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Review: Violectric V800 DAC - Page 16

post #226 of 688

Nice looking cable for sure.

post #227 of 688
Thread Starter 
Available at Tamaudio.com for $100

http://tamaudio.com/store/index.php?route=product/product&path=37_50&product_id=101
post #228 of 688
Sorry Odessey...I thought you you were just looking for that brand of cable or a place to buy it. I am new here..and I don't know a whole lot but my experience with hooking up my V200 to my V800 took me down a path of cable websites, connectors and solder. I could not find any short cables. The XLR cables that I made were only one-foot long total: from connector tip to connector tip. That length allowed just enough bend in the cable so that it wasn't strained.
I could not find any short cables like the ones in the photo. I think you have to make them or pay someone to fabricate them for tou. Not sure though.
post #229 of 688
Damn..I did not see P86's post BEFORE I posted. LOL! Well...mine were a LOT less expensive and I had fun with it. ...based on my experience, though.... the handmade cables from Tam Audio are priced correctly ! ....but I am so proud of mine. :-)
post #230 of 688

RE-EDITED

 

- some words about the internal of DAC V800.

 

There is a great uncertainty about how it sounds.

Well, we have made big efforts that it does not sound.

Sound is a very subjective matter and the taste of person A must not be the one of person B.

 

Basically, when we are going to design a specific piece of equipment we measure first and listen after. Only when there is nothing more to improve in the FFT spectrum we are satisfied.

For this purpose our measuring equipment includes "UPL" from Rohde & Schwarz and two "D-Scope III" from Prism Sound. Furthermore we own 4 digital and and 2 analog storage scopes from Tektronix.

 

Don’t expect significant differences in sound with "good" actual DACs, but for my opinion there are more than subtle differences.

 

Why is that?

If we assume that a perfect digital signal is input, then all "premium device" will convert at a high level with the same D/A chips.

These are namely PCM1792 (Texas Instruments) and AD1955 (Analog Devices) and derivatives.

Somewhat lower quality can be found on CS4398 (Cirrus Semiconductors) or PCM1793 (again TI).

Theoretically, the top is represented by ESS9012/9018 (Ess Technology).

We evaluated these converters and in deed the dynamic range was the best we ever measured. Unfortunately THD(+N) was not as good as can be found with PCM1792 / AD1955, so we saw no real need to employ these chips  ...

 

So we can state that the converter chips are not responsible for sound differences.

For our opinion the analog output is the key.

Here the signal is filtered, buffered, amplified.

And here all manufacturers work with different approaches.

The one from DAC V800 is somehow tricky.


All modern D/A converter chips offer current outputs instead of voltage outputs, so they must necessarily use the inverting inputs of an operational amplifier. Here, no wide bandwidth is required, in contrary, because also the high cut filter is situated at this place which cuts the high frequency noise from the D/A converter.

At this point we also cut the DC voltage coming out of the D/A converter because modern D/A converters are operated with only one voltage of 3.3V or 5V. But our analog output electronics is powered with +/ - 18 V.

A conventional D/A converter chip has an output voltage of about +8 dB (approx. 2,5 Veff).

 

After the I/U conversion and filtering stage inside DAC V800 the level matching stage is situated - unfortunately inside the unit because the circuitry is so sensitive that long lines should be avoided.

Here, analog output voltages of +24, 18, +15, +12 and +6 dBu may be set for a digital full scale signal. The above values ​​are for the balanced output.

The unbalanced output has its own independent drivers and offers always 9 dB lower levels.
 

When some people realize that you don’t need additional line drivers to operate remote active speakers or you may even power your headphones with the outputs from DAC V800, the reason is that these output circuits are really professional.

The balanced output signal is treated in the same way as we did 100,000 times for broadcasters, TV stations, studios, exhibition halls and airports - with low output impedance and excellent values for THD, frequency response, dynamic range, common-mode rejection.


To do so, low impedance outputs and accurate matching impedances are necessary. Inside DAC V800 these outputs are furthermore adjustable (see above) and remain low impedance – a feature that is missing in most other gear in the market !  

