Xindak DAC-5 mods

Cobra2

Member
Paid Member
2002-04-06 12:47 am
Stavanger, Norway
I have one of these:
http://www.xindak.com/english/products/showditail.asp?id=326

and started modding...

First question; it has a 6922/E88CC/(6DJ8) output buffer, (cathode-follower), how do I improve this?

It has a regulated plate-supply of 100V, can be increased to 120-125V, (with added zener), and still have regulation, (132V after bridge).

Arne K
 

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Hi

I have just sent for one of these DAC's and was wondering about mods.

I have no experience of electronics at all, so wanted to know if there are any mods that can be done with no experience or soldering skills etc?

I was going to try some new tubes, so any reccommendations are welcome?

I was wondering if it would be possible and not stupidly expensive to find a compnay to add USB input to the Dac-5?

Thanks


PS. Do you think the DAC will be as good as those in my Denon AVC A1SE?
 
Xindak's very latest DAC is based on the DAC-5, but with some improvements and additions like USB input etc.

It has isolation cages over the trasformers and I was wondering if this is a mod that could be done to the DAC-5?

Remember, I have no experience when it comes to mods, so any advice is welcome.

BTW, I read one person replaced the stock tubes with some 6922's from the 1960's. I have read that in some cases the stock tubes are by Sovtek and in others Electro Harmonix.

With regards to adding USB to the DAC-5, I instead bought a HagUSB, USB to SPDIF converter, as the user reviews sounded great.
 
How difficult and expensive would it be to add a Superclock output from the Xindak DAC-5?

According to Less Loss's website, it's easy to mod practically any CD player/transport to accept an external clock.

They also say that their tests showed that it makes zero difference which transport/player is used (cheap or expensive), the jitter readings are the same.

They used the cheapest CD player they could find and got fantastic jitter measurements when connected to thier DAC, with the DAC as maseter and CD player as slave.

I was thinking of trying to mod my Toshiba SD900E in this way, but I want it to be able to use it's own clock when playing DVD-A discs (yes, I have some). Would the mod on thier website dissable the internal clock altogther?

Cheers
 

Uunderhill

Member
2008-12-27 11:27 pm
BTW, I read one person replaced the stock tubes with some 6922's from the 1960's. I have read that in some cases the stock tubes are by Sovtek and in others Electro Harmonix.

I've tried a ton of vintage tubes in my DAC-5.
Without any question, a 1960's Siemens ecc88 is the best match for this Xindak DAC.

Sonics can be improved even more, by adding a Monarchy DIP Classic to reduce jitter.
Monarchy DR-1 is the best digital cable I've heard with this DAC.
 

Uunderhill

Member
2008-12-27 11:27 pm
Do you use matched triodes ecc88 for your DAC 5 or unmatched are fine too? I'm looking for a NOS tube for my Xindak.

I'm guessing that the tube output stage is a Cathode follower,
so the gain is a touch less than 1.

If that's the case, having within 8% transconductance should be OK.

What is critical is that its a 1960's Siemens ecc88 tube.
These have a flat bar going up to the getter.
 

imnewbie

Member
2010-06-02 2:46 am
How are the rest of the vintage compared to Siemens since you've tried many of the vintage tubes? Like which tube is your #2, #3 etc.?
It's really hard to find Siemens 6922 with well matched triodes. How is the matching with the triodes of all the tubes you've tried?
 
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hi
one mans best match may not be the same as yours,this game is always subjective at best,just to many variables to be other wise.
so may i surggest to start just get afew different sensible priced valves and have a play and see what you think of the differences then your get a idea what your after from your valve regarding sound quality,plus your have afew spares if some should die,which can be a real event with older nos valves or any for that matter.
of course this is just one mans veiw and opionion,as always it comes down to you to decide...just remember to enjoy the journey and not make yourself broke:D
all the best
smithie
 

Uunderhill

Member
2008-12-27 11:27 pm
Tube sellection for the Xindak DAC 5

How are the rest of the vintage compared to Siemens since you've tried many of the vintage tubes? Like which tube is your #2, #3 etc.?
It's really hard to find Siemens 6922 with well matched triodes. How is the matching with the triodes of all the tubes you've tried?

Some of the 1960's Siemens 6dj8 / 6922 / 7308 can get very expensive.

