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REVIEW: Grant Fidelity TubeDAC-11 - Page 15

post #211 of 267

Thanks for the response. Now that you have confirmed it I will try it with different hphones (Denon AHD 7000 etc.). I thought the HE6 has great if not decent bass.I believe this is also the view of the author who compared the 50 flagships. Thanks again.


Edited by tigerkg13 - 6/16/13 at 5:44pm
post #212 of 267

Yes, those drum notes are there! It is not right at the beginning but 11 seconds into the song. If that's what you are referring to then I do hear them with the HE6. It's more distinct if I were to use the Emotiva to control the volume. It helps too if I were to increase the volume. Thanks again.

post #213 of 267

I have now had my Grant Fidelity Tubedac-11 for a few days and I must say I'm very impressed with the performance and how much dac / pre-amp this is for the money. Nice build quality and quality feel. The sound is transparent and the dynamics and signal-to-noise ratio impressive. The background is almost a dead quiet even with the volume at max level. I was a bit worried about the high 6V RMS output but thanks to the non-linear volume control this causes no problems (I have tried different power amps with input sensitivity between 0.5 to 1.4 V). The volume pot feels very nice as well.

 

The only negative I've found is that it emits click noise when switching between songs that have different sampling rate which is a bit annoying and that the DAC fails in the intermodulation test below: 

 

If you're curious about the performance of your own system, the following samples contain a 30kHz and a 33kHz tone in a 24/96 WAV file, a longer version in a FLAC, some tri-tone warbles, and a normal song clip shifted up by 24kHz so that it's entirely in the ultrasonic range from 24kHz to 46kHz:

 

Intermodulation Tests:

 

30kHz tone + 33kHz tone (24 bit / 96kHz) [5 second WAV] [30 second FLAC]

 

26kHz - 48kHz warbling tones (24 bit / 96kHz) [10 second WAV]

 

26kHz - 96kHz warbling tones (24 bit / 192kHz) [10 second WAV]

 

Song clip shifted up by 24kHz (24 bit / 96kHz WAV) [10 second WAV]

 

(original version of above clip) (16 bit / 44.1kHz WAV)

 

Assuming your system is actually capable of full 96kHz playback, the above files should be completely silent with no audible noises, tones, whistles, clicks, or other sounds. If you hear anything, your system has a nonlinearity causing audible intermodulation of the ultrasonics. Be careful when increasing volume; running into digital or analog clipping, even soft clipping, will suddenly cause loud intermodulation tones.

 

Source: http://xiph.org/~xiphmont/demo/neil-young.html

 

I hear noises in all the above tracks, noises that I suppose should have been filtered out by the DAC... 

 

Because of this I have to restrict sample rate to 44.1 KHz in the software player (Audirvana+). If the DAC can't handle samplerates correctly, then the feature becomes pretty useless... 

 

 

Then I wonder if anyone knows if you can just disconnect the tube because I believe that the tube does not add anything but noise and literal warmth. 


Edited by WinstonOboogie - 6/27/13 at 5:55am
post #214 of 267

I'm using foobar and I have the "Visualization: Spectrum" docked so it runs from left to right, and when foobar is maximized to be a full 1920 pixels across it shows 4 bars dancing at the top end of the spectrum toolbar.  The 30khz and 33khz @ 24/96 file does not have the dancing bars, and it's the only one that is playing silent on my 2008 Sound Blaster Audigy.  This makes me suspicious of these files.  Sadly, on my main system driven by an atom netbook => JKSPDIF-MK3 => Yulong D18 I can hear a steady tone in that one file -- I'll have to do more tests to identify what component is responsible for that.

 

Concerning my spectrum toolbar -- I assumed that the spectrum in foobar only covered 20hz-20khz.  If I'm right than that means these files (accept the one) are asking my DACs to play tones in the audible spectrum, which would invalidate them as instruments for testing ultrasonic behavior.

