[nathan_h]

Quote:

Originally Posted by dr.larkos /img/forum/go_quote.gif Nathan, definitely it is not. The inside diameter, I believe, is either 1.35mm or 1.3mm (both seem to work)....unfortunately, I have not heard or read any statement regarding outside diameter. Must likely it is 3.5mm but it could be 4.1mm. I called the MF importer in the US and they say will call me back with confirmation of exact diameters (we'll see if they deliver). In any event, easiest solution is to cut off plugs at plug end of stock and new PS cables--leaving about 1 inch tail--and exchange them keeping polarity correct: center positive, I believe, which should be clearly indicated in the casing of the PS's (a partially open circle with a dot in a center with a line pointing to the center dot and a + sign...or a minus sign if center negative). If by any chance one is center negative and the other is center positive, then, simply solder the stock plug reversing the color coded twin wires in the cable (one of the twin wires always has a white line over all of its length). I would recommend exchanging the plugs and not the cables as the new cable is likely to be a bit more substantial that the cable of the stock PS and, therefore, sturdier and more apt to handle the higher amperage of the new PS (if any higher amp demand may ever occur). Cheers......................dr.larkos

Thanks for the word of caution (the one I linked to won't have the right connector) and advice about how to work around/adapt it.

I actually want to keep the original PSU in tact, in case of re-sale, or in case I decide my ears cannot hear the difference.

But I may see if a place like FRy's has an in stock adapter that will work -- by taking the stock PSU with me and matching it's output and plug size/polarity spec at the store.

Alternately, since that's a bit of a long shot, if you do hear back from the distributor about the specs, please post them, which will make an internet search easier.

 

[Calvin&Hobbes]

Quote:

Originally Posted by dr.larkos /img/forum/go_quote.gif Back to the V-DAC mods. Cheers………………………….Carlos

I would then opt for replacing NE5322 opamp with the apparently excellent OPA2604.
Q: How many output capacitors need to be replaced and by which type of capacitator?

I believe these were also the two main mods being advised by Josep.
@Spore: Farnell part numbers, please? Imagine: I need to have a shopping list like a boy being sent to the grocer by his mum

BTW: my CDP is also from 1993 and is slowly, but surely, loosing track. It's certainly a class A laser product to live for 16 years. Will it's death be sudden or will the number of tracks that can be played shorten over the years? During this period: is there a loss in SQ due to lesser accuracy, or is it simply a matter of "all or nothing" (can read / cannot read)?

 

[dr.larkos]

Quote:

Originally Posted by Calvin&Hobbes /img/forum/go_quote.gif I would then opt for replacing NE5322 opamp with the apparently excellent OPA2604. Q: How many output capacitors need to be replaced and by which type of capacitator? I believe these were also the two main mods being advised by Josep. @Spore: Farnell part numbers, please? Imagine: I need to have a shopping list like a boy being sent to the grocer by his mum BTW: my CDP is also from 1993 and is slowly, but surely, loosing track. It's certainly a class A laser product to live for 16 years. Will it's death be sudden or will the number of tracks that can be played shorten over the years? During this period: is there a loss in SQ due to lesser accuracy, or is it simply a matter of "all or nothing" (can read / cannot read)?

C&H the process is actually a gradual one. It stars by the inability, as the laser power becomes weaker, to read CD-R's and CD-RW's (it is CD-R/RW brand dependant, depending on disc surface reflect ability) and, eventually, it stops reading all CD’s. But keep in mind that there are other causes of reading failure different than an actual problem with the laser. Symptoms and diagnostics are rather well explained in link below. Author, however, seems not to be electronics savvy as he chides away from some basic electrical adjustments--he turns them into a uncertain trial and error process when, actually, all is required is a voltmeter and, of course, knowing the required voltages for specific unit and circuit points where to measure them (need to have access to service manual or someone that knows that information).

Laserology

Cheers...................dr.larkos

 

[MPG1]

Hi guys. New member here. Was reading up on the V-DAC before purchase, so here's my story:

ust got this DAC. It replaces my Lite DAC-AH given the COEM-like mods. Just as a background, I was actually looking at a speaker upgrade, since I was getting the upgrade fever after auditioning the B&W CM1. Given the cost though, I needed to sell my current speakers to finance that.

That being said, I stumbled upon the V-DAC while surfing the net. The reviews were quite good, and I was surprised that it was an MF component with a very un-MF price. At that point I was not contemplating a DAC upgrade, since the DAC-AH was such a big improvement over the DAC in my Pioneer DVD player and the DAC in my Apple Airport Express (which I use for wireless streaming).

