[MatsudaMan]

Really cool stuff man! Thanks for the info and the pics - I'm starting to get the mod itch myself.

I think I'll read up on soldering....find out if I'm really up for it. My wife would kill me if I accidentally killed the v-dac (B-day present from her).

 

[josep]

Glad te mods worked for you too

(even if they are nothing new). Yes the two coupling caps will improve things: I have not measured yet but if you see no DC offests (under 10mV) from ground to its inputs they may be bypassed, is the easiest thing to do

Matsudaman this is not difficult but you must practice your soldering skills before with some discarded electronics (old computer parts are perfect), specially if your unit is a wife present!

 

[spore]

Actually, I am a newbie when it comes to modding dac. Josep, your detailed high resolution picture helped me greatly. I do not have any specialized tools to measure DC offsets. Will try out using my multimeter to see it can detect the 10mV. Thank you for sharing your findings.

For me this is the first time doing de-soldering/soldering on op amp and capacitors. I used a 20W soldering iron and solder pump. This may sound like a joke to experienced guys but I took 2 hours just to de-solder and solder 4 capacitors. Another 2hrs the next day to de-soler and solder the op amp.

 

[josep]

Nice, you just do not want to do it too fast and damage the copper traces on the board. If this happens one can always, with this style of boards, do something about (with a bit of wire etc) but... it is better to play safe and to it slow. If you do not plan to use the opamp, you can start by cutting (dremel disc, or hand cutter and care+patience) its legs then desolder them one by one (easier but you obviously destroy the original opamp).

Any multimeter will detect mV, just put in in DC scale and highest sensibility. I have not mentioned but it also is a matter of what your system does have: if your preamp/hp amp after the DAC is not DC coupled (it does have its own caps on the signal path) then you can bypass the output caps. There is no need of more than one coupling pair in the signal path to avoid any DC going all the way to your speakers/hp's.

 

[spore]

i am using v-dac connected to my speakers. I am using Bryston BP25 preamp and just downloaded the schematic from Bryston website. Unfortunately I am not very well versed in audio schematics and not able to determine if there is any dc coupling caps in the schematics.

I wil only get back my mulitmeter end of the week and did not measure if there is any dc voltage across C3 and C4 capacitor. However, I still went ahead to replace C3 and C4 with Nichicon bipolar capacitor, 47uF 50V BP-P. I believe that its there for a reason but I could wrong.

Music imaging improved slightly with much clearer separation of instruments. Now, I need to turn up the volume of my preamp compared to previously.

The v-dac is now transformed and sounds totally different. This has been a good learning experience and I am satisfied with the results considering that I only spent an additional 10% of the cost of v-dac to have a much improved sound.

 

[josep]

Nice. Seems those Nichicon's are almost the height limit of the case...

BP25 is a nice preamp, with discrete circuitry (no opamps in signal path) and if I remember well DC coupled all the way, probably with DC servo at outputs (this I am not sure). So it seems as you are better with caps in place.

 

[nhat_thanh]

I just received the V-DAC this week, I only put about 10 hours on them. This is the upgrade from my iBasso D3 - which I used as a DAC to feed the EF1. First, out of the box, it sounded good, great and very smooth mids, the bass was punchier and more refined, but somehow the attack was a bit slower. I didn't hear much changes in the treb, it just slightly silkier. The biggest different was the detail, V-DAC provides the great amount of detail, I could pick things I couldn't hear before very easy.

After like 10 hours of burn-in, it is better now, more transparent, the sound is very clean but still have the warmth. The mids is even smoother now, bass is now have greater impact and textured, the attack still remains the same, but it really not a big deal to me, but I prefer a bit faster. I'm not sure if it have more detail now or not, I haven't heard it yet, but I'm sure some detail become more clearer. The soundstage starts to become more lively, the presentation is more foward, makes everything sound so clear.

So far I'm very happy what the V-DAC gives me, absolutely an upgrade from the D3 DAC. The V-DAC really makes my ATH-AD2000s strengths shine: the mids, the detail and the impact. However I still expect more since it has just only had 10 hours

 

[spore]

yup, Nichicon are almost the height limit of the case. Actually, they just slightly protude out of the pcb board as they are much bigger. Luckily they are still able to fit into the case. Now I understand why the shop asked me if these capacitor are too big!