 

There are plenty of operational amplifiers in the signal path. Nevertheless, we achieve a dynamic range of 120 dB and THD of -112 dB.

 

The digital receiver in front of the D/A converter is also a sample-rate converter.

Here - if activated – the incoming digital signal is resampled.

The USB receiver has the little peculiarity that it is powered from the connected computer. The recovered PCM digital audio signal out of the USB data stream is passed through an isolation transformer to the main circuitry of DAC V800. So the computer and the D/A converter are safely isolated and possible hum insertion is eliminated.

 

The sample rate converter extracts the digital audio data from the incoming data stream and recombines it with its own internal low jitter clock.

By doing so the possible input jitter is eliminated almost completely.

This applies to all input signals. So for USB signals the technically less demanding "asynchronous mode" can be omitted.

 

Sample rate conversion is a highly complex matter. The first integrated solutions were introduced in the mid '90 ies.

Since then there was a rapid development which has come to standstill since several years because the physical maximum has been reached in practice.

A modern SRC offers distortion and dynamic range beyond 140 dB, thus making it superior to any software computer solution. Especially with odd conversions e. g. from 44.1 to 96 kHz!

 

There are different modes selectable for DAC V800:

- OFF = SRC off

- x 1 = SRC activated, input and output clock rates are identical

- x 2 = SRC activated, input to output clock rate ratio is 1:2

Input clock rates above 110 kHz input clock are automatically forced to “x 1” mode.

- x 4 = SRC activated, input to output clock rate ratio is 1:4

Input clock rates above 55 kHz input clock are automatically forced to “x 2” mode

-  Best = all incoming sample rates are converted to 96 kHz as this sample rate is technically the best solution concerning dynamic range and THD.

 

Most people are not aware that each D/A converter will halve its oversampling above 110 kHz. So, about 3 dB THD and dynamics and lots of storage space will be lost – due to the vague prospect of a tonal event between 45 to 90 kHz ...

 

The overall volume of DAC V800 is controlled in the digital domain in 256 steps of 0.5 dB.

 

Some analog people claim sonical disadvantages because bits are cut during attenuation - but that's not as bad as it is sometimes reported.

 

Some do it differently, namely analog with digital control, with so called DCA's - Digital Controlled Attenuator. Lake People did that way at the end of the last millennium inside the quite successful 7.1 controller named VOL CON-F38. And so we know from the technical and sonic .... peculiarities.

 

The benefit of digital volume control at first glance is, that there will be no more scratching, there will be no channel mismatch, there will be no crosstalk issues any more.
Digital volume control can be made with up-down buttons or incrementals or real potentiometers – like Violectric does.
In that case a linear tapper is used, because the volume control itself is made dB-linear inside the D/A converter.
As this mirrors a “real life” feeling only imperfect when turning the potentiometer, we added some resistors to “bend” the responding law from the potentiometer to have a nearly perfect analog feeling. 
A simple DC voltage is attenuated by the pot. The result is fed to a A/D converter, here a digital control signal is made to attenuate the digital audio signal inside the D/A converter BEFORE converting it to analog.
A digital 24 bit signal represents a dynamic range of 144 dB – much more than can be found in real life !!
People who are doing real world recordings can tell, that it is nearly impossible to record more than 60 dB dynamic range with a microphone - although microphone makers claim dynamic ranges from their microphones to be more that 130 dB.
This may be true when recording a cricket near a starting F-14 Tomcat. But - who needs that.
Also, sitting in you living room, it is hard to follow dynamic ranges of more that 20 – 30 dB unattenuated without having trouble with your neighborhood afterwards.
Today´s pop music´s dynamic range is reduced during recording to 2 – 3 dB …
Please also note that harmonic distortion inside the signal cannot be smaller than the dynamic range.
It is not possible to have 100 dB THD (0,001%) with 90 dB dynamic range, but it is possible to have 110 dB THD (0,0003%) with 120 dB dynamic range !
The CD format offers 16 bit which means a dynamic range of 96 dB and distortions which cannot be lower than 0,0016%.
A 24 bit signal offers a dynamic range of 144 dB with theoretical minimum distortions at 0,00001%.
This is not possible to achieve in real life.
The best today´s A/D converters offer dynamic ranges from 120 dB with distortion figures about –110 dB THD.
Lots of losses have to be faced during recording, editing, mixing …   