 

One interesting thing is that I easily hear a difference between WASAPI-event and WASAPI-push while playing these files.

post #215 of 267

Reading again your review, project86, I noticed the TubeDAC only uses its tube when it's working as a dac, am I right?

post #216 of 267
Quote:
Originally Posted by ebiscaia View Post

Reading again your review, project86, I noticed the TubeDAC only uses its tube when it's working as a dac, am I right?

nope. the tube drives one of the output buffers.

 

there are 3 sets of rca analog outputs.

 

one is the dac out. it can only derive it's signal from the dac. the volume control on the td-11 does not have any effect on this output. so, from this you get the dac's output unprocessed by any td-11 preamp type of functions (no volume, no tube effect/affect, no changes of any other type imparted by the circuits of the td-11 beyond it's DAC).  

 

the other 2 outputs are the tube out, and the line out.  both of these are controlled by the volume pod. the line out is solid state. the tube out is, duh, tube driven.

 

so, you can chose to take the input signal from the dac (via the usb or spdif or toslink) or from one of the sets of rca inputs. i for instance have used one of those for my turntable's output (via a phono preamp). so, you can simply turn one dial and select the dac or other input, and turn the other and send that signal out thru the tube path or the solid state path or use DAC OUT if you've selected a digital input and dont wanna apply any preamp functionality.

 

fun huh? this is why they call it a swiss army knife.    

post #217 of 267

Quote:

Then I wonder if anyone knows if you can just disconnect the tube because I believe that the tube does not add anything but noise and literal warmth. 

 

forgot to mention -- I said the same in my very first post.  The only other person I saw reaching this same conclusion was here...

http://www.highfidelityreview.com/grant-fidelity-tubedac-11-review.html

post #218 of 267
Thread Starter 
Quote:
Originally Posted by Wynnytsky View Post

forgot to mention -- I said the same in my very first post.  The only other person I saw reaching this same conclusion was here...

http://www.highfidelityreview.com/grant-fidelity-tubedac-11-review.html

 

I can see how the tube would be appealing for some systems. And also how the solid state outputs could be a better match in other cases. Glad the device has so many options!

post #219 of 267

Thanks for the review Project86. Although I'm new to this hobby (still holding on tight to the wallet), I still enjoy reading your thorough and insightful reviews. This DF DAC caught my eye due to the swiss-army-like functionality and I hope to add it to my desktop rig in the near future. 

 

One question...I can only sample the tube "flavor" by using the tube out on the back with a high impedance headphone like a HD6xx? Otherwise, I'm only using the front headphone out with my current low impedance headphones. Is there plenty of current to drive low impedance cans from the headphone out? I DO hope to add a HD600 to my lineup with a month or so. 

post #220 of 267

What a relief analog'd,

 

I thought the topology was as it follows:

 

Digital: dac+buffer (tube) -> pre amp (ss) -> amp (ss)

Analog: pre amp -> amp

 

But the correct is the one bellow, instead:

 

Digital: dac -> buffer (tube) -> pre amp (ss) -> amp (ss)

Analog: buffer -> pre amp (ss) -> amp (ss)

 

What is great! Another question: is using the tube in the buffer section more impactful to the sound character than using it in preamp? I mean, I'm between the Tubedac 11 and TubeMagic D1+ and their main difference is the topology. If there is someone who listened to both and want to share his/her experience I'll glad to read it.

 

Thanks for everybody

post #221 of 267
Thread Starter 
Quote:
Originally Posted by Cla55clown View Post

 

One question...I can only sample the tube "flavor" by using the tube out on the back with a high impedance headphone like a HD6xx? Otherwise, I'm only using the front headphone out with my current low impedance headphones. Is there plenty of current to drive low impedance cans from the headphone out? I DO hope to add a HD600 to my lineup with a month or so. 

