View Full Version : Valve Output DAC Designed by Nick Gorham
Ali Tait
09-09-2011, 17:52
Thought I'd post something about this new DAC I've acquired.
This came about via a beer-fuelled discussion at the last Owston meet, where Nick had brought along one of the dac boards with a couple of trannies to run it. The board is one of these-
http://www.ebay.co.uk/itm/NEW-Hi-end-DAC-24-BIT-192K-HZ-AK4396-sc-/190538503414?pt=UK_AudioTVElectronics_HomeAudioHiF i_Amplifiers&hash=item2c5cfad4f6
Don't be put off by the low price, this is a serious DAC, and is used in the Logitech Transporter amongst others. It has been called a "Miracle" DAC, a true 24 bit 192kHz chip, and is DSD capable. It has a virtually flat noise floor all the way up to 80kHz.
Anyhow, when I heard the board at Owston, I was struck by how good it sounded (the board is self contained and includes an opamp output stage. The opamp is socketed, so easily swapped out) and I mentioned to Nick how good it might sound with one of his valve output stages on the end.
A good few beers later, I offered to bankroll the valved dac to see how it sounded, reasoning that if I didn't like it, it would be easy to swap the dac board for something else. I already knew how good Nick's output stage was.
The upshot is what you see below-
http://img405.imageshack.us/img405/5315/imag0226uw.jpg (http://imageshack.us/photo/my-images/405/imag0226uw.jpg/)
http://img710.imageshack.us/img710/6107/imag0227d.jpg (http://imageshack.us/photo/my-images/710/imag0227d.jpg/)
http://img88.imageshack.us/img88/8973/imag0228up.jpg (http://imageshack.us/photo/my-images/88/imag0228up.jpg/)
http://img5.imageshack.us/img5/7037/imag0229b.jpg (http://imageshack.us/photo/my-images/5/imag0229b.jpg/)
The DAC is single input at the moment, though Nick has said adding switcheable inputs is no problem. It also has balanced outputs, useful as I intend to go that way with the direct coupled electrostatic amps.
So how does it sound? Bloody good IMHO! Bags of air, space and detail, but the usual digital glare is totally absent to my ears. It's an overused term, but this really does sound analogue.
It way outclasses my AN Dac Zero, and I always thought that was a very good DAC.
There is a marathon thread on this board on diy audio-
http://www.diyaudio.com/forums/digital-source/186245-dac-2496-ak4393-dac-kit-cs8416-ak4393-5532-a.html
I have ordered an unpopulated board in order to try a board with all boutique components as detailed within the thread. It'll be easy to swap over, so easy to see if I've wasted my money! Be fun trying it out though.
Ali Tait
09-09-2011, 17:54
PS, sorry about the crap photos, my phone camera is rubbish.
Covenant
09-09-2011, 17:58
Wow, a serious piece of kit. Why three trannies?
Ali Tait
09-09-2011, 18:11
You mean the toroids? Two for the dac board, and one for the valves.
There are two off the shelf toroids for the DAC and one custom one for the valve stage (B+ and heater). The three EI transformers are one choke for the B+ and the two Sowter output TX's.
Awesome, Nick. I'd like to hear that sometime! What are those fat mothafukka cables connecting the two boards? :eek:
I don't think I've ever seen cables so thick being used internally inside equipment!! :respect:
Marco.
Ali Tait
09-09-2011, 20:03
Dat's the signal cables from DAC board to Valve grid. :eyebrows:
I'd like to put this up against your Sony sometime Marco.
Reid Malenfant
09-09-2011, 20:05
I may be wrong, but it looks like balanced shark cable (http://www.maplin.co.uk/high-grade-audio-cable-26923) which is available from Maplin. For the money it's superb stuff if so... By the way, in reality the stuff isn't as blue as it appears on the Maplin pic :eyebrows:
Apologies if i'm out by a country mile ;)
Ali Tait
09-09-2011, 20:18
'Tis this I believe-
http://www.hificollective.co.uk/catalog/screened-silver-plated-copper-wire-19015-p-4266.html?osCsid=n7o0g84m1l45mk8monvgphb5a6
It may well be Shark, Its whats left over from when I built the 211 and the first balanced cable I put my hands on :-)
Ali Tait
09-09-2011, 20:26
Well whatever it is, this thing is sounding great. I keep trying to post, and get dragged back into the music!
Reid Malenfant
09-09-2011, 20:27
:lolsign: Like i said, i might be wrong... However your picture does look good enough for me to see what looks like a white & red signal lead exiting the end of one of the cables Ali (near the valve output stage) :scratch:
Take it from me, i wouldn't slag the stuff off even if it is the Maplin stuff as it's very good quality indeed for the money :) I have a 50M reel of it here for when i go fully balanced in my system...
