Eastern Electric Minimax DAC opamp rolling thread

Big Red Machine · « **Reply #80 on:** 22 Apr 2012, 02:44 pm »

I didn't want to, but I had to add extensions to the wiring connecting the selector switch to the PCB. I could not get the discretes into the sockets with the cabling right across that area. The downside is those original cables are shielded and I added unshielded 2.5" extensions to each. I did re-cover both bundles in ERS and copper to keep the noise down across the board, but am exposed for that last 3 inches.

No issue so far but I will keep my ear on it.

Right now the Dexas are my favorite versus the Bursons. I am using the tube circuit so forget which pair of opamps matter with the tube circuit, is it U1/U2 or U6/U7?

Wayne1 · « **Reply #81 on:** 22 Apr 2012, 02:51 pm »

U1/U2 are the dual op-amp positions that send the signals to both the analog output stages.

U6/U7 are single op-amps in the SS section.

etcarroll · « **Reply #82 on:** 22 Apr 2012, 03:43 pm »

+1

Having heard Levi's modded DAC at a DAC shootout over a year ago, I've wanted one since, and just bought another member's ver 1 who is looking at the ver 2.

Quote from: mjosef on 21 Apr 2012, 05:01 am

You guys should understand that Levi's DAC has quite a few modifications, and his results may not reflect what the stock unit with just the opamps upgrades will offer.
In short, Levi's EE DAC is one of the best I have heard in my short lifetime in DAC-Land.

setamp · « **Reply #83 on:** 23 Apr 2012, 01:43 am »

Has anyone compared the Dexa with the Bryston opamps and can describe the differences in sound in the minimax?

gkinberg · « **Reply #84 on:** 23 Apr 2012, 02:40 am »

Why is there so much discussion about opamps with respect to the minimax? I’ve never heard so much talk about opamps in any other component. Is it because most other components don’t have opamps? I realize this is probably a very naïve question and that most components have opamps, hence my confusion regarding all of the discussion. Infact, I thought that opamps were a substandard design and that manufacturers would replace opamps with discreat devices to improve their offerings. I’m sure that there are flaws in my memory and my comments so please feel free to correct my misstatements. I’m just trying to understand and educate myself.

Has anyone compared the minimax dac plus with the M2tech young DAC? I’d be interested to hear comments. Thanks, Garth

Levi · « **Reply #85 on:** 23 Apr 2012, 03:38 am »

Along with OPAmp upgrades. A full wave bridge rectifier modification is another good upgrade for anyone who has limited budget.

jonbee · « **Reply #86 on:** 23 Apr 2012, 04:10 am »

Quote from: gkinberg on 23 Apr 2012, 02:40 am

Why is there so much discussion about opamps with respect to the minimax? I’ve never heard so much talk about opamps in any other component.

For me, 2 simple reasons- they are simple and relatively inexpensive to swap, and the differences are audible and marked. End of story.

etcarroll · « **Reply #87 on:** 23 Apr 2012, 10:03 am »

By 'simple', the opamps in most components are soldered in, so you need to know how to solder to remove, then add new opamps. In the Minimax, they simply plug in, so no soldering skills required.

Thus, all the opamp discussion, 'cuz just about anyone can swap them out.

Big Red Machine · « **Reply #88 on:** 24 Apr 2012, 12:25 am »

Nothing earth-shattering here, just rolled some tubed with the Dexas in place. The Philips ECC82 was okay but a little less focused as compared to the Psvane. The Telefunken smoothplate 12AU7 was very smooth but in the end wasn't tight enough for me. The Mazda gray plate was like the Philips tube. The tube that comes the closest to, and I already knew this from last year, is the Gold Lion ECC82. What I like about the GL and Psvane is they give you the body of a tube but they are tight and detailed so the details you expect to hear come through but it is not sterile.

I keep trying but I cannot warm up to the solid state sound. It is so sterile. It's clean, but just no life to it (for me anyways).

Just a little update on rolling. I did order some E80CC / 6085 /12AU7 NOS Large gray plates Bill recommended, except I could not find the pinched waist version.

TJHUB · « **Reply #89 on:** 24 Apr 2012, 12:46 am »

Thanks for the update Pete. I've tried about 8 different tubes in my DAC Plus, and none of them beat the Psvane for me.

