Review of the Audio-gd DAC-19 DSP & C2 amp - The ACSS connection

[FauDrei]

Having signal (music or test tones playing) is better, but no - you do not need to attach your laptop for warm-up.

 

[Pricklely Peete]

The basic rule of thumb for A-gd gear is 350hours for the lower end stuff and anywhere from 400-750 hours for the higher end stuff. The initial 100 hours at the factory is to test the circuit for reliable operation (because 90% of the failures that do occur usually happen within the first power up and within the first 48 hours of operation).
 
I would recommended against leaving any of Kingwa's bigger Class A stuff powered up 24/7. As Regal rightly points out caps have a lifespan measured in hours at a max temp (look at the spec sheet for the part it will be listed ...85C caps operated at 60C will likely last 8000 hours) Again just because these things are SS does not mean they will last forever but with judicious use and proper ventilation Kingwa has estimated 20-30 years of normal use before a cap overhaul is needed. Most vintage amps (tube and SS) should be recapped before powering them up for the first time in years (unless you know for sure it works within spec). even then a lot of the old parts are much inferior to the new stuff being made.
 
I believe the RE1 and likely RE7 uses 150W or power ( a lot more juice then most dacs except those that are built similar in design). If you can afford to leave it powered up 24/7 then fine but remember the caps have a finite lifespan...might as well save that lifespan for actual listening (once you have the gear fully burned in) rather than running up your electricity bill.
 
Peete

 

[kunalraiker]

Quote:

The basic rule of thumb for A-gd gear is 350hours for the lower end stuff and anywhere from 400-750 hours for the higher end stuff. The initial 100 hours at the factory is to test the circuit for reliable operation (because 90% of the failures that do occur usually happen within the first power up and within the first 48 hours of operation).
 
I would recommended against leaving any of Kingwa's bigger Class A stuff powered up 24/7. As Regal rightly points out caps have a lifespan measured in hours at a max temp (look at the spec sheet for the part it will be listed ...85C caps operated at 60C will likely last 8000 hours) Again just because these things are SS does not mean they will last forever but with judicious use and proper ventilation Kingwa has estimated 20-30 years of normal use before a cap overhaul is needed. Most vintage amps (tube and SS) should be recapped before powering them up for the first time in years (unless you know for sure it works within spec). even then a lot of the old parts are much inferior to the new stuff being made.
 
I believe the RE1 and likely RE7 uses 150W or power ( a lot more juice then most dacs except those that are built similar in design). If you can afford to leave it powered up 24/7 then fine but remember the caps have a finite lifespan...might as well save that lifespan for actual listening (once you have the gear fully burned in) rather than running up your electricity bill.
 
Peete

I'am under the impression that this is probably a more sensible approach.

• burn your DAC/AMP for 250 hours-about 10 days 24/7
• turn the units on  1 hour before every use.
   

 

[IPodPJ]

Quote:

I don't believe Kingwa when he says he burns in all gear for 100 hrs.  With the Dac19mk3 I didn't notice much of a burn in.  But with the bigger DAC3Se it was real because I didn't listen to the dam thing for two weeks and it sounded like a completly different unit.   Have you owned a bigger AudioGd DAC ?

Not sure what you mean.  I own the biggest Audio-gd DAC there is, the Ref-7.  I have never owned any other Audio-gd DAC except for the Ref-1.

 

[IPodPJ]

Quote:

iPodPJ: There was most definitely a sonic change with the Fun between first use and a couple of hundred hours of being left switched on. At first it was very definitely harsh, which it is no longer.  As well, the HDAMs go through quite wild sonic changes over the first 350 hours, including a complete drop-out in the treble at 250 hours.  With experimentation, I determined it happened regardless of whether music was playing or not, so was likely due to the heat of the gear.  I agree though that just switched on, my Ref 1 and Phoenix can be somewhat lack-luster.

