[Vinnie R.]

Sorry for the delayed response here.  Been busier than ever!    Lots of exciting things in the works that
I will go into later when I can...

First reaction: HOLY SHIT!
This album is killin' it right now!

Hi jtwrace,

That's a great first reaction!   

The Vinnie Rossi LIO DHT.  Tubes that don't sound like tubes.
I have no idea how he pulls this off but it's mind boggling. 

Actually, you are really hearing what a 2A3 sounds like with a super-low noise power supply,
no driver tubes, no output transformers, no feedback at all (not even a cathode resistor), and
not being loaded down by a speaker driver in a power output stage. 

All of this really means you get all of the harmonics, layering, tone, and openness that the DHT truly
excels at, without some the things that some people don't like about certain SET designs (mushy, slower
bass, overly thick sound, rolled off top end, noise, etc.).

Let me first say that I confirm and agree with all of the touchstones that Vinnie discusses on the website under the heading "I put a spell on you..."  I also agree with all of the comments made b Zybar under the thread "DHT upgrade is complete." So right now I am going to just give a short four word review and a shorter 1 word review.

4 word review: I could sell tickets.

1 word review: Delicious

Hi yardbird4,

Thank you for your initial impressions, and I love both of your reviews above! 

After more extensive listening I will give more details and expound especially on the term "delicious."  I know, I know ... other DHT recipients have said the same thing and you never hear from them again.  Well its hard to tear yourself away.  But I will ... "believe me."

No rush - if you are glued to the chair listening, then LIO DHT PRE is doing exactly what it was designed to do! 

Where to start: timbre is perfect, air air air everywhere. Soundstage is crazy good with picture placement of instruments. But for me the real killer is low level detail usually hidden underneath, between bigger sound on the soundstage. Another killer is the sound of violins, woodwinds and tympani (you can hear the membrane pulsing back and forth a delight usually enjoyed only in a live perfmance). I have played a lot of my old standbys and they are beautiful with a new life to them but some of my least played stuff is now finding a way onto my Hqplayer playlist. The soundstage has a trapezoidal feel: very wide up front, oodles of depth but a bit of shrinking in width ever so slightly at the very back. I'll take it. The dynamics are very very wide. I find myself gain riding the remote to not upset my amp.

Well done Vinnie man you did good on this one.

Thank you, Theobetley! 

I really appreciate all of your initial impressions, and it will also be fun later when those on the Tube Tour list get to roll in some different DHTs and hear what happens compared to the stock 2A3.

Happy listening,

Vinnie

PS: More soon, but I need to get back to the builds...

[BobRex]

PS: More soon, but I need to get back to the builds...

Yeah, I haven't seen my unit yet.....

[Vinnie R.]

Yeah, I haven't seen my unit yet.....

Getting very close to shipping yours, BobRex 

[rolls]

I have read the review of Vinnie Rossi’s dht tube preamp in 6moons with great interest.
I wonder how Mr. Rossi has implemented his tube stage in the LIO. Normally It would be an
offend to ask an engineer about his secrets, but this time there must be an exception for good reasons:
Mr Rossi said the dht tubes are driven from the internal capacitor bank supply, the filaments from outside.
The capacitor bank provides 24 to 20 Volts, and running a dht tube like a 300B's plate so low is quite extraordinary,
it calls for a very strange operating point, the grid had to be almost zero or even slightly positive, which would cause other problems.
The only solution could be a dc-dc converter, but Mr. Rossi said there is none.
I hope that Mr. Rossi or anybody else is going to unveil this mystery a bit.

thank you
Andre

[Vinnie R.]

I just received an email from Srajan Ebaen of 6moons.com.  Today he received his DHT PRE kit and already installed it, and posted
the installation sequence (pages 4 and 5 of his preview):

http://www.6moons.com/audioreviews2/vinnierossi2/4.html

http://www.6moons.com/audioreviews2/vinnierossi2/5.html

With the stock 2A3 dead quiet even with my ear on the tweeter, I'd have no need to hide the glow bottles from sight.

Stay tuned for the sonic conclusion...

 

[Theobetley]

How can any decent human being cover those lovely 2A3 tubes. I say it is a disgrace!

[jtwrace]

How can any decent human being cover those lovely 2A3 tubes. I say it is a disgrace!

Leaving them unwrapped did this...always wrap it. 


 

[ebag4]

Leaving them unwrapped did this...always wrap it. 

Thanks for the public service announcement! 

Best,
Ed

[jtwrace]

Thanks for the public service announcement! 

Best,
Ed

It's now the Phuckin' DHT!   

[jriggy]

It's now the Phuckin' DHT!   

 

They're multiplying!!

Hey J,

 Why two? just curious how your system is set up for them and why. Sorry if you explained already and I missed it --been gone for a couple weeks.

 Jason

[Vinnie R.]

I have read the review of Vinnie Rossi’s dht tube preamp in 6moons with great interest.
I wonder how Mr. Rossi has implemented his tube stage in the LIO. Normally It would be an
offend to ask an engineer about his secrets, but this time there must be an exception for good reasons:
Mr Rossi said the dht tubes are driven from the internal capacitor bank supply, the filaments from outside.
The capacitor bank provides 24 to 20 Volts, and running a dht tube like a 300B's plate so low is quite extraordinary,
it calls for a very strange operating point, the grid had to be almost zero or even slightly positive, which would cause other problems.
The only solution could be a dc-dc converter, but Mr. Rossi said there is none.
I hope that Mr. Rossi or anybody else is going to unveil this mystery a bit.

thank you
Andre

Hi Andre,

Welcome to the VR forum!