I can't fall in love with the solid state output either, and I've really tried. So are you liking Dexa's over the OEM opamps with the tube output?

pjnad · « **Reply #90 on:** 24 Apr 2012, 12:59 am »

Just my two cents...I am in agreement in re: the ss output is lacking that certain 'magic". My system is such that some tube warmth is helpful ( ss Krell amp) and while my Modwright pre supplies some of that, running the dac + tubed is more to my liking. The ss output is clean and detailed but seems to lack some harmonics.
Interestly enough I thought I had found a tube that I liked ( Amperex/Phillips ) but after rolling in the 2107/827 opamps the sound changed to leaner and brighter. I am currently running an RCA Cleartop which is okay...hopefully my Psvane will arrive tomorrow.

tz1963 · « **Reply #91 on:** 28 Apr 2012, 08:31 pm »

Quote from: Levi on 23 Apr 2012, 03:38 am

Along with OPAmp upgrades. A full wave bridge rectifier modification is another good upgrade for anyone who has limited budget.

As I have one of the early, 2010, Minimaxes, I was wondering what the recommended upgrade path is for someone with no technical abilities and who, living in the UK, can't easily send his dac to the US to have modified....?
It seems opamps are the way to go, but which ones?
Then there is the tempting lure of a "full wave bridge rectifier modification", if only I knew what that meant ... Is that something I can try at home?
Any advice will be welcome.
Tom

Levi · « **Reply #92 on:** 28 Apr 2012, 11:39 pm »

There are no recommended EE DAC upgrades out there besides the one made by Wayne of Boulder Cables.

Which opamps? You can start with LME49990 singles x2 on a brown dog single-to-dual adaptor for the U1/U2. I don't listen to the Solid state so I simply pulled the OPamps from those slots.

I am sure there are several lads in UK who can modify your EE DAC. If you can't find them here in AC, you can also check forums like Head-fi or audio asylum.

As for learning what rectifier does, there are lots of video tutorial in youtube.

Thanks for looking.

Big Red Machine · « **Reply #93 on:** 3 May 2012, 12:15 pm »

Here is a Dagogo review about rolling opamps. I have not read it yet but will shortly. Doug spoke highly of this methodology and the dac when we picked up the SoundScape 10's last month.

http://www.dagogo.com/View-Article.asp?hArticle=1029

setamp · « **Reply #94 on:** 3 May 2012, 08:39 pm »

I am currently running Bursons in the U1/U2 position to good effect. I still prefer tube output to ss but like the bass kick and dynamics of the ss. I am using OPA627 in U6/U7 and am wondering if there is a substitution that would smooth and flesh out the mids in the ss stage. I am considering trying the Bursons there but am nervous about the added current draw. I'm also considering the Dexa but some have found the Dexa to be thinner than the Burson. Does anyone have experience with U6/U7 that might help?

jonbee · « **Reply #95 on:** 16 May 2012, 06:25 pm »

Here's my latest experiences with op amps, tubes, etc. in my MINIMAX DAC plus.
I had been using 49990s all around, with the tube pulled out (SS output, that is). I like the dynamics, extended range and clarity when using my EVS modded OPPO BDP-83 as transport via coax.
I got bit by the music server bug, and built up an ASRock HTPC dedicated to audio, running JRiver, which will be my main source. I run USB into the DAC, using a Audioquest Coffee USB cable, the best sounding of what I've tried. The sound is definitely better defined, tighter, and cleaner than with the transport, but also more upfront sounding, a bit more than I prefer.
So- based on Bill McConnell and others' recs of the Dexa discretes, I bought a full set and plugged them in.
With only a few hours' running time, I can say some things for sure. They are indeed even clearer and better defined, more 3-D than the 49990s. I like all this a lot. However, at this stage, with the server input they are also even MORE upfront than the 49990s, which is saying a lot. Too much really.
I decided to go back to the tube output, employing a '60s Westinghouse black plate that I found to be good sounding when I was rolling a few tubes a while back. I originally settled on the PSVANE over the Westinghouse some months ago, but the PSVane is more upfront than the blackplate, and since I was trying to balance this out, in went the black plate.
Based on an hours' listening, I think this combo is a real winner for me. The balance is great, with still superb detail and openness, but the soundstaging is no longer pushed forward but is anchored very nicely between the speakers. If this sound holds up as the opamps burn in, this may be what I've been looking for when used with my server.
I appreciated Big Red Machines' posts on this; his Salks have a similar driver arrangement to my Selah Tempestas.
So are the Dexas worth roughly twice as much as the 49990s? (you can buy the Dexas from the mfr. for about $250 inc. fast shipping- a good experience, BTW).
For me the Dexas are notably better than the 49990s. The additional clarity is very nice, and a bit surprising, while the tube is giving a very nice, easy sounding soundstage. I feel I'm getting the best of both worlds now. So for me, yes. If I was to buy a new unit from Bill McC, I'd definitely spring for the difference.
Getting good matchups really make the stew in a high-rez system. Of course, in this light, YMMV.

