Nelson Pass B-1 preamp kit

kingnubian · « **Reply #620 on:** 14 Oct 2010, 01:30 pm »

A delivery from DiyHifiSupply came today! The Obbligato Premium 1uf matched pair.

Things are getting close to the final build. Got the naked Vishay's and both my Russian & Obbligato caps as well as the Gigaworks attenuator. Now just need a toggle switch, wall wart with matching power input jack, volume knob & enclosure. I was going for the ProjectX Enclosures from DiyHifiSupply but with an advertised internal height of only 63mm (~2.5"), it would be too tight a squeeze for the Panasonic caps that are on the board, unless I wire them to their connections instead of having them sit on the board directly. (Opinions??).

1More's case selection seems pretty good & I could easily go for the 4" height model also, I just like the look of the Diyhifisupply chassis more but it isn't a deal breaker. I have to admit I have very little experience with drilling Aluminium so this is what is really bothering me right now. I want this project to look very clean.

roymail · « **Reply #621 on:** 14 Oct 2010, 05:41 pm »

Quote from: kingnubian on 14 Oct 2010, 01:30 pm

I have to admit I have very little experience with drilling Aluminium so this is what is really bothering me right now. I want this project to look very clean.

Just remember to use painter's blue masking tape over the area where you want to drill the holes. Mark them on the tape, then drill small pilot holes. Be patient and work up to the proper size hole. Once the holes are drilled, clean off the debis, then remove the tape. Should be very nice and clean.

Since you're going top end on parts, consider using a Goldpoint/Elma stepped attenuator if you ever decide to upgrade your volume control. Absolutely first rate!

When you get it up and running, please let us know how it sounds in your system.

kingnubian · « **Reply #622 on:** 14 Oct 2010, 06:22 pm »

Quote from: roymail on 14 Oct 2010, 05:41 pm

Just remember to use painter's blue masking tape over the area where you want to drill the holes. Mark them on the tape, then drill small pilot holes. Be patient and work up to the proper size hole. Once the holes are drilled, clean off the debis, then remove the tape. Should be very nice and clean.

Since you're going top end on parts, consider using a Goldpoint/Elma stepped attenuator if you ever decide to upgrade your volume control. Absolutely first rate!

When you get it up and running, please let us know how it sounds in your system.

Thank you very much for the info!! After the final build I'll start tweaking stuff to get the recipe just right.

What kind of drill bits do you recommend? Carbide, Cobalt, step??

Just for size comparison's sake, here are from the top, Russian K73-16 10uf, Obbligato Premium 1uf & K73-16 1uf.

roymail · « **Reply #623 on:** 14 Oct 2010, 07:51 pm »

Quote from: kingnubian on 14 Oct 2010, 06:22 pm

What kind of drill bits do you recommend? Carbide, Cobalt, step??

I use standard Craftsman or Black & Decker drill bits, nothing special necessary since you're only drilling through aluminum. Be sure to use the tape and start with the small holes first, then work up to the desired size hole.

It's not difficult, just take your time. Remember the old saying, "measure twice, cut once."

kingnubian · « **Reply #624 on:** 14 Oct 2010, 08:30 pm »

Quote from: roymail on 14 Oct 2010, 07:51 pm

I use standard Craftsman or Black & Decker drill bits, nothing special necessary since you're only drilling through aluminum. Be sure to use the tape and start with the small holes first, then work up to the desired size hole.

It's not difficult, just take your time. Remember the old saying, "measure twice, cut once."

Lol, that old saying is very true.
Do you use some type of oil or as some have mentioned, WD40, for the drill bit?

roymail · « **Reply #625 on:** 14 Oct 2010, 08:33 pm »

Quote from: kingnubian on 14 Oct 2010, 08:30 pm

Do you use some type of oil or as some have mentioned, WD40, for the drill bit?

No, as aluminum is soft and it's not necessary. Just a good bit is all it takes.

sts9fan · « **Reply #626 on:** 14 Oct 2010, 08:59 pm »

Unibits are real nice to have.

1MOR · « **Reply #627 on:** 16 Oct 2010, 04:50 am »

I use a drill press. Keep your spindle speed at less than 1/2 of the recommended speed when drilling aluminum panels. I use high speed drills from Enco. I measure the diameters of the control shafts, rca barrel, etc, with a dial caliper. Then select a drill just a tad larger than your measurement, for clearance. Layout your panel on the backside, I use a good quality square combo and a small center punch. Then I use a center drill to locate the center of the scribed location lines, to drill a small hole, much smaller than the size of the finished hole. These work great and can be found in Grizzly, Harbor Freight, Enco etc. http://www.grizzly.com/products/4-pc-Center-Drill-Set-82-/H5931
You are always better off, by drilling your holes too small and then opening them up, than to drill finish size first and find that your drill had some wobble and your hole is way too large or not round. Nice cap selection!

