MDHT Havana 2 - Tube DACs vs. SS

Here in Seattle, we have gone a little crazy over the MDHT tube DAC lineup owning most of them. We have also gone a little crazy over the Schiit DACs/AMPs lineup owning most of them. Beyond the typical quarterly local Headfi meets, we also have a growing group doing mini-meets aimed at comparison, measurements, and optimization of the existing gear. This is probably what is most responsible for our growing MDHT/Schiit crazes.

Typical of our group, three of us decided to do a small MDHT DAC SQ comparison meet with tube rolling optimization intentions - but word got out and our small group is over 15 now. Our MDHT comparison goals still stand, but we will have the entire Schiit lineup to compare as well along with other interests - for example, we have an optimized HD800 setup that currently sounds like an Abyss. The meet happens on 1/30/16.

Does anyone care about the results enough for me to post here? If so, are there any questions that SBAF would like answered in this open lab? Feel free to post questions in the thread.

Meet Goals:

1. MDHT DAC Lineup Descriptions: We intend on comparing the DACs to post the similarity and differences.
2. Value: We want to see where the value lies in their lineup. Stay with Paridisea or move up to the Pagoda or something in between. Or is it all about the signature? Is there value in paying more for the more expensive models?
3. Tubes: What tube makes the DAC sound best and how does it vary between the available tubes?
4. Solid State: We buy tube DACs to add that tube flavor and sweetness to the SQ of our stack, but when is a solid state DAC better? Do we lose anything going tube? What are the differences.
5. Schiit DACs: What is the differences between the Schiit DACs and how do they scale?

Preconceived Bias: I have to tell you up front that I just sold my Mjolnir due to making my LCD2.2 sound bright. I originally purchased the Havana 2 to warm up my Mjolnir, but in the end felt like I could do better with another amp. I have an Eddie Current Black Widow on its way that should be here in time for the meet.

Some of us in this group find the Schiit lineup DAC/AMP to have a bright tinge to it to bring out detail while others strongly disagree. I personally feel that the Yggdrasil/Rok stack is the safest bet in head gear as a good value and SQ, but is different from the rest of the Schiit lineup. I furthermore, based on listening endlessly and my discussions with Schiit's Mike Moffatt, feel that the Yggdrasil is the key to the Yggdrasil/Rok stack. Regardless, the synergy between the Yggdrasil and the Rok are 1 + 1 = 3. I will be testing the Yggdrasil with the BW to see if I can get a better sound vs. the Rok. However, head to head using other DACs I suspect that I will like the BW better than the Rok having used both before.

Meet Rules:
There are none. In the end, with these meets, it is all about consensus, not what I think. We are looking for absolutes where everyone agrees chocking up everything else to individual signature preferences. Sometimes it is fun to get opinions down too to show variety of thought/preferences when diverse.

 

Sure - I'd be interested in your meet feedback.

I have an original Havana that I have upgraded the PCM56 chips, tube (2C51 LM Ericsson), and swapped in a r-core. I haven't gone cap crazy, but I know there is room for improvement there also.

 

Cool, we are starting to look at component upgrades too. One of the group just bought this: http://www.head-fi.org/t/791863/mhdt-labs-r-core-rn-20-transformer-fits-havana



Is this what you swapped? Was it as easy as it looks? Did you get absolute, or hair splitting results? It looks like it fits the Paradisea and Pagoda too.

Which upgrade gave you the best results and what did you notice?

 

I'm waiting on all the connectors to show up for that same R-Core - I'll let you know once it is done. Between the chips and the tube - the tube makes the largest difference.

 

Tube Sensitive
This sounds like a "no doh", but one thing I have noticed is that the Havana 2 is very tube dependent. With my Tesla, I could listen to the smooth detailed and euphoric tubey goodness all day. But I swapped at a meet and never switched back from a unmarked tube that came with it and found the Havana unlistenable. There was something that was just irritating about the sound that made me want to turn it off, brightness maybe. Going back to the Tesla, I was back in business. Now trying a Bendix 2c51 and loving it even while it burns in.

