[ginetto61]

 

 
Originally Posted by jeff7742 
 
This article explains the benefits of parallel amplification, but too technical for me! Apparently, it can increase the SNR:
http://www.linear.com/solutions/5657
The only thing I know about the stock opamps is that they are dual channel. I assume the pin config is standard, whatever that is.
 
Hi and sorry but I am confused.   I see just now that the 49990 is a single op-amp. It cannot be interchangeable with a dual OA. Completely different pins layout. 
Instead the 49860 mentioned below is indeed a dual OA.  How can they work in the same position ????
Maybe I am missing something ?
 
I am very impressed with the VA1's construction, especially the thick copper PCB (haven't seen that before), and how precisely everything is laid out.
The TRS and other connectors look high quality too.
 
Update: I put the old op amps back in and they sound good, but not as as good as mine. So most of the amp benefits I'm hearing i think are just due to amp break in - soundstage, etc.
The VMV DT/K opamps in the input stage still sound lifeless to me.
Maybe I should just break them in more, or maybe I should have gotten the HD version.
I tried 2 LME49860 in the input buffer, and that was big improvement. Very balanced sound, and they fit nicely with VMV opamps in the output stage. Just the right amount of bass too.
The LME49990 were the cleanest, but also the brightest, which some may not like.
 
Update: The VA1 continues to improve - soundstage, dynamics, everything. Using LME49860 in the input stage. This is a superb amp, and a joy to listen to.
I ordered several new opamps, including 2 OPA1612, 2 LME49720HA,  and more LME49860's. I went back to the to the SAP-8 for a bit, and the sound was blurry in comparison, with a smaller soundstage. It's still a nice amp, but I have no use for it anymore
 
So the VA1 is clearly the top design.   Please let me know which combinations of op-amps sound best.  
 
However and again I do not understand why the 49990 works in the same position of a dual opamp. 
 
Are you using an adapter that converts the pin configuration ?
Thanks again,  gino   

 

[jeff7742]

Yes, they are sold on ebay with an adapter. Usually someone (more skilled than me) solders two of the single channel opamps to the front and back side of small square board. The small board then soldered onto a dip8 adapter and sold as a dual opamp. This is also done for dual opamps that are surface mount (not dip8 compatible).
 
I spent the whole night last night, listening to the VA1 with a big smile on my face. Listening to this amp is like upgrading your 1080p monitor on your computer to a 4k monitor. Hi-res audio. But I guess that wouldn't matter unless you have a high-resolving set of headphones. At this amp's level of resolution, vocals are incredibly life-like, and instruments are right with you in the room.

I've been wondering why this amp isn't better known? Why isn't it selling, even at $110? Maybe because:
 
1. It's priced too low for audiophiles to take seriously
2. Sounds bad out of the box, people don't make it past the break-in, can take a while
3. They get past the break-in, but don't like the sound of the input stage opamps (not too bad actually, when broken in). A $7 upgrade to 2 LME49860 fixes that.
4. It's architecture is too simple to fuss over, even if it sounds great.
 
But if you want a really high-end sounding amp for the least possible money ($110 right now at amazon), man this is your amp! Especially if you like fooling around with opamps. I'm taking it to head-fi meet next month and see what others think.

 

[ginetto61]

Hi ! thank you very much again.  Now i think i have understood better.  
 
So you preferred config is with 2 LME49860 (one per channel) as input stages.  I see they come also in DIP8 package. Great !!!
I will buy two also myself. I trust you judgement completely.
 
Instead for the output stages ?
the stock ones are perfectly fine or you think that even here 4 x LME49860 (or  8 x LME49990) would provide a sensible improvement ? and which of the two would be better ?
Please report here about the head-fi meet next month. I hate to use the term giant killer but maybe it is the case ?
Thanks a lot again.
Kind regards,  gino 
 
P.S.  i start to think that the original has 6 dual opamps completely identical.  Could it be ?  
smart move to limit the parts types and design complexity.  

 

[jeff7742]

Well, I haven't got any of the opamps I ordered yet (slow mail during christmas season)., so I haven't tried many other combinations. But I think for most people, 2 LME49860 (and maybe LME49720HA) in the input stage will be the best. It is very well balanced with the 4 VMV opamps in the output stage, which are pretty good actually. It also has better bass than the LME49990. The LME49990 is a little clearer, but also brighter with less bass. I have also ordered four more LME49860 (they are cheap), but I don't know how they will sound in the output stage yet. I have ordered a lot of opamps, but they might take a while in this season.
 