Dat's the signal cables from DAC board to Valve grid. :eyebrows:
I'd like to put this up against your Sony sometime Marco.
Love to do that, matey... I think the Sony might lose!
Marco.
Ali Tait
09-09-2011, 20:32
:lolsign: Like i said, i might be wrong... However your picture does look good enough for me to see what looks like a white & red signal lead exiting the end of one of the cables Ali (near the valve output stage) :scratch:
Take it from me, i wouldn't slag the stuff off even if it is the Maplin stuff as it's very good quality indeed for the money :) I have a 50M reel of it here for when i go fully balanced in my system...
Yep,spot on mate, red and white cables. Agreed about Maplin, some of their cable is very good, and not expensive.
I have to agree its a superb bit of kit, listened to it for a few days and it is rather special, I am ordering one for myself when I get some back pocket money!
Reid Malenfant
09-09-2011, 20:48
For the money it's incredible value, no kidding! All OFC copper with damn near 100% coverage by the screen & also a total screen via aluminised mylar. Foam dialectric, in all honesty you couldn't ask for anything better at the price!
Just because i rate it doesn't make it "the best" as i'm sure if you are willing to spend shed loads more you could improve on it, but at the price it's pretty unbeatable in all honesty.
I have used a lot of shark stuff, you just wouldn't believe how good the 75ohm stuff is for use as a component or scart cable :eyebrows:
Or maybe you would...
Looks like a serious bit of kit by the way, nothing like lots of independant transformers to sort things out :)
Ali Tait
09-09-2011, 20:54
Aye, I've been talking to Nick about getting a bigger case and regulating the B+, which should further improve the sound. Then I might look at some custom cobalt output trannies from the likes of Bud Purvine.
Not for a while yet though, it's not even run in!
The Vinyl Adventure
09-09-2011, 22:06
So what's something like this £'s wise then?
Someone's gotta ask! ;)
What do you feed it with Ali?
Ali Tait
09-09-2011, 22:14
I feed it with a Touch. As for price, you'll have to ask Nick!
Ah, thats the catch. Starting with a £20 dac it very quickly gets past £400 in parts
https://docs.google.com/spreadsheet/pub?hl=en_GB&hl=en_GB&key=0Ao1igJbzEAF4dC1wZHB3Qk1oMWxpUVU1eEpLM21sRnc&output=html
The Vinyl Adventure
09-09-2011, 22:49
doesnt seem that unreasonable ... :)
Ali Tait
09-09-2011, 22:51
It isn't for the SQ on offer IMHO. If this was a commercial dac, it would probably retail around 2k or more I'd say.
The Vinyl Adventure
09-09-2011, 22:54
Is there a way to give something like this a listen Nick?
Ali has the only example at the moment.
Looks like a nice bit of Kit and sounds like a bargin with its performance level
tube output service offered here:
http://www.ebay.co.uk/itm/CD-player-vacuum-tube-triode-output-stage-out-DAC-/320750498252?pt=UK_AudioTVElectronics_HomeAudioHiF i_CDPlayerSeparates&hash=item4aae3831cc#ht_2263wt_907
Ali Tait
10-09-2011, 08:52
Anyone who wants a listen is welcome to come over.
Anyone who wants a listen is welcome to come over.
Ali,
Please let me know if and when you move back to Leeds :lol: .
Dave.
Ali Tait
10-09-2011, 10:20
:lolsign:
Been think about this while walking dogs (do most thinking that way). Almost everyone who has asked about this dac and its output stage wants more than the one input (Ali included). While it is possible to kludge a spdiff switcher on the front of the board, it will be a hack. I am musing if a better idea would be to start from the fact that the £20 is brilliant as it is, and what it shows is that the dac chip itself is very capable. But maybe a better thing to do now is start again with a new board design, aimed at allowing more inputs. The board will cost a bit more, but in the realm of this output stage the price of the dac board is eaten up by the iron and other bits.
What I was thinking was a board that had the four inputs the receiver chip offered. space for a simple USB receiver. dac, with just direct output off board, so either a valve stage like I used here could be used, or a op amp stage added. Maybe better regulators could be used next to the chips. and maybe a a i2c buss added so input selection and volume could be controlled by a controller board.
Just thinking out loud at the moment.
Ali Tait
10-09-2011, 13:11
Sounds great Nick. I'm in!
May I suggest the option of adding a volume pot, then you have a dac/pre in one box. I daresay that would appeal to a lot of peeps, seeing how well Stan does with his dacs.
