Nelson Pass B-1 preamp kit

vinylb · « **Reply #680 on:** 10 Apr 2013, 11:25 am »

Quote from: Nick77 on 9 Apr 2013, 02:19 pm

Yes the DCB1 is a cut above the B1 even with TX2575 although I also use TX2575 in my DCB1. I purchased boards only and used exotic parts. Mine is the hotrodded version running at about 600mA.

I put my order in for kit and pcb with Teabag for DCB1. I am also going to hotrod mine. Thanks for your comments. Do you mind if I pick your brain if I have questions?

Nick77 · « **Reply #681 on:** 10 Apr 2013, 11:41 am »

Be happy to share my experiences with parts selection, but i relied on Wushilu's build tutorial.

WireNut · « **Reply #682 on:** 26 Jul 2013, 02:27 am »

Hi wushuliu,

Thanks for the build thread. I received most of the parts last week except for the case which has been the hardest thing to find so far. Par-metal only builds cases on an order by order basis and there's a 3-6 week waiting period. No cases are kept in stock I was told. Looks like I’m going to try a Lansing enclosure. Their twice as much as par-metal but Lansing keeps cases in stock.

I think I’m going to mount all 5 Sonic Caps on a second board behind the B1 board due to their size and use small terminal strips to make it easy to try different caps in the future.

Also, it looks like the 4 Jfet's might be a SMALL bear to solder in place. I can barely see the dam things and the eyelets on the board are very tiny and close together in all 4 locations. I bought the Jfet’s from NP so I don’t wanna screw those up.

If you guy's have any suggestions/cautions about how to solder in those Jfet's let me know. I'm all ears.
I'm intimidated by these little things.

Thanks,
WN

Jfet's

vinylb · « **Reply #683 on:** 26 Jul 2013, 11:07 am »

Hey Wirenet, use a magnifying glass or one of those "helping hands" with a circular magnifying glass. Its not too bad, also make sure you use a small solder and the right iron size and you'll be ok.
Follow orientation that son board - flat side faces to left if you looking at pcb as in your pic posted.

Dont forget the 1K resistors are in the signal path and benefit from boutique part, but having said that, will work and sound fine with just a regular resistor

The holes for the caps are not much bigger than the resistors if I recall so you might have to put in left over cuts from trimming resistors in place and then solder cap leads onto them.

djtw · « **Reply #684 on:** 26 Jul 2013, 12:48 pm »

I have also heard that JFET's can be sensitive to heat, so I would put a small clip on the lead to be soldered to absorb some of the heat during the soldering process.

Also, pre bend the leads and don't cut the leads too short, in case you have to remove the part later.

Hope this helps...

Speedskater · « **Reply #685 on:** 26 Jul 2013, 02:03 pm »

With the exception of the 6 power supply resistors, all the other resistors are in the signal path. Just because one end of a resistor is connected to circuit ground doesn't take it out of the signal circuit.

vinylb · « **Reply #686 on:** 26 Jul 2013, 06:13 pm »

These are all good pointers, one more thing if you are going to be swapping out resistors either make the legs/leads longer so they further away from the pcb or just use
those connectors commonly found in Arduino diy kits - stackable headers. they come in all different lengths.

I trim mine so that I am able to put one pin in each resistor hole and yank out the pins in betweeen so that the header sits flat. This has saved me a lot of frustration when trying to get the right sound.

WireNut · « **Reply #687 on:** 26 Jul 2013, 08:23 pm »

Hi djtw and vinylb,

Thanks for all the tips. I like the idea of stackable headers. Think I’ll pick some up on digikey or mouser if I can find them. Your right about the eyelets for the 1UF caps, they are too small for the leads on my caps so using the scrap resistor leads was a good idea.

I believe the resistors most folks change are R102 and R202. Not sure if any other locations are as critical. I may pick up some naked Vishay’s for those spots.

vinylb · « **Reply #688 on:** 28 Jul 2013, 12:01 pm »

In an earlier post, Nick77 described resistors as:

Vishay TX2575 Foil very resolute and neutral
Riken Carbon warm and fairly resolute
PRP Metal film good metal film
Takman Carbon, warm but conjested

in my opinion he is 100% right with his description of each. In this project I settled on TX2575 (built 3 of these) and other projects I have used Riken.

If you only using one input then you dont need to buy all resistors for input1 and input 2. I compared my 2 builds (one with a switch and one without) and could not tell
the difference in sound.

WireNut · « **Reply #689 on:** 1 Aug 2013, 02:52 am »

I know the B1 was not designed to drive 2 power amps, NP built the First Watt B2 for driving multiple amps. But If I'm running the output of the B1 into an active crossover (audio research ec22) that drive's two amps from it's own outputs, do you all think that will work?

vinylb · « **Reply #690 on:** 1 Aug 2013, 10:31 am »

I have no experience with that ARC product but I dont see why not. Check to see the impedance is what the EC22 is wanting or in the range and i think you should be ok.
btw I love ARC products, had SP5,SP9,SP6.

