[ginetto61]

 ...   I just don't want to stick a dual in a single socket or vice versa.

 
Hi again !
 
i think you can determine the if they are single or double just looking where the bypass caps are connected
 
single and double have a the different pinout:
 

 
 

 
Of course the input opamps are dual (only one for each balanced input)
I would not touch them for sure
 
Replacing the output opamps could give great benefits if well done. 
They are also mounted on sockets without soldering.  
Swapping them for something better should be easy.  I will have a look at them.
Regards, gino 

 

[cgouy]

Hey guys, I'm interested in the VA1 amp, but from the specs, I'm confused to how much power it produces. I'm currently using the SMSL Sap-8 and was wondering if this had significantly more power to drive my Hifiman HE-500.

 

[jeff7742]

I just got the VA1 and the SAP-8 for use with my T1, and I must say, these are great sounding amps for the money - but ONLY when you replace the opamps and break them in. The default opamps are lifeless and bland to my ears. In the SAP-8, I replaced all three opamps with LME49990 (with dual adapter) and it sounds like a much more expensive amp after a three day break-in. I kid you not. On the VA1, I replaced the input stage with LME49990 and two of the outputs with LME49860NA. It sounds much better, but I intend to replace all six with LME49990. That opamp just sounds so good  - very open, dynamic, and clear. They do get hot, so it might be a good idea to get opamp heatsinks for them.

There are apparently two versions of the VA1: The HD and DTK versions. They seem to have different opamps in the input stage (and a different label on the back). I guess the HD version is brighter to match the warmer HD650, and DTK verison is warmer for the brighter DT880. I got the DTK version, and it sounds warm. With the new opamps it sounds a little brighter, but just perfect for my T1.1.

When comparing the amps, the VA1 is little clearer and more refined sounding, but the SAP-8 (wth opamps) can have an edgy sound that is also appealing. The VA1 is better constructed. I wonder if all the empty space in the VA1 helps the high crosstalk specs? They could have made it much smaller. The VA1 also sounds a little better through the balanced inputs (slightly bigger soundstage and a little more bass), while I don't notice any difference on the SAP-8 inputs. The SAP-8 is not spec'ed for 600 ohms, but it seems to handle my T1 just fine. In fact, it seems a little more powerful than the VA1, but the VA1 sounds totally clear even when turned way up.

The VA1 is one the cleanest amps I've heard, and when you replace the opamps, it's also very open and dynamic. Both of them are better than the Beyer A20 (about $500) for my T1. 

The VA1/DTK is on sale right now at amazon for about $130. There is also an SAP-9 (balanced amp) just released.

 

[ginetto61]

Hi ! thanks a lot for the very helpful advice. 
Did you take any picture of your mods ? that would be very interesting.
I have both amps and currently been using the SAP-8 with a possibly better psu than the stock one.  Just a 12V/2A smps. 
I can say that when the amp is warmed-up it sounds good through my k501.  
I am quite sure that compatible and better opamps can improve the performance even further.  
Regarding the VA1, now stored away because I am moving,  I can say that it is very silent.  I cannot hear any particular noise.
However I have some doubts.
Unfortunately the marks on the opamps have been cancelled. 
The capacitance used inside the psu is quite a low but quality is unknown.  I would have preferred more capacitance locally especially around the output opamps.  It can help with the kick on bass.
I have the feeling that is a nice amp that could be very good indeed with some thoughtful mods.
The LME49990 looks to be a great part but maybe a little weak in out current ?  from the datasheet I read 24 mA ... not a great current. 
I think that it should be perfect to buffer the inputs but maybe a stronger one could be used at the output to drive any HPs around ?
I would replace the psu caps ... and maybe I would take out the Transformer ... I like external transformer a lot.  
Then just a xlr socket on the back and the transformer out.  A bigger one. 
Thanks a lot again,  gino  

 

[jeff7742]

I could take a picure, but it would only show new op amps I put in. The input buffer has the (2) LME49990 dip8 opamps. Actually the LME49990 is single channel, so there are 2 LME49990 chips soldered onto an adapter for each socket - you buy them from eBay that way.
 