Personally, I think the VA1 might be a giant killer even with the 2 LME49860. It really does sound high end.

 

[ginetto61]

Thanks thanks and again thanks.
Please keep us posted about your findings.
Here in Europe the VA1 is slightly more expensive (i am thinking to buy another one to keep as a backup)
There are many voltage feedback dual opamps that could work as output stages.
http://www.ti.com/lit/ds/symlink/lm4562.pdf
http://www.njr.com/semicon/PDF/NJM4556A_E.pdf
but the fact that even stock ones are fine is a very good news.
I will read your findings with the greatest interest.
Kind regards,  gino 
 

 The LME49990 is a little clearer, but also brighter with less bass

could it oscillate a little ?  opamps swapping is tricky sometimes.  

 

[jeff7742]

Not sure what you mean by oscillate. You mean how hearing can change? No, it's definitely brighter and most people like more bass than me, so that's why I recommend the LME49860 for now. The opamps completely determine the tone and coloration on this amp. I don't think the VA1 has any amplification other than opamps. The VA1 is simply a super clean signal transmission platform for opamps (I bet the copper PCB really helps). In a way that's good, because the amp is future-proof. When new and better opamps come out, the VA1 can sound even better.
 
I'm comparing the balanced vs unbalanced inputs on both the VA1 and SAP-8. I'm actually plugging unbalanced into balanced with an adapter. The balanced inputs require more power to reach the same volume, which is to be expected, since they are usually powered up by 6db, I think. The odd thing though, is that on both the VA1 and SAP-8, the soundstage shrinks significantly when using the balanced inputs. I wonder if this shrinkage would go away when using real powered balanced inputs? Also as I've mentioned before, even with the smaller soundstage, the balanced inputs seem cleaner somehow. Instruments seem more natural and imaging is more pinpointed and accurate in the soundstage. The imaging is less precise using the unbalanced inputs. Strange, since I don't have balanced headphones (yet), and the VA1 does not have a balanced output stage, only a balanced input stage.  
 
Update: now that I've had a chance to play with it, maybe the more accurate imaging is due to the smaller, more compressed soundstage from the balanced inputs. Unpowered balanced inputs shrink the soundstage down to about the size of the SAP-8. The unbalanced soundstage is almost too wide.

 

[jeff7742]

Ok, here is the list of VA1 opamp configurations I've tested so far, and my comments. #1 is the clearest but too bright in the VA1, as I feared.  LME49990's work well on the SAP-8 because that amp is warm to start with.  #2 is the best overall, I think. Everything sounds great and in balance, and the soundstage is great. It is clearer and much better overall than the previous #6. #9 is the stock setup. VMV chips all seem to have a laid back sound compared to the others. I have other opamps coming, but from China, so it they may take awhile. #2 would cost about:  $41  ((2 x 13) + (4 x 3.50))

   Input (2):      Output (4):
1 LME49990    LME49990     Great Highs, good bass, great clarity, good dynamics, good soundstage, pinpoint imaging
2 LME49990    LME49860     Good highs, good bass, good clarity, balanced, good dynamics, good soundstg
3 LME49990    VMV A6         Good highs, ok bass, laid back, ave soundstage
 
4 LME49860    LME49990     ave highs, ave bass, clear, good soundstage, ave dynamics
5 LME49860    LME49860     ave highs, good bass, good clarity, balanced, good dynamics, good soundstg
6 LME49860    VMV A6         good highs, good bass, laid back, balanced, good soundstage
 
7 VMV DT/K    LME49990     soft highs, ave bass, laid back, balanced, clear, good soundstage
8 VMV DT/K    LME49860     soft highs, ave bass, laid back, ave dynamics,ave soundstage  
9 VMV DT/K    VMV A6         soft highs, ave bass, laid back, ok dynamics, ave soundstage
 
The LME49720NA can be substituted for the LME49860, and is a little cheaper ($2.50). They are tonally very much alike, with the same treble and bass. I find the LME49720 to be slightly clearer. The LME49860 seems a little woolly in comparison, but may be less fatiguing for some listeners. Nothing seems to beat the LME49990 for clear highs when placed in the input stage, as long as you have the bass covered in the output stage, but the LME49990 may be fatiguing for some. If it is, then replace it with the LME49720. Six LME49720 sounds very good, clear, and balanced.
 
Update: It looks like I'm fooled by breakin again. 6 LME49990 has the best sound quality by far, and it keeps getting better with more breakin. There's plenty of bass and a wide soundstage.

 

[ginetto61]

Not sure what you mean by oscillate. You mean how hearing can change? 

