Xindak DAC-5 mods

[Cobra2]

I have one of these:
http://www.xindak.com/english/produc...ail.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

[Kane Williams]

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?

[Kane Williams]

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.

[Kane Williams]

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]

Originally Posted by Kane Williams

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.

[imnewbie]

Originally Posted by Uunderhill

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.

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.

[Uunderhill]

Originally Posted by imnewbie

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]

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?

[smithie]

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
all the best
smithie

[Uunderhill]

Originally Posted by imnewbie

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.