Well perhaps not all gear gets the same treatment.  You know me, I am not afraid to talk about changes I am hearing in gear, although I have "curbed my enthusiasm" quite a bit as I've pretty much attained the ultimate dynamic headphone rig.  To this day I still maintain there are sonic differences between the 70/99 step option on the Phoenix.  But when it comes to burn-in I'm just not hearing it on the DACs.  I did notice slight burn-in on the Phoenix, but not really enough that it couldn't be due to brain adjustment.  With the Ref-1 and Ref-7, it just doesn't seem to be there -- at least mine didn't change.  Perhaps because Kingwa did custom work to them he let them run in longer and that ironed out the burn-in at the factory, but he says he only let them run for 100 hours.

 
Quote:

The basic rule of thumb for A-gd gear is 350hours for the lower end stuff and anywhere from 400-750 hours for the higher end stuff. The initial 100 hours at the factory is to test the circuit for reliable operation (because 90% of the failures that do occur usually happen within the first power up and within the first 48 hours of operation).
 
I would recommended against leaving any of Kingwa's bigger Class A stuff powered up 24/7. As Regal rightly points out caps have a lifespan measured in hours at a max temp (look at the spec sheet for the part it will be listed ...85C caps operated at 60C will likely last 8000 hours) Again just because these things are SS does not mean they will last forever but with judicious use and proper ventilation Kingwa has estimated 20-30 years of normal use before a cap overhaul is needed. Most vintage amps (tube and SS) should be recapped before powering them up for the first time in years (unless you know for sure it works within spec). even then a lot of the old parts are much inferior to the new stuff being made.
 
I believe the RE1 and likely RE7 uses 150W or power ( a lot more juice then most dacs except those that are built similar in design). If you can afford to leave it powered up 24/7 then fine but remember the caps have a finite lifespan...might as well save that lifespan for actual listening (once you have the gear fully burned in) rather than running up your electricity bill.
 
Peete

 
Seriously, at the rate digital/analog conversion and audio formats have been steadily improving, who would be using the same DAC in 20-30 years?  Are you still using 8-tracks and cassettes?

  I'm not saying that the Ref-7 couldn't or wouldn't stand the test of time, but digital audio formats and transmission will change vastly in the next 20-30 years.  S/PDIF and AES/EBU will most likely be non-existent.  USB and I2S might still be around then, but who really knows.
 
Hell, at the very least even if you could use the same DACs, you might be able to pick up the MSB Diamond DAC IV for about $500, versus it's current $26,000 price tag.
 

 

[regal]

  And you would have been a guy who sold a box of Western Electric 300B's for $1 at a garage sale in 1965.
 
Audio quality has progressively gotten worse the last 35 years not better.
 
 
Quote:

Well perhaps not all gear gets the same treatment.  You know me, I am not afraid to talk about changes I am hearing in gear, although I have "curbed my enthusiasm" quite a bit as I've pretty much attained the ultimate dynamic headphone rig.  To this day I still maintain there are sonic differences between the 70/99 step option on the Phoenix.  But when it comes to burn-in I'm just not hearing it on the DACs.  I did notice slight burn-in on the Phoenix, but not really enough that it couldn't be due to brain adjustment.  With the Ref-1 and Ref-7, it just doesn't seem to be there -- at least mine didn't change.  Perhaps because Kingwa did custom work to them he let them run in longer and that ironed out the burn-in at the factory, but he says he only let them run for 100 hours.

 
 
Seriously, at the rate digital/analog conversion and audio formats have been steadily improving, who would be using the same DAC in 20-30 years?  Are you still using 8-tracks and cassettes?

  I'm not saying that the Ref-7 couldn't or wouldn't stand the test of time, but digital audio formats and transmission will change vastly in the next 20-30 years.  S/PDIF and AES/EBU will most likely be non-existent.  USB and I2S might still be around then, but who really knows.
 