WireNut · « **Reply #691 on:** 27 Aug 2013, 02:00 am »

Can the B1 be built inside an all wood case or do you all think there will be a hum issue?

Thanks

G Georgopoulos · « **Reply #692 on:** 27 Aug 2013, 03:02 am »

Quote from: WireNut on 27 Aug 2013, 02:00 am

Can the B1 be built inside an all wood case or do you all think there will be a hum issue?

Thanks

wn there wont be hum issue in wood case...if all is done properly...go ahead and build it...

Kooka · « **Reply #693 on:** 30 Dec 2014, 07:41 am »

Quote from: sondale on 1 Apr 2010, 07:25 pm

I think it is the board - if you look at the left/right inputs for 1 the left goes to the bottom pin on S100 and the right goes to the top pin of S200!

Alan

Sorry to revive an old topic but I have this Jim's board around with all the parts ready and was readind this: is it confirmed that that the chinese boards are WRONG? That would be very strange, actually.
If any one Can help, please...

Speedskater · « **Reply #694 on:** 30 Dec 2014, 03:50 pm »

Now that it's just about 2015, almost any product (including lights) that you buy that plug's into the AC power has the possibility of generating EMI/RFI interference. Wood cases and EMI/RFI interference don't get along well together.

I.Greyhound Fan · « **Reply #695 on:** 12 Nov 2015, 07:55 pm »

I know that this is an old thread but I am going to build the B1 for my son Parasound A21 amp.

I am curious as to what caps people are using. I want a slightly warm, detailed, tubey sound with good air and transparency. I am using Vishay TX2575 1K resistors in the input section and Carbon Riken 1K resistors in the output section.

I would appreciate any comments on caps as well as resistor selection for the remaining 10K, 15K and 221K resistors. I was considering trying some PIO caps but I am open to suggestions.

Has any one used a remote volume control?

Thanks!

navi · « **Reply #696 on:** 2 Dec 2015, 05:08 am »

Just completed mine.
Resistive Ladder attenuator off Ebay $38
Obligato capacitors
Silver plated RCAs
Sonic art silver plated PTFE cable, Oyaide and Mogami cable
Rubycon and Vishay parts from divi-key

Sounds great so much more bass and detail in the lower notes but I think midrange detail isn't as good.

Ivan.

Nick77 · « **Reply #697 on:** 2 Dec 2015, 11:45 am »

Quote from: I.Greyhound Fan on 12 Nov 2015, 07:55 pm

I know that this is an old thread but I am going to build the B1 for my son Parasound A21 amp.

I am curious as to what caps people are using. I want a slightly warm, detailed, tubey sound with good air and transparency. I am using Vishay TX2575 1K resistors in the input section and Carbon Riken 1K resistors in the output section.

I would appreciate any comments on caps as well as resistor selection for the remaining 10K, 15K and 221K resistors. I was considering trying some PIO caps but I am open to suggestions.

Has any one used a remote volume control?

Thanks!

PRP resistors and Auricaps would be a good choice to meet your sound target. IMHO......

I.Greyhound Fan · « **Reply #698 on:** 3 Dec 2015, 01:08 am »

Nice build Navi.

I just ordered most of the parts. I went with Mundorf MCap Supreme's for the 1uF's and Clarity ESA's for the 10uF's. I was going to go with the Obbligato's instead of the ESA's but I am leery about their bass being a little too thin. I can always swap in the Obbligato's.

For resistors I went with the Tx 2575 for the input and Riken Carbon's for the output. Other resistors are Audio Note Tantalums, Takman Rey's and Vishay-Dale's.

I am thinking about using one of these case's - the A28-A or the A28-C

http://diyclub.biz/catalog/index.php?cPath=1_284_298

And this Remote AlP's volume pot-

http://diyclub.biz/catalog/product_info.php?products_id=601

I would prefer a 20K or 50K pot but I can't find a decent kit for a similar price.

navi · « **Reply #699 on:** 7 Dec 2015, 12:49 am »

Quote from: I.Greyhound Fan on 3 Dec 2015, 01:08 am

Nice build Navi.

I just ordered most of the parts. I went with Mundorf MCap Supreme's for the 1uF's and Clarity ESA's for the 10uF's. I was going to go with the Obbligato's instead of the ESA's but I am leery about their bass being a little too thin. I can always swap in the Obbligato's.

For resistors I went with the Tx 2575 for the input and Riken Carbon's for the output. Other resistors are Audio Note Tantalums, Takman Rey's and Vishay-Dale's.

I am thinking about using one of these case's - the A28-A or the A28-C

http://diyclub.biz/catalog/index.php?cPath=1_284_298

And this Remote AlP's volume pot-

http://diyclub.biz/catalog/product_info.php?products_id=601

I would prefer a 20K or 50K pot but I can't find a decent kit for a similar price.

Have you tried the Obilgato's in the past and thought the bass was lacking?
I tried the B1 board with old 10yr old slagle/intact audio autoformers (AVC) and couldn't get enough bass from it. Maybe my stacking of the cores wasn't right but I could never get deep bass from it in the past