View Full Version : Pass B1 Buffer Clone with LDR Volume Control
Can ya tell what it is yet? :eyebrows:
http://img98.imageshack.us/img98/4399/dscf0038l.jpg
The box is a bit of a red herring...
It started out as 'one thing' and then had 'another thing' added, so it's never going to fit in there now. :rolleyes: I will provide clues as we go along!
A chocolate Noddy will be awarded for the first correct guess, answers on a postcard please......
Tony Moore
08-05-2010, 16:48
Headphone amp? :scratch:
Stratmangler
08-05-2010, 16:55
Is it a buffered pre, as per Pass DIY ?
Is it a buffered pre, as per Pass DIY ?
You win half a Noddy!
That's the 'one thing'... now we need the 'another thing'!
The contents of the silver bag (bottom right) would be a dead giveaway! :eek:
Stratmangler
08-05-2010, 17:09
I'm guessing the bag contains LDR's.
Bah!... You're too good at this game, Chris! :lolsign:
Stratmangler
08-05-2010, 17:19
Spotting the Alps Blue and the large caps was a clue, the LDR's bit was just a guess.
:lolsign:
Ali Tait
08-05-2010, 17:26
That should sound very nice Mike.
Ali Tait
08-05-2010, 17:27
Do you have a circuit board or are you hard wiring?
Yep, the Alps is there coz it was just going to be a regular B1 Buffer clone. It was while pondering whether or not to use it 'shunted' I thought I may as well incorporate a 'Lightspeed' attenuator clone (which is something I fancied trying), and here we are!
I cocked it up a bit with the LDR's though. I was merrily clicking away with the RS order and didn't notice (until after submitting) that they were from their 'extended range'... a ten day wait and a ten quid surcharge! :doh:
It's not quite turning out to be cheap as initially intended! :rolleyes:
Do you have a circuit board or are you hard wiring?
Both. Sort of. ;)
Ali Tait
08-05-2010, 17:47
Uh huh!
I'm going to use some of that prototyping board stuff, and hardwire underneath. ;)
Ali Tait
08-05-2010, 19:06
Put some pics up as you go.How much was all the bits?
john blackburn
08-05-2010, 21:08
I assume you are aware of this site for matched LDRs?
http://www.buildanamp.com/
He had a set to me within two weeks.
John
Why would youuse LDR's in an audio circet unless you want it to come on at night?
Why would youuse LDR's in an audio circet unless you want it to come on at night?
http://diyaudioprojects.com/Solid/DIY-Lightspeed-Passive-Attenuator/
:)
now if you could just put in in line with the clap on /clap off switch you would be in buisness.http://www.youtube.com/watch?v=-XUOhjW2AXM
It really is a different approch,but how do you regulate the diode? with a veriable capacitor?
john blackburn
09-05-2010, 22:53
Hi Goraman
It is all here.
http://diyaudioprojects.com/Solid/DIY-Lightspeed-Passive-Attenuator/
The name "Lightspeed" is a commercial product made in Australia. If George didn't make it, it isn't a lightspeed.
http://members.optusnet.com.au/~georgehifi/
Very smart man but a terrible eye for colour!
They are a very nice thing if you can live with a couple of quirks.
John
Well, nothing much has happened yet!
If I could just get away from making stuff for other people for a while.... :confused:
Actually I did make a start but made a bit of a cock-up and killed a jfet, I've got a replacement now so hopefully I might be able to do something soon. I hope! :lol:
PS> I've changed the thread title.
Mike - this is my implentation of the LSA/B1 - a thing of beauty!
Looks good, AND you've got the proper PCB! :eek:
Did you put the LSA on the input or output of the B1?
It goes:- 3 inputs into a selector (middle silver knob), into "LSA", into B1 input (single - one or two), B1 pot is omitted replaced by a resistor (same value as the pot) and I removed the switch on the B1 connecting the chosen input (one or two) directly to the switch output. I can try drawing a schematic of the LSA/B1 as I implemented it - I will post later this weekend.
If you are going to build as a point to point here is how I built one - not tested! One of the problems with LDRs is that they do not like heat! So when I did the ptp I used the board you see with two connectors - it dissapates the heat a bit better.
Anyone remember this?... it seems ages ago now!
Well, believe it or not, I actually got round to finishing it!
http://desmond.imageshack.us/Himg835/scaled.php?server=835&filename=009zet.jpg&res=medium
I'm impressed!
Impressed enough to look at buying a proper PCB and investing in a few "boutique" components. I sort of cobbled this together just to see if the concept was worth pursuing, and it is! At least I'm my opinion anyway.
