[TJHUB]

Picking up from the other thread...

I'm currently breaking in a 2604/827 combo, and I also own LME49990 duals.  It seems for me, I can't find anything that works better than the OEM opamps.  I also seem to prefer the tube output with a Psvane tube.

For me, I lose too much dimensionality with the SS output, no matter what opamps I try.  I admit the 2604/827 combo might be the best SS output I've heard, but I hear a hint of distortion from the 2604's, and combined with my Psvane tube, the lower midrange/upper bass gets sort of thick sounding and really detracts from any sense of realism from the sound. 

The 2604's have definitely changed as time has gone on.  I think I have around 100 hours on them now, but I didn't get to listen today.  I just installed the 827's for the SS output yesterday.  They now have just over 24 hours on them.  I'm hoping to listen tomorrow evening for bit to find out how things have progressed. 

The LME49990 duals were incredible when I first installed them some months ago, but they became a bit thin for my setup.  Not that they don't do some good things, but my setup can't afford the loss of any weight.  However, before I give up on all of this, I plan to try the LME49990 duals with the 827. 

For the record, all SS output listening has been sans tube.  And just so you guys don't think this is only my opinion, I just had a fellow AC'er over this past Saturday to objectively listen to all of this.  He too found the OEM opamps with the Psvane tube to easily sound the best for my setup.  It was very important to me to get this figured out with someone else as I have a big GTG coming up on the 14th.  I really need my setup performing its best. 

[bunky]

Picking up from the other thread...

I'm currently breaking in a 2604/827 combo, and I also own LME49990 duals.  It seems for me, I can't find anything that works better than the OEM opamps.  I also seem to prefer the tube output with a Psvane tube.

For me, I lose too much dimensionality with the SS output, no matter what opamps I try.  I admit the 2604/827 combo might be the best SS output I've heard, but I hear a hint of distortion from the 2604's, and combined with my Psvane tube, the lower midrange/upper bass gets sort of thick sounding and really detracts from any sense of realism from the sound. 

The 2604's have definitely changed as time has gone on.  I think I have around 100 hours on them now, but I didn't get to listen today.  I just installed the 827's for the SS output yesterday.  They now have just over 24 hours on them.  I'm hoping to listen tomorrow evening for bit to find out how things have progressed. 

The LME49990 duals were incredible when I first installed them some months ago, but they became a bit thin for my setup.  Not that they don't do some good things, but my setup can't afford the loss of any weight.  However, before I give up on all of this, I plan to try the LME49990 duals with the 827. 

For the record, all SS output listening has been sans tube.  And just so you guys don't think this is only my opinion, I just had a fellow AC'er over this past Saturday to objectively listen to all of this.  He too found the OEM opamps with the Psvane tube to easily sound the best for my setup.  It was very important to me to get this figured out with someone else as I have a big GTG coming up on the 14th.  I really need my setup performing its best.

you are not the only one who prefers the tube output. i prefer it as does Levi and several other folks here at AC.  i run a Amperex Holland long plate 7316 PQ which is a 12AU7 varient  and use the LME49990 in both the dual and single positions i replaced the stock fuse with a Create Audio 1 amp gold/rhodium fuse.i used to run a Black Cat Veloce digital cable but i switched to the new Black Cat Silverstar 75. the Silverstar 75 has more weight and body and i really like it in this DAC. i wanted to try discrete opamps but someone with tastes that are similar to mine has tried a few types and went back to the conventional Opamps. i need to hear more reviews on the discrete opamps before i decide to test the waters or not.

[Jon L]

Picking up from the other thread...
It seems for me, I can't find anything that works better than the OEM opamps. 

That's why I have been saying to potential users to make SURE to try the stock op-amps before just "upgrading" op-amps and never seriously trying them. 

Still, 49990's all around followed by a great tube preamp (and no, the stock tube output stage does not qualify) seems to be where the game is at.

[pjnad]

I'm still getting familiar with the dac, having only had it since Thursday...but so far, I prefer the tube to ss in my system.
Last night, my wife finally sat down to listen and we did some switching back and forth and she also preferred the tube..."better harmonics and less digital sounding".
The tube that we were listening to was an amperex ( herleen factory, Holland).

[TJHUB]

One thing that is for certain, opamps do break in.

