[Quadman]

Gonna dig in the innards of Gustard #1. Leave #2 alone for awhile.

Atta Boy, 

 
Please report back.  1) bypass fuse or audiophile fuse 2) disconnect the white plugs at IEC board cut shrink twist re-attach (the one to the front panel may be easier to unplug at front panel), do same with digital and analog board wires 3) pull tranny bolts, nuts and washers.  Close and listen after hour or so of signal to re-stabilize.  Use music you are very familiar with.

 

[nc42acc]

My plans are nylon bolts for the transformers, Furutech IEC, chassis damping and wire dressing.

 

[Quadman]

What furutech?  That cutout will only accommodate one furutech IEC, the one with a 5x20mm fuse holder I think it is FG03??  So you still have to bypass fuse.  I will eventually do that too.  The other IEC's are to large unless you want to cut chassis and re-drill and tap screw holes.

 

[nc42acc]

Furutech FI-03 R. If it doesn't fit I have a big hammer.

 

[SimonBromley]

Nice write up Quadman
 
I've done pretty much the same mods as you over the last few weeks.
 
However, I would only recommend dedicated DIY bodgers attempt any of
this stuff. Those who aren't comfortable playing with electronics and happy 
to void their warranties should leave well alone. The X20 sounds very good 
as it is in stock form.
 
That said. My modifications differ in using earthed insulated copper sheeting
rather than the 3M shielding. This is folded into various boxes that separate 
the power supply parts from the digital components. The 3M stuff is much easier 
to use, but I didn't have any, however I did have plenty of copper sheet when the
urge to do it came upon me. Lol ... I may add additional 3M screening later.
 
I also added aluminium sheeting, to create a minimum 6mm thickness of material 
all round the transformer enclosure, in an attempt to contain and reduce EMI.
Plus added a Mu-metal can over the three clocks that sit a bit close to the 
transformers for my liking, just as an extra precaution. The clocks and capacitors etc
currently have Deflex and C37 on them for resonance control. Also, I went the whole
hog, and now have a captive power lead hardwired directly to the transformers. As well 
as upgrading the internal earthing.
 
As you can tell, I'm the type of person who can't resist taking things to bits
and having a play around. 
 
So, does any of this make a difference ? I think it does, and am happy to take
the associated risks. YMMV ...
 
For the money, I think this is a great DAC and I'm enjoying it. But like most 
Hi-End gear, it is a bit of a Prima Donna. In my office system, running single ended 
direct into power amps from a fairly standard power supply, it sounds pretty decent, 
but not outstanding. However, in my main system with dedicated spurs, balanced power 
transformers, balanced valve pre, custom chokes and star earthing. It sounds one hell 
of a lot better. No surprise there of course, but does go to show the X20 can really 
shine with some effort put into the power supply side of things.
 
The only slight issue for me, is that I suspect the power supply section for the digital
board may be a touch under rated. When I first got the X20, the capacitors in that section 
got much warmer than in the analogue section. The right hand capacitor in particular, getting
hotter than I'd like. Pulling the USB card, and going I2S via an external WaveIO card with
it's own dedicated linear PSU seems to have lowered those caps temperatures a bit. I do know 
that the XMOS chips can draw a fair bit of current, especially at the higher frequency 
rates people are commonly up-sampling their music to these days. It may be nothing, but there 
does appear to be rather a lot of stuff going on on that digital board for just those two caps to
cope with ...
 
Anyway, I might try using the transformers externally, to see if this makes any appreciable 
difference. But, that will probably be the last of my bodging on the X20. It's good enough 
as it is, and I've other projects to play with now.
 
Best regards to everyone.
 
Simon

 

[Quadman]

Furutech FI-03 R. If it doesn't fit I have a big hammer.

Yes that or the G version.  When I pulled my IEC out it measured 36 mm c-c on the holes, the cutout in the chassis was apprx 27mm wide and 31 mm tall.  
 
@SimonBromley That is quite a few more steps than I, guess I am lazy.  I do have deflex laying around and could use that instead of blu-tac and cork and see.  Ric is also playing with quantum chips on some parts and even replaced the coax connector with a home brewed version soldered to the board rather than thru a connector as now.  All I can say for now is I am really happy with the sound this dac makes.  Stock is certainly good.  I am dumbfounded why they did not twist the AC wires tho

 

[crazychile]

Have any of you guys used the X20 in a system with HD800s? (both unmodified) I was wondering if you had any brightness or sibilance issues without having to compensate for it somewhere else in the system.
 
thanks.

 

[Quadman]

I have not used with any headphone.  Sorry

 

[nc42acc]

Chile I will give it a try with my Mjolnir 2 and HD800. Might be next week as I am fighting an awful sinus and ear infection.

 

[crazychile]

Chile I will give it a try with my Mjolnir 2 and HD800. Might be next week as I am fighting an awful sinus and ear infection.

Thanks, I appreciate it. No hurry.

 

[SimonBromley]

Just out of interest for those in the UK. 
 
I didn't really think about the voltage of my X20 much once I'd got it, beyond checking it was set 
correctly when it arrived in the post. However, when I recently modified the power supply section, I 
took out not only the IEC connector, but also the voltage selector. 

