[jtwrace]

Hey Vinnie,

Post pics of the tube covers whenever you get the chance. Hoping to see both looks. I still need to choose my color 

Thanks!

I'm going all black.  Case, top, knobs & covers. 

[jriggy]

I'm going all black.  Case, top, knobs & covers.

Ive ordered black chassis, black knobs, silver top. Getting the glow/reflection w/ the silver top will be cool.

[jtwrace]

Ive ordered black chassis, black knobs, silver top. Getting the glow/reflection w/ the silver top will be cool.

No doubt!  I just like no lights when listening as I tend to do more listening in the dark.   

[zybar]

I'm going all black.  Case, top, knobs & covers.

Same here.

Although some silver knobs could look good as well...

George

[TomS]

I have black case, silver knobs which I really like. I ordered silver top, silver tube covers, but I'd like to see it with the covers first.

[BobRex]

Same here.

Although some silver knobs could look good as well...

George

That's a good contrast.  The silver knobs make the LIO look "Levinsonian".  I've been running topless for the past few weeks while I screw around with cartridge loading.  Yes, I hear the relays, but it doesn't bother me.

[Vinnie R.]

Another tube for LIO DHT PRE! 

Just received a pair of matched NOS Cunningham CX301-A tubes!





5V, 0.25A filaments (cool running).  Higher plate resistance (about 10k), and they
have very rich tone, thicker bass, and a very sweet top end.  If your speakers
are on the "dry / analytical" side and you want a richer, more toobey sound, these
are worth a listen! 

They pick up some hum, but I will try with the metal tube covers to see if it goes away (it should).

I have a feeling there will be even more to add to the growing list of NOS 4-pin DHTs that will work
in LIO DHT PRE... 

Vinnie

[sfox7076]

Vinnie,

Try to tun them at the lower heater voltage (if you can).  The microphonics and hum will go down a lot. It's an amazing tube.

Shawn

[Vinnie R.]

Vinnie,

Try to tun them at the lower heater voltage (if you can).  The microphonics and hum will go down a lot. It's an amazing tube.

Shawn

Hi Shawn,

Will do (I'll try at 4V this evening).  I really like this tube:

- low microphonics
- Barely any heat - doesn't even get warm!
- Shorter height and no heat is great for tighter spaces
- Nice glow! (but not as illuminating as the SV811 / SV572)

Perhaps other 01-A tubes will work just as well?

Thanks for the recommendation!

Vinnie

[jtwrace]

I really like this tube:
Vinnie

Just tell me which tube to buy and I will.  I'd much prefer to go the less is more route.     You know what I prefer sonically now.   

[sfox7076]

Vinnie,

Glad it is sparking interest and really bringing you some joy.  Especially awesome when the tubes are usually less than $75 per pair NOS (assuming just RCA or Cunningham).

All of the 01A tubes are basically the same tube (except for really early brass base ones with short UV pins (like the WE 101Ds), they are UV-201As).  The 01 (not 01A) would also work in your circuit I am sure as they are the same tube with a 5v, 1A draw, but they also cost about 4 times the price and were last made in 1925 or so.  Anyway, the 01A tubes were rebranded and made by about 100 different makers.  01A, 201A, 301A are all the same.  UX-201A, CX-301A, OK-201A, etc.  All the same tube...  Cunningham and RCA are exactly the same in this time frame as the RCA v. Cunningham suit had concluded and RCA was making all Cunningham tubes.  Those are the most commone ones.  The ones to really look for are the ones with the oddball labels or boxes (if you get boxes).  Those are collectible, and so are the ones with pointy tops where the glass is peaked.  In any event, watch out buying them.  They generally do not sound different than any of the others (except those that are microphoic or noisy and there are no real fancy makers of this tube (there is allegedly a Northern Electric version from Canada, but I have never seen one, and an Arcturus, but it isn't blue so I am not sure it commands a high price), and many of these tubes can be noisy at full filament voltage.  Starve them at 4 volts and you should find sonic bliss regardless of the label.  All that said, some are occassionally too noisy to be saved. 

I have about 30 of them for my DIY linestage project (which should be coming together in time).  The other great thing about 01A tubes is that you can regenerate them if they start to get worn out.  That discussion is for another time, but man do I love those tubes.  They will never be the tube of choice for an output tube because of low power.  However, they only spec 1.25 Watts (5v x .25A) of power on the filaments to operate.  If you run them at 4 volts, it's 1 Watt.  I think that you will barely notice a sonic difference in the tube, but you will notice a lack of noise.  Battery tubes can be awesome (and cheap!).

The only two other DHT tubes made that I like for preamp work that your line stage won't take are the 26 and the 10Y. I could be happy forever with 01As though.  The 10Y is very different, but it needs 7.5 volts on the filament.  The 26 only takes 1.5v (at 1.05A)!    Making a linestage that includes all three of those tubes is my goal.  That is my project, but I think it will involve a seperate power supply and possibly two different DHT modules.  Sigh...  I am following your project closely as it is the natural follow through to my DIY project if it fails. 