I've had a 2604/827 combo (tube pulled) running 24/7.  I finally got to sit down tonight and listen.  I'm having a hard time hearing any distortion at this point, and over all, the sound is good.  I do hear a shift in timbre though.  Everything has a deeper tone.  There is also very little ambiance in the music, and the treble is too subdued.  All things combined, this combo lacks the realism of the oem opamps with my Psvane tube.  I do plan on giving this combo until the weekend to fully settle in.  Then I'll switch back to the oem opamps/Psvane tube.  This usually will allow me to figure out my preference.  As I'm not excited about what I'm currently hearing, I'm positive the change back will be the obvious best sound for me.

After that, I will try the LME49990/827 combo.  That one could be interesting...

[MttBsh]

I'm at a loss as to why the op amp swapping continues to be such a hot topic when, to many, the improvements over the stock amps seem negligable. I tried going tubeless but preferred a Psvane with tube output. But the differences were very minor overall in my system.

On the other hand, I just replaced my tube preamp with a DYI Dodd buffer and the sound improvement was at least 30 times greater than the improvements I heard swapping things out in my Dac+. If you are looking to improve your system, I just think there are much bigger gains to be realized away from the Dac and for not much more cash.

[wilsynet]

Probably depends on the system what amount of difference opamp rolling makes.

But for less than $100, what would you do instead?

[setamp]

I much prefer the tube to SS output. 

I also got the biggest positive impact by adding a Dodd buffer.  Whether it is the high output impedance of the minimax or simply the excellent sound of the buffer, my system moved to a completely different level when I inserted the buffer stage.

[wilsynet]

According to the posted specs:

Original DAC Output Impedance: Tube 22K, Solid State 10K ohm
DAC Plus Output Impedance: Tube 3K, Solid State 200 ohm

Hard for me to believe the posted specs of the original DAC as not many preamps would be able to do 20X the output Z.  But I can certainly imagine then the utility of the Dodd Buffer here ...

[mfsoa]

One more data point here-

To me, op-amp rolling made a tremendous improvement to the sound quality for very little $$ and effort.

Still haven't heard a tube that wasn't too indistinct and vague in the bass relative to upgraded op-amp SS section. Just too much info glossed over w/ the tube, though I can see how that might be a good thing.

[setamp]

Still haven't heard a tube that wasn't too indistinct and vague in the bass relative to upgraded op-amp SS section. Just too much info glossed over w/ the tube, though I can see how that might be a good thing.

for me this is definitely not the case.  possibly a function of my beta22 amp / LCD2 headphones but my bass with tubes is extraordinary - textured and controlled.  SS does not improve my bass but loses midrange reproduction.

[munosmario]

I'm at a loss as to why the op amp swapping continues to be such a hot topic when, to many, the improvements over the stock amps seem negligable. I tried going tubeless but preferred a Psvane with tube output. But the differences were very minor overall in my system.

On the other hand, I just replaced my tube preamp with a DYI Dodd buffer and the sound improvement was at least 30 times greater than the improvements I heard swapping things out in my Dac+. If you are looking to improve your system, I just think there are much bigger gains to be realized away from the Dac and for not much more cash.

Wonder how did you mange to measure so precisely (30 times!!!), as an absolute number, sonic quality improvement which involves so many characteristics, for the most, of a totally subjective nature.

In any event, and I don't mean to be sarcastic or disrespectful, assuming that you really have the ears to quantify so objectively without any sort of instrument(s) and  a credible/accurate measuring scale as a defined benchmark--and given that you are using a MiniMax plus not the original with those actually absurd output impedance specs, as wilsynet points it out (which is likely to not only introduce source signal gain losses but to also alter frequency response performance when combined with the LCR circuit characteristcs of the interconnects being used and the input impedance of  preamp/amp)--the only logical explanation (to me) of such observed large improvement  from inserting an inexpensive (never mind good quality) tube buffer and removing your tube preamp is that there most be something wrong with your tube preamp (unless it is a low quality one to begin with).

munosmario

[jonbee]

I'm at a loss as to why the op amp swapping continues to be such a hot topic when, to many, the improvements over the stock amps seem negligable. I tried going tubeless but preferred a Psvane with tube output. But the differences were very minor overall in my system.
On the other hand, I just replaced my tube preamp with a DYI Dodd buffer and the sound improvement was at least 30 times greater than the improvements I heard swapping things out in my Dac+. If you are looking to improve your system, I just think there are much bigger gains to be realized away from the Dac and for not much more cash.

Different systems show changes to varying degrees. In my system, the stock op amps were veiled and "blah" sounding compared to the 49990s, which are also more extended on both ends. I also tried several tubes, including NOS and PSVane, and found "no tube" to be superior to all. These were not minor changes in my system- they really made the Dac+ sing, whereas before these changes it was just very good.
Obviously, others are getting different results. It is important for all to report their findings as they hear them. We do well to remember system building is more like cooking than not. Context and personal taste are key to getting personal satisfaction.