The moral of this story is that we will use the same tube when comparing the lineup to keep things fair. We will also see if they each fare best with the same tube or if there is a variance. And then retest.

 

Tube Pre-amp Substitute
Another point of interest is that I have been feeding my Havana DAC into my speaker system as a source to drive my Maggies with some nice results. The Rotel is all SS in its 800 watt dry presentation, but adding the wet tube sound provides some nice euphonics to the signature. Just finding out that others have been doing this with their EC ZD tube amps to add euphonics to hard to drive speakers. Wish I would have known this when I had a ZD in house.

 

Very interested in Havana lineup, Thanks for doing this for us. Subscribed!

 

yes very interesting for me also thanks for this thread and efforts...

 

I would be interested in this. I hope there will be a Stockholm 2 in the mix. And Gungnir Multibit...

 

Yes, I'm very curious how these compare to the Gungnir Multibit!

These seem comparably priced to the Gungnir Multibit, so it could make for an interesting alternative.

 

Hm i've always been interested in the tube dacs, in particular the modded lite DAC60. There was a sale of one heavily modded recently on head fi, but missed the sale =(

Question though, its my understanding that best practices for DACs is to keep them turned on. Since its a tube DAC and tubes have a limited shelf life, would these be left off and turned on only when needed?

 

I tend to leave my equipment for the better sq. however, turning off at night and on at the beginning of the day doesn't seem to degrade the sq. in fact, most of the sq seems to be there in the first 20 minutes IMO. I happen to be burning in a few tubes as well so I am not overly bothered by leaving it on.

Then again there is the thought that we shouldn't leave tube equipment on unattended.

 

Ah ok good to verify, I figured tube dacs should probably not be kept on 24/7. Didn't know about the tda chip tho. I actually have a cheap muse4x tda dac that's plugged in and on all the time, i guess I should disconnect that lol

I think the mhdt dacs are pcm63 if I remember correctly

 

Some Data Points on Tube Rolling - Baseline Test
Last night I did a baseline test to prepare for the meet on Saturday. I know that this is of limited use due to my inability to specifically identify the tubes being used due to worn identifiers, but it demonstrates the changing SQ between tubes. Being new to tubes, my understanding is that even the same make same year may have a wide ranging SQ variability based on manufacturing variations, storage, and use to date. Feel free to add your knowledge on the subject.

What I do know is that I was told that I was originally given two Tesla 2c51 tubes - one of which is pinched - and the stock 2c51 tube that came with the amp - GE maybe. The other two I have received since is a Sylvania and a Bendix. Here is what I heard in my own listening head to head last night.

Disclaimer: Please remember that rolling tubes requires time to turn the DAC off, cool down, swap, DAC on, warm up so a direct comparison is not possible making my findings suspect and faulty. However, good listening notes with well known music selections help keep things fair. With tube 4 and 5 as mentioned, the SQ was starting to blend further diminishing my ability. I paired down the notes to the bigger differences that I felt others would be able to hear themselves and agree with and eliminated the subtle subjective observations due to the mentioned testing limitations.

Play order: 2, 1, 3, 4, 5 – numbers do not imply preference, for tracking only.

1) Tesla: Came with Havana

• a. Female voice upgraded from Bendix with more treble focus but still smooth, forward voice
• b. Feels more detailed and euphoric than Bendix
• c. Little more bottom end than Bendix, enough not to miss bass – very balanced without over doing it.
• d. More neutral across frequency range
• e. Evenly drives HD700/LCD, maybe prefers LCD louder and HD lower.
• f. Better pluck, but not good enough to be satisfied, almost. Better loud on LCD
• g. Bass good enough loud on funk/EDM with LCD.

