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?
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)?
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?