1MOR · « **Reply #628 on:** 16 Oct 2010, 05:11 am »

I layout the panels on a piece of cardboard first, to check the appearance and the final dimensions of the holes. Cardboard is scrap and zero cost, finish panels are not!

wushuliu · « **Reply #629 on:** 16 Oct 2010, 06:57 am »

Can't do that (drill press) in a small 2br apartment. *sigh*

kingnubian · « **Reply #630 on:** 16 Oct 2010, 01:48 pm »

Quote from: wushuliu on 16 Oct 2010, 06:57 am

Can't do that (drill press) in a small 2br apartment. *sigh*

These may be the ticket. They are small both in size & price. It looks to be exactly what the DIY'er could use for projects. I'm going to check both out today & I'll report back what I find.

http://www.homedepot.ca/webapp/wcs/stores/servlet/CatalogSearchResultView?D=930979&Ntt=930979&catalogId=10051&langId=-15&storeId=10051&Dx=mode+matchallpartial&Ntx=mode+matchall&N=0&Ntk=P_PartNumber

http://www.rona.ca/shop/~drill-10-in.-drill-press-with-table-haussmann-440068_!drill-press_shop

Any comments?

NOTE: The price quoted is in Canadian.

1MOR · « **Reply #631 on:** 16 Oct 2010, 02:39 pm »

RYOBI offers a quality product. If you purchase the Ryobi, make sure HD will take it back/replace if you have excessive spindle play/slop. A small drill press is all that you will need for constructing cases for audio equipment. Harbor Freight had a sale, I had a 20% off coupon. I got the larger DP for $149. The used Craftsman stand came from Epay, $16. All of these drill presses are made in China.

roymail · « **Reply #632 on:** 16 Oct 2010, 03:16 pm »

Drill presses are great if you have a shop or other dedicated room. As stated, always start with a smaller bit.

Once, I asked my wife if I could turn our spare bedroom into a hobby room, you can guess the outcome...

1MOR · « **Reply #633 on:** 19 Oct 2010, 12:20 am »

Update on the PS! I started with a 18 volt wall wart, nice but a little dry, top to bottom. This afternoon, I switched in the 24 volt wall wart. No smoke, no burning B1. Just a noticeable improvement. Improved dynamics and bass response. For the associated equipment and the listening space, this is a very worthwhile upgrade. That is my story, and I am sticking to it!

I had paralleled the output jack to allow use of a second set of output RCAs to attach a subwoofer. Got that working this morning. One of my pics shows that detail.

nodiak · « **Reply #634 on:** 29 Oct 2010, 03:16 am »

Just getting back to audio after summer break. Getting the B1 buzz, have read this thread and am getting ready to source B1 parts. Ordered the Pass pcb's/jfets and gigaworks 20K ebay pot.
Open to buying parts from anyone not finishing the project (been there...).
Have a CDA-254 amp now, hope it matches well. Speakers are 90db 4ohm.
Nice to have such quality available for such price! Thanks to NP, and yous guys too.
Don

AUDFILE74 · « **Reply #635 on:** 31 Oct 2010, 12:40 am »

what are the voltages if i want to go with a transformer instead of a wall wart?

1MOR · « **Reply #636 on:** 31 Oct 2010, 01:03 am »

Its a bit more complicated than just using a transformer. You will need to convert the AC from the transformer to DC. You will also need to provide some type of regulation for the DC. So, you can use batteries, you can use an existing cicruit that provides rectification and regulation or, you can follow the recommendations of the circuit's designer, Nelson Pass and use an appropriate wall wart. NP sells his commercial product with power supplied by a wall wart. And, you will pay about $1000 for that product!! HTH

AUDFILE74 · « **Reply #637 on:** 4 Nov 2010, 06:58 pm »

good point 1MOR, http://www.amb.org/audio/sigma11/ next week i will be ordering this for my b-1 project. i tihinkit's time i get it in gear her. thanks wushuliu

nodiak · « **Reply #638 on:** 13 Nov 2010, 12:31 am »

Am ordering the parts from wushuliu's list. Have a Pass pc

Don

nodiak · « **Reply #639 on:** 2 Jan 2011, 12:05 am »

Worked on B1 board today. Soldered the small resistors. Serious appreciation to Wushuliu for the run through. I used the soldering demos he linked to, and they were very helpful. Made some classic poor joints and think/hope have redone them well...trying to get the hang of small soldering. May get a big magnifying glass as my eyesight isn't really good enough for this small work.
Have a good soldering station, but had to practice setting temperature and using best tip for the work. In college took jewelry/metalworking classes and one of the best things about it was working nights in the lab when everyone would help and encourage each other on our projects. Would be cool if my audio projects could be done that way, sure some folks arrange that with buddies.
So, will try to make more time to finish this up soon, it's a short project but have a busy 2 weeks ahead at work.