http://www.ebay.com/itm/1PC-DUAL-SOIC-LME49990-OP-AMP-MODULE-DIP8-/201562948955?hash=item2eee16855b:g:A9QAAOSw6oBXEnVs
 
The LME49990 is a tough fit for many amps because of its current or power draw. I don't know the details, but I can say for sure it works well with both amps. It does get hot,  but so do VMV's proprietary opamps. I just suggested heatsinks to be safe (I don't have them on mine yet),
 
If you want to save money, the LME49860 is good too, and much cheaper. But the LME49990 is best I've tried. The LME49990 is more powerful than the VMV opamps. On the SAP-8, you turn up the volume less and it sounds really good. But its a good idea to use a powerful opamp in the output. Replacing caps and transformers is beyond my goals right now. This amp sounds great already, and I'm sure will be even better after I replace all opamps. It's the best resolving amp I've tried, and great for the money, and with opamps the whole character of the amp is changed. The price keeps dropping on Amazon, which makes me angry because its even cheaper than when I bought it.
 
I don't know what you mean by marks cancelled, but op amps in the VA1 are VMV proprietary. Obviously, they want to save money by making their own op amps, which are inferior to others out there. They sound lifeless to me. I can tell you that the (2) input buffer ones are labeled "VMV DT/K". If you had the HD version, I assume it would be labeled "VMV HD". The other (4) chips are labeled "VMV A6". When you replace these 4 chips, you should use the same opamp for all of them. The VA1 uses something called "parallel amplification", so 2 opamps work on one channel. I don't know how that works.

 

[ginetto61]

Originally Posted by jeff7742 
I could take a picure, but it would only show new op amps I put in. The input buffer has the (2) LME49990 dip8 opamps. Actually the LME49990 is single channel, so there are 2 LME49990 chips soldered onto an adapter for each socket - you buy them from eBay that way. 
http://www.ebay.com/itm/1PC-DUAL-SOIC-LME49990-OP-AMP-MODULE-DIP8-/201562948955?hash=item2eee16855b:g:A9QAAOSw6oBXEnVs
The LME49990 is a tough fit for many amps because of its current or power draw. I don't know the details, but I can say for sure it works well with both amps. It does get hot,  but so do VMV's proprietary opamps. I just suggested heatsinks to be safe (I don't have them on mine yet),
 
Hi ! thanks a lot again for the very valuable advice.
Do you mean that the opamps used in the VA1 are made by SMSL Audio ?  it sounds strange to me.
Are you sure ?  and did you find any datasheet/specification about them ?
 
If you want to save money,
 
No money, up to a limit, is no object.   I am willing to make some sacrifice for a nice sound.  And I have already made others.
 
the LME49860 is good too, and much cheaper. But the LME49990 is best I've tried. The LME49990 is more powerful than the VMV opamps.
On the SAP-8, you turn up the volume less and it sounds really good. But its a good idea to use a powerful opamp in the output.
 
Yes.  My feeling is that a more powerful part could be better at driving difficult loads.  With more control also. But I could be exaggerating the issue.    What I like of the sound of the SAP-8 is that is very spacious and natural.  I like it very much driving my old but nice k501.   I have even a weird idea.   To gut it to make a line preamp with a very nice attenuator.  I would be curious to listen to it.  But it will take time to do it.
 
 
Replacing caps and transformers is beyond my goals right now. This amp sounds great already, and I'm sure will be even better after I replace all opamps.
It's the best resolving amp I've tried, and great for the money, and with opamps the whole character of the amp is changed. The price keeps dropping on Amazon, which makes me angry because its even cheaper than when I bought it.
 
Sorry now are you referring to the VA1 or the SAP-8 ?   I have the sensation that the VA1 is even cleaner but a little flat and dry.  But very very silent and of very robust construction.  I like it.  It seems like a brick.  I like robust and massive cabinets.   The feel they provide. 
 
 
I don't know what you mean by marks cancelled, but op amps in the VA1 are VMV proprietary.
Obviously, they want to save money by making their own op amps, which are inferior to others out there.
 
This is strange to me because opamps bought in quantities are very cheap, even some good ones.  But I trust you.  It would be interesting to see at their datasheet.  
 