Ali Tait
10-09-2011, 13:12
Whoops scratch the vol pot bit, I missed the end bit of your post.
The Vinyl Adventure
10-09-2011, 14:19
so are you thinking of makeing a few of these are you nick?
with the extra features you mention it might work very well for what i was after when i asked you a month or so back ...
im trying to further shrink the system in my lounge, my current thinking is to move my pre and majik ds to the loft system and just have pc with fancy dac into adam actives ...
the adam actives have balanced inputs, so this fancy dac might be the right option for me
my only concern is how to get the absolute most out of the pc as it would be my main source ... :/
PLEASE Hamish, don't let the lack of balanced outputs bother you regarding good domestic preamps. For runs of far less than 10m they really aren't necessary if you use well shielded mic cables wired up properly.. In fact, it could be argued thatthe extra circuitry and/or transformers may get in the way and modify the sound too much. of course, you may well prefer this "modification :)"
Ali Tait
10-09-2011, 15:28
There is nothing "extra" in the dac to allow for the balanced outputs. It was just easy for Nick to implement given the topology of the valve output stage, so he added them.
The Vinyl Adventure
10-09-2011, 15:52
PLEASE Hamish, don't let the lack of balanced outputs bother you regarding good domestic preamps. For runs of far less than 10m they really aren't necessary if you use well shielded mic cables wired up properly.. In fact, it could be argued thatthe extra circuitry and/or transformers may get in the way and modify the sound too much. of course, you may well prefer this "modification :)"
all good, ive had the same convo regarding the above with a good few people now ... im aware of this ...
its just if something did have balanced out puts id give them a try because of my speakers having balanced inputs ...
Covenant
10-09-2011, 16:09
A dac as a pre-amp makes sense to me as its one less box to bother about but having the ability to try different valves would be a big bonus.
How about adding the 'Lighter Note' attenuator, then volume control isn't dictated by an expensive pot?
I suggest leave Nick to get on with it, whatever he produces will be exceptional going off my experiences with his equipment builds. Orders will be gratefully accepted I am sure.
I have placed my order. :)
Pity a lot of you are southern woofters otherwise you could come round for a listen. Up the Yorkshire. Huddersfield 2 - Tranmere 0
:lolsign:
There is nothing "extra" in the dac to allow for the balanced outputs. It was just easy for Nick to implement given the topology of the valve output stage, so he added them.
Then that's great news for Hamish and others who need this, as I used to. I'm all single ended, pushed and pulled and cack handed these days :D
I suggest leave Nick to get on with it, whatever he produces will be exceptional going off my experiences with his equipment builds.
+1 (with knobs on)! :)
Marco.
Still thinking :-)
The volume I was originally thinking of was using the attenuator in the DAC, but its clearly not ideal as it is loosing bits. The problem is that adding a analog volume to the circuit I want to use is possible, but I will have to think more on it about how to do it in such a way that the pot doesn't become the thing you are hearing. The main point of the output circuit Ali has is the lack of things between the DAC and the output (ok there are several things, but things that my delusions regard as doing less harm than a volume pot).
Ali Tait
11-09-2011, 12:10
Nick, I'd venture to suggest remote control for input selection and volume would go a long way to making this a commercially attractive proposition.
Very nice Ali, did you see the dac Duncan (Tubehunter) made that i now own, that started out as a board from Ebay, i still have an upsampling board on my desk that needs putting in a case :rolleyes:
Edit, just realised after spending an hour looking for them that your board comes from the same seller as my Copper Dunc dac board, very good it is too
Ali Tait
11-09-2011, 17:57
I did indeed, and very nice it looked too. Duncan makes some lovely cases.
Nick, I'd venture to suggest remote control for input selection and volume would go a long way to making this a commercially attractive proposition.
Yep, that would be simple enough once it was all controlled via i2c.
As it happens I am reading about bluetooth at the moment with a mind to using that to control things via smart phone.
Ali Tait
11-09-2011, 18:50
Sounds good.
aquapiranha
11-09-2011, 19:50
That looks incredibly well put together, with quality bits. I bet it sounds great.