Here are my top sellections for the Xindak DAC-5

1. 1960 Siemens ecc88 (6DJ8) - steel pins, small o getter
with a flat bar holding up the getter
In the US these were often inked with Raytheon
Clearly, this is a best value tube.
Has neutral sonics, with lots of detail and little harshness

2. 1970's Siemens e88cc (6922) or e188cc (7308)
A frame holding up a flat disk getter
These often fetch serious money
More warmth and bass than the tube above, but less detail

3. 1960's Siemens e88cc (6922) or e188cc (7308) - gold pins
very small o getter held up by a flat bar
these go for quite a few pennies
Very difficult to find

4. Amperex 6dj8 - Orange Globe - small o getter with shield - Holland
There are lots of variations on this tube - But its this exact tube I recommend
Lots of warmth, but not as focused as the tubes above.

5. Amperex 6922 - white label - large O getter - USA - gold pins
often inked with Beckmann or Hewlett Packard
This is a famous tube that goes for serious money.
Sonically the most dymanic tube here and has lots of bass.
IMO the high frequencies are not as focused as any of the tubes above.


Also, as important as the tube, I highly recommend a Monarchy Classic DIP.
This unit reclocks the bits before going into DAC.
The clock in the Monarchy DIP is made by Fox and can be upgraded to one made by Tentlab.

Best digital cable I've heard between the Monarchy DIP is the Monarchy DR-1.
But its a garden hose - that has little flexibilty.
Also, I've found the DIP needs a well sheiled power cord.

PLease let me know how things turn out.
 

imnewbie

Member
2010-06-02 2:46 am
Thanks and I will.

Does using this DIP make a big noticeable difference with Xindak DAC? Is it possible to make the transport accept the DAC's clock instead of buying a separate DIP?

How you use transport output to DIP input via coaxial or optic when the transport has both outputs available?

I was totally unaware of this DIP info., I'll keep looking for a used Classic DIP for my DAC 8. BTW, I'm looking at early 60's Tesla 6922 which is said to be copy of the Siemens you recommend. I don't expect it to match a Siemens performance-wise but I'll try it out.
 
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Uunderhill

Member
2008-12-27 11:27 pm
Thanks and I will.

Does using this DIP make a big noticeable difference with Xindak DAC? Is it possible to make the transport accept the DAC's clock instead of buying a separate DIP?

Think most DAC's just use a PLL (Phase Lock Loop) to bring in the bits and not re clock them.
However, I see the Xindak DAC has a 24.576 MHz clock.
So I suspect it divides this down 128 times and then reclocks the bits.

To cut a long explaination short, after quite a bit of listening,
in this case, adding the Monarchy DIP makes a minor, but noticable improvement.
With DAC's that only use a PLL, the DIP makes a dramatic improvement.

However, since the Xindak DAC also reclocks the bits, rather than buying the Monarchy DIP & 2 more cables,
think you may be better off having the clock in the Xindak DAC rebuilt.
 

imnewbie

Member
2010-06-02 2:46 am
Considering tentlabs clock or may be their transport kit. Thanks for tentlabs suggestion.

1. Does it matter if I get a decent transport or I should be fine with my old CD player since I'm getting a DIP/clock upgrade with DAC 8?

2. What cables you are using with your DAC 5? I think I should upgrade from monster cables.
 

Uunderhill

Member
2008-12-27 11:27 pm
Considering tentlabs clock or may be their transport kit. Thanks for tentlabs suggestion.

1. Does it matter if I get a decent transport or I should be fine with my old CD player since I'm getting a DIP/clock upgrade with DAC 8?

2. What cables you are using with your DAC 5? I think I should upgrade from monster cables.

With DAC's that lock the bits in with a PLL only, I've found the DAC generally
takes on the personality of the transport.

However, I think the Xindak reclocks the bits, so changing the transport will
make some difference but not a huge one. I would suggest looking at other things first.

Recommned you replace the Monster cables.

For the cables in the back of a DAC, I've found the quality of the sheilding is important.
For a power cord, I suggest making your own from Belden 19364 and some Furutech or Marinco connectors.
For a digital cable, I recommend a Tributaries V1 silver plated, triple sheilded - 2 meters in length.
These have a yellow jacket and are quite inexpensive.
Atlas and Monarchy DR-1 are also very good digital cables.
Analog interconnects is a tough one.
Maybe DH labs interconnects or Musical Fidelity Nu Vistas.