[bunky]

Wonder how did you mange to measure so precisely (30 times!!!), as an absolute number, sonic quality improvement which involves so many characteristics, for the most, of a totally subjective nature.

In any event, and I don't mean to be sarcastic or disrespectful, assuming that you really have the ears to quantify so objectively without any sort of instrument(s) and  a credible/accurate measuring scale as a defined benchmark--and given that you are using a MiniMax plus not the original with those actually absurd output impedance specs, as wilsynet points it out (which is likely to not only introduce source signal gain losses but to also alter frequency response performance when combined with the LCR circuit characteristcs of the interconnects being used and the input impedance of  preamp/amp)--the only logical explanation (to me) of such observed large improvement  from inserting an inexpensive (never mind good quality) tube buffer and removing your tube preamp is that there most be something wrong with your tube preamp (unless it is a low quality one to begin with).

munosmario

In prior posts the gentlemen stated that he had a Eastern Electric MiniMax preamplifier which is not a bad little preamp at all.sound quality is a subjective thing based on personal preferences and if he feels he had a dramatic improvement switching to the Dodd Buffer good for him 

[nnck]

Looks like there are at least 3 op-amp combos folks are trying and reporting to have varying degrees of beneficial (or negligible) effects on the SS output sound from this DAC.

What I havent heard is whether there is an op-amp combo that has benefitted the tube output sound for those of us who still prefer the tube out. Are most of those who prefer the tube out sticking with the stock op-amps, or have we found an op-amp combo that is the most likely to help with the tube out?

Also, FWIW, I'm using the DAC +

[groovybassist]

nnck:

I just installed Dexas all around on Sunday night - burning them in now.  After a couple of weeks, I do plan on re-inserting the tube and comparing that with the SS out, with tube pulled.

From my perspective, the opamp change is pretty subtle.  I felt there was a much greater change going tube out to ss out vs. changing the opamps.  This may change as things burn in a bit.  To give you an idea relative to other system changes, I also just installed an Audio Art Statement I power cord on my amp (substituting for the Audio Art Power1SE I had been using) - the change in power cords made a bigger difference to the sound than the opamp switch. 

[munosmario]

In prior posts the gentlemen stated that he had a Eastern Electric MiniMax preamplifier which is not a bad little preamp at all.sound quality is a subjective thing based on personal preferences and if he feels he had a dramatic improvement switching to the Dodd Buffer good for him 

Thank you for the info, bunky. Yes, the EE tube pre is not a bad little preamp...so, you are actually confirming my point. Namely, if the gentleman observed a 30 times improvement, that is, a 3000% improvement (not 30%, which is already a very large one for this kind of exercise), then, something has to be wrong with that preamp!! Otherwise, if a DIY Dodd buffer can improve sound so dramatically, and if that  post and claim have any value and are to be believed (rather than being treated as forum spam), I am better advised to sell my CARY Audio SLP05 ($7k when I bought it back in 2006; not bragging, just reinforcing the point) and get one of those DIY Dobb buffers (actually a few of them to make sure I have a life time supply), and call it a day. If we assume that my CARY is at least 2 times (200%) better than the poster’s EE preamp, which I doubt, in line with the posters appraisal, I should be likely to get 2800% improvement (I will not be mad if I just get half that or even one fourth)...it would be  a no brainer and not just me but all of you, who don't already own such marvel of a buffer, should be doing likewise. 

Bunky, you kindly remained me that posters are entitled to express preferences but, please, remember that the gentleman is using that claim to pronounce and dismiss as a waste of time the opamp rolling efforts of all participants in this thread. One thing is to express personal preference and another to debate (pontificate?), or try to influence on the basis of, pardon me, incongruous claims.

munosmario

[Levi]

Believe it or not, Your first impression is the one that weighs a lot.

Levi:

My last post on the prior thread wasn't a review of the Dexas - merely a first impression.  I plan to run them in for a couple of weeks before making any significant judgments.

[setamp]

I am getting a lot of dropouts and stuttering with 192/24 files.  I understand the digital cable could influence this.  Has anyone solved this problem with a digital cable?  What cables work best?  I have tried a Canare bnc, Downsize RCA and WyWires AES/EBU.

[wilsynet]

What comprises your transport, a computer, right?  What are the specs for the computer, how are the files stored, etc, and are you using USB, coaxial or optical?