Nelson Pass B-1 preamp kit

parodielin · « **Reply #180 on:** 7 Apr 2010, 05:20 pm »

Grounding Question

I read it somewhere that you need to do chassis grounding. From wushuliu's build pictures, I did not know if there is a "grounding" step in there. If I plan to build the case using scrap MDF, how should I "ground" it?

sondale · « **Reply #181 on:** 7 Apr 2010, 05:25 pm »

Quote from: parodielin on 7 Apr 2010, 05:20 pm

Grounding Question

I read it somewhere that you need to do chassis grounding. From wushuliu's build pictures, I did not know if there is a "grounding" step in there. If I plan to build the case using scrap MDF, how should I "ground" it?

The short answer is - you cannot! However if you want to shield the buffer you could spray the insides with a metal paint designed for RFI.
However I have run my B1 open - sitting on a block of wood - no problems.
I do remember that some people on DIYAudio had suggested that the grounding on the board is not optimal and that tracks could be cut and everything wired to the -ve on the psu cap. This again I have not done.
So another short answer - dont worry about it!
Alan

parodielin · « **Reply #182 on:** 7 Apr 2010, 05:36 pm »

That's certainly great to hear. I read someone is hearing "hum" and they suspect it's grounding issue. However, what if I line sheet metal at the bottom of the chasis - would I be able to ground it in this case? if so how?

Quote from: sondale on 7 Apr 2010, 05:25 pm

The short answer is - you cannot! However if you want to shield the buffer you could spray the insides with a metal paint designed for RFI.
However I have run my B1 open - sitting on a block of wood - no problems.
I do remember that some people on DIYAudio had suggested that the grounding on the board is not optimal and that tracks could be cut and everything wired to the -ve on the psu cap. This again I have not done.
So another short answer - dont worry about it!
Alan

sondale · « **Reply #183 on:** 7 Apr 2010, 05:44 pm »

Quote from: parodielin on 7 Apr 2010, 05:36 pm

That's certainly great to hear. I read someone is hearing "hum" and they suspect it's grounding issue. However, what if I line sheet metal at the bottom of the chasis - would I be able to ground it in this case? if so how?

I do not think that you will get hum - try the buffer first.

Are the people reporting the hum using the Nelson Pass boards or the Ebay ones?

I know of no problems with the NP boards.

Alan

parodielin · « **Reply #184 on:** 9 Apr 2010, 10:46 pm »

wushuliu,

Would you mind sharing where you got the enclosure? (the only thing not on your BOM

)

How did you drill the holes?

Thanks!

Quote from: wushuliu on 11 Mar 2010, 05:26 am

Power supply Caps.

wushuliu · « **Reply #185 on:** 9 Apr 2010, 11:12 pm »

Quote from: parodielin on 9 Apr 2010, 10:46 pm

wushuliu,

Would you mind sharing where you got the enclosure? (the only thing not on your BOM )

How did you drill the holes?

Thanks!

From seller 'Tedss' on ebay. Search under Pactec. For the holes I just used my drill with a 3/8" wood boring bit for the volume pots and rca's. Regular 1/4" bit for the switch and power supply. My enclosure skills are pretty weak and I'm too impatient (and broke!) to get any fancier.

hth

parodielin · « **Reply #186 on:** 10 Apr 2010, 03:16 am »

That helps. Another question: is there any benefit of using two volume pots?

Hate to answer my own question - I just figured if I use Stereo volume I only need one.

Quote from: wushuliu on 9 Apr 2010, 11:12 pm

From seller 'Tedss' on ebay. Search under Pactec. For the holes I just used my drill with a 3/8" wood boring bit for the volume pots and rca's. Regular 1/4" bit for the switch and power supply. My enclosure skills are pretty weak and I'm too impatient (and broke!) to get any fancier.

hth

parodielin · « **Reply #187 on:** 10 Apr 2010, 03:32 am »

The wall wart has a lead time until 6/1/2010. Any other option over digi-key?

wall wart
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=T987-P5P-ND

wushuliu · « **Reply #188 on:** 10 Apr 2010, 04:58 am »

Quote from: parodielin on 10 Apr 2010, 03:32 am

The wall wart has a lead time until 6/1/2010. Any other option over digi-key?

wall wart
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=T987-P5P-ND

here you go!