Digital attenuation is done by shifting the signal from MSB (Most-Significant-Bit) in direction LSB (Least-Significant-Bit).
Shifting a complete bit in LSB direction (and replacing it with a 0) means 6 dB attenuation.
When a 16 bit CD signal is input to a 24 bit DA converter, this signal may be attenuated by 6 dB x 8 Bit = 48 dB = factor 200:1 WITHOUT changing anything from the original data.

We learned from the above that also a real 24 bit signal carries a maximum of 20 “senseful” bits - in practice there are no more than 16-18 bits.
So, also a 24 bit signal may be attenuated by a minimum of 6 dB x 4 Bit = 24 dB = factor 35:1 without doing any harm to the original data.

 

A 16-bit CD signal is extrapolated inside DAC V800 to 24 bits.

Now you can cut 8 bits = 48 dB = factor 200 before the original quality of the CD is affected.

... and at such low volumes, no one can make a statement about the quality of the program material!


So – for our opinion - digital attenuation is the best what can happen to a signal (except not being attenuated).
 

Greetz

Fried

post #231 of 688

You can ask Lake People to build you custom XLR cables. They are very well made and professional, no Quacksalberei, jawohl!

post #232 of 688

@project86

 

You mentioned the Audinst HUD-MX1; Is the V800 much better?

Would you recommend the upgrade? (The money is here and ready to be spend etysmile.gif)

post #233 of 688
Thread Starter 
Quote:
Originally Posted by odyssey2001 View Post

@project86

 

You mentioned the Audinst HUD-MX1; Is the V800 much better?

Would you recommend the upgrade? (The money is here and ready to be spend etysmile.gif)

 

No contest. The Audinst is a nice little unit, and does a good job for its price considering the compact size and versatile feature set. But in no way is it anywhere near the V800 in terms of performance. I would definitely call that a worthwhile upgrade if you can afford it. 

post #234 of 688
Quote:
Originally Posted by project86 View Post

 

No contest. The Audinst is a nice little unit, and does a good job for its price considering the compact size and versatile feature set. But in no way is it anywhere near the V800 in terms of performance. I would definitely call that a worthwhile upgrade if you can afford it. 

 

I just ordered an Violectric V200 but for now my only DAC is the HUD-MX1.

 

Do you think the V200 + HUD-MX1 will improve anything compared to just the HUD-MX1 as an DAC + HP amp or do I need to get an V800 for any improvement?


Edited by odyssey2001 - 9/4/12 at 7:04am
post #235 of 688
Thread Starter 
Quote:
Originally Posted by odyssey2001 View Post

 

I just ordered an Violectric V200 but for now my only DAC is the HUD-MX1.

 

Do you think the V200 + HUD-MX1 will improve anything compared to just the HUD-MX1 as an DAC + HP amp or do I need to get an V800 for any improvement?

 

You should definitely still notice an increase by just adding the V200 for amplification. IMO the Audinst is a better DAC than it is an amp, so you are keeping it's stronger part and upgrading the weaker link. The V800 would be the final link in the chain, but for now you should be pleased with the HUD-mx1/V200 combo. 

post #236 of 688

Thank you so much for your help.

 

What will the V800 do better than the HUD-MX1? Overall improvent of sound quality?

post #237 of 688
Quote:
Originally Posted by project86 View Post

 

You should definitely still notice an increase by just adding the V200 for amplification. IMO the Audinst is a better DAC than it is an amp, so you are keeping it's stronger part and upgrading the weaker link. The V800 would be the final link in the chain, but for now you should be pleased with the HUD-mx1/V200 combo. 

 

I must say and congratulate project86 on.....besides writing a great review, your house keeping on the thread is awesome too!!!

 

Should add the V200 thread too......


