MHDT Labs: R-2R NOS Tube DACs

Discussion in 'Dedicated Source Components' started by luckbad, Feb 13, 2016.
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  1. lordcloud


    Last edited: May 25, 2017
  2. willsw
    I've had the new Orchid DAC in-house for about a week and unfortunately at some point could not deny that there was distortion and not burn-in weirdness. MHDT seems to have realized that there was something not tested enough and may be delaying further distribution of the Orchid. Not great news, but I'll be excited when it's available again. I've read great things about the Audial Model-S DAC and MHDT's implementation of the 1541A chip seems to be modeled on theirs. Plus it was looking so pretty!

    I bought the ECC88 converter . . . but for some reason haven't bought any tubes.

    The Orchid:
  3. lordcloud
    I have a question. I'm a tube noob, so forgive my ignorance. But both tube types are 9 pin, so why is a converter necessary?

    Update: nvmd, found the answer. I guess I should Google things first.
    Last edited: May 28, 2017
  4. lordcloud
    So I tried the "Siemens", but they seem to be fakes.

    I also have a pair of Amperex 7308's and wow are they an improvement over the stock tubes, in every way!!! Much more dimensional and realistic sounding.
  5. Luckbad
    I have an Orchid on the way. It's been a long time since I've had a proper DAC in the house and I have to hear it.
    lordcloud likes this.
  6. Luckbad
    MHDT Labs Orchid in the house! TDA1541A. It still has the stock R1 chip in it, though I have a late production N2 chip that I'm going to order soon.

    Tube I popped in first is the 6n26p, which is my favorite in the Atlantis by a fair margin.

    First impression is that this has the most stage depth of any MHDT DAC to date.

    Ah, to have a proper DAC again.
  7. Guidostrunk
    For the folks interested in the E88CC/6922 variants. I've rolled just about every one of those variants.

    Of course this is a subjective topic, but I'd like to add a list of my favorite tubes, out of everything I've rolled.

    #1 Valvo(Heerlen) CCa mid 50's to late 60's . Yellow print was tops for me, but they also come in a white print. Extremely Holographic tube, with a very 3D soundstage, and a midrange to die for. Very emotional tube. The pinched waist version is the rarest of the bunch, and the price is premium. Eindhoven made these in 56. Heerlen started somewhere in 57.
    #2 Siemens CCa(grey shields&plates). Pre 65 is what to look for. 65's, had stamped plates on the getter post. Everything before has acid codes on the side near the bottom.
    These are soundstage masters. A very airy ,layered 3D presentation. Deeper than the Valvo, but fall a little short on the midrange I prefer. I haven't heard nor seen anyone that I know who's just as enthusiastic about these tubes, review the late 50' horseshoe getter. They're extremely expensive.
    #3 Telefunken CCa or E188CC. These are somewhat similar to the Siemens, with a tad more warmth. They have a little dryer texture compared to the first 2. Many prefer them to the 2 above.
    #4 Mullard Blackburn early to mid 60's E88CC/6922(goldpins). These tubes by far have the best bass reproduction of the bunch. Vocals are spooky good. They're pretty holographic, but lack air and soundstage that the above have. If you shop for these, look for the "B" in the beginning of bottom code. "R" is a common code from the Mitcham plant. To my ears they just don't have the Blackburn magic.

    To go back a bit. Regarding the Valvo Heerlen tubes. I'd definitely look into the E188CC versions as well. They're not that far off from the CCa. Red and white labels are the common color.

    If you guys & girls are vigilant, these tubes can be had for far less than what the tube stores are charging.
    My yellow Valvos , I paid $175 for the pair NOS. I pretty much stole them at that price. Singles are even cheaper.

    Siemens CCa , I Paid $275 for my 65's, and $250, for my 63's.

    Valvo E188CC's can go anywhere from $100 to $200 depending on the year and test results.

    Tele E188CC's/CCa from $250 to $350. I've seen them sell at $200 before.

    Mullard Blackburns E88CC/6922. These are getting harder to find. I still see them sell for $125 to $200.

    Check out the Lyr tube rolling thread if anyone is interested in these variants. Lots of helpful people there.

    Happy rolling
    lordcloud likes this.
  8. lordcloud
    Thanks Guido..! I'm looking for all of the opinions on these tubes as possible.

    A 3D soundstage is very important to me. As are midrange and frequency extremes. I'm really wanting a transparent, information rich, and neutral a tube as possible. I don't want to feel as though information is being held up in the tube.