Very nice Ali, did you see the dac Duncan (Tubehunter) made that i now own, that started out as a board from Ebay, i still have an upsampling board on my desk that needs putting in a case :rolleyes:
Edit, just realised after spending an hour looking for them that your board comes from the same seller as my Copper Dunc dac board, very good it is too
was that the one i had a session with at the 2nd wigwam show?
it was very nice and i would have sneaked it away had you not turned up....
it was that dac really got me thinking i needed an upgrade from the early berrisford i had,... i would guess ali's latest is very close...? cant wait to hear it,... good work nick...
steve
Ali Tait
11-09-2011, 20:50
Well I haven't heard Duncan's dac, but this dac is easily the best I've heard in my system.
was that the one i had a session with at the 2nd wigwam show?
it was very nice and i would have sneaked it away had you not turned up....
it was that dac really got me thinking i needed an upgrade from the early berrisford i had,... i would guess ali's latest is very close...? cant wait to hear it,... good work nick...
steve
That was the one before my current one which was built around a Gigawork's board which has a very long thread running on Diyaudio about all the upgrades etc, Duncan breathed on the board and installed a valve output with no feedback that was all housed in a perspex and wood case, that has now gone into a mates system, my current Dunc dac is built around this (http://www.ebay.co.uk/itm/190558306748?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649) board which has switchable inputs via the built in volume control knob, you push it to change inputs and turn to adjust the volume, not much between them on sound but convenience won over.
This is the new copper one, i just goes to show what can be done with skills like Nick and Duncans from a basic board
http://i419.photobucket.com/albums/pp272/jonboy_01/DSC_0506.jpg
I may be wrong, but it looks like balanced shark cable (http://www.maplin.co.uk/high-grade-audio-cable-26923) which is available from Maplin. For the money it's superb stuff if so... By the way, in reality the stuff isn't as blue as it appears on the Maplin pic :eyebrows:
Yes Shark is good stuff, Mark. Their early balanced cable was pink in colour, I still have good lengths of it here from when I used it extensively. Bloody thick to get inside connectors, though.
The Vinyl Adventure
11-09-2011, 21:56
Yep, that would be simple enough once it was all controlled via i2c.
As it happens I am reading about bluetooth at the moment with a mind to using that to control things via smart phone.
Ha cool!
I was just saying this evening it would be a shame to lose iPhone control..
I wonder if there is anthing clever to control fobar or similar with an iPhone ...
Probably not I suppose
Stratmangler
11-09-2011, 22:31
I wonder if there is anthing clever to control fobar or similar with an iPhone ...
Probably not I suppose
Googling can be quite useful ;)
Stratmangler
11-09-2011, 22:33
Googling can be quite useful ;)
That's quite a useful 3000th post, eh ?
I didn't plan it, it just turned out to be that way :)
The Vinyl Adventure
11-09-2011, 22:44
http://www.foobar2000.org/components/view/foo_upnp
This then?
Stratmangler
11-09-2011, 22:50
http://www.foobar2000.org/components/view/foo_upnp
This then?
Might work :)
dave2010
12-09-2011, 09:26
Interesting thread this, and drew me in nicely! Then I started to look more closely. The basic board - http://www.ebay.co.uk/itm/NEW-Hi-end-DAC-24-BIT-192K-HZ-AK4396-sc-/190538503414?pt=UK_AudioTVElectronics_HomeAudioHiF i_Amplifiers&hash=item2c5cfad4f6&clk_rvr_id=264303805930&afsrc=1 appears good, but of course it's a kit, and it doesn't include a PSU. Actually getting one of those and making it is perhaps very easy for someone who does this kind of thing often. Getting one made up would probably put the cost up considerably. As pointed out by Nick, simply the component costs for the transformers, case etc. to produce the valve output unit is going to push the cost over £400, and that again doesn't include the cost of paying someone to do the work - unless you (can) do it yourself.
Nevertheless it's a nice idea, and maybe if I ever get more time Id give a project such as this a go, but for many of us, despite the possible quality advantages relative to price, it may be just easier to go out and buy ready made kit.
Interesting thread this, and drew me in nicely! Then I started to look more closely. The basic board - http://www.ebay.co.uk/itm/NEW-Hi-end-DAC-24-BIT-192K-HZ-AK4396-sc-/190538503414?pt=UK_AudioTVElectronics_HomeAudioHiF i_Amplifiers&hash=item2c5cfad4f6&clk_rvr_id=264303805930&afsrc=1 appears good, but of course it's a kit, and it doesn't include a PSU. Actually getting one of those and making it is perhaps very easy for someone who does this kind of thing often.
Hi FWIW the seller will supply a fully built board for US$7.00 extra and a suitable transformer for US$32, all prices including delivery. Only problem is that the TX is designed and built for 220v and 110v. You will also need a case obviously.
This information is direct from the seller because I am hovering over a decision to see how it competes with a fully Caimanised 7520 StanDAC.
Cheers,
Dave.
