[zybar]

In an effort to help maximize your investment in the LIO DHT Preamp (and keep Vinnie building them as quickly as possible), I have volunteered to run the Vinnie Rossi LIO DHT Preamp Tube Tour 2016.

This is an opportunity to audition a pre-selected and packaged set of DHT tubes.  These tubes are just a small sampling of the possible tubes that are available and will work in your LIO DHT Preamp.  Don’t think of it as a definitive list of what works well or is best - rather, here is a chance to try DHT tubes from different families to get an idea of what you may or may not like in your LIO DHT Preamp.

So how will it work?

First off, you need to be a LIO DHT Preamp customer located in the continental US - sorry, this isn’t a general tube loaning program and it can’t go outside the US.

Please request to be added to the tour via PM to myself (Zybar).  Please don’t PM Vinnie for the tour. 

When requesting to be added to the tour, you MUST include the following info:

Subject: LIO DHT Preamp Tube Tour 2016 
Full Name:
Full Shipping Address:
Phone Number (home or cell):
Email:
 
People will be added to the tour based on when they request to be added and notified via email of their week.  If they can’t meet their assigned week, the next person will be moved up and a new week will be assigned.

You will have 1 week from the time your receive the tubes to audition them in your system.  If the box is damaged in any way, please notify Zybar via PM immediately for next steps.   

At the end of the week, it is your responsibility to ship it to next person on the tour (shipping info will be provided in advance via PM by Zybar). 

You can ship either USPS Priority Mail, FedEx Ground, or UPS Ground. Regardless of the vendor you choose, three things are mandatory: 

You must insure the package for $1000.00
You must have tracking on the package
You must provide tracking info to the person receiving the tubes and Zybar

The tubes selected are packaged specifically for the tour and need to ship in the box that they arrived in. There are four sets of tubes (see info below).  Please pack the tubes up in the same manner as they arrived (see pics below). 

It is extremely important that you ship the package on time and to the next person in order for the tour to run smoothly.

Finally, please post your thoughts and comments on Audio Circle in the LIO DHT Preamp Tour 2016 thread in the Vinnie Rossi Circle.  It would also be great if you share what other equipment is in your system.  You can write as little or much as you like, but please keep in mind that the more you share, the more it benefits current and future LIO DHT Preamp owners. 

This tour contains four (4) sets of tubes.  It is extremely important that you select the proper voltage for each set when installing them.  If you have any questions on how to set the voltage, please refer to the .PDF manual that you have been provided with your LIO DHT Preamp. 

EML 2A3 Mesh Plate (2.5V setting only)
Svetlana SV811-10 (5V setting only)
Genelex Gold Lion PX300B (5V setting only)
NOS Cunningham CX301A (start with the 5V setting, but you can use any of the settings with this tube)


Any questions about the tour, please post in this thread or send me (Zybar) a PM.

If you have any technical questions about the tubes or the LIO DHT Preamp, please post in this thread and Vinnie will get back to you.

Have fun and enjoy!

George


SHIPPING BOX



SHIPPING BOX - OPENED



SHIPPING BOX - TUBE LAYOUT

[zybar]

Started a new thread in order to clean things up.

No need to send me a new PM asking to join the tour.

I will be putting together this first phase and sending out PM's over the next 24 hrs.

George

[matthewpartrick]

Great idea.  I'm very interested but will wait to put my name on the list until the DHT PRE arrives.

[Vinnie R.]

Hi George,

Thank you for starting this thread and for volunteering to run the DHT PRE Tube Tour!

I also want to mention something to all LIO DHT PRE owners:

Regarding tube pins and tube sockets, it is very important to make sure you are getting a good connection.
I have found DHT tubes have some level variation in the diameter of the tube pins (even from batch to batch of
the same tube... it's not *that* uncommon it seems). 

So if you use a tube with a larger pin diameter, it can stretch the tube socket pins to accommodate the tube pin.  However,
when you go back to use a tube with pin(s) of a smaller diameter, the connection might not be as good as it was previously
due to the stretched out socket pin. 

No problem - here is what you do about it:

The Yammamoto Teflon UX4 tube sockets used in the DHT PRE have female pins with a slit in the middle, and
this allows you to push the two halves of the socket pin together (closing the diameter of the female socket and making
a better connection with the tube pin).  See:



If you use a very small flat head screwdriver (e.g. google "jewlers screwdriver," or "eyeglass screwdriver"), you can
easily tighten them up if/as needed.  Just be careful as you do each socket pin.