 
Hi again ! sorry for the delay but i am in the middle of relocating myself.  A lot of boxes to make and move 

I was referring to the issue explained very well here 
 
http://www.diyaudio.com/forums/analog-line-level/191389-swapping-op-amps-you-have-checked-see-its-stable-havent-you.html
 
i have the feeling that oscillations will be very evident anyway.  So this is not the case.
Thanks a lot for disclosing the opamps comparison.  Very very helpful indeed.
Kind regards,  gino 

 

[jeff7742]

   
Hi again ! sorry for the delay but i am in the middle of relocating myself.  A lot of boxes to make and move 

I was referring to the issue explained very well here 
 
http://www.diyaudio.com/forums/analog-line-level/191389-swapping-op-amps-you-have-checked-see-its-stable-havent-you.html
 
i have the feeling that oscillations will be very evident anyway.  So this is not the case.
Thanks a lot for disclosing the opamps comparison.  Very very helpful indeed.
Kind regards,  gino 

 
Good point! I wish I had an oscilloscope. But I am not hearing anything unusual, bright or thin on any opamp yet, except on breakin, where the LME49990 sounded bright to me. It disappeared after about 6 hrs. The LME49990 worries me more than any other opamp due to its high power draw. I've used it without opamp heat sinks for about 2 weeks with no ill effects, but I probably should get those heat sinks.
 
I tested two new opamps today, but I only have two of each, so they were tested on the input stage only. Four LME49990 were used in the output stage. The input stage seems to influence the sound character more than the output stage. These are my comments after breakin:
 
MUSES 8920: This is one of the few bassy opamps I've tried. It is not as bassy as the 8820 I tried a few years back, but it's more bassy than the average opamp. I test for bass using an acoustic orchestral piece. If the bass seems unnatural or overwhelming, I view it as bassy. The 8920 is not a basshead opamp, but the bass is a slightly emphasized. It's fairly well balanced, but not quite as detailed as the LME49990 or OPA1612. Still, it's a good all around opamp if you like some bass. If you're a true basshead, the 8820 is a better choice.
 
OPA1612: This opamp is very detailed, almost as detailed as the LME49990. It's very smooth with slightly more bass, but the flip side is the lack of dynamics in comparison to the LME49990, and the soundstage and imaging aren't quite as good either. The big advantage of the OPA1612 is its low power. This opamp is hardly even warm to the touch, so a heat sink isn't needed at all. The LME49990 still sounds better IMO, but has a much higher power draw. I would put this opamp in second place. It's slightly cheaper than the LME49990.
 
So the winner is still (6) LME49990. It wins in every category except power draw, and possibly bass. Personally, I find its bass just right when broken in, but others might feel differently. Nothing yet can match the clarity, soundstage, imaging, and dynamics of the LME49990. I haven't tried the discrete opamps yet (Sparkos and Burson), but those are at least $50 or more a piece. I would expect those to be even better. I would also like to try some classics like OPA627 and AD797 for comparison. So far, my ordering would be as follows:

LME49990 > OPA1612 > MUSES8920 > LME49720NA > LME49860 > VMV DT/K > VMV A6

 

[drhiziracil]

Good point! I wish I had an oscilloscope. But I am not hearing anything unusual, bright or thin on any opamp yet, except on breakin, where the LME49990 sounded bright to me. It disappeared after about 6 hrs. The LME49990 worries me more than any other opamp due to its high power draw. I've used it without opamp heat sinks for about 2 weeks with no ill effects, but I probably should get those heat sinks.

I tested two new opamps today, but I only have two of each, so they were tested on the input stage only. Four LME49990 were used in the output stage. The input stage seems to influence the sound character more than the output stage. These are my comments after breakin:

MUSES 8920: This is one of the few bassy opamps I've tried. It is not as bassy as the 8820 I tried a few years back, but it's more bassy than the average opamp. I test for bass using an acoustic orchestral piece. If the bass seems unnatural or overwhelming, I view it as bassy. The 8920 is not a basshead opamp, but the bass is a slightly emphasized. It's fairly well balanced, but not quite as detailed as the LME49990 or OPA1612. Still, it's a good all around opamp if you like some bass. If you're a true basshead, the 8820 is a better choice.

OPA1612: This opamp is very detailed, almost as detailed as the LME49990. It's very smooth with slightly more bass, but the flip side is the lack of dynamics in comparison to the LME49990, and the soundstage and imaging aren't quite as good either. The big advantage of the OPA1612 is its low power. This opamp is hardly even warm to the touch, so a heat sink isn't needed at all. The LME49990 still sounds better IMO, but has a much higher power draw. I would put this opamp in second place. It's slightly cheaper than the LME49990.