Hell, at the very least even if you could use the same DACs, you might be able to pick up the MSB Diamond DAC IV for about $500, versus it's current $26,000 price tag.
 

 

[IPodPJ]

Audio quality has not been getting worse.  Where did you get that idea from?  Some people's choice of formats have been getting worse.  The technical abilities of digital are far superior to vinyl.  You may prefer vinyl to your ears, but it is not technically superior to PCM.

 

[regal]

OK take vinyl out of the equation,  DAC's sold now aren't as good as R2R like AD1862 or PCM63k,   many people agree with this.
 
Hell the top studio engineers go to the PM2 ADC over anything made this decade.  The DAC19DSP is a retro DAC,  the PCM1704 was brought out of obsolete status by TI only because their big instrumentation customers went nuts at the inferior sigma-delta PCM179x series.  The only area audio is getting "better" is the resurgance of retro tube amps and computer as transports.  I'm not alone in this sort of thinking,  but we all have different ears and brains and am not saying you are wrong,  just that there is a strong likelyhood that a ref7 will be worth major dollars in a couple decades,  analogous to the  1940's WE300B we see today selling for$3000 .  Its not all nolstagia,  believe me.
 
 
Quote:

Audio quality has not been getting worse.  Where did you get that idea from?  Some people's choice of formats have been getting worse.  The technical abilities of digital are far superior to vinyl.  You may prefer vinyl to your ears, but it is not technically superior to PCM.

 

[Black Stuart]

Regal,
your statement about longevity of caps flies in the face of the 'actual' performance of my PSU and 63KI mk11, which is corroborated by Kingwa.
 
If you actually look at the specs for caps they all state number of hours @ a certain temperature.
 
Pearl Coolers had a lot of info on their site which I believe is now missing  about longevity of components. Basically dropping the operating temps. of caps - for a 10C drop = doubling of the usable life. Re. resistors dropping the operating temp. by the same 10C meant the resistor staying within rated value again doubling the life.
 
Now I realise there is a big difference in operating temperature between a CDP and the more modern DACS. In pictures that Slim sent me re. his Audio-gd DAC I could hardly fail to  notice the many heatsinks.
 
For many years I have raised the issue of badly designed audio equipment enclosures that fail to address in any real way the 'heat issue'. Flat rectangular boxes are a joke precisely because of the heat issue. Couple this with PCBs - just how exactly is the heat generated going to escape?
 
It is accepted  that mosfets will work quite happily at high temps, this maybe so but what is the affect on other components?  A Dutch friend who has the same h/amp - a BADA PH12 challenged this and removing the bottom plate used a couple of Papst computer fans underneath the Bada, he also drilled out the top plate and removed the mains Tx which is sited right on top of the mosfets. So that the whole h/amp ran cool.
 
I decided to use the same Papst fans but did'nt see the need to drill out the top plate - the h/amp runs cool and we both found that there was a small but easily identifiable uplift in detail overall.
 
Since not only the mosfets but all the components are operating at substantially reduced temps. We have both changed certain values which mean the6f8g/6SN7 valves are'nt being pushed and indeed it is possible to touch the top of the 6SN7s without burning your hand - the bottom line is that all the components should last for an awful long time.
 
Back to the DACs - imagine these DACs operating vertically and not horizontally with real ventilation slots in both bottom and top plates - the very heat produced by various components would produce a natural convection current, constantly drawing in cooler air- so simple and effective.
 
It's obvious to me which pieces of equipment need fan cooling and which don't. As more research is carried out on classD amps, I feel certain that these are the future - they use relatively little juice and why, because they are so efficient - 90% +. Contrast that with a valve power amp - hugely wasteful and so producing massive amounts of heat., the same can be said of powerful SS amps as well.
 
If an amp has been specced according to need and not to price (far too common) and if by any means the working temp. is greatly reduced then as Kingwa says, caps can indeed expect a useable working life of 30 years +
 
The fact that my 63KI mk11 was bought s/hand in 96 and with a few short breaks is still making music after all this time being left on all the time - this is a real world example of component life, same goes for the PSU powering it.
 
