I've not heard anything definitive from EE, but one theory is that the power supply would see less of an overall load and perhaps lower noise level on power rails to opamp.
Whatever the reason, I've tried the tweak and do find it an improvement. |
Thanks for the info Doug. Just placed my order. I have an Ah!Tjoeb CD player in a second system and can attest that opamp rolling has made a difference over stock unit. For roughly $75 - $150 I think this is worth trying.
For now I have ordered the 2604's and 827's. Would be interested in feedback from folks who have tried and liked other combinations.
Love the fact that the EE DAC + allows swappable opamps. It greatly adds to its versatility. Agree 100% with Doug that the unit in SS mode with tube removed is the way to go. |
Quick follow up. I swapped out stock opamps with 2604 and 827's. My impression is that there is more detail with a tightening up of the soundstage. Between SS mode, tube removal and the opamp changes, the DAC is indeed a step up from the stock unit. Grand total was $80 for opamps and extraction tool. Took me all of 10 minutes to perform the opamp "operation". Highly recommended for EE DAC plus owners. Note that this voids your warranty. However, it really is plug and play if you get the opamps pre-mounted on the brown dog adapters.
Have some National Semi Opamps coming for some additional experimenting. Fun stuff. |
Well, I went off the deep end and ordered some Dexa Discrete Opamps as well to try in the U1/U2 position. They are a lot more expensive ($170 plus shipping) but I'm very curious to see if the discrete opamps are as good as people say they are. Will report back...
The EE DAC Plus is a wonderful way to upgrade your digital experience without breaking the bank. Great value and versatility for the $. |
I've been experimenting some more with opamps and have to say that the only combination I like a tad bit better than what Doug recommended (2604 in U1/U2 and 827 in U6/U7 with tube removed in SS mode)is to replace the 827's with Dexa discrete opamps. I'm finding the discrete opamp seems to add a bit more air around the instruments while making things a tiny bit warmer. However, the cost of the discrete opamps is rather high and the difference is not night and day. I think the 2604/827 combo is probably the best mod for the $.
I'm going to try two more experiments. The first is to go back to tube mode with a NOS mullard 12AU7. The second is to add Dexa discrete opamps in U1/U2 and see how an all Dexa system works.
More to come ... |
Here's an update on some of my tinkering.
As I mentioned before, the setup I've settled in to this point is 2604 opamps in U1/U2, Dexa Discret opamps in U6/U7 (just a smidge better than the 827s) in SS mode with tube removed.
I'm on record as stating I did not like the Dac+ in tube mode with the stock EH tube. I felt the sound was veiled and muddied. However, I have read where several people liked tube mode with a better tube. So in the spirit of giving tube mode one more shot, I ordered a mullard NOS 12au7. Well, after some more extended listening I need to ammend my original statement. While the SS mode still has more detail, the mullard tube is much less veiled than the EH tube and scored points by smoothing out rough patches in bright recordings.
At this point, which mode is better really becomes a function of the recording in my system. If a recording is bright or hard, I prefer the mullard tube mode. In exceptionally well recorded music, I find I enjoy the additional detail of SS mode. I guess the take away is don't ignore tube mode until you first try it with a better tube.
My next experiment will be to replace 2604's in U1/U2 with Dexa Discrete opamps. Will see how an all Dexa opamp unit sounds.
The good news is that regardless of your personal views, the Dac + allows for tremendous flexibility and experimentation. I'm sure almost everyone can find a setting which will be optimal in your system. |
Hi Mr. Tennis:
Moving from the stock opamps to 2604's and 827's gave me a sharper and larger soundstage. It was very noticeable. Not a subtle change. Since then I have swapped out the 827's with Dexa Discrete opamps. This move was more subtle. A little bit more air around the instruments but not as dramatic a move as changing out the stock parts.
My tube is a standard plate mullard rebranded as Daystrom from the early 1960's I believe. Now that I know that NOS tubes makes a difference, I will probably try some additional NOS tubes. Pricing is pretty good when you only need a single.
Changing out opamps is not that expensive. With Brown Dog adapters (which makes installation a snap) I believe I spent about $85 or so including shipping. Well worth the effort IMO. |
Hi Mike:
Dexa can be purchased from Partsconnexion in Canada or directly from the Mfg in Denmark (NewClassD). There may be other places out there but these are the ones that came up with a quick google search.
I really like the S30. I also have a bunch of SET's but the S30 is the least colored of anything I have. I tend to switch things up a bit but can't envision a situation where I would not have an OTL. It's like having the accuracy of a top notch SS amp with the liquidity of tubes.
I agree with you on vinyl. While the Minimax has greatly improved my digital experience I still prefer analog. The convenience of digital is nice, though. I've been dipping my toes into computer audio and can appreciate the reasons why many shy away from analog. |
Update time. Have spent time with an all Dexa Discrete opamp system in both U1/U2 and U6/U7. Impression is that the sound is softer and rounder than the 2604/827 combo. It does a good job of taking the edge off harsh or bright recordings but does not have the same degree of detail or resolution of the 2604/827 combo.
If you want the most detail and resolution I would go with the original recommendation - swap out stock opamps with 2604/827 and remove the tube. It will cost you about $80 and is a noticeable difference.
If you want to tame some digital harshness, replace the stock EH tube with a good NOS tube like Mullard, Amperex or Brimar. If you want some more resolution, you can then swap out the stock U1/U2 opamps with 2604's.