Edited by spkrs01 - 9/4/12 at 7:18am
post #238 of 688
Thread Starter 
Quote:
Originally Posted by odyssey2001 View Post

Thank you so much for your help.

 

What will the V800 do better than the HUD-MX1? Overall improvent of sound quality?

 

All the main areas should improve - instrument separation, soundstage, depth of bass, realism and sparkle of highs, open mids, natural timbre, etc. Plus you get more functionality - Toslink and coaxial SPDIF ins, AES/EBU in, balanced outs, selectable upsampling, high quality digital volume attenuation, etc. 

 

 

 

Quote:
Originally Posted by spkrs01 View Post

 

I must say and congratulate project86 on.....besides writing a great review, your house keeping on the thread is awesome too!!!

 

Should add the V200 thread too......

 

Thanks, but I feel that there are some folks around here who do a far better job. I just manage to "keep up" with questions as best I can.

post #239 of 688

Tonight,

both for fun and serious listening (i'm a part time audio mastering engineer) i did a more in depth comparison between my old mytek stereo96 dac and the V800.

The V800 has won hands down.Better in every aspect.So much more detail, transient response and bass articulation.The test has been made level matched.

Both dacs output audio at +24dBu.

 

I guess this product is a little gem.Maybe the best 24 bit dac i've tried.

 

Unfortunately i had no chance to try the new ESS Sabre 32 bit dac.So i don't know if the game is worth the candle.

 

What really surprised me is the fact that mr Freid Reim said this :

 

Theoretically, the top is represented by ESS9012/9018 (Ess Technology).

We evaluated these converters and in deed the dynamic range was the best we ever measured.

Unfortunately THD(+N) was not as good as can be found with PCM1792 / AD1955, so we saw no real need to employ these chips  ...

 

Fot me the V800 is a pro audio product with terrific specs(with all the lake people know-how behind) dressed in an audiophile suite.

 

I've listened carefully to the different upsampling settings.Let's say that "best" is the one size fits it all setting.

Valuable for all kinds of music.I prefer to leave the upsampling off to get the closer the source's original sound.

I've tried some wavs and flacs at 16 bit 44.1 khz with 1X but things tend to get brighter than they really are so no upsampling is the best for me.

 

Just to complete the picture the guy who sold me his V800 now has an MSB Usb dac.I've tried that dac with my hd 800 and my amp.

Apart from the different price range what has impressed me much is the stunning sound quality.When the dac takes the power from the internal battery

everythings comes really close to a live performance in a perfectly treated room.Oh well.. but that's another story. ^__^

 

By the way i guess what Violectric will do next.What will be the successor of the V800 and where the sonic level will arrive.

 

I'm confident that the new dac (if they'll put out a new one) will be amazing as this one and hopefully more ^__^


Edited by fradoca - 9/4/12 at 1:54pm
post #240 of 688

Being new..with my Violectric V800, V200, Audeze LCD-2's and (now) Amarra....(I tried a HiFace 2 USB interface but could discern no difference in the sound in my Mac setup so back it went to Amazon)....  I am rediscovering my whole catalog of music in a new sonic environment. What I am finding is something good and something bad.... some recordings that I merely "liked" before are so well recorded (and that fact is brought to light by this equipment), and I am more than WOWED by that sonic purity along with the music,  while some of my other recordings where I have really "LOVED" the music in the past are poorly recorded and this fact is screamingly obvious now...and it is disappointing as the poor tech quality of the recording takes away from the music big time.  It took me a little time to realize what was going on.  At first I thought, Hey this expensive equipment is no better the my Skull Candy Buds plugged into the headphone jack on my Mac....but alas...I think I realize the truth now.  So this is kind of a love hate thing for me right now!!!! LOL! Has anyone else experienced this mini roller-coaster ride?

I plan on purchasing a Anedio D2 DAC (as I am on the waiting list for the Sept. batch), for a small 300B tube amp/bookshelf speaker set up I am putting together,   so I will have something to compare the Violectrics to when I get the new DAC. This should be fun and interesting and I am looking forward to it.

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