It will be interesting to listen to the 1st generation Marantz CDP that is after I have changed out the PSU caps. I am seriously thinking about buying a s/hand Variac to deal with just these types of situations.
 
If you must switch your system on and off I reckon a soft start device for your whole system  would be a very good investment.
 
 
 

 

[haloxt]

Quote:

I believe the RE1 and likely RE7 uses 150W or power ( a lot more juice then most dacs except those that are built similar in design). If you can afford to leave it powered up 24/7 then fine but remember the caps have a finite lifespan...might as well save that lifespan for actual listening (once you have the gear fully burned in) rather than running up your electricity bill.
 
Peete

Oh my, 150W??? I thught it was like 30W. I'm definitely not leaving my gear on 24/7 now . Can anyone measure with a watt hour meter to make sure.
 
Black Stuart, what's so good about a soft start device? I think some of audio-gd gear have a softstart, it takes like 8 seconds from turnon before the phoenix plays music.

 

[IPodPJ]

I think the RE1 was somewhere between 120 and 140W and the RE7 is around 110 - 120W.  I can tell you that the RE7 runs much cooler than the RE1.  I'm sure the ventilated top plate has something to do with that, as does the more efficient regulation.

 

[vlach]

 
Quote:

 

Another variable to keep in mind regarding comparative listening is how our ears clear/equalize just from swallowing. Sometimes you take an elevator ride or drive your car up & down a hill and your hearing is affected but you are not necessarily aware of it (i am not talking about the obvious ear blocking you get from a plane landing), this can be very suttle and my point is that our ears are not always exactly the same from one listening session to the next. How many times have you swallowed and all of a sudden you ears clear and the sound becomes slightly clearer? Anyway, i think it's just one more thing that should be accounted for since we are on this topic...

 
I meant yawning to clear/equalize the ears...
 

 

[jimmychan]

 
I remember Kingswa said that the RE1 is about 40W.

 

[IPodPJ]

Quote:

 
I remember Kingswa said that the RE1 is about 40W.

You are mistaken.  He didn't say that, and if he did he must have been confusing it with something else.  The Ref-1 and Ref-7 use more power than any DACs in existence.

 

[Black Stuart]

haloxt,
what is there to explain  -  a soft start device is exactly what it says. You have an amp - it's cold - you hit the on switch and bam suddenly there is surge of electricity 110V/230V and many times there will be an over voltage surge this hits first the PSU caps, even when these caps are sensibly over rated it is in essence an attack on the components.
 
When an amp starts to go wrong you can nearly always find the problem in the PSU caps or following regs.
 
I'm surprised that so many who pay serious money for gear don't invest in a few basic books on electronics.
 
A TT or CDP will use on average 6-7W, someone quoted specs for caps - an 8000 hour cap would be called 'long life' many caps have a rated life of only 2000 hours - these are minimum active life figures, specified by  specific temp. figure.
 
I have 2 Kenwood KD TTs the first was badly treated, dropped in transport but played superbly. I had it arse up to work on the phono outs. I had other things to do and left it like that for about a month. I then fixed the vented  hardboard base plate, levelled it and hit the switch - BAM a PSU cap blew and took with it some other components.
 
What should I have done - levelled it and left it for a few days or better still change out all the PSU caps and most importantly used a Variac. Had I done so I doubt if the cap would have blown - a Variac is essentially a soft start circuit and the amount of power fed through to equipment is controlled by the user. Most keen electronic hobbyists own one, I have been remiss in not buying one, it's on my must have list.
 
Does Audio-gd use soft start circuits - before I would buy I would want to know the answer. Soft start circuits will always lengthen the life of electronic equipment - bad news for the makers which is why so many do not fit them. Simple PCB ones can be bought for E10-15.