There's little I've ever heard that comes as close to removing itself from the music. It doesn't add any "valve magic" or any "solid state grain". As far as I can tell so far, it's close to invisible as any component I've ever heard.
Seriously worth further investigation and investment!
Ali Tait
03-01-2012, 21:48
Nice one Mike, lovely job.
Nice one Mike, lovely job.
Hi Ali,
Get the lid off your DAC-Zero and replace the LM7805 with an Audiocom supereg or similar! ;)
Ali Tait
03-01-2012, 22:21
Nah, I'm past that now!
http://theartofsound.net/forum/showthread.php?t=13204
:eyebrows:
Mike,
Nice to see a prodigal son return :) - welcome back - now the numptie question: -
what exactly is it? :lol:
Dave.
what exactly is it? :lol:
Dave.
Box wi knobs on!
Nah, I'm past that now!
http://theartofsound.net/forum/showthread.php?t=13204
:eyebrows:
Bah!... you have too much money! :lol:
Ah, that clarifies it then :lol: Actually I can now identify it as a form of Nelson Pass Buffer amp (having seen another post in another place ;) ) - not that I'm much wiser even now :lol: .
I shall watch developments with interest, particularly with regards to what you are going to fill the empty space with :) .
Cheers,
Dave.
Dave,
I'ts basically a "unity gain" preamp. So not really an amp at all. There's no gain! :D
Err...
Ali Tait
03-01-2012, 22:38
Bah!... you have too much money! :lol:
I wish!
Seriously, it's a very good dac though has some teething troubles which will hopefully be resolved in the next version, which will have some O'netics output trannies.
I like the B1 too, I have one that was built by Dave (Swampy). Nice bit of kit, though I'm currently messing with a Pre3.
Does the reg make a big improvement to the Zero?
BTW, nice to see you around again mate, hope all is good with you.
Does the reg make a big improvement to the Zero?.
Yeah, more than the output cap changes have made, so far!
And the supereg cost me nowt coz I "harvested" it (along with some others) when my modded unidisk player died!
Just need to find a use for the new Audiocom Superclock 4 now...
sq225917
03-01-2012, 22:46
I ran a B1 for a year or so. Goldpoint pot, all Charcroft naked foil resistors, all teflon caps, big ass Mundorf caps in the PSU, silver wired, all silver cmc sockets, fed by a superteddyreg. No matter what i did with it it always sounded soft in the bass and with quite indistinct stereo. Apart from that it's a racking little thing. if you haven't got speakers that go down to 20hz you might never notice the bass. ;-)
I always wondered what it would sound like with perfectly matched transistors. I have the pcb for the shunt regged Dc coupled version sat here, doubt I'll ever build it. Apparently it fixes the bass issue and then some.
Dave,
I'ts basically a "unity gain" preamp. So not really an amp at all. There's no gain! :D
Err...
Ah, that's good to know (I think :lol: ) - it's all getting clearer now - a non-amplifier that doesn't amplify - everybody should have one, you may have cornered the market ;) .
Cheers,
Dave.
No matter what i did with it it always sounded soft in the bass and with quite indistinct stereo. Apart from that it's a racking little thing. if you haven't got speakers that go down to 20hz you might never notice the bass. ;-)
Well, that's pretty odd. :scratch:
The first thing I noticed was how much better defined and powerful the bass was! Well, that's compared to the passive attenuator I was using anyway.
I wonder, could there be a difference in the way we use them? Mine doesn't have a crappy pot in front of the B1 for a start. I use a fixed 100K Vishay S102 Bulk Foil resistor in place of it. The "Lightspeed" attenuator comes after the buffer.
Just a thought as mine sounds pretty fast and even right across the spectrum, so far at least...
sq225917
04-01-2012, 10:01
Mike, maybe my point of reference was higher to start with ;-) I just know the pre-amp in either my Weiss 202 dac or my Audiolab Mdac are better than the B1 was in those areas. I did prefer it to the Naim 72 I was using at the time, but I was only using stand mounts at the time of the swap so the bass issue wasn't an issue.
Mine didn't have a crappy pot in front of it, it used the Goldpoint stepped attenuator, the one with the 0.1% Vishay smt resistors in it, so considerably fewer components and significantly more linear with less distortion than the Litespeed attenuator is measured to be.
Maybe your transistors are better matched.
howlindawg
04-01-2012, 17:22
I ran a B1 for a year or so. Goldpoint pot, all Charcroft naked foil resistors, all teflon caps, big ass Mundorf caps in the PSU, silver wired, all silver cmc sockets, fed by a superteddyreg. No matter what i did with it it always sounded soft in the bass and with quite indistinct stereo. Apart from that it's a racking little thing. if you haven't got speakers that go down to 20hz you might never notice the bass. ;-)
I always wondered what it would sound like with perfectly matched transistors. I have the pcb for the shunt regged Dc coupled version sat here, doubt I'll ever build it. Apparently it fixes the bass issue and then some.