They sound lifeless to me. I can tell you that the (2) input buffer ones are labeled "VMV DT/K". If you had the HD version, I assume it would be labeled "VMV HD".
The other (4) chips are labeled "VMV A6". When you replace these 4 chips, you should use the same opamp for all of them. The VA1 uses something called "parallel amplification", so 2 opamps work on one channel. I don't know how that works.
 
In my experience the lack of life sometime has to do more with some issue in the psu.  
I followed a discussion once.  A guy was saying that one problem with op-amps is that when asked to drive a tough load they need like 2x1000uF close to them to get some kind of energy reserve during the musical peaks.   I bought his point.  
In the VA1 close to the output opamps I can see only little plastic bypassing caps with very little uF (i.e. not energy stored/available locally for the op-amps).  They are there for filtering maybe high Hz noise from the psu ?   
I would try to add at least some 470uF of high quality from the +/- V to ground very close to the output opamps. 
So when a musical peak comes the opamp will take the energy from these local caps and not from the ones located far away in the PSU.  
Some amps design follows the same principle.   You can see an example here, with many uF placed very close to the output devices. 
 
http://img.aussieaudiomart.com/uploads/large/578788-mccormack_dna_1_deluxe_power_amp.jpg
 

 
 
But it is not very easy.  I will try to do it.   Some good quality caps like Nichicon or Panasonic for instance.
Thanks a lot again, gino   

 

[jeff7742]

VMV is the same as SMSL: it's what they call themselves when they want to sound more elite. So, yes the opamps are made by SMSL. I haven't looked for any datasheets. Might be good to have them, though.

Yes, the SAP-8 sounds good, and even much better with (3) LME49990! Very dynamic and open. I couldn't stop listening to it after replacing the opamps. Also, you have to let them break in for day or two with the new opamps. The VA1 sounds worse then the SAP-8 without the opamp upgrade, but sounds even better than the upgraded SAP-8 with the opamps I have so far - spacious and natural, and more resolving too. Can't wait to get my extra LME49990's.

I assume SMSL makes their own opamps to save money, but I don't know for sure. All I know is they aren't nearly as good as the LME49990. The LME49990 is much more full of life. Buy three of them and upgrade your SAP-8! You'll be amazed.

 

[ginetto61]

  VMV is the same as SMSL: it's what they call themselves when they want to sound more elite. So, yes the opamps are made by SMSL. I haven't looked for any datasheets. Might be good to have them, though.
Yes, the SAP-8 sounds good, and even much better with (3) LME49990!    Very dynamic and open. I couldn't stop listening to it after replacing the opamps.
Also, you have to let them break in for day or two with the new opamps.
The VA1 sounds worse then the SAP-8 without the opamp upgrade, but sounds even better than the upgraded SAP-8 with the opamps I have so far - spacious and natural, and more resolving too.  Can't wait to get my extra LME49990's.
I assume SMSL makes their own opamps to save money, but I don't know for sure.
All I know is they aren't nearly as good as the LME49990. The LME49990 is much more full of life.
Buy three of them and upgrade your SAP-8!  You'll be amazed.

 
Thanks a lot again.  No more doubts about the op-amps swapping to be very beneficial.   I am a little scared to perform it because I am not very good at DIY.   But I am very tempted. 
I will study the issue.  Is any smd soldering  needed ? in that case I am out.   I am a dog at soldering, especially smd parts. 
Anyway, found a very interesting graph here
 
http://www.wisetech.co.jp/opampdou/story/12/img5.png
 

 
Kind regards,  gino

 

[jeff7742]

Gino,
 
No, there is no soldering required. I'm not very good at it either. All you do is pull out the old opamps and insert the new ones. Just be careful when pulling the old ones out not to bend the pins, and insert the new ones in the correct orientation. I use a small screwdriver to carefully pry them loose without bending the pins. There is also a special tool -an opamp puller, but I usually don't need it.
 