I also love the 4P1L (DHP (direct heated pentode) that can be triode strapped), but it is a loktal socket, wrong voltage (only 2v) and is the most microphonic tube I have ever heard.


Shawn

[Triode Pete]

The only two other DHT tubes made that I like for preamp work that your line stage won't take are the 26 and the 10Y. I could be happy forever with 01As though.  The 10Y is very different, but it needs 7.5 volts on the filament.  The 26 only takes 1.5v (at 1.05A)!    Making a linestage that includes all three of those tubes is my goal.  That is my project, but I think it will involve a seperate power supply and possibly two different DHT modules.  Sigh...  I am following your project closely as it is the natural follow through to my DIY project if it fails. 

Shawn

Don't forget about the UX171 & UX171A variants, originally made by RCA in 1925! In one of my systems, I have a 171A Directly-Heated Triode Line stage (powered by dual mono tube regulated power supplies)... Superb sound but can be microphonic... Design started early 1925, adopted by RCA in October 1925 but available only at June 1926, replaced in November 1926 by the UX171A (oxide-coated filament). The UX171 has a thoriated tungsten filament, operating at 5 volts and 0.5 ampere. Delivers 0.7 watt output (plate dissipation) at the maximum recommended anode voltage of 180 volts.

Vinnie - I have a few pairs, if you ever want to try them...

Cheers,
Pete

[TomS]

You guys are traveling soooooo far down the rabbit hole with all these 90 year old tubes. What on earth have I signed up for

[sfox7076]

Another tube pile I have is 5-6 40 tubes.  One day I will drop these in for an 01A somewhere.  They have the same filaments and similar max plate voltages, but much lower grid voltage, higher plate resistance (150k), higher amplificaiton factor and lower transconductance.  Odd tube. 

[Vinnie R.]

Hi Shawn,

Thanks for your posts - I'll be trying other DHTs down the road!

Vinnie - I have a few pairs, if you ever want to try them...

Hi Triode Pete,

Sure - send them over the next time you send me cables!  Thanks for letting me borrow them.

You guys are traveling soooooo far down the rabbit hole with all these 90 year old tubes. What on earth have I signed up for

Hi TomS,

Rabbit hole, hmmmm - reminds me of:

http://matrix.wikia.com/wiki/Redpill



"You take the blue pill, and you enjoy the stock 2A3s (great tube!) - game over."

"You take the red pill, you stay in Wonderland, and we show you how deep the rabbit hole goes with
the many DHT possibilities." 

They have the same filaments and similar max plate voltages, but much lower grid voltage, higher plate resistance (150k), higher amplificaiton factor and lower transconductance.  Odd tube. 

Yikes, 150k - way too high of a plate resistance for LIO DHT PRE.   


LIO DHT PRE UPDATE 

- We're building away and I hope to start shipping a few DHT PRE orders next week! 

- The finish on the tube covers did not come out the way I wanted (too dull a finish, too rough texture),
so they will need to be redone.   In the meantime, I will still start shipping a few orders next week because I don't
want to hold up shipments.  Then I will ship out the covers separately when they arrive.

- I have 220-240V transformers for the linear power supplies coming next week (for international customers).

- Top covers look great and I am ordering more of them because I did not plan for this many pre-orders.

I'll post another update early next week.

Vinnie

[sfox7076]

Glad to discuss this stuff.  Update me when you try the 01A at 4v.  Are there limitations on your power supply design that would stop you going to 7.5v?  I get you may need a bigger transformer, resistors, etc.  I assume not, but wanted to ask.  I know that I ask a lot.

[zybar]

Here are a few pics of the LIO DHT without the cover and with the SV811 tubes.  Sorry for the so-so image quality - these were taken with my phone instead of my DSLR.

These were taken when Vinnie brought over the DHT for a listen a few weeks ago.

Can't wait to get my DHT!!

George

[zybar]

Hi yardbird4,

I'll have to check those out next!  I'll contact George Lens (Tubesusa / importer of Emission Labs) and see if I can get a pair...

This weekend I also met Rachel of Grant Fidelity.  She imports Psvane and Shuguang Treasure tubes from Asia (a few different models of 2A3 and 300B, as well as 101D/205D replica tubes), so I hope to try those out in the future as well!

Vinnie

Those EML 45's range in price from ~ $500-700 a pair!!  Not saying if they are or aren't worth it...but that's a lot of coin.  2A3 and 300B are even more!   

The Psvane and Shuguang are more affordable (but still far from inexpensive).

Hopefully, Vinnie will be able to get some and let us hear for ourselves.

George

[sfox7076]

I am a big fan of National Union ST shape 45s from the 40s and 50s.  Worth a shot at $200 a pair max.

[zybar]

I am a big fan of National Union ST shape 45s from the 40s and 50s.  Worth a shot at $200 a pair max.

Where do you get them?

George