- Does this need to be done often?   
Not necessarily, but if you are getting an intermittent connection (could be noise, popping, crackling, or any noise that was not there before) with a particular tube, doing what I mention above will take care of it.  It's good to do this if you are tube rolling often, and as I mention in the DHT PRE Owner's Manual, you want to make sure the pins of the tubes that you install are clean *before* installing them!  This is especially important with NOS tubes that might have dirt and oxidation on them.  And you want to make sure your tube socket pins are also clean and free of dust and other contaminants.   

A clean, secure connection is going to provide best results (best sound, lowest noise). 

This adjusting of the socket pins and cleaning them and the tube pins are all part of "normal maintenance" that goes along with tube rolling.  If you confirm a tight connection and don't tube roll often, you probably won't need to do this that often (if ever).

I hope this tip helps!

Vinnie 

[jriggy]

Vinnie,

Thanks for this nice visual explanation.

What is your preferred method of cleaning the pins on NOS tubes? Alcohol and a Q-tip good enough?

Jason

[Vinnie R.]

Vinnie,

Thanks for this nice visual explanation.

What is your preferred method of cleaning the pins on NOS tubes? Alcohol and a Q-tip good enough?

Jason

Hi Jason,

Something like this should work well:

http://www.musicdirect.com/p-1158-caig-vacuum-tube-survival-kit.aspx



I usually use *fine* steel wool or metal brush and brush as the pins first.  Then
use contact cleaner, and finally a Caig DeOxit Gold contact "conditioner." 

A fine brush and contact cleaner as in the link above should also be good at cleaning the female tube socket pins,
but if your tube pins are always clean before you install the tubes, you should not have to do this often. 

Vinnie

[Vinnie R.]

All,

This diagram is in your LIO DHT PRE manual, but I'll post it here as well:


LIO DHT PRE (TOP) 3-Way Filament Voltage Switch Settings

NOTE:  As shown above, the 2.5V and 4V switch settings are different for the L and R tubes!

WARNING: Failure to use the correct filament voltage can easily damage your tubes, so please do not forget to set it correctly and double-check the setting before installing your tubes!

For your reference, here is a list of 4-pin DHT tubes that may be used with your LIO DHT PRE, and the correct filament switch setting to use:

Tube / Switch Setting

2A3 / 2.5V
45 / 2. 5V
300B   / 5V
SR71A / 5V
SV811-10 / 5V
SV572-30 / 5V
CX301-A / 5V
PX4 / 4V
PX25    / 4V
101-D / 4V
205-D / 4V

Also (for debugging), looking at the front of the LIO, the tube on the left side is used
for the RIGHT channel, and the tube on the right side is used for the LEFT channel.

[Theobetley]

How do we sign up for the tube trial?

[zybar]

Read my post above. 

George

[zybar]

Almost done with putting together the schedule for the 9 people who have asked to participate (so far).

I will be sending out an email later today and ask that each person replies by the end of the weekend in order to secure their proposed slot.

Thanks,

George

[zybar]

The proposed schedule for the tour has been sent out via email. 

Please check the email address you provided me via your PM and review the schedule.

I need your feedback on if the slot assigned to you will work.

George

[matthewpartrick]

Will the tubes come back to you once the tour is over?  I'm not sure when I'll be getting my DHT PRE so I don't want to sign up for the list yet.

[JP78]

You may want to consider including the correct screwdriver and contact solution with the tour.  The negligible mass / packaging increase won't be more than an additional $1 or so per shipping address.

Best,

[Theobetley]

Hey zybar (George) did you get my pm with my email id?

[zybar]

Hey zybar (George) did you get my pm with my email id?

I did.

I will be sending out an adjusted schedule later today or tomorrow.

I am shipping the tube package to the first person on the list within the next couple of hours.

George

[Theobetley]

thanks

[yardbird4]

Here are my impressions of the tubes on the DHT Pre Tour. Let me state up front that all of the Tubes seemed to offer something special and generally sound great, although I still had my favorite and least favorite.  Excuse my lengthy discourse. My impressions as I noted them while listening, and edited for some uniformity:
EML 2A3:
Great body, detail, instrumental weight, tonal purity.
Very open and transparent.
Big soundstage. Wide with good depth, and layering.
Very good detail.
Great instrumental placement.
Good speed, attack and decay.
Great tonal color and texture saturation.
Bass is more tubey than I prefer, soft and somewhat indistinct on some rock and R&B. 
Excellent, probably the champ, on classical music.
These tubes are more lush and warm than the stock EH2A3 and not as linear because of bass response.  Probably more extended on top than stock tubes but not by much.