Very low distortion on the LME49990! Here's another chart comparing opamps:
http://www.cycfi.com/projects/six-pack/op-amp-shootout/

 

[jeff7742]

One other thing I should mention. I'm comparing the two amps using the VA1 with balanced inputs (I have two adapters that convert single-ended to balanced). When I switch to using the unbalanced inputs on the VA1, the sound is not as good. The soundstage shrinks quite a bit. In the specs for the VA1, they say it has a balanced input stage, and I can definitely hear it. On the SAP-8 it doesn't seem to make a difference. When using the balanced inputs, the VA1 definitely beats the SAP-8, otherwise it's clearer but not as spacious.
 
Update: looks like I have to eat my words. Two hours of breakin on the VA1 using the single-ended inputs has them sounding just as spacious as the balanced inputs, and somewhat richer. The balanced inputs are still a little clearer and more refined though. Maybe that will change too.

 

[jeff7742]

The VA1 just keeps getting better and better with more hours breakin. With the op amps I have, this is a stunning amp! So rich and detailed and spacious through the RCA inputs. The best I've heard yet. Gino, are you sure you gave it a fair breakin? Even with the stock opamps, I think this amp will blow away the SAP-8. It sounded very compressed and small at first, but after the hours I put on it, it is a completely different animal.
 
Update: in the last hour or so, the soundstage has grown. It is immense! The biggest I've heard on my T1. I've never seen an amp change so much on breakin.

 

[ginetto61]

Originally Posted by jeff7742 
Gino,  No, there is no soldering required. I'm not very good at it either. All you do is pull out the old opamps and insert the new ones. Just be careful when pulling the old ones out not to bend the pins, and insert the new ones in the correct orientation. I use a small screwdriver to carefully pry them loose without bending the pins. There is also a special tool -an opamp puller, but I usually don't need it.
Hi again and thanks a lot !  now I am very tempting for sure. 
I will try it as soon as I will complete my relocation in Italy.
Very low distortion on the LME49990! Here's another chart comparing opamps:
http://www.cycfi.com/projects/six-pack/op-amp-shootout/
wow !  it comes out on the top of the list for performance
a great part indeed.  I see 26mA of consumption.  Now I understand why it should be heathsinked.
Maybe it is working in class A ?
One other thing I should mention. I'm comparing the two amps using the VA1 with balanced inputs (I have two adapters that convert single-ended to balanced).
When I switch to using the unbalanced inputs on the VA1, the sound is not as good.  The soundstage shrinks quite a bit.
In the specs for the VA1, they say it has a balanced input stage, and I can definitely hear it. On the SAP-8 it doesn't seem to make a difference.
When using the balanced inputs, the VA1 definitely beats the SAP-8, otherwise it's clearer but not as spacious.
Update: looks like I have to eat my words. Two hours of breakin on the VA1 using the single-ended inputs has them sounding just as spacious as the balanced inputs, and somewhat richer.
The balanced inputs are still a little clearer and more refined though. Maybe that will change too.
Thanks a lot for the very valuable advice.
I think that both are not 100% balanced designs because the volume pot has only two sections and not four.   But I like a lot the idea (if I am taking it rightly)  of inputs buffered on the VA1.  
They provide a more “steady” signal before the attenuator.
In the VA1 I see 6 opamps in total.   Have you replaced all 6 with LME 49990s  ?
The VA1 just keeps getting better and better with more hours breakin.
With the op amps I have, this is a stunning amp! So rich and detailed and spacious through the RCA inputs. The best I've heard yet.
Gino, are you sure you gave it a fair breakin?   Even with the stock opamps, I think this amp will blow away the SAP-8.
It sounded very compressed and small at first, but after the hours I put on it, it is a completely different animal.
I am quite sure of the opposite actually. I have listened to it very shortly like 4 or 5 times 2-3 hours each time.  
Your impressions give me a great hope for good sound.  
And the fact that the op-amps swapping do not involve soldering is a great news for me.
I am pretty sure now that I will be amazed by this little and very robustly built amp.
It looks like it is very long lasting.
I am mostly a solid state guy.   I know that valves can sound very fascinating but the ease of use of solid state is for me winning.  It works, it is reliable, it can sound very decent. 
Update: in the last hour or so, the soundstage has grown. It is immense!
The biggest I've heard on my T1.
I've never seen an amp change so much on breakin.
Very interesting again.   Personally I think that a lot has to do with the psu caps.
There are a lot in the psu.   I would love to see some more famous part designed for audio but on this topic opinions are discordant.  
Your experience shows that the stock ones are quite good.
As I said I heard a very clean sound but not very spacious or particularly dynamic.
Now I am pretty sure I should give this amp more time to show its potential.
I have grown a great respect for this SMSL Audio brand.  
I have also some small digital amps that sound interesting with easy speakers.
I will report asap on my impressions, but this will need some time. 
I am in the middle of relocating myself.
Thanks a lot again.
Have a nice day,  gino