If you are using the DAC-8, even though it has a built in pre,
I suggest you use a tube buffer or preamp before the signal goes into the Amp.

Anyway the starting point is to replace the stock tube and digital cable.
 

imnewbie

Member
2010-06-02 2:46 am
If you are using the DAC-8, even though it has a built in pre, I suggest you use a tube buffer or preamp before the signal goes into the Amp.

This question may sound stupid as I have zero experience. I'll be using integrated tube amp (Xindak MT-1). Even with a tube amp, adding a tube buffer or pre-amp will further improve the sound?

What RCA interconnects as outputs from DAC-5 to preamp/main amp worked out best?

BTW, have you tried Belden 19364 and compared against other power cords? I've read very unfavorable Belden cable + Futuretech adapters DIY reviews from a quick search saying some $100 range (assembled) power cords are better than them. Also, where did you purchase the Tributaries cable from? No one on the web seems to be carrying Tributaries digital cables. Especially your particular cable.
 

Uunderhill

Member
2008-12-27 11:27 pm
This question may sound stupid as I have zero experience. I'll be using integrated tube amp (Xindak MT-1). Even with a tube amp, adding a tube buffer or pre-amp will further improve the sound?

What RCA interconnects as outputs from DAC-5 to preamp/main amp worked out best?

BTW, have you tried Belden 19364 and compared against other power cords? I've read very unfavorable Belden cable + Futuretech adapters DIY reviews from a quick search saying some $100 range (assembled) power cords are better than them. Also, where did you purchase the Tributaries cable from? No one on the web seems to be carrying Tributaries digital cables. Especially your particular cable.

Haven't heard the Xindak MT-1 but have heard the MT-3 and was quite impressed.

Forget about the tube buffer, I though you might be running a Xindak DAC-8 straight into a power amp.
The preamp in the DAC-8 is not bad,
but a buffer will add more current capability to drive the front end of a power amp.
But since you are feeding a DAC-5 into the MT-1 Integrated, forget the buffer.

From a few very experienced DIY'ers, I asked the question on how to improve on Beldon 19364.
They thought Neotech NEP-3003 power cord is very good for a CD player.
Certainly, this cable has both a foil and braided sheild and the quality of the copper is very high.
However, the Belden is $2.60 a foot and the NEP-3003 is about $20 a foot.
I'm of the opinion that DAC's are sensitive to the quality of a power cord and sheilding.

Finding a good pair of analog interconnects is a tough call.
I hesitate to make a recommendation on this.

The Tributaries V1 silver plated digital are an older model and have a yellow jacket.
They were also used as 75 Ohm video cable cables.
1.5 meters is the ideal length for a digital cable, but a 2 meter length also seems to work fine.
Assorted Tributaries audio and digital cables - Canuck Audio Mart
Unfortunately, these are 1 meter long.

I didn't read the artical, but UHF magazine said that 1.5 meters is the ideal length for a digital cable.
I suspect the reason for this has to do with termination impedance and signal reflections,
propagation velocity and duration of the S/PDIF protocal.
Its a long story.
 

Uunderhill

Member
2008-12-27 11:27 pm
What is the ideal length for power cords?

Which cord you use works best with your DAC-5?

Right now I'm using a Monarchy power cord.
I'm guessing that the actual cable was made by TDK using the Ohno Continuous Cast process.
But not totally sure.

I have it plugged it an Equi=Tech Balanced isolation transformer to clean up the Hydro a bit.

Think later on this summer, I'll have a go at making a couple of cables using Neotech NEC 3003
and listen for any improvement.
Again, I suspect the quality of the sheilding around a DAC is important
so that the digital cable doesn't talk to the power cord.

I would suggest keeping a power cord under 6 feet.

What is it about your system that you would like to improve ?
I take it you listen to Jazz or Classical.
What speakers do you have ?
Think everyone has been in "system pergatory" which is not much fun.
However, it sounds like by getting matching cables and some vintage signal tubes
your Xindak equipment should sound enjoyable with the right speakers.