 

That's pretty much it - the front panel headphone out it pure solid state. High impedance phones have the option of using the rear tube out via adapter. The actual headphone jack has plenty of current and a low output impedance to avoid interactions. It's a pretty nice amp by itself. 

post #222 of 267
Quote:
Originally Posted by Wynnytsky View Post

forgot to mention -- I said the same in my very first post.  The only other person I saw reaching this same conclusion was here...
http://www.highfidelityreview.com/grant-fidelity-tubedac-11-review.html
Reading that review, I don't see where you draw that conclusion from.
post #223 of 267

I was wondering the same thing. I thought it was my bad English that got Wynnytsky to misunderstand me. After trying "line-out" and "tube-out" side by side, my conclusion is that the "tube-out" does not add anything other than heat and noise. The latter becomes significantly noticeable at idle. I would like to disconnect the tube so I do not have any unnecessary heat that stress components. I guess this can be done without anything other than "tube-out" affected.

post #224 of 267

ASQuote:
Originally Posted by ebiscaia View Post

What a relief analog'd,

 

I thought the topology was as it follows:

 

Digital: dac+buffer (tube) -> pre amp (ss) -> amp (ss)

Analog: pre amp -> amp

 

But the correct is the one bellow, instead:

 

Digital: dac -> buffer (tube) -> pre amp (ss) -> amp (ss)

Analog: buffer -> pre amp (ss) -> amp (ss)

 

What is great! Another question: is using the tube in the buffer section more impactful to the sound character than using it in preamp? I mean, I'm between the Tubedac 11 and TubeMagic D1+ and their main difference is the topology. If there is someone who listened to both and want to share his/her experience I'll glad to read it.

 

Thanks for everybody

 


sdsdsdQuote:
Originally Posted by ebiscaia View Post

What a relief analog'd,

 

I thought the topology was as it follows:

 

Digital: dac+buffer (tube) -> pre amp (ss) -> amp (ss)

Analog: pre amp -> amp

 

But the correct is the one bellow, instead:

 

Digital: dac -> buffer (tube) -> pre amp (ss) -> amp (ss)

Analog: buffer -> pre amp (ss) -> amp (ss)

 

What is great! Another question: is using the tube in the buffer section more impactful to the sound character than using it in preamp? I mean, I'm between the Tubedac 11 and TubeMagic D1+ and their main difference is the topology. If there is someone who listened to both and want to share his/her experience I'll glad to read it.

 

Thanks for everybody

 

From what I read in another post by Ian at Grand Fidelity this is not really true. TubeDac-11 operates with a fixed gain. The only difference between the "line-out" and "dac-out" is different attenuation. The only level that adds something to the chain is "tube-out". 


Edited by WinstonOboogie - 7/2/13 at 11:44am
post #225 of 267

Greetings,

 

I know some of you here as I have posted  on the audiokarma- Grant Fidelity forum (I generated the tube rolling spreadsheet for the TubeDAC-11).  Other than complimenting Project86 earlier in this thread for a fantastic review of the TD-11, I seldom post at head-fi since I have always been about my 2 channel main system.  Well, that is changing dramatically in a few months as we are moving to a downtown condo in a 1927 building.  Even with sound treatments in place, the main system will be reduced significantly loudness-wise.

 

So with that, I am ready to delve aggressively into the headphone world so I can “crank it up” when the mood strikes (which is often).  I have already chosen my closed cans for this journey: the new Mr. Speakers Alpha Dogs (heavily modified Fostex T50RP’s).  Rest of system is Mac Mini dedicated music server w/ J Keny USB/SPDIF converter, TubeDAC-11, “amp to be determined”, Alpha Dogs.

 

The Alpha Dogs have a 50 ohm impedance,. 250 mW  min & 1 w/ ch or greater recommended. Sensitivity is 94 dB/ mW.  With a Rat Shack SPL meter, I generally set volume to 82 dB or so w/ 85 dB peaks.

 

So I could use the headphone out of the TD-11 (I have some cheaper JVC HA-S400’s but wasn’t all that impressed).   I assume the Tube Out probably is too much for these cans since 300 ohm or greater is mentioned by Ian in his TD-11 specs.  Since these AD's are said to be harder to drive, does that allow the Tube Out to possibly be considered?  Does the TD-11 back panel Y adapter to Line Out or DAC out garner any improvements vs. the front panel headphone out ? I’ll be adding a better headphone amp later on, but just curious what TD-11 owners think.

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