Now, whilst the manual states that the input voltage is an EU harmonised 230 volts. The actual physical 
selector on the back of the DAC clearly states 220 volt (on my unit anyway).
Why this is of interest to me is that if the DAC is actually manufactured to 220 volt standards, then it 
might only be rated up to a maximum of 242 volts, as per standard supply specs.

Of course, extra tolerance has more than likely been built in, and there's probably no reason for concern. 
However, when I was working on the PSU section, I measured the voltage of my incoming supply at around 
249/250 volts ( not that uncommon here in the UK ).
Having always been a touch concerned that the two capacitors supplying the digital section of the board
always seemed pretty hot to the touch, whereas those on the supposedly more demanding output side always 
remained totally cool. I decided to have a play around.

In my system the X20 is powered by a EquiTech balanced transformer, with input and output voltages both 
handily displayed on it's built-in screen.
So, I wired up a 'buck' transformer in front of the EquiTech and ended up lowering the overall input voltage 
to 216 volts ( not perfect, but well within the 220 volt spec ). The X20's two transformers now measured 
much more consistent output levels than previously, at 8.9 and 14.9 volts respectively. ( should be 9 & 15 ).
And after a few hours of playback, the two digital supply capacitors were running much cooler than previously.
 
Is any of this relevant ?
 
Well ... The fact that originally the X20 was sold with a stated output by vendors of 2.3v rca and 4.6v xlr, 
and 'still' is on many sites. Which totally contradicts the official Gustard manual which gives output stats 
of 2.8v rca and 5.6 xlr. Whilst the actual measured output of an X20 has been shown to be 3.3v rca and 6.6v xlr.
Doesn't exactly inspire me to have confidence in any of the DAC's stated tech specs. And, the fact that the X20
now seems to be discernibly smoother sounding with an improved noise floor, at the lowered input voltage, does
have me wondering ...

Despite being a good value product, the X20 is not a cheap item. I understand that Gustard design the DAC and 
then have an electronics sub-contractor manufacture it. But, I simply don't see this sub-contractor building in 
a switch that has 220v printed on it, if it were not specified. They would quickly go out of business if they 
couldn't get something as simple as this correct.
 
Don't get me wrong. I really like the X20, I thinks it's a very good buy for the money. The power supply 
modifications I've done recently have brought out a particularly deep rich smooth character to the sound.
However, on a pretty Hi-Tech item like this I don't think I should have to be wondering about what it's 
input voltage really is, or what its output ratings really are. These should be clearly stated and correct 
from the very beginning, and there's no excuse for them not to be, as this is really basic stuff.
 
Of course, the voltage side of things only really effects UK based customers, as we are on a 240 volt 
supply. Those in europe should be fine with their 220 volt supplies. 
 
Anyway, sorry for the rant, but stuff like this does rather annoy me. Lol ..
 
Lets not get started on the fact that Lucian, who produces the WaveIO USB/I2S card manages to supply 
a full registered custom version of the latest Xmos Thesycon drivers. As well as first class customer 
service. Whereas, it looks like Gustard (a vastly larger concern) are happy to leave their X20 customers 
only able to use an old pirated? version of the Thesycon drivers. Which is why they state that the USB 
input only goes up to DSD 128, whereas with the proper drivers it goes to DSD 256 no problem at all.
Leaving X20 users having to get something like the Tanley or WaveIO etc, if they want the better drivers 
and sound quality.
 
Anyway, I'll run the X20 at 216 volts for a while, then swap back to my normal 240+ish in a few days to 
see if I notice a difference in sound quality when I do so, and will report back then.
 
Cheers.
 
Simon

 

[BrainFood]

I'm in the UK too and maybe that partly explains the awful lack of air/ sparkle using the internal USB (can't find the multimeter but it's not uncommon in this country for AC to fluctuate to 250 volts and beyond).  Sounded similar with a Tag Maclaren CDT20R into the BNC/ SDPIF inputs as well.  Maybe I just got a lemon though..
 
Anyhow, I'm back to my (noticeably airier) £40 dongle for now and looking elsewhere for its replacement.

 

[SimonBromley]

Hey there Brainfood Good luck with your search for a new DAC ...
 
I've just rewired my 'Buck' transformer and the X20 is now seeing dead on 220 volts.
I checked the internal transformers, and they now read 9 and 15.1 volts respectively.
Which I am much happier seeing, but also makes me suspect that the X20 is actually
engineered for 110 and 220 operation, and running the 250 volts we commonly see here
in the UK may not be the best thing for it.
 
She really likes a good earth path too .. The earth tag attached to the back of the IEC socket
was pretty loose when I inspected it, and something I'd recommend people to check is tight and
secure in their units.
 
Anyway, whilst it's taken a fair bit of messing around, I have to say the sound is now very very
good indeed.
 
Cheers
 
Simon

 

[BrainFood]

  Hey there Brainfood Good luck with your search for a new DAC ...
 

Thanks dude 

 

[fperra]

  Have any of you guys used the X20 in a system with HD800s? (both unmodified) I was wondering if you had any brightness or sibilance issues without having to compensate for it somewhere else in the system.
 
thanks.

I replaced my Schiit Gungnir MB with the X20 four says ago and I've been listening every night for a couple of hours with my HD800S. No sibilance or brightness issues. And it is a step above the Gungnir. Wider sound stage, better perceived  space around instruments and a little more detail.