Suffice to say that I gave in and bought the V-DAC to give it a try. I figured the cost was modest enough so that if I made a mistake it would not be too painful.

But I digress. . . here's my initial take using this setup:

Macbookpro-->320kbps wirelessly streamed to an Airport Express-->Output to V-DAC using toslink-->V-DAC to AMX tube amp-->Castle Speakers

Size

- this DAC is surprisingly light and compact, with an external appearance more in place with the lower-end chinese DAC products
- small size, but the RCA output jacks fit Amphenol plugs quite comfortably
- unusual input/output layouts a bit wierd, would have preferred all the connections at the back of the unit
- very light, almost fell when I pulled on one of the connections by mistake
- no power botton though, will have to get a plug adaptor with an on/off switch

Sound (as compared to my DAC-AH)

I was half-expecting no difference, and a sharper sound, given this is an upsampling DAC and not a NOS DAC like my DAC-AH. Right out of the box though I noticed:

- what you would call a "blacker" background
- a bit louder vs my DAC-AH, might be that the DAC-AH was modded so that it's output stage in via Clarity Caps vs opamps originally and in the V-DAC
- tighter bass, my DAC AH now seems a bit flabby by comparison
- more detailed, using tracks I'm familiar with; I noticed a percussion beat in the intro of "Hotel California" in my Hell Freezes Over album which I had not noticed before

So, just out of the box, the V-DAC seems a successful upgrade.

It has quelled my urge to upgrade the speakers, since the sound seems brand new. . . will hopefully update this as the unit is broken in.

Also, I'm waiting to pick up a PSU upgrade for the DAC. It's a 1 X 12V regulated power supply, with 1.2A output. It was made by the same guy who did my tube amp. I asked if he could do something like a V-PSU, but he recommended just 1 regulated supply per component used, to maximize the benefits and forestall any problems - all for under USD100. Will try to post some updates and a pic of the PSU when I get my hands on it.

 

[spore]

[Modding]
Calvin&Hobbes, a quick search on farnell website yields p/n: 1097431 for opa2604.

Changing dual op amp NE5532 at location IC7 and quad op amp at location IC5 yields the most obvious and significant improvement to the v-dac which can be clearly heard. Changing the caps to better ones in the v-dac helps to 'refine' the sound of the v-dac further.

I have replaced almost all caps in the v-dac to better rated ones with the same original value except for C14 which I have changed from 10uF to 47uF. I am done with my modding and pleased with the results.

you can pm me for my list of mods. We can set up a separate thread on modding for further discussion if necessary. I think v-dac is great value for money with a lot of potential. I will like to share that for a little fraction of the cost of v-dac to mod it, you can improve the v-dac sound significantly.As usual, your mileage will varies.

 

[JTori]

A question for the technically savvy bunch frequenting this thread: I had my V-DAC hooked to the Toslink S/PDIF out fom an X-Fi ExtremeMusic. For comparison I hooked it to the RCA S/PDIF out via a 75-ohm digital cable. After disconnecting, I noticed the green link light remains faintly lit (power is plugged in but no digital cable). Issue was not present before connecting the RCA S/PDIF.

Also, everything was operating fine with the RCA out for a few minutes before the music stopped. Now I am unable to get sound using the RCA S/PDIF. The Toslink works fine.

Any thoughts on this?

 

[dr.larkos]

Quote:

Originally Posted by nathan_h /img/forum/go_quote.gif Thanks for the word of caution (the one I linked to won't have the right connector) and advice about how to work around/adapt it. I actually want to keep the original PSU in tact, in case of re-sale, or in case I decide my ears cannot hear the difference. But I may see if a place like FRy's has an in stock adapter that will work -- by taking the stock PSU with me and matching it's output and plug size/polarity spec at the store. Alternately, since that's a bit of a long shot, if you do hear back from the distributor about the specs, please post them, which will make an internet search easier.

Nathan, finally got an answer from US importer... which was not a useful answer. MF told him that they don't know the diameters but that is "one with the black tip." He said MF claims those tips are color coded.... but in US most of them have the black outer rim at end of tip. In any event, I beleive the one in link below (Digikey) is a good bet--certainly inexpensive (US$0.93). Incidentally, US importer (KEF Americas) said that replacement of "cheap" stock wall-wart is US$60....amazing!!!