    I'm going to look into your recommendations. I haven't seen anyone else mention the Valvo before, so I'm doubly interested!
  9. Guidostrunk
    Siemens CCa is exactly what you want if you're looking for extreme transparency, and a neutral presentation. These tubes will extract the most subtle nuances in the mix.
    Teles would be second.
    Valvos, are on the warm side of neutral.

  10. Luckbad
    My Orchid arrived last week. Sounds great! No distortion. It has the best stage depth of any MHDT DAC I've heard. It's a pretty special combination of detail and musicality.
  11. lordcloud
    Is that including the Pagoda? And if so, I'm wondering what's different that's making it so.
  12. Luckbad
    Yep. I've now owned: Havana, Stockholm 2, Atlantis, Atlantis+ (modded), Pagoda, Canary, Orchid

    To be fair, the Pagoda didn't sit super well with me because I'm very sensitive to treble and most of the good tubes I had when I had a Pagoda didn't help matters. I have a half-working Pagoda that I'm going to work on fixing this weekend time-permitting.

    The Orchid is vivid, dynamic, and high-res. Airy and punchy. It's something of a hybrid in sound between the Stockholm 2 and Pagoda. Less musical than a Stockholm, less in-your-face than a Pagoda.

    I managed to procure a 1998 TDA1541A of the same ilk as Audial uses in its Model S. This chip is clearly a step up from the R1 that comes stock in the Orchid. It's actually a little smoother, but better with microdynamics at the same time.

    I've done a little bit of tube rolling, but nothing extensive. I spent months comparing tubes maybe a year ago now and only held onto a few of my favorites. The GE Triple Mica is a great all-rounder and is very musical and punchy. The 6N3P-DR is actually a great tube with similar characteristics, though even a touch more musical and less detailed (but don't touch the standard 6N3P tubes... they are very bad). My favorite tube is the 6N26P. Not super easy to find, but extremely dynamic with excellent separation and good musicality.

    I found I liked that tube the most with my Atlantis+ because it did a good job of accenting areas the Atlantis lacks a bit (the Atlantis is fairly mids-centric and a touch thin compared to the Stockholm or Pagoda).

    I have a 6N26P in the Orchid right now. It might get too into traditional hifi territory for me with this tube, but I'm leaving it in since it's not burned in at all. I might end up having to shift gears a bit with the Orchid and lean toward a more mids-centric tube that is a little less airy. That's probably the Western Electric 2C51/396A D-getter. Of course, I sold my stash of those.

    I've got a new Atlantis(almost)+ now as well. The main missing component is a matched pair of 1uF 200V K40Y-9 paper-in-oil capacitors, but I have those on the way right now. Those are a simple enough soldering job that I can handle it and I don't have to beg a friend to help for my 10th anniversary. :p

    Anyway, depending on how things pan out I'll probably have to let go of either the Orchid or Atlantis+. The Orchid with a rare TDA1541A chip in it and the Atlantis+ a unique beast with a bunch of upgraded or changed components (okay, there is one other and I sold it to @humzebra a while ago).

    Or I sell some of my guitar gear and keep both? The thing that sucks is that both really need a good transport to sound their best, and that's hardly an option at work. Anything I do there has to be a USB solution and those are quite expensive for good ones--maybe a Singxer SU-1. I'm being ridiculous, though. I only used IEMs at work now because they're the best at shutting out the environment, and a DAC of this caliber is complete overkill.

    At home I currently have an ESI Juli@ XTe but will be getting a Lynx E22 again. That went in my great purge of 2016 along with all of my other high end headphone gear.

    I'm rambling.

    Last thing worth mentioning is that my comparison is done from memory. I'm using Sennheiser HD650s with a couple mods and a Garage1217 Project Horizon w/ 6N6P. Most of my time with the Pagoda and Stockholm was with an ampsandsound Mogwai. I can't afford another one of those yet.
    Last edited: Jun 22, 2017
    humzebra likes this.
  13. ericr
  14. Luckbad
    @ericr Yep. I primarily use Future Sonics Spectrum G10 at work. They isolate well, are easy to take in and out, sound good, and have nice bass. Of the ungodly number of IEMs I've tried they're my favorite for the use case.

    I have owned or had on loan ~50-60 IEMs, including a few in the four figures, and I found just about any IEM over ~$250 wasn't worth it for work. My favorite work earphones were Future Sonics Spectrum G10 and Aurisonics Kicker, with the former being significantly easier to pop in and out as people talk to me.

    I don't do serious listening with in-ears, so going into the stratosphere on price (which is basically anything from 64 Audio) isn't appealing anymore.

