DC-Coupled B1 Buffer Build

toxteth ogrady · « **Reply #20 on:** 14 Sep 2010, 12:49 am »

Cheers.

wushuliu · « **Reply #21 on:** 15 Sep 2010, 12:25 am »

hot rod info added.

toxteth ogrady · « **Reply #22 on:** 15 Sep 2010, 01:04 am »

Now you tell me.

I figured it out this morning spending a couple hours going through the various DCB1 threads on diyaudio. Christ, there has got to be a better way of organizing information on that site.

Didn't want to guess what I'd be missing so I ordered the parts for the hot rod build.

wushuliu · « **Reply #23 on:** 15 Sep 2010, 06:26 am »

Quote from: toxteth ogrady on 15 Sep 2010, 01:04 am

Now you tell me.

I figured it out this morning spending a couple hours going through the various DCB1 threads on diyaudio. Christ, there has got to be a better way of organizing information on that site.

Didn't want to guess what I'd be missing so I ordered the parts for the hot rod build.

Sorry. I figured the hot rod option could be saved for the end because there's plenty to get taken care of before considering it. And it's a good idea to listen to it stock first I think so you can gauge the improvements when hot-rodding and thereby decide how hard you want to push.

Nice avatar, btw. I just spotted a very young Rik Mayall in the pub scene in 'An American Werewolf in London'...

toxteth ogrady · « **Reply #24 on:** 15 Sep 2010, 05:45 pm »

No worries Wushuliu, if it wasn't for this thread I wouldn't have undertaken the project. I was just being lazy avoiding those monster threads at diyaudio.

'the Young Ones' were an obsession of mine when I was in my teens. I picked up the dvd set a few years back to see if the show was as funny as I remember it to be...and it was! Brilliant show imo. You can spot all these now famous English actors getting their starts on the show. Can't imagine Rik Mayall playing any other role.

poseidonsvoice · « **Reply #25 on:** 19 Sep 2010, 03:47 am »

Wushuliu,

There is something a little confusing about this board. Look dead center where the 10 LED's are installed (5 LED's per rail). I remember you saying that the flat back corresponds with the cathode or shorter lead of the LED. I also noticed that the LED's have a square hole side and a circular hole side. You'll see that the square hole for the 3 LED/rail section corresponds with the cathode, but this doesn't seem to be true for the 5 LED/rail side. So is the pictograph of the LED accurate or is it the hole shape that is accurate to designate which way the LED's should be mounted?

Anand.

wushuliu · « **Reply #26 on:** 20 Sep 2010, 02:04 am »

Quote from: poseidonsvoice on 19 Sep 2010, 03:47 am

Wushuliu,

There is something a little confusing about this board. Look dead center where the 10 LED's are installed (5 LED's per rail). I remember you saying that the flat back corresponds with the cathode or shorter lead of the LED. I also noticed that the LED's have a square hole side and a circular hole side. You'll see that the square hole for the 3 LED/rail section corresponds with the cathode, but this doesn't seem to be true for the 5 LED/rail side. So is the pictograph of the LED accurate or is it the hole shape that is accurate to designate which way the LED's should be mounted?

Anand.

Hi Anand, as confirmed on diyaudio, I followed the pictograph. When I tested the board, all LEDs lit and voltages were matched within spec...

wushuliu · « **Reply #27 on:** 20 Sep 2010, 02:06 am »

Just an FYI that I forgot to mention: the dcb1 boards can also be used just as power supplies for other low current devices. Just ignore the audio part of the board and take the power straight from the +/-V and G shown in the pics...

For instance, the Hagerman Bugle phono pre...

Probably cheaper (and just as easy if not easier) than the Bugle PS.

poseidonsvoice · « **Reply #28 on:** 20 Sep 2010, 02:39 am »

Quote from: wushuliu on 20 Sep 2010, 02:06 am

Just an FYI that I forgot to mention: the dcb1 boards can also be used just as power supplies for other low current devices. Just ignore the audio part of the board and take the power straight from the +/-V and G shown in the pics...

For instance, the Hagerman Bugle phono pre...

Probably cheaper (and just as easy if not easier) than the Bugle PS.

And most likely superior in sound quality. Shunt regulation is just in a different league than series regulation imho.