2) Bendix: New, needs more burn-in

• a. Warm mid focused/forward, thick, with good bass quality, missing bass quantity, nice smooth treble
• b. Soft string plucking, want more dynamic snap and texture – easy listening
• c. Good musicality with euphoric quality, easy to get lost in music
• d. Favors the HD700 over the LCD2.2

3) Tesla Pinched: Came with Havana

• a. Best yet, most euphoric, clear, bass, bass, bass, did I say bass?
• b. Somewhat V shaped with voice pushed back a bit.
• c. Great on both but favors the LCD with sharper treble on the HD.
• d. Better strings, feel more pluck. Feel finger work
• e. More elegant SQ and layering while more constricted sound stage.

4) 2c51: Came with Havana

• a. Starting to blend a bit, but this one sounds voice/mids forward with nice bass.
• b. Nice body to note, some sharpness to treble, but ok – euphoric
• c. Passes Rude Boy test with colors. Most low bass, but also sharper treble.
• d. Favors LCD - turned up, sharp treble in HD – needed to turn down.

5. Sylvania: Given by Friend

• a. Blending, but feels like best strings pluck and detail.
• b. Sharper treble on both HD/LCD, but nice bass. Maybe too much treble.
• c. Hi detail coming from treble
• d. Love the detail, but feel like I need to turn things down.
• e. Guitar has nice crunch to it for rock.

First round preferences go to: 3, 1/4, 2/5


Conclusions: After going through the exercise, my conclusions are:

1. AMP: The EC BW is a warmer amp vs. my bright Mjolnir requiring a re-optimization of the tube choice.
2. HPs: The different tubes favored different HPs. The brighter typically liked my LCDs while the warmer generally liked my HD700s. However, there were some that took the middle ground and worked well with both but not as good as the optimized option.
3. Volume: Some tubes played better with the LCD at higher volumes and the HD at lower volumes.
4. Staging: The staging was never overly wide with any tube, but forward mids favored voices and bright favored strings bringing them forward while neutral was good with everything.
5. Optimized SQ: I listen to wide ranging genres as my mood changes so I could go crazy changing HPs, tubes, etc. to perfect the SQ, but then I would need to do it again when my mood changes or I hear that new song that I wish to listen to on my rig. Some tubes did very specific things very well that I missed when removed, but my preference was to go to the pinched tesla that made everything sound good enough for ease of use.
6. Tube Rolling: Is a PITA! While it is important to optimize and understand the capabilities, I would like to standardize on something that works well across the board rather than constantly rolling tubes. On the up side, it is like getting new equipment as it sounds very different keeping things interesting when done on occasion.
7. Euphonics: I like tubes for their euphoric musicality. The added even order harmonics are addicting. However, there seems to be a limitations that I can hear going between tubes in exchange for the euphonics - the down low, transparency, and neutrality. Even tubes can sound bright.
8. Bottom Line: Tube selection is critical.

More to come after the meet.

 

You must know Soundsgoodtome.

I'm hoping to get an MHDT Atlantis soon. Tough because of Lunar Year in Taiwan.

What would you say is the ideal 5670 tube for maximum bass and smooth treble (not emphasized)?

 

Oh also...

How do you adjust bias in a tube dac? I see no way to do it in MHDT dacs.

Does it auto bias? That's a fairly rare feature and would probably be mentoned if it did.

 

Soundsgoodtome is a friend here locally and part of this shootout. The tesla's mentioned above feel like a good compromise of euphoric, bass, and smooth treble for easy listening without being too thick where you loose detail. What is nice in the shootout above, is that by having a selection of tubes, I can optimize for a particular can or re-calibrate for a new amp as I did with the Mjolnir to EC BW switch. But what was interesting was that we all heard things differently where Soundsgoodtome and EricR both liked the Bendix better. Of more interest was the adapter (Jeremy who builds Ember created it) that EricR brought that allowed larger 6SN7 tubes to be used. This gave me the best bass yet with a very clear and neutral frequency range that actually felt more detailed. Didn't get a great opportunity to play with it to fully review, but will probably buy one to play with. The disadvantage is that the tubes are too big for the hole requiring the cover to be removed. However, the adapter/tube selected had the potential of replacing my tesla's as my favorite.