TJHUB · « **Reply #96 on:** 16 May 2012, 07:13 pm »

Thanks for the update jonbee. I wish this thread hadn't died off, but maybe things have settled down for most people. Not me!

The current configuration for my Plus is LME49990's in U1/U2, nothing in U6/U7, and my Psvane tube. The Psvane is the only tube I've really liked thus far, and I just can't seem to love the SS output no matter what opamps I install. This configuration sounds pretty good, but I'm still looking for a little more weight to the sound. After reading the review linked above, I decided to go for the "meaty" sounding Burson's for positions U1/U2. They were $155 shipped on sale, and I installed them in my last DAC with great success. I hope I made the right decision.

jonbee · « **Reply #97 on:** 23 May 2012, 10:56 pm »

Quote from: jonbee on 16 May 2012, 06:25 pm

Here's my latest experiences with op amps, tubes, etc. in my MINIMAX DAC plus.
I had been using 49990s all around, with the tube pulled out (SS output, that is). I like the dynamics, extended range and clarity when using my EVS modded OPPO BDP-83 as transport via coax.
I got bit by the music server bug, and built up an ASRock HTPC dedicated to audio, running JRiver, which will be my main source. I run USB into the DAC, using a Audioquest Coffee USB cable, the best sounding of what I've tried. The sound is definitely better defined, tighter, and cleaner than with the transport, but also more upfront sounding, a bit more than I prefer.
So- based on Bill McConnell and others' recs of the Dexa discretes, I bought a full set and plugged them in.
With only a few hours' running time, I can say some things for sure. They are indeed even clearer and better defined, more 3-D than the 49990s. I like all this a lot. However, at this stage, with the server input they are also even MORE upfront than the 49990s, which is saying a lot. Too much really.
I decided to go back to the tube output, employing a '60s Westinghouse black plate that I found to be good sounding when I was rolling a few tubes a while back. I originally settled on the PSVANE over the Westinghouse some months ago, but the PSVane is more upfront than the blackplate, and since I was trying to balance this out, in went the black plate.
Based on an hours' listening, I think this combo is a real winner for me. The balance is great, with still superb detail and openness, but the soundstaging is no longer pushed forward but is anchored very nicely between the speakers. If this sound holds up as the opamps burn in, this may be what I've been looking for when used with my server.
I appreciated Big Red Machines' posts on this; his Salks have a similar driver arrangement to my Selah Tempestas.
So are the Dexas worth roughly twice as much as the 49990s? (you can buy the Dexas from the mfr. for about $250 inc. fast shipping- a good experience, BTW).
For me the Dexas are notably better than the 49990s. The additional clarity is very nice, and a bit surprising, while the tube is giving a very nice, easy sounding soundstage. I feel I'm getting the best of both worlds now. So for me, yes. If I was to buy a new unit from Bill McC, I'd definitely spring for the difference.
Getting good matchups really make the stew in a high-rez system. Of course, in this light, YMMV.

Now that I've put more than 50 hours on them, I can say that they have smoothed out and now sound very neutral. Definitely better than the 49990s across the board in the naturalness and ease of the presentation.

TJHUB · « **Reply #98 on:** 23 May 2012, 11:18 pm »

I received my Burson opamps (duals for positions U1/U2) this past Monday. I've had them in ever since. They've been sounding different almost daily, so I'm not sure where they are going to land. My initial impressions are that they will be staying. I plan to give things a week or so before I post impressions compared to the OEM opamps and the LME49990's I just switched from.

Noseyears · « **Reply #99 on:** 28 May 2012, 07:00 pm »

Quote from: TJHUB on 23 May 2012, 11:18 pm

I received my Burson opamps (duals for positions U1/U2) this past Monday. I've had them in ever since. They've been sounding different almost daily, so I'm not sure where they are going to land. My initial impressions are that they will be staying. I plan to give things a week or so before I post impressions compared to the OEM opamps and the LME49990's I just switched from.

Cool, have they reached the 100+ hours?