[Lucus]

Congrats for your DAC ! You did decide for the Lab12 finally. Good to have your feedback
Yes, changing the 6922 with the Philips one should definitely improve the sound: What kind of tube are they ? E188CC ?
Philips made the best E188CC / ECC88.
Strange your story with "distortion": Normally the human ear is not able to perceive the low distortion of a DAC, even the tube output stage...

 

[running wild]

@Lucus
Hi,
i take a look at my backup tubes and found these ones:
Sylvania USA 6DJ8 3x
USA 6922 3x
Ultron ECC88 4x
??? ECC88?? 2x (lable is not readable anymore)
Ultron E88CC 1x
Amperex Holland ECC88 2x
Valvo ECC88 2x
Philips USA JAN 6922 4x
EH 6922 4x (2x DAC1 + 2x Cayin CDT15A)
What do you think about which tube is the best of the bunch?

 

[Lucus]

Hi
The best tubes are the E188CC-7308 (professional/military usage) or the ECC88-6DJ8 (domestic use). You should avoid the E88CC they don't have microphonic protection, and are usually poor in term of HiFi/audio quality. The 6DJ8 is the US naming for ECC88, so they are certainly good. But I see that you have Amperex Holland ECC88 = I would assume that they are pretty fine !
In these category of tubes, the Philips one are the best with their relatives (RT, Miniwatt, Dario, Valvo, Amperex): Best if they are matched

 

[running wild]

@Lucus

Did you get yours?
I still have the problem with the distortions.
It is also not genre-dependent.
It is strongest with fast metal or even Hans Zimmer.
Other things even work quite well, although you can easily hear something.
I have already switched from USB to coaxial - no change.
Changed from XLR out to RCA out - no change.
Upsampling from my Aries - no change.
Swapped tubes for other Amperex 6DJ8s - no change.
Is it possible that the output voltage from the DAC could be too high for my SPL Phonitor?

 

[running wild]

Switching to the Flux Labs FA-10 as HPA instead of the SPL - same problem.
Switching to the inbuild DAC of the SPL - everything is fine as it should be.

 

[George Hincapie]

To each their own, but Holo and Denafrips are nothing alike other than that they have r2r products and are from China. Circuit design & methodology, chassis design, fit & finish, etc are very different between the two, speaking from experience. The lab12 stuff does look interesting though. A bunch of it popped up on The Music Room recently, would be interesting to audition.

Excuse me? There is nothing wrong with Denafrips fit and finish. They are beautifully built.

 

[kingoftown1]

@George Hincapie you really got in the time machine, went back two years, took that post out of the context of the discussion and wildly misinterpreted the point. I wasn't bashing anything in that post. Different means different, nothing more nothing less. I happily own both Denafrips and Holo products.

 

[Lucus]

Switching to the Flux Labs FA-10 as HPA instead of the SPL - same problem.
Switching to the inbuild DAC of the SPL - everything is fine as it should be.

Is it a new one or a used one ?

 

[Lucus]

Switching to the Flux Labs FA-10 as HPA instead of the SPL - same problem.
Switching to the inbuild DAC of the SPL - everything is fine as it should be.

Is it a new one or a used one ?

@Lucus

Did you get yours?.
Is it possible that the output voltage from the DAC could be too high for my SPL Phonitor?

No still waiting for delivery
The output voltage is 2.5V, so rather on the low side....

 

[running wild]

@Lucus

it´s a used one.
I had no issues buying used gear before.
Everything worked fine.
I contacted Lab12 of this issue.
I hope i will get a message from them.
Perhapse i can send it to them for check.
The original invoice was included and they have a 5 years warranty.

 

[Lucus]

Yes, that's a danger when you are buying used gears...It happens to me once where the gear I received was not up to my expectation and to what I had heard before: A quick check showed that it had some defekt, not mentionned by the seller of course. Looks you are experiencing the same bad luck. If you can put a note/comment to your seller because it is really not fair to sell a gear with an issue !!
I really hope that Lab12 can repair it. Will be good to follow on this thread if they can deliver the warranty !

 

[George Hincapie]

@George Hincapie you really got in the time machine, went back two years, took that post out of the context of the discussion and wildly misinterpreted the point. I wasn't bashing anything in that post. Different means different, nothing more nothing less. I happily own both Denafrips and Holo products.

OK. I apologise.

 

[running wild]

Yes, that's a danger when you are buying used gears...It happens to me once where the gear I received was not up to my expectation and to what I had heard before: A quick check showed that it had some defekt, not mentionned by the seller of course. Looks you are experiencing the same bad luck. If you can put a note/comment to your seller because it is really not fair to sell a gear with an issue !!
I really hope that Lab12 can repair it. Will be good to follow on this thread if they can deliver the warranty !

@Lucus
I contacted the seller yesterday evening and got a reply that the unit is fully working correctly at his equipment with different amps.
Yesterday evening i send a mail to LAB12 with that issue and i hope they will contact me shortly.

 

[running wild]

@Lucus
Got a replay from Lab12.
-------------------------------------
Answer form Lab12:
"Thank you for your reply and your analytic information you provided to us.

It looks like both of your amplifier has unusually low input impedance (3.3 to 10 Kohm).

This might not be a problem with a single-ended DAC. However, Dac1 Reference is tube output and like all the tube output devices is not ideally matched with to such a low input impedance.

This may be the reason for the problems you are facing. Maybe it would be better to try your Dac1 Ref. with an amplifier with more usual input impedance.

If you still feel that there may be a problem with your device, you can contact our distributor in Germany for a full evaluation."
-------------------------------------

Looks like that the my DAC1 has no problems - just with my other gear....
With what gear do you want to use the DAC1 Reference?

 

[Lucus]

I have a Lavardin integrated, with 10Kohm input impedance. Normally these impedance issues are only sensible between preamp and amp, not between source and preamp/integrated, because you are always in the KOhm area. Maybe hearing via headphones amplify the issue ?
Nevertheless I have tried to find what is the output impedance of the DAC1 ref: Nowhere to be found....
Can you perhaps ask them ?
EDIT: The "usual" relation is to have at least a factor 10 between output and imput impedance. This would mean that the Lab12 has an output impedance of >1KOhm to be a problem for a 10KOhm imput impedance amplifier ?. This is rather unusual for a DAC to have such impedance....= To be checked