Nelson Pass B-1 preamp kit

wushuliu · « **Reply #640 on:** 2 Jan 2011, 02:18 am »

Quote from: nodiak 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.

cool. keep us posted!

nodiak · « **Reply #641 on:** 3 Jan 2011, 11:35 pm »

Got a visor style magnifier with several magnification choices and I'm set. Now I can see what I'm doing! My solder joints from the other day look decent, shiny and conical. (Good to get this setup as my next project is a much smaller board - Ampslab LM60 amp.)
Today did the jfets. Large caps to go. Have some North Creek caps - 1uf Harmony, 10uf Zen, and four Sonicap .1uf g2 for bypasses. Probly try those combos.

nodiak · « **Reply #642 on:** 15 Feb 2011, 11:45 pm »

Got it up and running. Will let it play a few days and see how we break in to each other. Have been using a tube pre which is clear, open and 3d. With the cda254 it's been a little thin sounding (was contemplating speaker tweaking) but otherwise nice.
B1 has much bigger and warmer bass (not a BIG bass guy, like depth but not too much weight/bloom). In fact the whole range has warm sq in my system. Surprised as didn't expect that from cda254 with their little PS.
edit: I had knocked the lead off one tweeter without knowing it. So there's better balance now, not as bass heavy. B1 sounds nice after a day, transparency coming through.
I don't want to swap out parts for sq except the 1 uF caps (maybe the 10uF too). Have North Creek Harmony 1uF caps in it now. Have gen II Sonicaps for bipassing. May try other 1uF known for clarity, like gen I Sonicaps. But will wait a bit and hear what happens.
Using 10K Bourns pot.
Using chassis from dvd player.

roymail · « **Reply #643 on:** 16 Feb 2011, 12:41 am »

Glad it's working for you. Keep us posted of the changes and progress.

yeldarb · « **Reply #644 on:** 1 Mar 2011, 08:32 pm »

Just curious, since some of you have modded for two outputs, will the B1 drive a fairly long sub cable (12 feet), in addition to a normal length?

walkern · « **Reply #645 on:** 1 Mar 2011, 08:49 pm »

I'm driving 9 feet of cables without any problems what so ever. I'm sure 12 feet will not be an issue.

Neil

roymail · « **Reply #646 on:** 1 Mar 2011, 10:43 pm »

Yes, I agree. Not a problem...

nodiak · « **Reply #647 on:** 2 Mar 2011, 04:07 pm »

After a couple weeks of playing the B1 with cda254 the frequency response has evened out (only took ~ 20 hours) and it's sounding very nice. Clear, much more open than expected, room filling soundstage. Adds a sense of power, more like I'd expect a bigger amp would. Currently using 24v walwart, wiill get an 18v one to compare. Bass remains strong but cleaner than at first. Makes the cda254 sounds better, but am anxious to try B1 with other amps. B1/cda254 combo allows full use of volume control which I like. It plays as loud as I need at 2:00 mark and up, but 11:00 is getting loud.
I would say if you can build B1 it's very much worth having to compare other pre's/buffers to, and it could improve the rest of your system. Am not really missing out on the sense of space I like from tubes, but may try a Dodd buffer when able as I bet it's another goody.

Just wanted to add that the B1 cured my systems slight bass shyness. I was considering working on the speakers as it seemed the bass drivers weren't as loud as the mids and tweeters. But now frequencies are even spl wise. Bonus.

roymail · « **Reply #648 on:** 2 Mar 2011, 08:06 pm »

Quote from: nodiak on 2 Mar 2011, 04:07 pm

Currently using 24v walwart, wiill get an 18v one to compare.

Although I have no plausible explanation, and for what it's worth, I've read that the 24v actually sounds better than the 18v. I don't see any reason to try it unless you just want to, but doesn't cost much to try. However, SLA battery power would definitely be a step up. Thanks for sharing your impressions.

sl_1800 · « **Reply #649 on:** 3 Mar 2011, 01:03 pm »

I just built a B1 and I'm running it on 24V AGM batteries, two 12's in series. I also use it with a Class D Audio CDA 254, sounds like a good combination. I was thinking of going with 18V batteries since I have a charging system for that from another older piece of gear but the 24V is sound so good I may just leave it alone.

porfido · « **Reply #650 on:** 15 Mar 2011, 11:27 pm »

Hi everybody,
as usual, sorry for my english first of all....
Thank you very very much for this topic that helped me so much building also the second B1 buffer....
This time I wanted a remote controlled unit, so I decided to use a cheap ebay pcb with remote to control a motorized pot on the Lightspeed attenuator kit by Uriah Dailey....
These cheap remote pcb's are not so good for working on signal but using it only for controlling the 5v supply to the LDR's I don't risk any kind of noise....
This time I used k73 caps bypassed by teflon k40, only precision resistors on board and 0,01% res on signal...

This time I use three 6v sla batteries for 18v B1 psu and a simple charging/mantaining circuit for charging them....
About Lightspeed attenuators everybody says that the 5v supply to the LDR's has to be the "cleanest" possible, so I used a JLH Ripple Eater after a simple 7805 regulator....
With a 24v switching PSU and a simple quadripolar switch, with one movement, I can select between powering the charging/mantaining circuit or giving power to the 5v to LDR's, 18v to remote pcb and connecting batteries to B1...