Thanks for your insights on my LED orientation question

Anand.

walkern · « **Reply #29 on:** 8 Oct 2010, 08:32 pm »

Wanted to show off my now completed DC B1. Photos show everything mounted in a Hammond steel chassis, using the Antek trafo (from the BOM). I am using a Glass Ware Audio stepped resistor based volume control which also provides balance control options. The inside bottom of the chassis has a sheet of sticky backed linoleum tile on it, which I've found to effectively damp steel chassis ringing and vibration quite well. These shots were with everything looking neat and tidy (before wiring up the input and outputs - I use a powered sub - and the volume controls). Wushuliu populated my board (thanks AC!) for the step-by-step instructions at the start of this thread, so I was confident that everything was assembled and working correctly even before I fired the little bugger up. Compared to my original Pass B1 using PEC mono pots and battery power this DCB1 seems to have even better dynamics (amazing!), more extension at the top and bottom, perhaps slightly better imaging (more 3D), and is overall more engaging and exciting. It was a little tizzy at the top end until it had about 40 hours of settle in time, but is now accurate to the recording.

poseidonsvoice · « **Reply #30 on:** 8 Oct 2010, 10:07 pm »

Nice job.

Looks like you went for the standard current version. Nichicon Gold caps, and PRP resistors right?

Anand.

walkern · « **Reply #31 on:** 8 Oct 2010, 10:27 pm »

Thanks Anand,

Yup... went with the Nichicon Gold caps and PRP resistors. I figured I could always swap out the PRPs for other more exotic resistors down the road, and/or go for the all out hot rod option. Just wanted to get a standard version put together and hear how it compared to the standard Pass B1... which I've been very happy with.

Neil

ajaxmike · « **Reply #32 on:** 29 Dec 2010, 12:07 pm »

Quote from: walkern on 8 Oct 2010, 08:32 pm

Wanted to show off my now completed DC B1. ... I use a powered sub....

Walkern,

Doe the DCB1 drive both a power amp and a sub without difficulty?

Wushuliu,

Thanks so much for the thread. You have given me the confidence to attempt this.

ultrafi · « **Reply #33 on:** 29 Dec 2010, 02:39 pm »

ajaxmike,

The B1 has an output Z of approximately 50 ohms, and will source around 5 mA. So, the parallel combination of the input impedance of the amplifier and the sub amplifier should be, as a general rule of thumb, at least 10 times greater than 50. So, suppose 50k (assuming bjt) for each the amp and the sub amp. This is (50k*50k)/(50k+50k), or 25k, which in fact is much greater than 50 ohms, so you're ok. As to the current, you're fine if it is a jfet or tube input stage in the amps. If, bjt, then things are a bit more current hungry; but, I'd be really surprised if you weren't ok too.

In short, you should be just fine.

ajaxmike · « **Reply #34 on:** 29 Dec 2010, 03:24 pm »

Thank you ultrafi!

walkern · « **Reply #35 on:** 31 Dec 2010, 07:58 pm »

Hi Ajaxmike,

The B1 drives both the sub amp and my SRS Class D amp without any trouble at all. As Ultrafi noted, this should not be a problem from a technical standpoint, and indeed, my experience confirms that the DCB1 will certainly pass plenty of everything to more than one amp at a time.

Neil

ajaxmike · « **Reply #36 on:** 1 Jan 2011, 04:22 pm »

Thanks Neil -- one less thing to worry about.

TimS · « **Reply #37 on:** 2 Jan 2011, 12:10 am »

Hi

Just confirming; the blue board PCB described in this thread - Is it the exact same board that is currently available in the latest GB at http://www.diyaudio.com/forums/group-buys/147075-gb-dc-coupled-b1-buffer-shunt-psus-54.html#post2406762?

Thanks

toxteth ogrady · « **Reply #38 on:** 2 Jan 2011, 12:43 am »

Yes, but there are two different boards being offered. The 'Hypnotize' is for a single source, is hot-roddable??(is that a word?) and is the board Wushuliu so kindly showed how to assemble. The Mesmerize' should be your choice if you have more than one source.

Bemopti123 · « **Reply #39 on:** 2 Jan 2011, 01:50 am »

I have a simple but stupid question, how do I sign up for that GB at DIY? I am a member but I am unaware of the logistics of GB.