[BrandonB]

I usually hang out in a different circle but I have a tube question and think you guys would have the best answer.  Is it better to add tubes to a preamp or a DAC?  Do they have different sound qualities in each?  I already have a very nice SS amp and just want to add some tubes.

[musicdre]

hi:  i dont think that this is going to be the answer you wanted to hear but imho IT DEPENDS.   not all tube preamps or tube dacs sound the same - they can sound very different.   and there is system synergy to consider, your listening space, and, most importantly, your personal taste.

i think that you have to experiment.  but DO add tubes and see how you like the tube thing.

hopefully others will jump in with more defined views on the question.

[Tyson]

A tube DAC does more to make the system sound 'non-digital' than a tube preamp, IME.

[FullRangeMan]

https://www.tungsol.com/html/faqs14.html

https://www.soundbridge.io/tube-distortion

https://en.wikipedia.org/wiki/Tube_sound

[Early B.]

Buy whatever sounds better. This process takes time and requires a lot of experimentation. I have a tube DAC and tube preamp (and tube amp) because they sound better than any other SS gear I tried. 

[kmmd]

These are difficult questions to answer and depends on what your goals are.  All of the gentlemen here have provided excellent answers.  I agree with Tyson that if you’re looking for a more analog sound, then a tube DAC would achieve this more than a tube preamp. 

With that being said, a tubed preamp with a SS amp is a very good combo.  I’ve been using this combination for decades.  A tubed preamp will allow for tube rolling and allow you to tailor the sound to your liking.  Preamps using 6H30 tubes will limit your choices while one with 6922’s will allow you to roll galore.  Brent Jessee’s website will provide you with a wealth of information regarding the qualities of the tubes that he sells.  He is very helpful in providing guidance too.

Have fun, experiment and happy listening.

[WGH]

I have a solid state amp, a tubed preamp and a solid state DAC. But preconceived ideas of tubed vs solid state sound does not apply.

My speakers need a solid state amp because they have an 88dB efficiency.

The VanAlstine Fet Valve CFR preamp has 4 tubes - two 12AT7 tubes for gain and two 12AU7 tubes as cathode followers. The sound is un-tuble like, even changing the original JJ tubes to NOS Mullard and Genalex made just a slight change to the sound. The AVA is not a tubey sounding preamp.

My DAC is the HoloAudio May KTE, this is a true non-oversampling (NOS) ladder DAC. The sound is natural without any digital brightness. Almost all other DACs oversample internally. Removing noise at a higher sampling rate is easier, cleaner and sounds better than a 16 bit/44.1kHz brick wall analog filter. An well designed digital filter can sound better than a poorly implemented digital filter with a tube in the circuit to warm up the sound and hide the nasties.

You will find glowing reviews for every DAC ever made. How do you make a decision?
#1 - Your budget.
#2 - How many digital inputs you need
#3 - Functional requirements. I wanted to listen to hi-res downloads (new music in 24bit/192kHz, 352.8 kHz and DSD256 is not unusual these days) and play with HQPlayer upsampling software. The HoloAudio DACs are one of the few that accept any resolution and does not manipulate the digital input at all, what goes in is exactly what comes out without any hidden upsampling.
#4 - Listening to as many different DACs as possible.


Looks like our big DAC shootout is happening sometime this summer. Our audio group has 3 NOS DAC's lined up: Audio Note ANK 1.1, the ANK 5.1 and my HoloAudio May KTE. The ANK DACs have tubes, mine doesn't but all are true non-oversampling DACs. The ANK DACs only go up to 24 bit/96kHz while the HoloAudio supports DSD1024 native and PCM 32bit/1.536MHz. By necessity we will be listening to 16bit/44.1kHz music. Speakers will be the Nola Metro Grand Reference speakers driven by restored Quicksilver Audio V4 monoblocks running KT88's and a tubed preamp with Hapa Audio RCA and USB cables.

[opnly bafld]

My speakers need a solid state amp because they have an 88dB efficiency.

 

[kmmd]

My YG Hailey’s are only 87dB, but I’m sure that VAC has a few Master or Statement amps that’ll power them just fine.     
My CODA No 16 has been really amazing with the Hailey 3’s. 

[audioengr]

Like most things, there are tube designs and other tube designs, and the types and brands of tubes makes a huge difference too.

Tube amps and preamps I have found to be superior to SS, but with the caveats that the designs must be sound, and the tubes must be optimized.
Designs that are DC-coupled are better in general.  No capacitors in the signal paths.

Tubes have the major advantage of having a very small voltage swing within a very large voltage envelope.  This results in excellent linearity
They also have the advantage of very little change in the behavior from small signal to large signals.  Temperature makes almost no difference.

Transistors on the other hand are quite sensitive to the signal magnitude and change characteristics a lot with temperature changes and heating.
The voltage swing on most transistors is just a bit smaller than the voltage envelope, so nonlinearity can be an issue.  Different response to small signal than large signals.

So, what is a sound tube design?  One that uses point-to-point wiring, preferably with cotton-insulated silver wire.  FR4 circuit boards are the enemy of good analog sound quality.
One that applies HF decoupling caps near the tubes.  One that has a well-regulated power supply.
One that avoids crossover distortion of class B.  This is why I like SET amplifiers and class-A preamps.

What are optimized tubes?  They need to be fast and yet extended HF and LF.  Low noise and low acoustic feedback, so built solidly.  NOS military tubes are some of my favorites.

Once you have these tube optimizations, it becomes more difficult to tell a really good SS from a tube amp or preamp.  The difference with the tube amp is that it is usually more lifelike,
particularly for vocals.  I have found however, with my particular SET tube monoblocks, which are all DC-coupled, that the bass extension and control beats any SS that I have had.
A surprising result.