So the winner is still (6) LME49990. It wins in every category except power draw, and possibly bass. Personally, I find its bass just right when broken in, but others might feel differently. Nothing yet can match the clarity, soundstage, imaging, and dynamics of the LME49990. I haven't tried the discrete opamps yet (Sparkos and Burson), but those are at least $50 or more a piece. I would expect those to be even better. I would also like to try some classics like OPA627 and AD797 for comparison. So far, my ordering would be as follows:

LME49990 > OPA1612 > MUSES8920 > LME49720NA > LME49860 > VMV DT/K > VMV A6

Hi! I'm pretty noob in this audio thing. I'm using a5pro and hd598sr for headphones. Using a smsl sanskrith 6th dac. I was using fiio a3 amp before. And was quite happy with if it doesn't go above level 3(it has 9 level). Above level 3 it distorts. Then I decided to do a upgrade and bought a SMSL VA1 DT/K. I'm using it only for 10 hours now. It has really good detail and much better imaging ,superior seperation, really clean over my fiio a3. Fiio a3 seems to me it was degrading the audio.

Now here is my real problem: It is too bright for me. I dont like listening bright music it is too much fatiguing for me. And I dont know what "laid back" sound means. But I found vocals and upper treble are high but the punchier side of the music is feeling low somehow(As I said I am noob I cant describe exactly where). It is like music isn't much alive. Bass is ok for me but it stays a little behind fiio a3.
I want to use this amp especially for clean sound, detail and seperation but I want it to be warmer.

So do you think it will get warmer as I burning it in? And if so how do I burn them in? If not gonna get warmer should I change opamp which opamp should I buy and how many of them?(I have never done before) And if I need heatsink what size and type do I need?

Sorry for asking too many quesitons I'm really noob and your answers are appreciated

 

[ginetto61]

Hi ! i would wait a little more.
At first i had the same impression of a sound very clean but quite hard and flat. In a word fatiguing.
At the point that i started using the sap8 instead as i found it more musical.
But new caps need more time.
I think that 200 hours can be a good reference for breaking in time.
In many cases the sound changes quite sensibly and usually for the better.
Before any other mod/change i would wait for sure.
I have little patience and often i have made mistakes for this.

 

[drhiziracil]

Hi ! i would wait a little more.
At first i had the same impression of a sound very clean but quite hard and flat. In a word fatiguing.
At the point that i started using the sap8 instead as i found it more musical.
But new caps need more time.
I think that 200 hours can be a good reference for breaking in time.
In many cases the sound changes quite sensibly and usually for the better.
Before any other mod/change i would wait for sure.
I have little patience and often i have made mistakes for this.

Thank you for the answer. I guess I was being impatient. I'll be patient and let it burn-in for 200 hours then gonna share the result

 

[ginetto61]

Yes please let us know the outcome. Mine is stored away because i am on the move.
However i said 200 hours and maybe it is too much.
If you use it continuously maybe two-three weeks should be enough.
Another way could be to leave it on connected to a radio if you cannot listen to it.
But of course with the HPs connected to let the current run through the circuits.
Good luck !
and report

 

[drhiziracil]

So I have burned in the amp. And the harshness is gone its warm and more clear now. I really liked the clearness, detail and imaging of this amp. But two things I didnt like still: low bass and lifeless sound. Sound just didnt feel alive to me despite all the waiting for burning in. So I decided to give it a try to a fake chinise muses01 opamp. And guess what it became alive! And much better bass too. But fake is fake it has a little distortion. I didnt want to pay for the real one before trying something cheap and see if it worked. And also because my country's custom clearance it is really bothersome for me to buy the original. I have to pay extra taxes anyhing costs more then 30 euro, which isnt problem for me .But paperwork I can not do. Because the customs is in another city(which I have to go with plane) or I have to give authorization to someone willing to. If I could buy on amazon they deal all those trouble for me but sadly there is no fullfilment by amazon seller I could found that sells the original. I will try to contact to mouser and see if they can help me.

Smsl va1 dt/k stock amps are real good quality but so lifeless. I suspect they say it is tuned for bright beyer dt series headphones might have to do something for that

 

[ginetto61]

Thanks for the feedback.
is the Muses01 a voltage or a current feedback opamp ?
https://www.njr.com/semicon/PDF/MUSES01_E.pdf
Are you going to try other alternatives ?