Nelson Pass B-1 preamp kit

Lyndon · « **Reply #480 on:** 14 Aug 2010, 07:18 pm »

wushuliu,
Has anyone on this thread or the other one on diyaudio compared the sound of the B-1
to a tubed preamp, such as the Grounded Grid, or the 12b4 linestage? I am considering building a newer version of the Grid, but was wondering if I could find some feedback.
Lyndon

poseidonsvoice · « **Reply #481 on:** 14 Aug 2010, 07:34 pm »

Do what I am doing, build both and make your own decision.

I have a differential parafeed 6N6P preamp I am building with switchable 6dB/12dB of overall gain.

And I'll be building a differential direct coupled B1 w/shunt regulation with 0dB overall gain.

It's diy, have fun. They all sound good, great, bad, and different.

Anand.

roymail · « **Reply #482 on:** 14 Aug 2010, 08:07 pm »

Lyndon, you might contact Jon L, Walkern or Anand with a PM. They should be able to answer your questions.

wushuliu · « **Reply #483 on:** 14 Aug 2010, 09:37 pm »

Quote from: Lyndon on 14 Aug 2010, 07:18 pm

wushuliu,
Has anyone on this thread or the other one on diyaudio compared the sound of the B-1
to a tubed preamp, such as the Grounded Grid, or the 12b4 linestage? I am considering building a newer version of the Grid, but was wondering if I could find some feedback.
Lyndon

I believe someone compared theirs to a grounded grid on diyaudio. You may want to do a search there or post in the B1 Buffer Preamp thread.

Jon L · « **Reply #484 on:** 14 Aug 2010, 09:58 pm »

Quote from: Lyndon on 14 Aug 2010, 07:18 pm

compared the sound of the B-1
to a tubed preamp, such as the Grounded Grid, or the 12b4 linestage?

My grounded grid is not stock, but I have compared it to B-1.

First of all, as nice as stock grounded grid is, it simply does not compare with B-1 in terms of transparency and impact. After doing much of everything possible to my GG as described here, it's a different story, though.
http://www.audiocircle.com/index.php?topic=72652.0

Now we have two VERY different sound paths, but one could argue he prefers one over the other for very valid reasons. B-1 is still more transparent and "straight with gain" while giving great defined bass and dynamic impact.

Tweaked GG still has that expansive, richly harmonic, warm yet clear sound that simply tugs at your ear more. Depending on one's tastes and system configuration, I can appreciate somebody preferring one over the other. Just for reference, I've had Audible Illusions L1 tube pre and SAS Labs 10A tube pre in my system before (both wonderful preamps!), and I prefer the tweaked GG more.

Of course, now I'm looking into improving the B-1 with better resistors, volume control, wire, etc, so we'll see. I even found a pair of 1 uF teflon caps in my drawers, so I may even do that to even the playing field since my GG has teflon output caps

Lyndon · « **Reply #485 on:** 14 Aug 2010, 10:01 pm »

Jon L,
Thanks so much for that.
And the link.
wushuliu, I'll check over at the other forum as well.
Don't have the time or resources to do both this fall.
Lyndon

poseidonsvoice · « **Reply #486 on:** 14 Aug 2010, 10:05 pm »

Quote from: Jon L on 14 Aug 2010, 09:58 pm

My grounded grid is not stock, but I have compared it to B-1.

First of all, as nice as stock grounded grid is, it simply does not compare with B-1 in terms of transparency and impact. After doing much of everything possible to my GG as described here, it's a different story, though.
http://www.audiocircle.com/index.php?topic=72652.0

Now we have two VERY different sound paths, but one could argue he prefers one over the other for very valid reasons. B-1 is still more transparent and "straight with gain" while giving great defined bass and dynamic impact.

Tweaked GG still has that expansive, richly harmonic, warm yet clear sound that simply tugs at your ear more. Depending on one's tastes and system configuration, I can appreciate somebody preferring one over the other. Just for reference, I've had Audible Illusions L1 tube pre and SAS Labs 10A tube pre in my system before (both wonderful preamps!), and I prefer the tweaked GG more.

Of course, now I'm looking into improving the B-1 with better resistors, volume control, wire, etc, so we'll see. I even found a pair of 1 uF teflon caps in my drawers, so I may even do that to even the playing field since my GG has teflon output caps

This is what I found true to the nature of diy and why it is so gratifying. You can somewhat tailor the sound. I have found, in recent years, that properly designed differential/balanced circuits are out of this world, even though I am not running hundreds of feet of cables...

Anand.

walkern · « **Reply #487 on:** 15 Aug 2010, 12:16 am »

Quote from: wushuliu on 14 Aug 2010, 09:37 pm

I believe someone compared theirs to a grounded grid on diyaudio. You may want to do a search there or post in the B1 Buffer Preamp thread.

