Nelson Pass B-1 preamp kit

walkern · « **Reply #400 on:** 15 Jul 2010, 05:08 pm »

I just got my battery set up done yesterday, and spent some time listening to it this morning. I had been using a 24V wall wart (per the BOM). I chose 2 12V Powersonic SLA batteries (wired in series) and picked up a cheap 12 V Battery Tender Jr from Amazon for recharging purposes (although I'll need to disconnect the batteries from one another to charge them... I couldn't find a cheap 24V charger).

Here is what I noticed in terms of sonic shifts. First off, the decay associated with instruments seems more obvious, and lasts and lasts beyond what it did before. There is an increase in clarity with the battery power that makes lyrics easier to understand, and background instruments or singers easier to pick out or listen to. The dynamics (one thing I really admire about the B1) remain more or less unchanged, with the possible exception that very soft passages are more clearly articulated (maybe due to less grunge or background noise?). Bass, midrange and treble balance seems very much like before, but each range's details seem a little clearer. I also noticed that the soundstage seems a little more precise, and layered from front to back. The only "down side" to the change is that the battery powered B1 seems a little less forgiving of marginal recordings. Cymbals that are spitty or gritty in the recording are simply and clearly revealed that way. Raspy violins, glaring brass, and lumpy one note bass are all also more clearly revealed. Mediocre recordings don't sound worse than they are. Their faults are more obviously laid bare... but the music can still be involving and enjoyable. I found it even more difficult than usual to pull myself away from listening to come to work... which is always a good sign.

Hope this helps folks who are considering battery power for their B1s. I found the whole process of switching over to batteries pretty simple and reasonably inexpensive (total cost under $60). I don't know how long the batteries will hold a decent charge (my B1 has no on/off switch), but I can always get in the habit of unplugging the connector if they won't hold a charge for a good stretch of time.

Neil

porfido · « **Reply #401 on:** 15 Jul 2010, 06:39 pm »

Thank you very much, Walkern!
Your feedback tells me that this is the way to go, then....
I'm feeding 18v to my B1 and so I want to link in serie 3 6v sla batteries....
I already made an "automatic charging" unit for my class T amps, using sla battery and an automatic charger coming from house alarm system, but I can't find a 18v charger in Italy....
I will keep searching and will try....

mightym · « **Reply #402 on:** 16 Jul 2010, 11:30 am »

IIRC from calculations I did last year ( and I've slept since then ) A pair of 9V Alkaline batteries would last around 420 hrs ( I think ). An On/Off Switch, and a couple of battery connectors is all that is required to try it out.

That being said, there may be something to the capacity of the SLA batteries that would affect the resultant sound too.....

John

wushuliu · « **Reply #403 on:** 16 Jul 2010, 07:14 pm »

Quote from: mightym on 16 Jul 2010, 11:30 am

IIRC from calculations I did last year ( and I've slept since then ) A pair of 9V Alkaline batteries would last around 420 hrs ( I think ). An On/Off Switch, and a couple of battery connectors is all that is required to try it out.

That being said, there may be something to the capacity of the SLA batteries that would affect the resultant sound too.....

John

?

9Vs typically only have about 500-600mA. With a current draw of 20mA, that only gives you about 25 hours...

mightym · « **Reply #404 on:** 16 Jul 2010, 09:25 pm »

My bad Wushuliu, You are of course right.

I think that most of the capacity I was able to find for plain 9V were 420 MA.

You can however, still purchase 2 Nimh 9V's and a charger for less than $ 25 from Amazon.... It'll even charge them both at the same time.

John

HAL · « **Reply #405 on:** 16 Jul 2010, 09:30 pm »

Or you can get the two Hi Tech Li Ion 9VDC/600mAh batteries and dual charger from Batterymart for $37

daniloreyes · « **Reply #406 on:** 16 Jul 2010, 09:56 pm »

Quote from: HAL on 16 Jul 2010, 09:30 pm

Or you can get the two Hi Tech Li Ion 9VDC/600mAh batteries and dual charger from Batterymart for $37

wow that is a beautiful find:
http://www.batterymart.com/p-c-rli-9600-9v-lithium-ion-charger.html

wushuliu · « **Reply #407 on:** 19 Jul 2010, 04:53 am »

FYI, I still plan on doing the DCB1 tour for those that are interested. Just waiting for the enclosure to arrive (from HK, so probably a couple of weeks).

porfido · « **Reply #408 on:** 22 Jul 2010, 04:41 am »

I'm for sure VERY INTERESTED!

exojam · « **Reply #409 on:** 24 Jul 2010, 01:52 pm »

I am wondering were most folks picked up their RCA connectors from? Thanks.