 

[jeff7742]

I have left the amp running continuously throughout the night. It has gotten even a little bit more refined, and there is a little more bass. Honestly, I think I'd have to spend maybe a thousand dollars or more to equal the quality of this amp. Rich and very resolving with an immense soundstage. I was really fooled by this amp - it sounded so small and compressed at first. The SAP-8 is a nice amp, but the VA1 is in another league entirely. I wonder how this amp would compare with the Gustard H10? I'm still waiting to receive my other LME49990's. I think I will put the original opamps back in just to see how it compares. I think the real improvements are coming from the amp itself and not the opamps.
 
Here is a vendor who lists more detailed parts and construction of the VA1 (the translation to english is a little rough):

http://www.headphonesguru.net/products/smsl-vmv-va1-hd-headphone-amplifier-with-balanced-input-hifi-exquis-va-1-amp-special-tuning-for-hd650-hd600/
 
Update: the VA1 does have some weaknesses though. It could use a little more power and more bass. I think the bass can be increased via bassy opamps like muses02 and muses 8890, 8920. I know adding more LME49990's will also increase the power somewhat. The output stage uses four of them (two in parallel for each channel), so the added volume from the LME49990's should be doubled. This amp seems to be a vehicle for letting your opamps sound the best they can.

 

[ginetto61]

Originally Posted by jeff7742 /img/forum/go_quote.gif  ...   Update: the VA1 does have some weaknesses though.  It could use a little more power and more bass.
I think the bass can be increased via bassy opamps like muses02 and muses 8890, 8920. I know adding more LME49990's will also increase the power somewhat.
The output stage uses four of them (two in parallel for each channel), so the added volume from the LME49990's should be doubled.
This amp seems to be a vehicle for letting your opamps sound the best they can.

 
 
Hi and thanks again.   I have a weird idea.   Why instead of using 2 opamps paralleled for each channel not using just one more powerful opamp for each channel ?
As a principle I do not like paralleling parts because no part is made equal to another.  Like output transistor for instance.  
Even when picked from the same batch they can have different characteristics.
One powerful opamp with a robust output current (like 50-100mA) should drive even tough load. 
I am thinking to the nice AD797 for instance
 
http://www.analog.com/media/en/technical-documentation/data-sheets/AD797.pdf
 
Or this one very powerful
 
http://www.njr.com/semicon/PDF/NJM4556A_E.pdf
 
1st thing is to understand which kind of opamps are the stock ones :
1)   single or double ?
2)   voltage or current feedback ?  
3)   pin configuration ?
 
I have the feeling, and some of your impressions confirm, that often the sound we attribute to the opamps depends instead from the design/other parts/psu.  
What is very very important is that this little amp looks very well designed.  
Another idea is to use the pin left open from the opamps removed to put some bypassing caps in.   Of the best quality around.
I think I will have something to play with.
Thanks a lot again,  gino  
 
P.S.  an interesting read about op-amps here
 
http://nwavguy.blogspot.no/2011/08/op-amps-myths-facts.html

 

[jeff7742]

   
 
Hi and thanks again.   I have a weird idea.   Why instead of using 2 opamps paralleled for each channel not using just one more powerful opamp for each channel ?
As a principle I do not like paralleling parts because no part is made equal to another.  Like output transistor for instance.  
Even when picked from the same batch they can have different characteristics.
 
 
1st thing is to understand which kind of opamps are the stock ones :
1)   single or double ?
2)   voltage or current feedback ?  
3)   pin configuration ?
 
I have the feeling, and some of your impressions confirm, that often the sound we attribute to the opamps depends instead from the design/other parts/psu.  
What is very very important is that this little amp looks very well designed.   
 

 
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.
 
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