Valve based Digital Analogue Converter

[Tourmaline]

Originally Posted by NickW

Hi all,

Just to add to the debate....I recently ordered a RAKK DAC-2 with passive output board. It uses the BB PCM1794 DAC with asynchronous upsampling - the modern school I believe? - and the opposite end of the spectrum to the NOS DACs with zero upsampling/reclocking (?).

I have to say it blows my old Meridian 606 DAC out of the water!, and I had thought that the 606 (coupled with the 602 transport) was pretty good. I'm told an active valve output stage will make things even better, but I can't stretch that far yet. However, all in all, the passive output RAKK DAC-2 has more "music", detail, etc than anything other than the best CD player I've heard to date which was/is the Krell Evolution 505 at ~ £9k at Oxford Audio Consultants in the the process of buying near speakers.

The RAKK DAC-2 has so far cost me ~ £350 (the current US Dollar rate really helps), and I'm chuffed to bits with it. It works really well with the Meridian 602 transport, but I suspect any other transports would be ok too due to the asynchronous upsampling.

Ok, I shall now keep my head down amidst the barrage of offended Forum readers that truly believe the NOS side is best.....

NickW

If you like lifelike sound, then yes, NOS tube dacs are the best. If you like detailed, then fet driven dacs are nice. All comes down to preference but that those filters and technical chit chat makes a dac automatically better is voodoo.

[NickW]

Originally Posted by Tourmaline

If you like lifelike sound, then yes, NOS tube dacs are the best. If you like detailed, then fet driven dacs are nice. All comes down to preference but that those filters and technical chit chat makes a dac automatically better is voodoo.

Hi Tourmaline,

I don't believe its a simple divide between NOS or the newer Asynchronous oversampling. All players I've heard differ to varying extremes, regardless of the technology involved. The Meridian 602/606 bit-stream combo that I own was/is still pretty magic, but this is widely recognised to be due to the particular detailed implementation rather than the particular chip set used (and that many other manufacturers followed). Until very recently I was convinced that CD could never really rival LP, but hearing the Krell 505 (at only roughly £9k - yerr, right) changed my mind. I went to audition new loudspeakers, but was totally blown by what a totally brill CD player can do today. By chance I had several LP and CD copies of the same material. The turntable was a top-line Avid with SME arm and Ortofon K-B cartridge. Previous listenings with a lesser CD player but the same LP source only played to my thoughts that LP was still easily the best. The Krell 505 has made me doubt things and make me want to listen more widely...
I think what I'm saying is that I'm no longer sure that a simple NOS or otherwise argument is still valid. There are just so many variables. What I can say is that the the very simple RAKK DAC2 has blown my Meridian 606 out of the water. Listening to several Claire Martin CDs through the RAKK DAC is a revelation. What it suggests to me is that the combination of a well recorded CD and a good DAC offers a healthy alternative to the LP. For the record, I have Claire Martin's "Too Darn hot!" on both CD and LP. Its a close run thing, but for my taste the CD (602 and RAKK DAC2) just beats the LP (Linn LP12/Ittok/Ortofon K-B).

Each to their own I guess, but nevertheless an interesting debate.

Head down again......

NickW

[David Mccallum]

I've been following this thread with some interest because i was thinking that building a kit valve dac would be a nice project.
Audionote do one but it's pricey and bloody huge, a nice compact wd version would be a good option for me and by the look of it quite a few others.

Has this idea gone dead or is there a chance of a kit in the future?

[steve]

I would highly recommend this design to anyone:

http://members.chello.nl/~m.heijlige...tml/dactop.htm

The digital and low voltage PCB and other hard to find Digital components can be ordered from Tentlabs. You will have to make your own high voltage/output PCB though.

I built this design and have been very happy with it. You can find 2 further posts in the gallery under "DIY DAC" in the "others" section

[bencat]

I have to own up and say I am well behind most of the contributors here and have not heard many of the DAC,s mentioned. I have heard quite few , Arcam Black Box , Cambridge Dac Magic I , II , II Cambridge Dacplat , Meridian 203 , 506 , Wadia (not sure the model number but cheapest in their range), Theta Cobalt .

All of the above have been in my system and in my room for at least a week. Most were good and the differences I feel were mainly cosmetic they all did a similar job some were better at the feel of music , others were more rhythmic some were more detailed but in most cases after weeks listening they were all enjoyable.

Currently I have a Micromedia Dac(never sure of the model numbers with this company but it is the full size unit with an AES/EBU balanced input) That last item is very important and using my Theta Data Basic II via the balanced connection made more difference than a change of Dac noise was lowered music was music and flowed better. I have now managed to try two other balanced input Dacs and in each case the difference using that connection was very marked.

So could I suggest to all considering making there own Dacs of whatever flavour and if you have a transport with a balanced output you really do owe it to yourself to include this connection as an option I do not think you will be dissapointed.

[dpogorman]

IF we all put our heads together I'm sure we can design a Valve output DAC for easy assembly by those who are interested. DAC kits are available at reasonable prices on the internet: http://shop2.hifidiy.net/index.php?m...dex&cPath=8_12 or here: http://stores.ebay.co.uk/gigawork-sh...=p4634.c0.m322 and a valve output stage could be sourced here: http://www.diyhifisupply.com/node/399 or here: http://cgi.ebay.com/DAC-TDA1543-NOS-...item33614264fd or even here: http://cgi.ebay.com/great-USB-valve-...item2a0a1e5e56


Chassis are available here (for example) http://shop2.hifidiy.net/index.php?m...index&cPath=18 and here: http://stores.ebay.com/davids-HIFI-S...=p4634.c0.m322

So all the various elements are available to construct a DAC with valve output to feed into a WAD/WD amp (or in fact any other amp)
DAC kits exist with multiple inputs, co-ax/ fibre optic and USB so it should be easy to satisfy any request.

[Revoli]

I would be interested.....

[bliza3017]

ok