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=T986-P5P-ND

xecluded · « **Reply #189 on:** 10 Apr 2010, 04:59 am »

I am running my B-1 without any 1uf bypass cap. Does it hurt anything and which cap does it bypass.

wushuliu · « **Reply #190 on:** 10 Apr 2010, 05:08 am »

Quote from: xecluded on 10 Apr 2010, 04:59 am

I am running my B-1 without any 1uf bypass cap. Does it hurt anything and which cap does it bypass.

It bypasses the power supply, and no I don't believe it's absence causes harm.

parodielin · « **Reply #191 on:** 10 Apr 2010, 01:59 pm »

Quote from: wushuliu on 10 Apr 2010, 04:58 am

here you go!

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=T986-P5P-ND

Thanks!
I am amazed on how fast you can find another one. All parameters on the Digi-Key is like crypto. Any advises on how to decipher them?

wushuliu · « **Reply #192 on:** 10 Apr 2010, 05:51 pm »

Quote from: parodielin on 10 Apr 2010, 01:59 pm

Thanks!
I am amazed on how fast you can find another one. All parameters on the Digi-Key is like crypto. Any advises on how to decipher them?

I just use the search function, never the directory. I just type in 'potentiometer' or 'switch' or 'capacitor', etc. and go from there. Practice makes perfect. And I have had a LOT of practice.

parodielin · « **Reply #193 on:** 10 Apr 2010, 11:03 pm »

Quote from: wushuliu on 10 Apr 2010, 05:51 pm

I just use the search function, never the directory. I just type in 'potentiometer' or 'switch' or 'capacitor', etc. and go from there. Practice makes perfect. And I have had a LOT of practice.

Quick question, why choose output of 6A?

wushuliu · « **Reply #194 on:** 10 Apr 2010, 11:31 pm »

Quote from: parodielin on 10 Apr 2010, 11:03 pm

Quick question, why choose output of 6A?

Do you mean 6W? the wall wart has .33A...

Mariusz · « **Reply #195 on:** 10 Apr 2010, 11:40 pm »

Hi Wushu
A quick thank you
Recieved the package
looks great
Will try it early next week

Awesome job

Best
Mariusz

parodielin · « **Reply #196 on:** 11 Apr 2010, 12:50 am »

My bad, yes 6W. My challenge in Digi-Key has been how do I know it's 6W, not 4W or something else.

Quote from: wushuliu on 10 Apr 2010, 11:31 pm

Do you mean 6W? the wall wart has .33A...

xecluded · « **Reply #197 on:** 11 Apr 2010, 10:10 am »

Quote from: wushuliu on 10 Apr 2010, 05:08 am

It bypasses the power supply, and no I don't believe it's absence causes harm.

Thanks. I will put in a bypass cap when i have a chance to monkey with it. It sounds so good that i did not feel like doing anything.

Would using battery power improve the sound even more. If it is, i may build another one with battery power. Not that i need anymore preamp but for the cost of putting one together, i can hardly go wrong

wushuliu · « **Reply #198 on:** 11 Apr 2010, 05:51 pm »

Quote from: xecluded on 11 Apr 2010, 10:10 am

Thanks. I will put in a bypass cap when i have a chance to monkey with it. It sounds so good that i did not feel like doing anything.

Would using battery power improve the sound even more. If it is, i may build another one with battery power. Not that i need anymore preamp but for the cost of putting one together, i can hardly go wrong

Some people on Diyaudio think battery power sounds better. If you could build one and compare that would be great!

xecluded · « **Reply #199 on:** 11 Apr 2010, 05:54 pm »

Quote from: wushuliu on 11 Apr 2010, 05:51 pm

Some people on Diyaudio think battery power sounds better. If you could build one and compare that would be great!

Great idea. I will do it if you would show me how to connect it with SLA battery instead of those 9V batteries.