On hindsight, I am glad that v-dac is using normal average capacitors and NE5532 op amp. This leaves room for much improvement to the v-dac sound using much better capacitors at the right place and especially replacing the op amp with LME49860. Kudos to Josep for sharing his mods and findings 1st!

 

[MatsudaMan]

Quote:

Originally Posted by nhat_thanh /img/forum/go_quote.gif I just received the V-DAC this week, I only put about 10 hours on them. This is the upgrade from my iBasso D3 - which I used as a DAC to feed the EF1. First, out of the box, it sounded good, great and very smooth mids, the bass was punchier and more refined, but somehow the attack was a bit slower. I didn't hear much changes in the treb, it just slightly silkier. The biggest different was the detail, V-DAC provides the great amount of detail, I could pick things I couldn't hear before very easy. After like 10 hours of burn-in, it is better now, more transparent, the sound is very clean but still have the warmth. The mids is even smoother now, bass is now have greater impact and textured, the attack still remains the same, but it really not a big deal to me, but I prefer a bit faster. I'm not sure if it have more detail now or not, I haven't heard it yet, but I'm sure some detail become more clearer. The soundstage starts to become more lively, the presentation is more foward, makes everything sound so clear. So far I'm very happy what the V-DAC gives me, absolutely an upgrade from the D3 DAC. The V-DAC really makes my ATH-AD2000s strengths shine: the mids, the detail and the impact. However I still expect more since it has just only had 10 hours

Hey, welcome to the v-dac club and thanks for your impressions. I have to say that they (impressions) are pretty much spot-on. While some have complained of missing PRaT, I think that it is not a blaring inadequacy. On the other hand, what you get in detail and overall textural and harmonic richness more than makes up for it.

 

[Calvin&Hobbes]

I was able to improve the "impact of sound" by removing the dampening I put under the v-dac (sorbothane feet): this dampening had a negative effect on definition and smoothened the sound, a fluidity that the V-DAC certainly doesn't need! In addition I swapped the RCA cable to a very transparant, neutral and dynamic one (AQ anaconda). Gives me the bigger part of the impact I was looking for, especially strong & defined bass. So playing with isolation and cabling makes sense.
My minor criticism remains with the lesser attack of the V-DAC (as noted above). It has to do with the snap and immediacy of live instruments. Also with socalled transients, the leading edge of a percussive sound (got this terminology from HFC glossary). Know what I mean?
Q: could this be the toll of upsampling? I mean, upsampling interpolates where bits are missing. In this way the downside of increased smoothness (stronghold of the v-dac in the midrange / voices) could be less immediacy? (Somewhere I read a comment from someone who thought it a pity that upsampling cannot be swithched off).

 

[josep]

I am not a big believer of isolation/cabling issues, that is, unless there is a problem to start with (really poor support on something with mechanic things or crappy cable-connector). Have you tried to re-do the dampening to see? Maybe is something else, maybe the output caps burn-in...
As for 'attack' I too found the V-DAC a bit 'soft'. The upgraded opamp on mine bettered this and I bet bypassing (if possible) or changing those output bipolar electrolytics may help too.

 

[spore]

You can try to improve the sound by using a better power supply. A better power supply also helps in that the v-dac runs cooler. For me, the soundstage widens and the music sound more natural.

 

[Calvin&Hobbes]

@Josep: I have to disagree on your valuation of cabling; not all cables are equal, let alone neutral. I agree that cables should not be used to fix a problem; however some cables are better in passing the analog signal than others.
@Josep & Spore: if you had 100 bucks to spend: would you invest it in a PSU (say little pinky) or in having the v-dac modified (I am not capable of that).
Thanks!

 

[spore]

you get better bang for buck by doing the v-dac modification as parts such as capacitor and op amp are cheap. The improvement in sound is much greater.

I am not sure how much is the PSU (little pinky) but I had good success with a desktop switched power supply rated for 2.5A@12VDC which you can get for around USD$60-80.

 

[josep]

+1

A decent PSU rated at least 50W will do, one 90-120W unit runing at 12 to 13'5V is perfect and you may have it for (well) under $50 (ePay).

The mods are IMO well worth. The components cost is ridiculous, and the skill necessary to do it not high: even if you have two left hands can probably find someone close able to do it, say some relative, friend or whatever.

But do not ask girls at night if they are good with a soldering iron unless you are looking for trouble