Nelson Pass B-1 preamp kit

roymail · « **Reply #580 on:** 3 Sep 2010, 11:17 pm »

Nice job, Keith. I don't have to ask how it sounds.

Chris Adams · « **Reply #581 on:** 3 Sep 2010, 11:48 pm »

Nick77,

That is gorgeous!

poseidonsvoice · « **Reply #582 on:** 4 Sep 2010, 12:13 am »

Quote from: Nick77 on 3 Sep 2010, 10:42 pm

Well i just i would post a couple of pic's since i am totally finished with this B1 project. Cleaned up some wireing and installed Gen2 bypasses and with the new naked Vishays it rocks!!

Whew! Finally...you are done!

Anand.

kingnubian · « **Reply #583 on:** 4 Sep 2010, 03:56 am »

Quote from: Nick77 on 3 Sep 2010, 10:42 pm

Well i just i would post a couple of pic's since i am totally finished with this B1 project. Cleaned up some wireing and installed Gen2 bypasses and with the new naked Vishays it rocks!!

Excellent! Thanks for the tips btw.

exojam · « **Reply #584 on:** 4 Sep 2010, 02:27 pm »

Nick,

Do you have other caps paralleled off of both the 1 and 10 caps in there? If so, what was the purpose of that? Thanks.

James

Nick77 · « **Reply #585 on:** 4 Sep 2010, 03:06 pm »

Quote

The Sonicap Gen I is basically a fairly balanced capacitor. However, some find our "balanced" slightly thin and bright compared to the more lush "colored" capacitors which would include the Gen II. While the Gen II has a nice Midrange bloom, Gen I has a slight advantage on the freq extremes (top and bottom). In many applications, larger values of Gen I bypassed with smaller values of Gen II yield a very favorable result.

The bypass added a little extra detail and lushness.

exojam · « **Reply #586 on:** 4 Sep 2010, 03:43 pm »

Interesting...

James

Jon L · « **Reply #587 on:** 7 Sep 2010, 03:27 am »

Jeez, that Hong Kong SMT volume control turned out to be very flimsy. The shaft and nut became loose, so I tightened the nut just a little bit more...and bam! the whole shaft separated off of the body

Luckily, I think I prefer the sound of Blue Velvet more anyway. It's more organic yet more sparkly IMO.

I finally replaced the 1 uF input cap to my secret-weapon, Penta Labs teflon caps which are well-used already. Very niice... I then replaced the wiring with solid-core silver in teflon/air. Nicer.. My camera is MIA but photos to come later.

Jon L · « **Reply #588 on:** 8 Sep 2010, 10:05 pm »

These 1uF Penta Labs teflon caps (white) are HUGE! Unfortunately, I can't close the lid anymore, but at least I have a DAC with huge caps I can't close the lid, either, so at least they'll match..

Nick77 · « **Reply #589 on:** 8 Sep 2010, 10:13 pm »

So how is it sounding??

roymail · « **Reply #590 on:** 9 Sep 2010, 03:52 am »

Jon, those MONSTER caps got me looking and reading, and I came across your articles in Enjoy the Music. Very nice reading, descriptions and pictures. Nice job!

For those who may be interested, here you go. It's two parts.

http://www.enjoythemusic.com/diy/0708/capacitor1.htm
http://www.enjoythemusic.com/diy/1108/capacitor1.htm

Maybe next you could try SLA battery power and a Goldpoint/Elma 20K stepped attenuation. WOW!

Jon L · « **Reply #591 on:** 9 Sep 2010, 04:01 am »

Quote from: roymail on 9 Sep 2010, 03:52 am

Jon, those MONSTER caps got me looking and reading, and I came across your articles in Enjoy the Music. Very nice reading, descriptions and pictures. Nice job!

For those who may be interested, here you go. It's two parts.

http://www.enjoythemusic.com/diy/0708/capacitor1.htm
http://www.enjoythemusic.com/diy/1108/capacitor1.htm

Maybe next you could try SLA battery power and a Goldpoint/Elma 20K stepped attenuation. WOW!

I do have a Goldpoint in my grounded grid, so I may "borrow" that for a while, but a proper, really transparent volume control at reasonable prices is a dilemma.

