[matthewpartrick]

No, not at all.

Is this because it's simply heating the tube and isn't involved in the circuitry?  I feel like I'm putting jumper cables on a 70's diesel Mercedes

[Vinnie R.]

Vinnie will enclosing the tubes in the covers while operating the unit shorten the lifespan of the Tubes?

Hi yardbird4 - not at all, and remember that we are using the DHTs in the linestage (not as a speaker power amp, so
we are already running them much cooler and treating them with kid gloves, so they should last a very long time).

I have a potentially dumb question.  Does the external power supply for the DHT PRE negate any benefit of the ultracapacitors?

Hi Matthew,

No - we still use LIO's ultracapacitor supply for the DHTs.  And we used the external linear supply to feed custom Belleson super-regulator
circuits "SPVR" (1 for each tube) that is only used for heating the tubes.  This is *mostly likely* the cleanest filament supply (low microVolt noise level) around! 

What voltages can you select for the filament supply (with 4A tubes usable, it has enough current to run anything)?

Hi sfox7076,

The SPVR's each have a 3-way slide switch to select: 2.5V, 4V, and 5V (DC).  You can run up to 4A for each tube - no problem.
But do NOT use any tube not listed on our DHT PRE website w/o first consulting with me.  I am sure there are other 4-pin DHT's
that should work, but I would want to look into it first to avoid any problems.  I don't mind trying them first in my LIO - just to
be sure it all works correctly. 

I don't wish to go into other specific details of this very unique design.  There are companies that exist with no shame about copying.     Some of them even come to your room at a show, snoop inside your product, and don't even introduce themselves.  Luckily this is not the case with Audiocircle manufacturers. 

As an aside, I have about 20 WE 101Ds and never had a hum traceable to the tubes.  Not saying it does not happen, but they are not usually hum prone in my experience.

I tried a 205-D (new production, from China) that had the hum problem until the cover was installed. 

For the WE 101D's that you have, are you using them in the linestage, or in an SET Amp?  Because in the linestage, it's a whole different
ballgame with regards to noise/hum...

If you want to use original 101Ds, you will likely need adapters (some sockets will allow a UV tube to lean against the filament connections, but that is a recipe for disaster in my opinion).

Thank you for sharing this information.  I was looking at the replica 101-D / 205-D tubes (e.g. Psvane), which appear to have UX4. 
I will look into where to get UV to UX adapters.  But I'm sure there will not be many using the rare/expensive original WE 101-D's. 

What's the DHT like with the HPA?

Delicious! 

Vinnie

[jtwrace]

Delicious! 

Vinnie

 

[sfox7076]

It is used in a line stage function.  And I was of thinking of the 26, 10Y, or the 01A.  The slide does kill my dream of the 10Y as it is 7.5v at 1.25A and the 26 as it is 1.5V at 1.05A.  All that said, the 01A is awesome and the only one that I have had microphonic issues with.  I have no real experience with the newly made 101Ds and only limited experience with 205Ds.  The new 101Ds sounded so poor to me that I could not listen to them for long periods.  The 01A is, to me, the most interesting in the lot and the cheapest.  They are hard to deal with at times because they are very microphonic, and really need to be run at a lower voltage then spec.  I am not sure if you could run an 01A at 4 volts, but if you did, it would probably be amazing.  They are dirt cheap, they only draw .25A and they are thoriated tungsten filaments.  If you could run those, you might get some interesting magic.  They also light up like light bulbs...  https://frank.pocnet.net/sheets/029/0/01A.pdf

One observation, the 101D is rated at 4.5V at 1A.  Unlike almost all other tubes, it is a current based filament.  I suppose if one used a CCS supply at 1A, it would perform the best.  No one does that very much until you hit really labor intensive applications where biasing is needed, or you add in some other features no one needs to discuss here.  That said, I wonder if you had hum and dropped the voltage to 4v, it may subside.  You would be within the +/- on the filament and it should tame any microphonics.

If you are patient, you can get real WE 101Ds for less than the current replicas.  I have a bunch and only spent a lot on one pair (original globes).

[Vinnie R.]

Hi sfox7076,

I haven't played with those, and in general I am curious how tubes with a plate resistance greater than around 2.5k is going to
work out.  I'd like to see how it works with the 01A.

They also light up like light bulbs...  https://frank.pocnet.net/sheets/029/0/01A.pdf

Cool - the thoriated tungsten filaments are gorgeous!  I like how the Svetlana 811 and 572s have this.

If you are patient, you can get real WE 101Ds for less than the current replicas.  I have a bunch and only spent a lot on one pair (original globes).

Patience, you say?  Hmmmmm     

Have a fun weekend,

Vinnie

[SteveKi]

Vinnie,
Do you have a 'specially configured' NUDE RVC in the shop that will work without the DHT? I was curious how the various volume controls would compare to each other in sound quality? NUDE RVC at number 2 or does it outperform the AVC.

1. RVC               Premium Vishay/Dale film resistors
2. NUDE RVC     Custom version of RVC with all Vishay Nude Z-Foil resistors, point-to-point wired onto the signal relays
3. AVC               Autoformer volume control
4. AVC-S            Autoformer volume control Silver (special order)

Steve

[kdbrink]

How tall is the LIO with the DHT tubes installed?

[TomS]

How tall is the LIO with the DHT tubes installed?

Covered earlier in the thread http://www.audiocircle.com/index.php?topic=142673.msg1523451#msg1523451

[kdbrink]

Covered earlier in the thread http://www.audiocircle.com/index.php?topic=142673.msg1523451#msg1523451

Missed that! Thanks for the heads up.

[Vinnie R.]