I built a Ground Grid several years ago shortly after they came out, and was quite happy with it (stock) until I got a chance to listen to some far more expensive tube and SS preamps. By comparison the stock unit was a little rough around the edges, although it had terrific speed and articulation. It lacked a bit of finesse, and didn't have the bass slam or definition that my B1 has. I was kind of hoping it would have a more classically tube kind of character... a little warm and forgiving, so it would match up well with a SS amp I was using at the time... but it was not warm or forgiving (nor was it cold or clinical... just pretty neutral). In any case, I sold it and bought the TVC and was happy until I built a B1. I'm sure (as noted above) that the GG can be tweaked and improved beyond stock, and adjusted to be an ideal fit for a given system... but the B1 is less expensive, and equally flexible (again, as noted above... one of the advantages of DIY).

Best of luck with your decision,

Neil

Lyndon · « **Reply #488 on:** 15 Aug 2010, 01:46 am »

Thanks, Neil
I just finished the 261 pages of the original thread at diyaudio, and that is not adding the other variations!
I guess I will think more on this option, but will want to include the remote volume control
(yeah, I know, I know) that I bought from some Dutch guy on diyaudio a few years ago.
Lyndon

roymail · « **Reply #489 on:** 17 Aug 2010, 06:46 pm »

Quote from: sondale on 15 Mar 2010, 09:39 pm

The B1 without a potentiometer is very useful as a pure buffer.
Alan

Hi Alan,

Can you tell me how to wire the B1 as a buffer only, using RCA's in place of the attenuators?

CW - input
W - wiper
CCW - ground

I wire the RCA with input and ground, but what about the wiper? I'm thinking the W (wiper) is only for attenuating or resisting the signal. Do I just leave it open?

I don't know a lot about electronics, but I can solder pretty well if I know what goes where. Please explain but keep it simple. Thanks.

I'll place the B1 buffer between my diy Goldpoint/Elma 20K stepped attenuator and amplifier.

I appreciate your help,
Roy in TX

sondale · « **Reply #490 on:** 17 Aug 2010, 07:40 pm »

Roy,

Connect CW to W, then solder a 25K resistor between W and CCW.

Effectively you have a potentiometer which is fully open.

Alan

roymail · « **Reply #491 on:** 17 Aug 2010, 11:38 pm »

This provides still another option for the B1 buffer. For me, since I already have a nice passive stepped attenuator, adding the B1 buffer to control any impedance mismatches is a great option. I'm really looking forward to trying it.

Yes, I can integrate the GP/Elma SMT 20K stepped attenuator into the B1, and I may do that later. But for now, I'm going to configure the Pass B1 buffer in the same way that Burson does their buffer.

Alan, thanks for the helpful information. Much appreciated.

HAL · « **Reply #492 on:** 18 Aug 2010, 12:08 am »

If you are putting a passive attenuator in front of the B1, you would not need a low value resistor like 25K. In this situation that would load the other passive attenuator depending on it's value.

Another idea would be to put a 1 meg ohm resistor in instead of the 25K ohm and then this will load the input attenuator very little, but keep the input terminated for DC offset incase the attenuator is ever disconnected.

Just a thought.

sondale · « **Reply #493 on:** 19 Aug 2010, 12:14 pm »

Hal,

Thanks for that - I will try 1Meg in that position.

Alan

Jon L · « **Reply #494 on:** 19 Aug 2010, 08:20 pm »

Vishay tx2575 resistors and eBay 20K SMT attenuator have been ordered

toxteth ogrady · « **Reply #495 on:** 19 Aug 2010, 08:45 pm »

I just picked up two dcb1 blue boards from the diyaudio group buy. Is anyone in the process of building one of these? Looks to be quite a bit more challenging than the original b1 build.

wushuliu · « **Reply #496 on:** 19 Aug 2010, 08:56 pm »

Quote from: toxteth ogrady on 19 Aug 2010, 08:45 pm

I just picked up two dcb1 blue boards from the diyaudio group buy. Is anyone in the process of building one of these? Looks to be quite a bit more challenging than the original b1 build.

stay tuned...

toxteth ogrady · « **Reply #497 on:** 19 Aug 2010, 09:46 pm »

roymail · « **Reply #498 on:** 19 Aug 2010, 10:35 pm »

Quote from: Jon L on 19 Aug 2010, 08:20 pm

Vishay tx2575 resistors and eBay 20K SMT attenuator have been ordered

Has anyone tried Caddock 132's or 020's?

Russellc · « **Reply #499 on:** 20 Aug 2010, 01:08 pm »

Quote from: Lyndon on 14 Aug 2010, 07:18 pm

wushuliu,
Has anyone on this thread or the other one on diyaudio compared the sound of the B-1
to a tubed preamp, such as the Grounded Grid, or the 12b4 linestage? I am considering building a newer version of the Grid, but was wondering if I could find some feedback.
Lyndon

I have. I have the B-1, but for speakers with less efficiency, the F-5 needs a little gain. I switch in the Audio by Van Alstein Super Pass III. wonderful combination, sometimes I think maybe it gives up a little transparency to the B-1, but then again it adds its tubey goodness. Very nice combo.

Russellc