I'm of two minds on the Dexa's. On one hand they are probably the most analog sounding opamps I've tried in the DAC but at about $250-$300 they are not great value. |
Yep, the smooth presentation of the Dexa's along with a NOS tube has won me over and I'm keeping this as my default set-up for now. It does not have the last degree of detail as the 2604/827 combo but it has enough detail and resolution for me while helping to reduce any digital harshness. Cost is only downside. It's $250-$300 for a full complement of Dexa's which may be a lot for people to invest on a $1100 unit. Never the less, I just love the flexibility of the EE unit. |
No, an opamp is an electronic part on the circuit board of the DAC. Many DAC's have the opamps soldered to the board which makes it extremely difficult to swap out. The EE opamps are not soldered so swapping them out is very easy. Many people (I'm one) find that changing opamps (like changing tubes) can influence the sound. What's very nice about the EE is that between tubes and opamps you can fiddle to your heart's content and tailor the sound to what you like. The only caveat on swapping opamps is that this usually violates the manufacturers warranty if anything goes wrong. |
I've been running the Dexas in my DAC + for about 6 weeks and there is no question that the discrete opamps produce a sound that is much more analog like than any of the IC opamps I've tried. Based on Doug's review I have also ordered the Burson discrete opamps and will do a comparision between the two when they arrive.
I will say that at least in my system (Shindo amp and preamp, Tonian Labs (12" PHY) speakers) some of the IC opamp combinations seem to have more absolute resolution than the Dexas but the Dexas just sound more natural with less listening fatigue.
I still prefer listening to my analog gear over digital but the DAC +/Dexa combo has greatly improved my digital listening experience. For under $2K, the sound has exceeded my expectations and represents an excellent value.
Will report back later when the Burson's come in... |
Time for a quick update. I've been running my minmiax dac + with Dexas for about 3 months and thought they were a significant upgrade over any of the IC opamps I tried. After reading Doug's review, I decided to try out the Burson's and report back.
First off I'll list my system for reference. Preamp is Shindo Vosne-Romanee. Amp is Shindo Haut-Brion (25W). Speakers are Tonian Labs Classic 12's (96db speaker featuring PHY driver with supertweeter). When listening to redbook CD I used PS Audio PWT as transport. When listening via USB through my windows computer I used flac files via JPLAY.
When I originally read Doug's review I was a little disappointed and thought he was hedging his bets by not declaring a clear preference. After living with both the Dexas and Bursons for a while I now understand his position. The Dexas and Bursons are to my ears a clear step up over any of the IC' opamps I've used. In addition, the inclusion of the discrete opamps makes digital more listenable over an extended time frame. The digital "edge" is gone. The music sounds more analog like than ever.
That being said, the Dexas and Bursons clearly sounded different in my system. With Dexas, the sound was clearer and cleaner with greater extention in the higher frequencies. With the Burson's swapped in, the sound was weighter, with more meat on the bone. The low end was also more impactful. I realize I'm pretty well echoing the comments that Doug made in his article. He pretty much nailed it.
Which do I prefer? If a gun was held to my head and I had to choose one I would probably pick the Dexas today based on my system. My Shindo electronics do a good job conveying weight and body to the music so I like the clean sound of the Dexas. However, if your system is on the lean side, I can easily see you prefering the Burson's.
My next step is to mix and match between the Dexas and Bursons to see if the combo can give me the best of both worlds. Will report back again with my thoughts in a few weeks.
For those of you who have the Minimax or Mimimax plus, go out and get some discrete opamps ASAP. The sonic bang for the buck is as high as anything I've tried in the 20+ years I've been dabbling in this hobby. |
Nothing1:
Agree with your asessment of the Dexas. You mentioned the level 3 Lampi had slightly more body than the Minimax. If you like that fuller sound, get a pair of Bursons. Compared to the Dexas the Bursons add (at least in my system) more body and weight to the sound. Having both Dexas and Bursons allows for tremendous flexibility. |
After several days of mixing and matching the Dexas and Bursons in the Minmax plus it has become pretty clear that I prefer the Dexas in both U1/U2 and U6/U7 in both tube and SS mode. The Dexas have a crispness and clarity that I really enjoy in my system while being much less fatiguing than any of the IC opamps I've tried. Those looking for more body and weight to the music should try out the Burson's.
After a bunch of experimenting, my current default listening setting (subject to change) is tube mode with NOS Mullard and all Dexa opamps. In addition to the stock EH tube, I have tried Amperex, Mazda/Cifte and Mullard. I prefer the Mullard but all NOS were a clear improvement over the stock tube. Will more than likely try a few other tubes for curiosity sake. For those looking for the utmost clarity and resolution, going all Dexas in SS mode with tube removed is a great choice as well.
That's it for now.
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I agree 100% with Jmbatkh's assessment. The discrete opamps I've tried (both Dexas and Bursons) sound more analog like than any of the IC opamps I've tried. I don't think you will necessarily get any more resolution with Dexas over 49990's but the presentation is more relaxed and organic. I can listen to the Dexa upgraded Dac Plus for hours without any listener fatigue.
The Dexas sound to me cleaner and clearer with more sparkle than the Bursons. The Bursons will add more body and weight to the music with better bass than the Dexas. Both are wonderful and dependent on personal taste.
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