I am sorry, but I cannot discuss the inner details of this design that you are looking due to
the risks of it then being copied.

As far as I know, there is nothing else out there quite like it.  It does NOT use any
dc-dc switching converters.  And it achieves a very high bandwidth from 10Hz to >250kHz (+/- 0.5dB)
with a voltage gain of 6 - 9dB (depending on the tube used). 

All the details that I wish to mention are listed on our website:

http://www.vinnierossi.com/dht_pre/

Thank you for your understanding,

Vinnie

[jtwrace]

They're multiplying!!

Hey J,

 Why two? just curious how your system is set up for them and why. Sorry if you explained already and I missed it --been gone for a couple weeks.

 Jason

That's a great question.  However, all I can say is Vinnie.  I have one pair of speakers currently but after buying the AVC LIO and that whole experience I wanted to support the little guy.  So rather than just upgrade the AVC to DHT I decided to invest in Vinnie some more and buy a new DHT LIO with all the same modules.  I've been at this hobby for many many years and I've never dealt with anyone like him before.  So while I don't use them both full time I have options and eventually I'll likely add some speakers for the AVC LIO too.  I'm waiting on something specific.   

[sfox7076]

Again, no request for secrets here, but are you saying you are not amplifying the DC voltage?   I assume that you have raised the plate voltage to one of the linear operating points on the data sheet.  Is that right?

[Audiophile58]

Hello Vinnie between the 300b ,and 2a3  sonicly would you say the 300b has more richness tunes to the mids ? Sonicly both very respectable DHT tubes . What is the best attribute of  each tube from your observations?
Thank you,PJ.

[zybar]

Hello Vinnie between the 300b ,and 2a3  sonicly would you say the 300b has more richness tunes to the mids ? Sonicly both very respectable DHT tubes . What is the best attribute of  each tube from your observations?
Thank you,PJ.

PJ,

It really depends on which make as much as which tube.  The tube that had the most richness in the midrange to my ears was the Svetlana SV-811's. 

I have heard multiple 2A3 and 300b tubes and each had its own sound and unique characteristics.

I will try and get something posted in the next few days on the tube tour thread (http://www.audiocircle.com/index.php?topic=144292.0) that will highlight this. 

As others get participate in the tube tour, you can read their thoughts as well.

George

[BobRex]

I have read the review of Vinnie Rossi’s dht tube preamp in 6moons with great interest.
I wonder how Mr. Rossi has implemented his tube stage in the LIO. Normally It would be an
offend to ask an engineer about his secrets, but this time there must be an exception for good reasons:
Mr Rossi said the dht tubes are driven from the internal capacitor bank supply, the filaments from outside.
The capacitor bank provides 24 to 20 Volts, and running a dht tube like a 300B's plate so low is quite extraordinary,
it calls for a very strange operating point, the grid had to be almost zero or even slightly positive, which would cause other problems.
The only solution could be a dc-dc converter, but Mr. Rossi said there is none.
I hope that Mr. Rossi or anybody else is going to unveil this mystery a bit.

thank you
Andre

You need to read more of the info.  The DHT comes with a larger linear power supply that provides the plate voltages, as well as the DC to the caps.  Nothing esoteric here and the plates are running at typical voltages.

[Vinnie R.]

Again, no request for secrets here, but are you saying you are not amplifying the DC voltage?   I assume that you have raised the plate voltage to one of the linear operating points on the data sheet.  Is that right?

Hi sfox7076,

Again, I don't wish to go into details about how I implemented it.  All the detail that I wish to provide can be found here:
http://www.vinnierossi.com/dht_pre/

Hello Vinnie between the 300b ,and 2a3  sonicly would you say the 300b has more richness tunes to the mids ? Sonicly both very respectable DHT tubes . What is the best attribute of  each tube from your observations?
Thank you,PJ.

Hi PJ,

When I get more caught up, I'll be posting about the different tubes that I've tried and their attributes (how they sound in this particular circuit).

PJ,
It really depends on which make as much as which tube.  The tube that had the most richness in the midrange to my ears was the Svetlana SV-811's.  I have heard multiple 2A3 and 300b tubes and each had its own sound and unique characteristics.

I agree with all three of these statements by Zybar.


BTW - I am confident that I'll get through with building/testing/shipping all of the LIO DHT PRE pre-orders this month! 

Thanks again,

Vinnie

[matthewpartrick]

Yep, Vinnie and I have listened to this a lot at my house.

I use "Drum Trip" and "Laugh As The Sun" as test tracks.   

When I turn it up loud, I feel like it is 1994 and I am standing 5' away from the band in a small bar in Rochester, NY.

George

This is too funny--I was just thinking of this album yesterday and it totally makes me think of Freshman year in college.  I'll have to pull it up on Roon now!

[Peterjauhal]

Just set up my system today and it sounds fantastic. Many thanks, Vinnie, for a great addition to the LIO.

[kdbrink]

Just set up my system today and it sounds fantastic. Many thanks, Vinnie, for a great addition to the LIO.

Are those tubes lit up, or is it a reflection of the camera?