Vintage DACs

Discussion in 'Digital: DACs, USB converters, decrapifiers' started by Luckbad, Apr 26, 2016.

  1. Enigmatic

    Enigmatic Friend

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    The prices of these 6922-and-variant tubes *are* ridiculous indeed. Occasionally I have came across a couple good deals on eBay but only sometimes, out of those notable ones I've recently seen (and have heard with the Sonic Frontiers):

    • Green/blue label Philips JAN 6922 tubes for ~10USD a pop performs quite decent and tends to be NOS with box. Don't pay more than 15USD per piece though. I can be happy with just these.

    • Siemens E88CC - The ones with gold pins - They sound more expansive and a tad smoother than the Philips 6922 tubes. But I will shy from paying more than 30USD per piece. Look hard enough and be patient, will occasionally come up for ~20USD per piece, without box and slightly worn, which works just fine. Problem is the cheaper ones tend to appear on the Euro-zone eBay microsites and at times sellers don't ship to US (if that's where you are living).

    • Another decent and most importantly, cheap, tube to look out for are those made in West Germany/Holland 6DJ8 tubes, sometimes labeled as RCA. Typically made by Siemens, steel pins instead of gold. They take more effort to identify so not for everyone, but can be bought for ~15USD per piece.

    Forget about those Telefunkens/Amperexes/CCAs for 200~400USD for a matched pair......... Those are some seriously weird prices..... I'd gain more pleasure taking my family out for a good meal together.
     
  2. tommytakis

    tommytakis Gear Cycler SoCal Edition

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    Thank you so much for the info, I’ll definitely be on the look out for the ones you listed above. Yeah, I don’t like the idea of spending couple hundreds on a pair of tubes, when that money could be spent on other gear or like you said, treat the fam out for a nice meal.

    I like the sound so much I didn’t even bother opening up the insides to see which tube it has LOL I haven’t heard this type of synergy since I had the Yggdrasil A1 + ZDS + HD650, and at a lower price! Vintage DACs are awesome
     
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  3. rtaylor76

    rtaylor76 Can't wipe his tag

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    So I am the one who purchased the Theta DS Pro Basic II.

    My question for some of you older guys, what is that glass optical input? What is is actually called? What are even the connectors called? And what actually used this interface?

    [​IMG]

    It looks like I can just take that grey wire and desolder it from that AT&T board replace the optical connector and solder it to an RCA connector and have a 3rd coax connection.

    Just wondering what is up about that particular type of optical.
     
  4. Mr.Sneis

    Mr.Sneis Friend

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    ST optical, but I am curious if that 3rd coaxial cable swap can be a thing! Very few transports use the ST optical.
     
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  5. Enigmatic

    Enigmatic Friend

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    AT&T - Or sometimes called ST Optical. Insanely smart people doing crazy things in the 90s (unlike cookie cutter stuff these days). I think it sounds great though, and most times prefer it over AES.

    The interface is rather rare as Sneis rightfully pointed - Just off the top of my head a few transports from Theta, PS Audio Lambda, California Audio Labs, Wadia would have that as an output, also all vintages so would likely not last too long. Alternatively one could look for a Bel Canto interface (USB LightLink or RefLink for example) or an Audio Alchemy DTI (the ST Optical interface is an add on).

    The cables are actually quite cheap and is still used in networking these days (the duplex ones mostly)........ Caveat emptor on the expensive ones.

    https://www.ebay.com/itm/5m-ST-ST-S...995534?hash=item4d72f2c8ce:g:xAMAAOSwBF1a7Oca
     
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  6. A Child of the Jago

    A Child of the Jago Facebook Friend

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    There is a balanced EAD DSP-7000 Mk 3 available to me - I'm kind of looking for a meatier, warmer, analogue source - appreciate a DAC isn't going to make a huge difference to the chain, but can anyone chime in where this DAC sits on the warm / neutral / cold spectrum? This DAC certainly has its fans, not least Zach at ZMF who has one in his main chain.

    All intel appreciated.
     
  7. je2a3

    je2a3 Facebook Friend

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    [​IMG]
    After going through a plethora of CD players, a couple of multi-bit DACs and DIY mods, this late 80s Arcam Delta DAC made me realize that even if the TDA1541 isn't the last word in detail and resolution, to my ears it converts red book standard digital bits closest to what I hear in a concert hall.

    [​IMG]
    It's also built to high standards. Separate power supplies for the digital and analog sections and discrete circuitry in the analog output section when most units until now rely on IC op-amps.

    [​IMG]
    Initially I felt the Arcam was sonically neck to neck with the Adcom GDA600. Each with their own virtues and faults. But after bypassing the SA7220P chip in the Arcam, my ears were convinced that this ancient DAC was the winner.
     
  8. bixby

    bixby Friend

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    I owned it many years ago. Probably one of the most expensive dacs I bought ever, $2.7k if I recall. It was good for many years. I cannot remember what I went to from it. It is on the warm side especially compared to many of todays dacs. Not sure if it meaty as compared to an early Bifrost Multibit. But it also had a bit of sand in the lower treble. Aside from that, at the time, a very good dac. If I were allocating money towards a dac like that one, I might spend $300 or more for it if you like the sound. Definitely better than other ladder dacs like the ack dac and others at lower prices.

    I think the DS Lavry DA-10 someone listed for $350 is on par maybe a bit better, I owned that one too. And if I had to rack my brain as to ultimate satisfaction I think I would go for a Gungnir over the EAD if you want a non DS, but that is based on really hazy EAD memory.
     
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  9. skem

    skem Friend

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    Ahh yes, but what if you also rendered the Adcom NOS and bypassed the OpAmps? Double PCM-63P’s might be quite magical.

    I wonder why there are physical cutouts around the TDA1541A chip.
     
    Last edited: Nov 19, 2020 at 1:58 PM
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  10. je2a3

    je2a3 Facebook Friend

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    Tapping the analog outs from the PCM-63Ps isn't within my abilities...I'm too lazy to study it. ;)

    Mainly, I didn't want to do anything irreversible on the GDA600 board. Besides, it would've been too difficult to mount a tube output stage inside that chassis which is my preferred route.

    The TDA1541 is socket mounted in the Arcam.
     
    Last edited: Nov 19, 2020 at 2:14 PM
  11. lehmanhill

    lehmanhill Almost "Made"

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    It's worth opening it up and seeing what tubes are there. If its like my SFD-1, the tube makes a huge difference. Mine was shipping with a pair of National (Panasonic) 7DJ8 tubes and it sounded good to me. But at some point, I looked in the big shipping box and found some old Russian tubes, 6H23N. Out of curiosity I tried them and wow. The midrange was sooo clear and I hadn't realized how much bass I had been missing.

    Since then I have been rolling a few tubes including a Mazda (French made Amperex) and Siemens. All very nice, but the 6H23N Russians have had great synergy with the SFD-1.

    Since the old tubes aren't being made anymore and tubes will wear out, I started looking for a spare pair. It turns out the Volkshod (rocket) 6H23N tubes I have are expensive and nearly unavailable, but I found 6H23N-EB (military low noise, long life) Reflektor at PCX as a matched pair for a reasonable price. I think I still prefer the Volkshod over the Reflektor very slightly, but the Reflektor are very close. Just a thought for when you get around to tube rolling.

    https://www.partsconnexion.com/NOS-64369.html

    Jac
     
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