Ebay SMT volume control guys have agreed to send me another 20K one after I told them the shaft broke at the body, so at least that's good. There's a small protrusion on these SMT to prevent it from spinning around the shaft, but how are you guys making the opening on the chassis?

avionic · « **Reply #592 on:** 9 Sep 2010, 06:23 am »

Hey Jon, I just took the wire cutters to that "small protrusion" and drilled a single hole. The nut holds the pot plenty tight with the lock washer and I have a nice flush mount.

Jon L · « **Reply #593 on:** 9 Sep 2010, 05:21 pm »

Quote from: avionic on 9 Sep 2010, 06:23 am

Hey Jon, I just took the wire cutters to that "small protrusion" and drilled a single hole. The nut holds the pot plenty tight with the lock washer and I have a nice flush mount.

That's what I did initially, and the SMT was nice and tight. But after some use, the volume control became looser and looser, rotating past the stop when turned. That's when I tried tightening the nut, which broke the shaft

If I decide to use the SMT again, I may try a power drill to make an opening for that protrusion to stick into.

Chris Adams · « **Reply #594 on:** 9 Sep 2010, 05:52 pm »

Jon, I did just that with a drill and it works fine. Your front panel looks a tad thicker than mine so it should work fine. In order to go deep enough on mine, I ended up with a small nipple on the front of the panel from the tip of the drill bit.

The volume knob covers it up just fine.

Jon L · « **Reply #595 on:** 9 Sep 2010, 09:37 pm »

Quote from: Chris Adams on 9 Sep 2010, 05:52 pm

Jon, I did just that with a drill and it works fine. Your front panel looks a tad thicker than mine so it should work fine. In order to go deep enough on mine, I ended up with a small nipple on the front of the panel from the tip of the drill bit. The volume knob covers it up just fine.

Are you happy with your SMT's sound quality (compared to?).

Since I haven't tried the SMT since the teflon cap upgrade, I will give it another shot when the replacement SMT arrives. I plan to let the teflons run in for a gazillion years before making up my mind, but already there is a removal of compression and a lot more dynamic freedom and energy. If I could only get some 10 uF teflon capacitors

poseidonsvoice · « **Reply #596 on:** 9 Sep 2010, 11:14 pm »

Quote from: Jon L on 9 Sep 2010, 09:37 pm

If I could only get some 10 uF teflon capacitors

You can get close. There is no reason why you have to settle on a 10uf cap value, if you have a high impedance amplifier you are driving (like something with an input impedance of 50K). The RC constant will still be plenty low with something like 4.7uf. In fact, VH Audio sells a 3.3uf TFTF which will settle you back a nice $700 each

And when the cap starts getting really large, then all you've got is an antenna to pick RF up...

But at that point I would ask myself, wouldn't a transformer coupled or a direct coupled design be better? Like the DCB1?

Anand.

Chris Adams · « **Reply #597 on:** 10 Sep 2010, 02:13 am »

Quote from: Jon L on 9 Sep 2010, 09:37 pm

Are you happy with your SMT's sound quality (compared to?).

Since I haven't tried the SMT since the teflon cap upgrade, I will give it another shot when the replacement SMT arrives. I plan to let the teflons run in for a gazillion years before making up my mind, but already there is a removal of compression and a lot more dynamic freedom and energy. If I could only get some 10 uF teflon capacitors

I've only had the SMT in it so far. Still burning the FT-1/3. I want to wait 'till they settle down before I do anything else. I do have Blue Velvet in another pre but it's 10k and the SMT is 20k. I don't know how much SQ difference the impedance change will make.

kingnubian · « **Reply #598 on:** 15 Sep 2010, 03:59 pm »

Here are some pics of my build. This is my first diy build of any kind and I had not picked up a soldering iron in years. Some things stay with you though & I remember my dad teaching me how to solder when I was still in primary school. The leads are still there in case I needed to remove & reseat any components but will be clipped off when the build is complete.

The build is obviously not complete. I'm still waiting on the Sonicaps & the naked Vishay resistors, got the invoice but no resistors.....strange.
I'm also toying with ideas of how to power the B1. Using batteries is very doable but not at the top of my list which also includes classic Toroid, mini SMPS or just a wall wart.

Chris Adams · « **Reply #599 on:** 16 Sep 2010, 02:17 am »

kingnubian, That's looking good. I presume you're getting Gen 1. Are you going to bypass them with anything? I ask because I had some 4.7 Gen 1s in a dac and when I bypassed with a .1 Gen 2, it smoothed out the top end nicely. Good luck.