Ali Tait
12-09-2011, 11:28
There is a built version in a case but again the caveat is the 220v transformer. Would be easy to change though. The opamp on the board is socketed, so easy to change too-
http://www.ebay.co.uk/itm/Finished-2496-AK4396-CS8416-DAC-Transformer-case-/120747012438?pt=LH_DefaultDomain_3&hash=item1c1d153156
Hi Ali,
Add suggests 110 or 220v R Core is included. Nice case - anyone tried it?
Regards
Ali Tait
12-09-2011, 13:02
Yes, it's just a case with the dac board and the transformer in. I would change the trannie for a 240v one. I have heard the board on it's own and it sounds very good. At the price charged for the cased version this is a bloody bargain IMHO. I'd put it as good as any commercial dac I've heard up to 4-500 quid. It certainly is easily better than my Audionote DAC Zero.
Yes, it's just a case with the dac board and the transformer in. I would change the trannie for a 240v one. I have heard the board on it's own and it sounds very good. At the price charged for the cased version this is a bloody bargain IMHO. I'd put it as good as any commercial dac I've heard up to 4-500 quid. It certainly is easily better than my Audionote DAC Zero.
FWIW the seller has just confirmed he will sell the fully built and case DAC, (but without TX for UK users to put in their own 240/250v TX) for £38 + £12 P&P to UK.
I'm not sure whether their case will accept a suitable UK sourced transformer - anybody got an idea?
Cheers,
Dave.
This thread began as Nick's DAC and now you have turned it into a thread to build one's own DAC, nice !
Ali Tait
12-09-2011, 15:17
Nah, the dac in the case on ebay does not have Nick's valve output stage. I'm happy to throw work Nick's way when I can, but I'm sure he'd have no objection to folk having a go themselves. The cased dac will be very good, but won't touch the one I have here with the output stage!
Ali Tait
12-09-2011, 15:18
FWIW the seller has just confirmed he will sell the fully built and case DAC, (but without TX for UK users to put in their own 240/250v TX) for £38 + £12 P&P to UK.
I'm not sure whether their case will accept a suitable UK sourced transformer - anybody got an idea?
Cheers,
Dave.
That sounds like even more of a bargain Dave. You'd get a UK trannie to fit no problem I'd say.
That sounds like even more of a bargain Dave. You'd get a UK trannie to fit no problem I'd say.
links to a trannie supplier would be good Ali :)
Ali Tait
12-09-2011, 16:04
I will ask Nick for the suppliers he used for mine, though he used two separate toroids in mine, which may not fit in the case (the dac board uses two separate supplies, though I think it can be run from one with the addition of a jumper, but I'd guess it would sound better with separate supplies). It would be better knowing the dimensions of the free space inside the case before ordering anyway. It should be easy to source a single trannie with two secondaries of the correct voltages that will fit once the dimensions are known.
Doesnt worry me, the DAC board is a bargain, and the more that build their own stuff the better in my mind.
If you want to get a custom TX wound to supply the two voltages, I am sure Terry will make you something toroidman@btinternet.com. Get it made with a shield while you are at it. But it is possible to power the board with a single transformer if you link the 9v and 15v supplies (think there is a solder pad on the board). I am sure the supplier would sell you them with the board able to be run from just the one transformer. In which case any toroid from Rapid or CPC will be just fine.
Ali Tait
12-09-2011, 16:42
Thanks Nick.
Thanks Nick.
Ditto, +1, wot he ^ said.
Dave.
That was the one before my current one which was built around a Gigawork's board which has a very long thread running on Diyaudio about all the upgrades etc, Duncan breathed on the board and installed a valve output with no feedback that was all housed in a perspex and wood case, that has now gone into a mates system, my current Dunc dac is built around this (http://www.ebay.co.uk/itm/190558306748?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649) board which has switchable inputs via the built in volume control knob, you push it to change inputs and turn to adjust the volume, not much between them on sound but convenience won over.
This is the new copper one, i just goes to show what can be done with skills like Nick and Duncans from a basic board
http://i419.photobucket.com/albums/pp272/jonboy_01/DSC_0506.jpg
Hi Jon
I have the same DAC here and was thinking of building it into the Headphone Amp that I am looking to build.
Do you know where the signal is picked up from on the dac board so as to avoid the built in OP amp section?
I'm having trouble finding a circuit diagram.
Thanks
Val
Hi Val, sorry i'm not that clever, it was built by Duncan (tubehunter) perhaps he can help you more :)
Hi! Im planning on getting the fac board and use a valve output stage.where cn I find the info on the valve output stage with the sowter transformer.tnx
Ali Tait
11-06-2012, 06:33
Hi, not recommended to use the Sowter transformers, we ended up having some O'netics made which are still being evaluated.
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