    Finally, I've hated or had minor qualms with 100% of the balanced armature IEMs I've tried. The Noble 5 was the best BA earphone I've ever owned (not the most expensive, but the only one I've ever truthfully liked).


    The Orchid.

    Still sounding excellent. The initial honeymoon phase is over. I've rolled 4 different tube types in it so far. It definitely responds well to tube rolling. Second only to Atlantis in the MHDT lineup for how audible (to me) the change is when I swap tubes.

    The 6N3P-DR might actually be my favorite thus far. I was expecting GE Triple Mica to mesh well, but it gets a little polite. The Sylvania is too bright for me with it.

    I'll have to retest all of the tubes next week, though. My initial testing was with an ESI Juli@ XTe. That is gone now and I'm using *gasp* TOSLINK with it. I have a Lynx E22 coming this week. It's my favorite overall S/PDIF transport (if you can call it a transport... whatever).
  15. Luckbad
    Basshead.Club review updated to include the Orchid:

    MHDT Labs Orchid Addendum


    In mid 2017, MHDT Labs introduced a new DAC to the lineup. This one uses a chip many of us have been asking for: The Philips TDA1541A. This chip is one of the most famous from the glory days of R-2R, mentioned in the same reverent breath as the Burr-Brown PCM63, Analog Devices AD1862, and Ultra Analog D20400A.

    It uses an R1 version of the chip, which is not one of the famous late production ~1998 chips or a “crown” chip (S1/S2). While the R1 is not a famed variant of the TDA1541A, it is socketed in the DAC and is extremely easy to replace if you want to buy a better version of the chip.

    My impressions of the Orchid can be summarized rather succinctly as: jack of all trades, master of all trades.

    It is, quite simply, the best overall DAC that MHDT Labs has ever produced. Even with the R1 chip, it has the most stage depth of any of their offerings, width at a similar level to the Pagoda, and a wonderfully vivid, dynamic presentation.

    If you want a non-oversampling, R-2R tube DAC that can do it all very well, the Orchid is the best I have ever had the pleasure to listen to. The bass digs deep without ever getting flabby or encroaching on the mids. The mids are luscious and elegant. The highs have detail and air without being fatiguing.

    To sidetrack a little bit, I’ll briefly talk about a famous DAC that uses the TDA1541A chip: The Audial Model S. Audial’s Pedja Rogic is a pioneer of building modern digital-to-analog converters with the TDA1541A chip.

    I mention this for two reasons: First, the Orchid utilizes a zero-feedback output stage scheme very similar to Audial by utilizing the OPA861 as an I/V transistor. In the DIY community, this is often believed to be the best way to implement an output stage using the TDA1541A, and MHDT Labs appears to agree.

    Secondly, Pedja did some very in-depth research to find the best examples of the TDA1541A apart from the rare and expensive S2 chips, and he discovered chips made in 1998 in Taiwan to be exemplary. I hunted around and found one to use as a replacement for the R1 that came stock.

    Was it worth it? Undoubtedly, yes. To replace the chip, I basically took two screwdrivers and slowly removed the R1 chip from the sockets to prevent any bending of the pins. Then a quick installation of the 1998 Taiwan chip (lining up the pins and pushing it down) and I was ready to go.

    Were the changes audible? I believe so, yes. Everything sounded effectively as described earlier, but slightly better in every way. If you can source a genuine TDA1541A chip, I do recommend replacing the stock R1. If you can’t find one, no big deal. You’re missing out on placebo and less change than a solid tube will get you.

    Briefly touching on tubes, I’ve found that different tubes complement the various MHDT Labs DACs. I wouldn’t use the same tube in the Pagoda and Stockholm because the DACs themselves have different characteristics. That said, I find the Orchid to respond to tube changes nearly as dramatically as the Atlantis. While the Pagoda and Stockholm are sonically influenced by the chosen tube, the Atlantis changes quite significantly, and the Orchid nearly as much.

    This means you have a potential chameleon on your hands and you will be able to find a tube that pairs well with your ears and the Orchid. The Pagoda, Stockholm, and Canary are all set well enough in their ways that a simple tube change isn’t going to push things far in any direction, while the Orchid and Atlantis can be tuned to taste.

    So I’ve been gushing about the Orchid for paragraphs. Is it my favorite DAC from MHDT? It may very well be. Previously, my favorite of the bunch was a heavily modified Atlantis (dubbed the “Atlantis+”), but the Orchid has so many beautiful qualities it might take the cake.

    Musical, dynamic, vivid, airy, and gorgeous, the MHDT Labs Orchid is sure to gain a cult following among fans of this style of DAC.
    shultzee likes this.
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