The sound of battery powered B1 with Lightspeed is IMHO very very good and I'm really happy I finally can sit on sofa controlling volume with the remote!

I'm really becoming the italian version of Homer Simpson!

Thank you very very much again for this really useful thread!

Howie · « **Reply #651 on:** 31 Mar 2011, 03:13 am »

Greetings, I just finished my B1 a week ago and was inspired by all the posts. I had a nice idea for battery power and want to share it. I realized, after wondering how to build a battery PS, that I had one almost ready to go. The battery for my cordless drill is 18v Lithium. (Measures 19.2v) I have the charger. It should power the B1 for about 60 hours. Here are some self explanatory pics.

I made the wood form to prevent polarity accidents. I will make a wood cap for the unit after glue up. You could also add a switch, but just removing the battery is easy. The large Ryobi battery has a power gauge, so you can monitor the charge. Battery does sound better.
-Howie

toxteth ogrady · « **Reply #652 on:** 31 Mar 2011, 05:04 am »

Brilliant! That's thinking out of the box.

yeldarb · « **Reply #653 on:** 31 Mar 2011, 04:14 pm »

Nice looking work. Where did you get the case? The battery dock is brilliant.

Howie · « **Reply #654 on:** 31 Mar 2011, 05:18 pm »

Thank you.

The case is from Context Engineering. I saw it on this thread.
http://contextengineering.com/desktop_enclosures.html

-Howie

wushuliu · « **Reply #655 on:** 31 Mar 2011, 06:56 pm »

Quote from: porfido on 15 Mar 2011, 11:27 pm

Hi everybody,
as usual, sorry for my english first of all....
Thank you very very much for this topic that helped me so much building also the second B1 buffer....
This time I wanted a remote controlled unit, so I decided to use a cheap ebay pcb with remote to control a motorized pot on the Lightspeed attenuator kit by Uriah Dailey....
These cheap remote pcb's are not so good for working on signal but using it only for controlling the 5v supply to the LDR's I don't risk any kind of noise....
This time I used k73 caps bypassed by teflon k40, only precision resistors on board and 0,01% res on signal...

This time I use three 6v sla batteries for 18v B1 psu and a simple charging/mantaining circuit for charging them....
About Lightspeed attenuators everybody says that the 5v supply to the LDR's has to be the "cleanest" possible, so I used a JLH Ripple Eater after a simple 7805 regulator....
With a 24v switching PSU and a simple quadripolar switch, with one movement, I can select between powering the charging/mantaining circuit or giving power to the 5v to LDR's, 18v to remote pcb and connecting batteries to B1...

The sound of battery powered B1 with Lightspeed is IMHO very very good and I'm really happy I finally can sit on sofa controlling volume with the remote!
I'm really becoming the italian version of Homer Simpson!

Thank you very very much again for this really useful thread!

Thanks for sharing perfido. I think using the motorized remote with the lightspeed is brilliant. I'm sure it sounds amazing!

Same to you Howie. It's great to see all these clever ways to get the best out of a component.

HAL · « **Reply #656 on:** 1 Apr 2011, 01:32 pm »

Quote from: wushuliu on 5 Jun 2010, 05:16 pm

I'll have a couple extra sets of 1k and 220 ohm PRP resistors for $7 for anyone who wants to upgrade their resistors and/or lower their ouput impedance w/ the 220. This way you don't have to shell out minimum fees and ups shipping, etc. just to get them...

wushuliu,

Do you still have the PRP resistors available? The lower output impedance might solve my noise pickup issue.

porfido · « **Reply #657 on:** 1 Apr 2011, 06:57 pm »

Quote from: wushuliu on 31 Mar 2011, 06:56 pm

Thanks for sharing perfido. I think using the motorized remote with the lightspeed is brilliant. I'm sure it sounds amazing!

Thanks to you, Wushuliu, for having opened this thread! Without it I don't think I could have built these two buffers!

For whom could be interested, here is a very simple circuit for charging and mantaining sla batteries:

Ten minutes of work on a veroboard and it's done! With the transistor you can mantain the battery in charge 24h a day, allowing the charger to decrease the current till zero when the battery is charged, and changing the value of R4 you can set the desired charging current...
Simple and useful, IMHO...

I use it also for mantaining the battery of my motorbike....

ik · « **Reply #658 on:** 15 May 2011, 02:22 pm »

Hi Washuliu

Thanks for this great posing!

I'm looking to build a B1 with more then 2 inputs.
On pg 18 you've mentioned "Grayhill rotary switches"
What is the deck # I need?
Which of these would you recomend?
http://search.digikey.com/scripts/DkSearch/dksus.dll

THanks
IK

ruphen · « **Reply #659 on:** 26 Dec 2011, 05:21 pm »

Hi,

Sorry for bringing this post back. i wanted to ask what the minimum/maximum voltage everyone is using. Reason i ask, is i have a power supply with a switch but the voltages are 13/30. would this PS work?

thanks in advance,

Ruphen