Digi-Key - CP3-1003-ND (CUI Inc - PP3-002D)

 

[nathan_h]

Interesting. Thanks for the tip. Over the weekend I got a chance to compare the VDAC with a Benchmark DAC1 and decided that the $300 more for the used DAC1 was worthwhile -- both for the extra clarity and for the useful if not perfect headphone amp built in. Also, I don't need USB, and having balanced output will be useful when feeding my amp directly. So the VDAC is headed back to Audio Advisor.

Really want to compare the Benchmark with a TADAC but they are no longer in production and the new TADAC Pre Amp, while likely very useful, is overkill for my one-source system.

 

[josep]

JTori,

Dumb question maybe but... have you tried to 'reset' the V-DAC? (power off, wait a minute, power on).

It does not sound much good however, do you have other links to the PC ground on your system? (say besides que spdif cable to the V-DAC, maybe the RCA outs of the V-DAC go to an amplifier were the line outs of the PC goes too).

This is why I try to avoid using electrical connections from PC anyway... but if USB is the bright light we are seeing on the horizon for digital audio use, we will be tied to this.

 

[JTori]

josep,

Good thoughts. I need to spend a little time tracking down the issue. My chain is as follows: Creative X-Fi ExtremeMusic (with digital i/o module connected to Flexijack) to V-DAC to AudioEngine AS8 subwoofer to AudioEngine A2 active speakers. Connections were RCA S/PDIF cable (75 ohm digital) from the i/o module to the DAC and analog RCA interconnects from the DAC to the sub and sub to satellite speakers. Incidentally, I tried plugging another high-quality (Audioquest) digital cable I had on hand into the RCA S/PDIF on the i/o module and received a jolt up my arm when I touched the connector body. Interestingly, the cable was not connected to the DAC, only to the S/PDIF from the computer. This was a little alarming. So, I've reverted to Toslink, removed the V-DAC from my system and substituted my trusty Theta DS Pro Prime II. Though it's an older unit, it sounds great! Full, rich, tremendous low end and air. And it images incredibly well. I guess upsampling isn't everything. I'd appreciate any additional thoughts you or other members of the forum may have. I'd still like to track down the root cause of this issue.

 

[josep]

Looks like you have, at least, a grounding problem. Is your computer properly grounded (IEC cable with ground to the wall)? Does have your house electrical instalation a good earth?
Btw I too like the sound of some 'vintage' DACs, Theta entry level ones were nice if memory serves me well (your PPrime and the cheaper Cobalt).

 

[MPG1]

Quote:

Originally Posted by dr.larkos /img/forum/go_quote.gif Nathan, finally got an answer from US importer... which was not a useful answer. MF told him that they don't know the diameters but that is "one with the black tip." He said MF claims those tips are color coded.... but in US most of them have the black outer rim at end of tip. In any event, I beleive the one in link below (Digikey) is a good bet--certainly inexpensive (US$0.93). Incidentally, US importer (KEF Americas) said that replacement of "cheap" stock wall-wart is US$60....amazing!!! Digi-Key - CP3-1003-ND (CUI Inc - PP3-002D)

I'd suggest you have a simple regulated PSU made and buy an off-the-shelf replacement cable with multiple adapters built in. That's what I did here. Had a guy make a PSU, then I used the cable, put electrical tape over the unused connectors, checked the polarity using my digital multi-meter and off I went. Total cost of the PSU + replacement wall wart cable for me was the equivalent of USD75, including a roll of electrical tape and pair of scissors.

I'll try to post pics, but the setup is much "tighter" now, for lack of a better word to describe it.

The PSU I had made puts out 12.6VDC, vs the stock MF wall wart of 17.65VDC. Mine also output 1.2A of current, vs the 500mA of the stock wall wart.

 

[MPG1]

As promised, here's the pics of the PSU I had made. . .

 

[nathan_h]

Nice!

 

[praganj]

Quote:

Originally Posted by spore /img/forum/go_quote.gif My updated list of Modifications: 1. Replace caps at location C25, C22, C45 and C61 2. Change dual op amp NE5532 at location IC7 3. Replace caps at location C3 and C4 4. Change quad op amp at location IC5 5. Replace caps at location C53, C34 C44, C21, C39 and C5 6. Change C52, C36 and C14 from 10uf to 100uf 7. Replace caps at location C20, C43, C37, C38, C30 and C32.

Number 4 - "Change quad op amp at location IC5"

With what should i exchange it ?

Cheers