Steve N.

[stylerb]

i think a lot of modern tube gear isnt very "tubey" anymore. personally, i'd probably go for the tube preamp vs dac.

[WGH]

I think 88dB isn't very efficient. A high powered tube amp like the VAC would be out of my budget. The VanAlstine Vision SET 400 at 225 watts per channel is in my budget.

I have heard the AVA Ultravalve tube amp (35w/channel) with my 88dB Salk HT2-TL's, at low volumes it sounds fine but turn it up and it runs out of gas, the AVA Vision SET 400 locks the bass in place. The HT2-TL speakers are power hungry. I have tried 4 different pairs of 13 AWG to 15 AWG speaker cable (ZenWave, Hapa & Kimber) and they all attenuate the bass compared to 10 AWG speaker cables. The HT2-TL speakers go down to 34 Hz with authority and needs a lot of current to strut their stuff.

A tubed preamp would allow all your sources to benefit from the beauty of tubes not just the DAC.



Hapa Torsion Speaker Cable Review
https://www.audiocircle.com/index.php?topic=183932.msg1944092#msg1944092

[FullRangeMan]

i think a lot of modern tube gear isnt very "tubey" anymore.

Unfortunately the loudspeakers and OPTs of today have changed a lot.

[viggen]

there are more variables than just ss vs tubes.  single ended vs pp, 45 vs 6550, class a vs class b-d.... each has it's own flavor versus others and even versus itself.

[BrandonB]

These are difficult questions to answer and depends on what your goals are.  All of the gentlemen here have provided excellent answers.  I agree with Tyson that if you’re looking for a more analog sound, then a tube DAC would achieve this more than a tube preamp. 

With that being said, a tubed preamp with a SS amp is a very good combo.  I’ve been using this combination for decades.  A tubed preamp will allow for tube rolling and allow you to tailor the sound to your liking.  Preamps using 6H30 tubes will limit your choices while one with 6922’s will allow you to roll galore.  Brent Jessee’s website will provide you with a wealth of information regarding the qualities of the tubes that he sells.  He is very helpful in providing guidance too.

Have fun, experiment and happy listening.

Thank you for the info.  I will check out that site.

[Early B.]

I think 88dB isn't very efficient.

Yep. Even speakers rated in the low 90's are suspect. Lots of other factors to consider, of course, but generally, I would label "high efficiency" to begin at 95dB. 

[BrandonB]

Looks like our big DAC shootout is happening sometime this summer. Our audio group has 3 NOS DAC's lined up: Audio Note ANK 1.1, the ANK 5.1 and my HoloAudio May KTE. The ANK DACs have tubes, mine doesn't but all are true non-oversampling DACs. The ANK DACs only go up to 24 bit/96kHz while the HoloAudio supports DSD1024 native and PCM 32bit/1.536MHz. By necessity we will be listening to 16bit/44.1kHz music. Speakers will be the Nola Metro Grand Reference speakers driven by restored Quicksilver Audio V4 monoblocks running KT88's and a tubed preamp with Hapa Audio RCA and USB cables.

Sounds interesting. I would like to here the results.

[BrandonB]

Is anyone running a single ended system?  Seems like everything that I have read lately is balanced with no feedback.  I want to know if who has a really nice single ended system.

[opnly bafld]

"I think 88dB isn't very efficient."
It isn't but it's a pretty typical sensitivity with the majority of mainstream speakers.

You said your speakers need it, not I need it with my speakers, big difference.

If I read the Salk specs accurately the speakers are more like 86.5 1w/1m.
In the past I successfully used 85 dB 1w/1m speakers with a push pull tube amplifier of moderate power, but I'm not running a night club here. 
How loud one listens may require higher power solid state (which reaches the point of diminishing returns VERY quickly), but it is certainly not just the sensitivity of the speakers. In case some are wondering very good to excellent amplifiers with 200 and more w/ch have been in my possession and the unused power made no difference.
To each their own.

[SET Man]

I usually hang out in a different circle but I have a tube question and think you guys would have the best answer.  Is it better to add tubes to a preamp or a DAC?  Do they have different sound qualities in each?  I already have a very nice SS amp and just want to add some tubes.

Hey!

     If you like your SS amp right now and it can drive your speaker fine. The easiest way to get tube in your system is to get a good tubed preamp. Just make sure your SS amp input impedance is high enough for the tube preamp that you want to pair it with.. at least 25K should be safe.

    Anyway, like most people I started out with an all SS system. Then I added my first tube component, a tubed preamp an Audio Note M1 Phono in my case... of which I have still have after 25 years, although I upgraded/modded it over the years.

    After I got a taste of tube with the preamp I couldn't help but also got tube amp after that. Now I have an all tubed system... DIY TDA1543 DAC with tube buffer---Helius Alexia turntable with Helius Omega tonearm and Hana EL cart ---Audio Note M1 Phono tube preamp--- Welborne Lab Apollo SET monoblocks amps with KR Audio 842VHD tubes and Bel Canto 845 SET amp... DIY TWQT Single Driver speakers based on 6" Fostex 94dB sensitivity with Fostex FT17H supertweeters.

   Beside my recent purchase of the Helius turntable/arm about 2 years ago and I just built tube buffer for my DAC my system have pretty stayed the same for the past 20 years.

   Anyway, tube is not for everyone. I'd recommend you go hear some tubed systems for yourself if you can before you decided to take a plunge. Don't know where you are or if there is any audio stores in your area or if you know or if there any other audiophiles in your area with tube system that you could check out. I'm in NYC area.

   Well, good luck, take your time and keep us posted.