu888]

Hi all,
After completion my first successful DIY phono, have decided to build this preamp by Nelson Pass.I can get the PCBs done locally and find out the source of matched JFETs.All other components are available with Digikey/Mouser.If anyone interested please let me know so we can save some shipping cost.
Some links:
Andy_H's Pass B1 Build - AudioKarma.org Home Audio Stereo Discussion Forums
Nelson Pass B-1 preamp kit
B1 Buffer Preamp - diyAudio
DIY Order Form



regards,
Sachin

 

[jetlag]

This, I believe is a passive pre-amp. Looks like a great kit. DIYA is head over heels about this. Now, I would like to know if it would suit a UCD180ST based amp? If so, I am very interested.

Jetlag

 

[sachu888]

This, I believe is a passive pre-amp. Looks like a great kit. DIYA is head over heels about this. Now, I would like to know if it would suit a UCD180ST based amp? If so, I am very interested.

Jetlag

Hi,
I think this is D class amp.IMO B1 should work with this.

Regards,
Sachin

 

[borg]

This, I believe is a passive pre-amp.

Jetlag

it is not passive , but a buffer with no gain, so good match with power amps with plenty gain imho

 

[gobble]

So its not a great match to the MyRef Gainclone with 35W per channel? :sad:

I'll take one kit anyways hyeah:

--G0bble

 

[sachu888]

it is not passive , but a buffer with no gain, so good match with power amps with plenty gain imho

Hi Borg,

I think B1 is a passive buffer preamp.

Regards,
Sachin

 

[borg]

i meant something like pass f4 which dont have any gain ,even f5 which also not high gain iirc
myref i am running straight off a dac without any pre. so should be ok
a buffer has high input impedance so it doesnot load the source and also can drive difficult load,
check with siva how much it helps

 

[borg]

Hi Borg,

I think B1 is a passive buffer preamp.

Regards,
Sachin

It need power isnt it?, so active enough for me. Atleast that is what we were taught,it is been more than a decade so i am a bit rusty

 

[sachu888]

Hi all,
I have 3 confirmed members for B1.The main hurdle was to get matched JFETs which have been sorted out, remaining parts can be ordered from Digikey.I am going to put order for 10 pairs of matched JFETs tomorrow,kindly confirm your participation for the kit.
PS: I don't know the final cost but it should be within RS 3000/-

Regards,
Sachin

 

[gobble]

Hi all,
I have 3 confirmed members for B1.The main hurdle was to get matched JFETs which have been sorted out, remaining parts can be ordered from Digikey.I am going to put order for 10 pairs of matched JFETs tomorrow,kindly confirm your participation for the kit.
PS: I don't know the final cost but it should be within RS 3000/-

Regards,
Sachin

Yes I am in for it. What about getting a bundle of source selectors like: Stereo selector switch and a bundle of 50 or 100K volume pots like ALPS Blue RK50: ALPS - Products Line. The 50K appears to be a quad unit though.

Edit: These may also suit: 12mm Size Insulated Shaft Snap-in Type RK12L Series

-G0bble

 

[sachu888]

Yes I am in for it. What about getting a bundle of source selectors like: Stereo selector switch and a volume pots like ALPS Blue RK27: RK27 Series - Products Line

-G0bble

Hi Gobble,
Alps would be better.

Regards,
Sachin

 

[gobble]

Hi Gobble,
Alps would be better.

Regards,
Sachin

You mean for stereo selector too? Thats fine.

I edited my original post with a link to RK50 and others instead of a 100K pot. Audiophiles tend to use 10K or 50K don't they?

--G0bble

 

[sachu888]

You mean for stereo selector too? Thats fine.

I edited my original post with a link to RK50 and others instead of a 100K pot. Audiophiles tend to use 10K or 50K don't they?

--G0bble

Yes Gobble,

This one is good http://www.partsconnexion.com/product7384.html

Regards,
Sachin

 

[jetlag]

I am in. It would be good to have the BOM and also a list of interested people.

 

[sachu888]

I am in. It would be good to have the BOM and also a list of interested people.

Hi Jetleg,
Pass did not list BOM anywhere,but it can be seen here:
Nelson Pass B-1 preamp kit
Interested so far:
1.Sachin
2.Omishra
3.Prasad(Quad)
4.Gobble
5.Jetleg

I will visit local PCB maker,tomorrow.

Regards,
Sachin

 

[gobble]

Thats a 10K pot. Does a 10K pot imply an input impedance of 10K? In that case I will take a 25K or 50K pot please.

Thanks
Edit: Oink!

If you put a buffer in front of a volume control, the control's low impedance looks like high impedance. If you put a buffer after a volume control, it makes the output impedance much lower. You can put buffers before and after a volume control if you want.

So whats this implementation going to be like?

PS: How about dual mono volume pots? Gives us some flexibility.. and it is useful as a L+R balance control for A/B comparison of dual mono recorded tracks with different IC's/Caps/Speaker Wires in L and R channel and also to fine tune the speaker imaging. Good for audiophool tinkering hyeah:

Edit: Please order a pair each of single gang 10K and 50K pots for me (if its possible to use them as balance control), I will swap out and in and experiment. And if these are only approximating a Log taper, I would prefer a linear pot. Else a dual gang 10K and 50K pot.

--G0bble

 

[grubyhalo]

The DC coupled version of the B1 with shunt regs is supposed improve the B1's performance substantially. There is a GB open on DIYA for the boards if anyone's interested:

GB for DC coupled B1 buffer with shunt PSUs - diyAudio

 

[gobble]

What is the scope for nude Vishay TX2575 and bulk foils, or Caddock TF020 in the signal path? Too expensive? Hard to get?

Edit: see this link: http://forum.audiogon.com/cgi-bin/fr.pl?htech&1218474065&openfrom&1&4#1

--G0bble

 

[sachu888]

The DC coupled version of the B1 with shunt regs is supposed improve the B1's performance substantially. There is a GB open on DIYA for the boards if anyone's interested:

GB for DC coupled B1 buffer with shunt PSUs - diyAudio

Yes this one is B1,Salas version with shunt regs.I will PM Salas regarding gerber files of PCB,but again we'll require matched JFETs.

Regards,
Sachin

 

[grubyhalo]

You'll find more info. on part selection, options and BOMs here:

Nelson Pass B-1 preamp kit