music hall 25.2 DAC mod

How do you like the stock unit? I was thinking about trying one, but haven't heard alot about. Have you listened to the PS Audio DAC III? That's the other one I'm interested in.

I just got it. I had also tried the Cambridge DacMagic. I like the Music Hall better. It just is better with tube systems. The DacMagic was very nice but was not as smooth as the Music Hall.

I will let it break in before I decide to do any mods. Might try tube rolling.

I have had the DAC for a about a week, using it with a squeezebox duet and my pioneer elite 05 dvd/cd player as a transport (thinking of getting something better as transport but not sure if that will be any better than pioneer). I have a new Cary 120s tube amp and using a calypso preamp from my dealer until my lector tube preamp comes in. I wrote Music Hall about break in time and Roy Hall wrote back telling me it takes a couple of days but recommended an EAT tube damper that makes a nice improvement. I put that on but never listened to the unit without it so cant compare. Plus I read an internet posting from somebody that compared a bunch of tube dampers and thought the EAT damper sucks. However, it may be tube/unit specific for the kind of improvement you hear. So far, (i am still on the first 50 hrs of amp break in) i think the music hall sounds very good, but not as good as my vinyl on a rega p3/24. That was why i was wondering about the mod. Affordable audio says i can come in an do an A/B comparison since i live in LA area. i want to slowly tweak the system but hate wasting money on stuff that makes imaginary improvements (i have not bought any high end IC or speaker cables yet).

Have a MH 25.2 modded by Dan Wright at Modwright.
Tube output, audioclock 4, caps, etc.
Not much out there that sounds much better.
Have the PS Audio Dac3 which is much easier on the ears than the Benchmark. Would assume the the Dacmagic is also a bit dry being from England.

Magnumpi205, thanks for the comments. I too had the Benchmark and didn't like it either. Kinda sounded like a computer, very fatiguing and bright in my system. I also tried the DacMagic and it was very lightweight and dull sounding...again "in my system".

I think I might try the PS Audio and see how I like it.

Mofi,
PS going for $699 this month at PS Audio. You can also put in a B stock order and wait.

I've owned the music hall 25.2 DAC for about 1 month and also contacted Gary regarding the mod. He let me know the mod includes a new tube, the JJ6922. He said to try the tube on my own, and if I liked that upgrade, I would like his mod. Well, I just got the European tube installed 2 days ago and it **immediately** made a dramatic difference. Warmer, more weight, more holographic, seemingly deeper bass, though there is a little bit of roundness in the bass as tubes are known to do....that's part of the sound. The JJ is supposedly a new tube that uses the old Tesla factory which is somewhat famous. It has gold pins and it just sounds way better than EH.

BTW, isn't that funny, I also tried the EAT on the Electro-Harmonix tube, and seemed to like it but wasn't too sure. It actually doesn't fit the JJ because the diameter is too small even though the tubes have the same spec.

I'm strongly inclined to get the mod. Gary has good feedback on Audiogon and seems to know what he's talking about. Go to google images and search for Music Hall Dac25.2. You'll come up with sellers that include photos of the 25.2's circuit boards. Compare these pics to photos of modded unit on Gary's site. Indeed, w/o being a techie, it seems he's really adding some premium parts that are immediately apparent due to larger size/different color, especially around the tube area.

Keep me posted if you pull the trigger, and I will try to post my impressions on the mod if I do that in the next week or two. BTW, I would definitely take him up on the A-B comparison/audition since you live in SoCal. Let us know!

Thanks,
Audiohound

Well I took the advice above and tried the JJ6922 tube and immediately noticed a more liquid sound and greater depth and seperation. Only thing is, the one I ordered does not have gold pins. I do not know if that will matter much ?

I AM LOOKING FOR A (DAC) THAT IS THE BEST OF ALL WORLDS THAT IS WELL UNDER $1,000.00! I HAVE LOOKED AT PRETTY MUCH EVERY (DAC) OUT THERE AND IT IS VERY HARD TO CHOSE ONE THAT WILL WORK FOR ME! I READ ABOUT THE (MUSIC HALL 25.2)THE (WAVELENGTH AUDIO PROTON) (PS AUDIO DAC III) AND ALOT MORE AND I HAVE NO IDEA WHICH TO CHOSE! I WILL BE DOWNLOADING ALOT OF OLD (70'S FUSION JAZZ & R&B ALBUMS, CASSETTES) DOWN TO (LOSSLESS FORMAT) TO WHICH I ALSO NEED TO KNOW ALL THE SETTING TO (RECORD-IN)FOR THE BEST SOUND QUALITY BUT I ALSO NEED TO KNOW IS IT BETTER TO RECORD IN (WAVE OR OGG) AND WHICH CODEC RECORDS AT THE BEST (SOUND QUALITY) AND USES THE LESS HARD DRIVE SPACE? I NEED HELP WITH ALL OF THIS FROM ALL THOSE WHO HAVE VAST EXPERIENCE WITH ALL THESE PROBLEMS AND CHOICES?

If it sounds good....then it sounds good! I got mine with the gold pins from Antique Electronic Supply in Tempe,AZ, however, it cost $23 which is more that the usual approx. $12 that I saw at other vendors. Maybe there's a cost differential for gold pins, not sure. They tested the tube before sending it for $1 and got it to me quickly since I'm in SF, but s/h was $10 (ouch!).