EH2A3 (stock tube):
Very good body and instrumental weight, only slightly less than presented by the EML’s.
Very good detail, better than EML and other tubes except maybe the 811-10’s
Big soundstage. Wide with good depth, and layering.  I thought these tubes were slightly better than the EML’s on depth and the champion on layering.
Very open and transparent, a little more so than the EML and other tubes on the tour (except the 811-10’s).
Very good on instrumental placement but slightly less focused than the EML.
Great speed, attack and decay, especially in the base region where you could hear more of the inner details of the bass notes.
Great tonal color and texture saturation on a par with the EML’s.
The bass response is excellent, fast, deep and articulate.  Better than tubes, better than transistors because of the fullness, detail, depth.
Excellent all around tube.  The most linear tube in the comparison.

Svetlana 811-10
Great top end sparkle and detail, but a little less body and instrumental weight.
Excellent tonal color saturation and purity.
Great soundstage width, layering, and depth.
Excellent transparency, may a little too much on some vocals which seemed slightly too etched on a few things … but overall a quibble and not objectionable.
Very good instrumental placement.
Good speed, attack and decay.
Great color saturation and very good texture saturation.
Bass was very good, but not quite as tight and deep as the stock tube but better than EML and Genealex 300B.
I love the musical presentation of these tubes on jazz especially.

Genalex Gold Lion 300B
Very good body and instrumental weight, only slightly less than presented by the EML’s.
Texture was excellent perhaps better than the EML’s but not tonal color saturation.
Good soundstage but… Wide with good layering.  However, on classical music the layering seems to be stacked vertically rather than horizontally, so to my ears depth seemed to be a problem.  I thought these tubes were less holographic than the other tubes and the presentation at time seem to slightly less distinct than the other tubes
Detail was not as good as either of the 2A3’s or 811-10.
Less open and transparent than the other tubes.
Good mid-range warmth. probably the king of warmth, which can be attractive when listening to vocals.
Good on instrumental placement but slightly less focused than the other tubes.
Speed, attack and decay, were good.
Good color and texture saturation.
The bass response is good but softer than the other tubes.

Cunningham 301
I wrote less about this tube category response because it was the last tube I listened to and did not expect much.  I was wrong.  I really enjoyed listening to this tube and here as my brief comments:

Very good overall presentation with lush romantic vocals.
Great vocal textures.
Great soundstage, depth and clarity but height and width seem significantly reduced compared to the other tubes.
Very good bass, maybe second only to the EH2A3.
Good instrumental weight.
My rankings:
1.   EH2A3:  I went with this tube because of its outstanding characteristics and it ability to play everything on an even par.  In my book I guess linearity is king.

2.   Svetlana 811-10: After listening to this tube for a while my first reaction was to go to the internet to price a pair.  A friend I had over for a rolling session was initially in love with the EML 2A3, until he heard the Svetlana 811.  However, after I put the EH2A3 back in the system I decided it was the one.  My friend had departed.

3.   EML2A3: Also a great tube and maybe my pick except for its loose base compared to the two above.

4.   Cunningham 301.  Great tube to listen to and for the money.  The shrunken soundstage was what killed the deal. Although maybe it only finishes a vey close 4th to Svetlana and EML even it had a better soundstage.

5.   Genalex Gold Lion 300B:  This tube while it had its good points just did not do it for me.

[zybar]

Great job on the write up.   

What speakers are you using and how big is your room?

George

[yardbird4]

Great job the write up.   

What speakers are you using and how big is your room?

George

Spendor FL 9 floorstanding speakers. 8ohm & 89 db sensitivity. The listening room proper is about 13 W by 19 L.  I listen on the long axis.  The room is open on the listening end to another  25 foot space that contains a breakfast nook and kitchen. The rest of the system is a fully loaded Vinnie Ross LIO with DHT Pre, no HPA. Primarily listening was done through a Computer Audiophile designed Zuma Music Server, fanless, SS bootdrive, copper heat sinks for the CPU. An Underwood Modified Denon 2900 Universal CD Player and vintage Technics SL-M3 Linear Tracking turntable was also used.

[Vinnie R.]

Hi yardbird4,

Thank you for all your effort in posting your impressions to this LIO DHT Tube Tour thread!  I really enjoyed the level
of detail you put in for each tube, and how you concluded by ranking them (great idea)!

I will be doing the same, but want to wait until others have posted.  I'll have around 8 - 10 different pairs of DHT's to post about, so
it will be long and I'll need a full day for this (not happening in the near future, but I'll get there...  ).

I suspect we all are going to have some similarities and differences in our findings based on different factors (our system, our room, music selection, tastes in sound, etc)  - but that is what makes it fun and keeps it interesting. 

Happy listening!

Vinnie