Vinnie,
Do you have a 'specially configured' NUDE RVC in the shop that will work without the DHT? I was curious how the various volume controls would compare to each other in sound quality? NUDE RVC at number 2 or does it outperform the AVC.

1. RVC               Premium Vishay/Dale film resistors
2. NUDE RVC     Custom version of RVC with all Vishay Nude Z-Foil resistors, point-to-point wired onto the signal relays
3. AVC               Autoformer volume control
4. AVC-S            Autoformer volume control Silver (special order)

Steve

Hi Steve,

NUDE RVC is only offered for DHT PRE, so it can't be ranked against the passive AVC.

In fact, AVC (w/o tubestage) is no longer going to be offered.  Going forward, the 3 linestage options will be:

1) RVC + Tubestage
2)  AVC/Tubestage (and one could use the jumpers to bypass the tubestage section of this if they only want to use AVC
for some silly reason  )
3) DHT PRE


Unlike the LIO Tubestage and AVC/Tubestage, the DHT PRE is not a cathode follower ("tube buffer") topology.  DHT PRE
provides voltage and current gain, and I found a while back that it sounds best with the NUDE RVC (no voltage gain) in front of it.
DHT PRE is a very high bandwidth design (flat response well over 100kHz, and into the 500kHz range with 300B and 2A3's I've
tested).  You lose this bandwidth with AVC. 

AVC/Tubestage is different in that the AVCs provide the voltage gain, and the tubestage buffered output provides the current gain.
They work great together!

I hope this helps,

Vinnie

[SteveKi]

Vinnie,
Thanks for the info.

When will DHTs that are ordered today ship?
Steve

[jtwrace]

Vinnie,
Thanks for the info.

When will DHTs that are ordered today ship?
Steve

See here.


http://www.audiocircle.com/index.php?topic=134307.msg1529556#msg1529556

[poseidonsvoice]

Hi Steve,

NUDE RVC is only offered for DHT PRE, so it can't be ranked against the passive AVC.

In fact, AVC (w/o tubestage) is no longer going to be offered.  Going forward, the 3 linestage options will be:

1) RVC + Tubestage
2)  AVC/Tubestage (and one could use the jumpers to bypass the tubestage section of this if they only want to use AVC
for some silly reason  )
3) DHT PRE


Unlike the LIO Tubestage and AVC/Tubestage, the DHT PRE is not a cathode follower ("tube buffer") topology.  DHT PRE
provides voltage and current gain, and I found a while back that it sounds best with the NUDE RVC (no voltage gain) in front of it.
DHT PRE is a very high bandwidth design (flat response well over 100kHz, and into the 500kHz range with 300B and 2A3's I've
tested).  You lose this bandwidth with AVC. 

AVC/Tubestage is different in that the AVCs provide the voltage gain, and the tubestage buffered output provides the current gain.
They work great together!

I hope this helps,

Vinnie

Interesting. So the DHT Pre is probably a common cathode gain stage without a cathode follower. What is your predicted/measured output impedance? Is it cap coupled or transformer coupled to the output? What outputs (RCA/XLR) are offered? And overall gain in dB?

Thanks,
Anand.

[Vinnie R.]

When will DHTs that are ordered today ship?

Hi Steve,

To be safe, I'd say mid-July.  I didn't expect so many pre-orders  , so I'm ordering all the parts
for another batch of DHT PREs.


Hi Anand,

Please refer to:

http://vinnierossi.com/dht_pre/

and check out 6moons' 3-page preview that goes into lots of detail:

http://6moons.com/audioreviews2/vinnierossi2/1.html
http://6moons.com/audioreviews2/vinnierossi2/2.html
http://6moons.com/audioreviews2/vinnierossi2/3.html

 

Vinnie

[SteveKi]

Hi Steve,

To be safe, I'd say mid-July.  I didn't expect so many pre-orders  , so I'm ordering all the parts
for another batch of DHT PREs.
Vinnie

Vinnie,
Thanks, order placed. I'm going to be real antsy by mid July. That's what I get for procrastinating. I'm also on the microRendu list for the second batch.
Steve

[Vinnie R.]

Vinnie,
Thanks, order placed. I'm going to be real antsy by mid July. That's what I get for procrastinating. I'm also on the microRendu list for the second batch.
Steve

All,

I received a lot more DHT PRE pre-orders than I imagined!  For those that ordered in the 2nd half of May, those
orders probably won't start shipping until later next month and into July.

For those that pre-ordered in the first half of May, those orders will ship in the queue all throughout June.

THANK YOU for all your orders and patience! 

Vinnie

[jtwrace]

All,

I received a lot more DHT PRE pre-orders than I imagined!  For those that ordered in the 2nd half of May, those
orders probably won't start shipping until later next month and into July.

For those that pre-ordered in the first half of May, those orders will ship in the queue all throughout June.

THANK YOU for all your orders and patience! 

Vinnie

That's awesome!  Happy for you and Alexis.     Go team Vinnie, or, uh, Alexis!   Team LIO! 

This keeps up and you're going to need an online queue progress tracker.   

[mirekti]

Too bad I cannot grab the May's discount on DHT, but given the waiting list I might have enough time to save some more by the time the delivery turnaround gets under 3 weeks. 

[jtwrace]

Too bad I cannot grab the May's discount on DHT, but given the waiting list I might have enough time to save some more by the time the delivery turnaround gets under 3 weeks. 

It's still May.

[zybar]

Too bad I cannot grab the May's discount on DHT, but given the waiting list I might have enough time to save some more by the time the delivery turnaround gets under 3 weeks. 

Today is May 31st.   

George