Any updates on mods for this DAC?

I am also very impressed with the DAC 25.2. I ended up rolling several tubes and settled on a NOS 7398 Mullard CV2493 military spec tube.

I also have recently bought a Music hall 25.2 dac.Wow what a nice sounding dac.Then I was looking into mods,then I decided to try a EAT tube.A expensive little guy.$225! Worth every penny! Took the dac up several price levels.I cant believe the music from my mini mac..What a bargain..

I replaced the tube by a Amperex 6922 Gold pins balanced triode sections (very important) since the tube only acts as a buffer after the operational amps sections Burr Brown OPA2134 etc. though the tube alone made a sizeable improvement I am toying around with OPA 627 doubled up in Brown Dog boards to replace OPA 2134's and replacing stock capacitors (eeack!) for Mundorf Audiophile series maybe even a Burson clock to reclock data at the input and cut down on jitter.
Also the diodes and rectifiers form the Power supply can be changed (SHatki) and will make an even bigger improvement.
I think the MH DAC 25.2 is simply a tweakers dream piece.
decent DAC to start with, then awesome when done with some mods and probably will compete with DAC costing 5 times maybe more.
I would like to hear a DAC that uses tubes for amplification instead of just a buffer stage, and see what it does for the sound, very partial of 6SN7'tube sound though must confess that 6922 family is a very nice tube also.
So far the best DAC with tubes I've heard is the CAL Alpha but does not have USB input bummer . . .
Also the Classé are very very nice but for the price the MH is a winner and a no brainer, if you get the upgrade itch just upgrade components inside for a few $ you're in heaven.

Good luck enjoy the music!

Gonzalo

It's great to hear positives about this DAC. I've had mine for about 2 months now and couldn't be happier. Tried swapping out the tube for a Matshshita and though the bass firmed up a bit, the top end lost air and life and never opened up. After what I've heard here, I just may try the JJ. With the stock tube and time on my hands, the unit has opened up several times and just gets better. Very resolving, detailed and nuanced. All the air I can ask for and no grain. I can only imagine (and I do, constantly) what some Burson opamp replacements can do along with the EAT tube but what I hear, right now, is simply wonderful.
My only complaint is getting used to the feeling that someone or something was in my room while listening to it: the musicians have a real and palatable presence.

I've had the DAC25.2 for about a month and it sounds very good. The EH tube not so good. Replaced it with a 60's Tesla (not JJ) E88CC as well as a 60's Amperez 7308. It's a tough choice between the Tesla's better bottom octaves and the Amperex overall Freq. balance which sounds "right", at least to me. Still going back and forth between the two.

It's interesting to also switch to between the 25.2 and the Benchmark USB. Definitely notice subtle differences.

I'm wondering about the mods as well. Keep us posted.

I recently got this DAC too. I have a NOS 60's French Mazda (Philips-owned) 7308 tube en route from Brent Jessee.

I'm also toying with opamp swaps in the RCA tube circuit - replacing the stock (2) OPA2134 and (1) OPA2604.

Not wanting to spend the cash on Burson's at this point.

Does anyone have any opamp swap experiences/recos for this DAC. I've been considering AD8066, AD8620, or LM4562.

Thanks,

Adam

I, too, got a NOS '71 Mazda from Brent Jessee (w/RTC label) and it really transformed this DAC. He said he'd put it up against any EAT valve as they
are reversed engineered replicas built to very high tolerances but can't use
the same metals used in the NOS tubes. Something about the AEC won't allow it.
Now I have no desire to swap out anything else.
I read a blog somewhere else (from '08) that the DACs take about 500 hours
to break in so don't be in any rush to mod this unit. I have about 200+ hrs on
mine and it continually improves. It's like watching a kid grow.
A really good kid.

Nonoise - I got the Mazda 7308 yesterday. It's a Miniwatt/Dario label from 1967. Installed it yesterday afternoon and have been breaking it in since - haven't done any serious listening yet.

As a side note - did yours have the actual Gm numbers on the box label?

Being a noob with tubes, please bear with me.
There is a label from Brent Jessee on the box that has a space for Gm1 & Gm2 and both have a 'check' after them.
Tube type is 6922 and brand is RTC, Mfg. = Mazda. Prod. type = 1971 France.
On the tube itself was a slip of paper with the numbers 27-29 &-18/-18.

Hope that helps and that you get the same results as I did.

On an aside, I tried a '70s Matsushita, from another site, that was touted as a great tube (not from that site but from various sites) with negative results: flat, closed in mids and highs and generally dull sounding and this Mazda is quite the opposite. Open, airy, fleshed out (more body), dynamic, very quiet, with decent bass. Almost organic. The top getter is tilted at a 45 degree (I thought it was damaged at first) and kinda looks like how one would wear a beret.
Fitting for a French tube.

Could someone familiar with this DAC clarify one thing for me?
My understanding is that the balanced output circuits on this unit are solid state and the single ended circuit goes through the tube. Is this correct?

Rja,

That is correct.

Nonoise - thanks. I was really just wanting to know if you had the actual Gm data or the check marks (because I thought it was strange that mine had the check marks on the label and no actual data). Looks like you got the check marks too, which tells me that it must be a fairly standard/common way for him to do the labels.

This was my first tube purchase, so I'm new to tubes too.