Interesting.
I've been experimenting with the B1 buffer myself recently.
Built a basic passive first of all.
Decent components, CMC sockets, silver wire, Alps pot etc... nothing exotic.
Then plugged a Pass B1 into it with a wall wart PSU and liked the results.
Then replaced the B1 with a Hypnotize which is basically a pair of B1 buffers, direct coupled, with a well regulated PSU.
The DCB1 was noticably better and I think would address your issues with stereo imaging.
I can't comment on your bass issues as I didn't notice that as a particular weakness of the design.
Then again the Veenas don't exactly go down to seismic levels :)
The next step is to rebuild the DCB1 with better quality components and add an MC phono stage to make a fully functional pre.
Whether it'll replace my active valve Pre remains to be seen.
Mike, maybe my point of reference was higher to start with ;-)
Yes, I'm sure that's the case.
My comments above are based on what went before it, a string of passives that the B1 beats hands down!
A 'proper' active pre should certainly bring further improvements, but at a cost, and I don't need the gain. A valve CF design might be the way to go but at the moment funds don't permit! :(
sq225917
04-01-2012, 22:33
I've got a Hypnotize board in my bits box so I might well build it out...
Hypnotoad
05-01-2012, 03:38
I built a B1 a while ago, it was very nice, I ran it off a nice little PSU I designed.
Being a cheap b@st@rd I didn't use boutique components though.
Never got to put it in a case.
http://i729.photobucket.com/albums/ww297/Hypnotoady_photos/BufferB1PSU.jpg
sq225917
05-01-2012, 08:19
You do your own boards, I'm jealous....
Hypnotoad
05-01-2012, 13:12
You do your own boards, I'm jealous....
I thought they would be difficult but I found they are really easy to do.
I have been thinking about a step by step post for anyone wanting to try.
sachu888
05-01-2012, 14:33
Hi all,
I have also assembled my PassB1,LSA and Regulated power supply(one for all + for my DIY phono pre).All PCBs have been made locally.
http://img716.imageshack.us/img716/4710/dsc04807g.jpg By sachu888 (http://profile.imageshack.us/user/sachu888) at 2011-12-02
http://img213.imageshack.us/img213/5923/dsc04828q.jpg By sachu888 (http://profile.imageshack.us/user/sachu888) at 2011-12-24
http://img851.imageshack.us/img851/2534/dsc04826x.jpg By sachu888 (http://profile.imageshack.us/user/sachu888) at 2011-12-24
Regards,
Sachin
Hi all,
I have also assembled my PassB1,LSA and Regulated power supply(one for all + for my DIY phono pre).All PCBs have been made locally.
http://img716.imageshack.us/img716/4710/dsc04807g.jpg By sachu888 (http://http://img716.imageshack.us/img716/4710/dsc04807g.jpg By sachu888 at 2011-12-02) at 2011-12-02
http://img213.imageshack.us/img213/5923/dsc04828q.jpg By sachu888 (http://http://img213.imageshack.us/img213/5923/dsc04828q.jpg By sachu888 at 2011-12-24) at 2011-12-24
http://img851.imageshack.us/img851/2534/dsc04826x.jpg By sachu888 (http://http://img851.imageshack.us/img851/2534/dsc04826x.jpg By sachu888 at 2011-12-24) at 2011-12-24
Regards,
Sachin
Ooh, Nice! :)
sachu888
16-01-2012, 14:32
Thanks Mike.
Regards,
Sachin
sachu888
15-03-2012, 03:30
Hi all,
I have finally completed my B1+LSA with regulated power supply.Few pics:
http://img651.imageshack.us/img651/9464/dsc04973s.jpg By sachu888 (http://profile.imageshack.us/user/sachu888) at 2012-03-03
http://img88.imageshack.us/img88/9508/dsc04976l.jpg By sachu888 (http://profile.imageshack.us/user/sachu888) at 2012-03-03
http://img811.imageshack.us/img811/3/dsc04980n.jpg By sachu888 (http://profile.imageshack.us/user/sachu888) at 2012-03-07
http://img685.imageshack.us/img685/784/dsc04979k.jpg By sachu888 (http://profile.imageshack.us/user/sachu888) at 2012-03-07
http://img43.imageshack.us/img43/4782/dsc04978xx.jpg By sachu888 (http://profile.imageshack.us/user/sachu888) at 2012-03-07
Regards,
Sachin
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