Scott Nixon TubeDAC mini-review
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chillysalsa

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The kit came together really quick and easy, a perfect second project. I decided to spice it up a little by putting in some lighting, call it the ‘Chor-ling’ or the ‘Shan-ord’ styling.



The strong suits of this DAC are dynamics, instrument separation, imaging, and a ‘live’ / organic / analog sound presentation. That’s not to say it’s a slouch in the other departments: frequency extension, and soundstaging. It has become one of those pieces of equipment that are making me rediscover my collection. I’ve had a number of instances already where I noticed something totally new about a record I heard a million times already! That’s a major statement, and I think the sign of any good component.

In the few cases where I have the same piece of music on CD and vinyl, I can readily recognize that the CDs now have some of that ‘magic’ that had been seducing me from my turntable. This DAC has stopped a 3 month streak of listening only to vinyl (even though only 20% of my collection is analog!). My overall impression is that his unit has indeed fulfilled my search for an analog sounding digital source. It’s definitely narrowed the gap between my turntable and CD playback, to the point where I’m no longer wishing one sounds like the other.


Massive Attack – Mezzanine:
Track 6, there is that echoing clack sound at 0:40, it totally startled me with how it came out of nowhere. The most amazing thing about this, is when you switch back to the internal DAC of the Yamaha, you listen for the same sound, expecting it, and it goes by with you saying “Oh, uh.. yeah.. there it was. Was that all?”
The TubeDAC has totally removed a layer of ‘haze’ from the ambient sounds in the background. Previously, these were filler noises to give some mood to the song. Now, they are more like a set to a movie - with intricate details that are exposed the more you examine and search for them. The vocals are equally intricate – breathy and delicate, and sound wonderfully organic.

Track 8: that distant piano in the opening. You can almost see what keys look like, it’s almost eerie how well that is imaged. Unbelievable. Through the headphone set-up, the bass is so full my ears get that ‘still vibrating’ feeling when I take the headphones off mid-song – and at only moderate volume.

Bjork – Vespertine:
Track 5, one of my favourites, involves a wonderful harp melody. I can finally track the notes so easily through all the other things going on. Clearly, the separation of instruments is one of the strong points of this DAC, previously everything sounded as though it originated from one source, a source that was always the same generic size and the images of the instruments flowed from it all blended together. But now, they are all distinct, with character and details of their own, and don’t overpower the other instruments / sounds.

Track 6, is a little melody played by a music box, and on the headphones, it sounds so real, you wouldn’t believe. In fact, the track starts with a sound of something sliding across a surface, and it startled the heck out of me because I thought it was something in the room! Sheesh… I was amazed.

On the downside, there is some audible hum. I’m not sure if it’s PS I’m using, or what. I’ve emailed Scott about it, and understand that others have said it’s dead silent. My noise is not intrusive until you get to volume levels that are dangerous to my ears or the equipment, so I’m not bothered. Would like to get to the bottom of it though.



[size=xx-small]Notes:
Audio Alchemy DTI used for reclocking, inversion, & convert Toslink>Coax signal, with Phase set to 180º
4.5 A, 12VAC transformer for power supply made by Ault.
Stock Miniwatt tube used.

Setup:
Yamaha 5 disc changer > Glass optical cable > AA DTI > Apogee WydeEye > TubeDAC > Homegrown Audio Super Silver to:

A) Audio Refinement Complete > PSB Image 2B
or
B) Grado SR-125 & RA-1 amp (via MIT T3 interconnect)[/size]

Edit: Scott got back to me about the hum. Pretty much what I observe: if you press Stop, and start turning up the volume, you don't notice noise until it's a volume you won't dare press Play at! So, it's effectively silent you could say.
 
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usc goose

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thanks for the review.


nice pics too.
 
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Sean H

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Thanks for the sharing your impressions. It's such an interesting little DAC, always good to hear impressions of it.
 
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lan

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Thanks for the nice review.

I wonder how this unit compared to dAck! and shigaraki. I've asked this question before
but it intruiges me. It's one of those things on my list I've got to check out. The minimalist in me is calling.

How long did it take you to build?
 
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chillysalsa

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It was really easy to put together, he gives some clear instructions. Took 2 evenings.

I'd also like to hear how it compares with those other non-oversampling DACs.. Maybe I could arrange a trade with someone down the road, and then exchange opinions.
 
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stymie miasma

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Nice review Chilly - thank you!

Are you able to try the TubeDAC without the Audio Alchemy DTI in the chain, or do you need it for Toslink->Coaxial conversion? I was wondering how important reclocking is in order to get good results with the TubeDAC.

 
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kugino

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i've been wondering the same thing. i know that the most pressing issue with transports is the amount of jitter they produce...the dti or the monarchy dip reclock to manage the jitter, but how important is the toslink->spdif conversion in this process? since the nixon tube dac only has a spdif input, the dti serves two purposes, but i think the jitter management is more important. dac chips also manage jitter, do they not? how good is the nixon dac's chip in managing jitter?
 
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chillysalsa

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My CD changer only has Toslink, thus I must convert it to Coax.

I toyed with the idea of modding the TubeDAC for a Toslink input, but have doubts about the quality of the result.

Both the DTI and the TubeDAC have a CS8412 reciever chip. So, in effect, the signal is re-clocked 2 times. before it reaches the DAC chip. I'm not sure if this lowers or raises jitter, but I can say that with my old dac, if I took out the DTI from the chain, there was a tiny amount of bass lost (like, 1 Hz !?!) and the sound, was less... solid? I couldn't put my finger on it, so maybe it was psychological.
 
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rickcr42

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Quote:

how good is the nixon dac's chip in managing jitter?


the nice thing about simple kit dacs is the open ended/easily modified nature of the beast

You can make decisions during the build stage to use upgraded parts instead of building the device then modifying it later and like the akk dak decide to use a battery instead of line power supply

the jiiter thing is a non issue if you take into consideration how many dacs have a spdif input only without being questioned and with the availability of not only coverters for toslink but antijitter reclocking devices that can be added to the dac it is up to the end user how far they want to go with the simple dac

I personally favor simple over complex and if it is not needed and can not be heard I leave it out and non os dac chip direct from input receiver (with glue logic in the case ogf the AD chips) is as direct as digital gets .


My dac is similiar but uses the AD1865K non os/tubed out with jung type regulator as a "pre-reg' and individual shunt regs at each stage

I have designed and built dacs with both BB and AD chips and prefer the AD chips .Less "soft" but not edgy and the botoom end has more slam . something i personally prefer

I likesies my drumsies !

With totally acoustic instruments the phillips chips non os rule !
There is a very relaxed non agressive sound from these dacs but at least for me are not as dynamic as i like when it comes to b*lls to the walls rock

I also likesies my rock - full speed ahead and hide the pets !


My DITB (DAC In The Box) is 4X oversampling with an opamp output stage that i bypassed and instead use a jfet IV converter to passive bessel filter to tubed output stage to 1:1 output transformer and even though it uses 4X OS sounds a lot like the former . The chip used is the AD1860 ,close to the 1865 but mono and not stereo so two dac chips are used

I can not honestly say if i like the tube stage running on an ac supply over the ditb stock but with the opamps running unregulated with a battery supply

one of those times where two things sound different but which is better ?

Being a wussy on this i just use a switch to select the output stage and go with how i feel that day ,phase of the moon ,etc.


 
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