Added info:
I found these in the B1 thread at diyaudio which look good and do not cost that much.

http://www.futurlec.com/RCA-ChassIns.shtml

James

porfido · « **Reply #410 on:** 26 Jul 2010, 09:52 am »

Quote from: exojam on 24 Jul 2010, 01:52 pm

I am wondering were most folks picked up their RCA connectors from? Thanks.

Added info:
I found these in the B1 thread at diyaudio which look good and do not cost that much.

http://www.futurlec.com/RCA-ChassIns.shtml

James

I took mine from ebay sellers in HK....
Like these:
http://cgi.ebay.com/Lot10-RCA-female-connector-chassis-socket-amplifier-/280537287363?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item4151534ac3

exojam · « **Reply #411 on:** 26 Jul 2010, 12:13 pm »

Thanks for the information.

The other thing I m looking for is the led. I saw some green leds at Radio Shack, are those the kind that I need? Thanks.

James

rtate · « **Reply #412 on:** 26 Jul 2010, 07:02 pm »

Question for all those using 24v to power their B1,

Did you upgrade the voltage rating on the power supply caps from the spec'd 25v??

Also is there a sonic benefit to using 24v instead of Nelson's 18v?

I'm trying to decide between 18 or 24v for my project...

Nick77 · « **Reply #413 on:** 26 Jul 2010, 08:21 pm »

Nelson has talked about there being a sweet spot, from what i have read most think that is closer to the 18v mark. I am using an old HP supply rated at 18.5v that is working nicely.

mightym · « **Reply #414 on:** 26 Jul 2010, 10:39 pm »

I used this guy on the 'Bay:http://stores.ebay.com/chanler-young?_rdc=1

Quick service, paid shipping, combined orders, quality looks good. I'll use him again.

John

walkern · « **Reply #415 on:** 27 Jul 2010, 03:57 pm »

Quote from: rtate on 26 Jul 2010, 07:02 pm

Question for all those using 24v to power their B1,

Did you upgrade the voltage rating on the power supply caps from the spec'd 25v??

Also is there a sonic benefit to using 24v instead of Nelson's 18v?

I'm trying to decide between 18 or 24v for my project...

I never tried 18V compared to 24V so I can't speak to any net sonic benefit either way.
I did not upgrade the voltage rating on the power supply caps, and so far have had no issues running either a 24V wall wart or 2X 12V batteries in series (started off at 25.3V). Maybe I'm pushing my luck?
I think if I had it to do over again I'd be tempted to go with the 9V rechargeable battery set up mentioned earlier. After all, the board is spec'd for 18V, and that way you can be sure that you are not overloading the power supply caps. Just my $.02.

Neil

exojam · « **Reply #416 on:** 28 Jul 2010, 02:33 am »

Well I have ordered everything except the case, RCA connectors (which I will get from the location mighty linked) and the 1uf and 10uf caps (I will be trying the Clarity ESA ones). I do need to say thanks to wushuliu for putting the parts list in such a nice cut and paste format for folks like me. I am very interested in getting this made and see how it sounds.

James

bundee1 · « **Reply #417 on:** 28 Jul 2010, 02:59 am »

Would this preamp work with my Red Dragon Amp-1 that have 10k input impedance?

wushuliu · « **Reply #418 on:** 28 Jul 2010, 04:22 am »

Quote from: bundee1 on 28 Jul 2010, 02:59 am

Would this preamp work with my Red Dragon Amp-1 that have 10k input impedance?

Yes

exojam · « **Reply #419 on:** 28 Jul 2010, 01:48 pm »

OK, I just got my Clariity caps ordered for C100-200, C101-201. Just a few more things to order up and than just wait till everything arrives.

James