[Dracule1]

one were to install the 101D tubes but have the 300B setting switched on instead of the 101B setting in the back of the DAC?

[sfox7076]

I am not sure.  If it were a voltage switch, it would overheat the filament and eventually burn it out.  That said, 2A3 is a 2.5 volt filament and the 300B is 5 volts.  See this minor discussion: http://www.audiocircle.com/index.php?topic=129512.msg1464554#msg1464554

I don't understand this because I have always assumed that a filament rated for 4 volts at 1.5 amps at 4 volts will pull 1.5 amps.  If you only gave it 3 volts, it might pull a bit more current, but it wouldn't pull 2 amps to equal 6 watts.  I am just not sure how it works.  If the voltage was below 4 volts, I don't see it being an issue unless it is somehow a constant current circuit with the voltage floating.  I have never seen that, but I imagine it could potentially be done.

[sfox7076]

This may prove an interesting read:  http://www.john-a-harper.com/FilamentHeating/

[wisnon]

It think it works on total watts. The lower setting being total 4.5w max and the higher setting being 6.5w. more than that, I cant say...

[sfox7076]

But that means constant current or voltage. You cannot have both float.  Constant current is harder to implement.  It is also harder to stabilize. That said, it would cause less thermal shock (which I don't believe matters) from turn on. 

[Dracule1]

I pulled a Donald Trump ...doing without thinking.  I inadvertently installed the 101D and left the switch on the 300B setting for about 12 minutes before realizing what I had done.  Well, it's not as bad as I thought.  I emailed Lampizator.  First, I got a response saying that I most likely damaged the 101Ds.  I think the response may have been from one of their techs.  Bummer since these Psvanes are not cheap.  Then I got another email (I think from Lukasz himself, although there was no e-signature on the email) that basically said not a big deal...I just shortened the life of the 101Ds from 30 years to 10 years. I'm listening to the GG with the 101Ds now and I hear no obvious degradation in sound. In fact, it sounds great 

[wisnon]

Dracule.

Dont panic...I just called Lukasz and asked. Its fine.

The excess electricity will only shorten tube life ---OVER TIME---. A few hours makes no difference. He said the difference to a new tube would be 10 years useful life vs 30 (assuming constant use on the wrong setting), so no big deal. There is likely no real change to your tubes and insetad of 30 years, you can now expect 29.9 years. LoL

Shawn, I asked about the auto balancing and yes, he confirmed both voltage and current are floating!

6L6 pentodes should work similarly to 6A3 but will also be underheated similarly, as the heatertops out at 5v and they both need 6.3v optimally.

[Dracule1]

Yes, thanks.  I'm having no issue whatsoever with the tubes.

Dracule.

Dont panic...I just called Lukasz and asked. Its fine.

The excess electricity will only shorten tube life ---OVER TIME---. A few hours makes no difference. He said the difference to a new tube would be 10 years useful life vs 30, so no big deal. There is likely no real change to your tubes and insetad of 30 years, you can now expect 29.9 years. LoL


Shawn, i asked about the auto balancing and yes, he confirmed both Voltage and current are floating.

6L6 pentodes should work similarly to 6A3  but will also be underheated similarly, as the heatertops out at 5v and they both need 6.3v optimally.

[sfox7076]

Odd.  Ok.  I have to think about how that would work.  It would seem to violate Ohms law.  Output current is determined by resistance load.  Current = V/R.  So, for instance, for a 2A3, the equation is 2.5A = 2.5V/1 Ohm.  In theory, the resistance stays the same (it does reduce a bit with longer heat, but putting that aside), you have one fixed variable (1 ohm).  Something else has to become fixed for Ohms law to hold true (and physics works like that).  If there is a current limiter, maybe that does it because it sets the outside limit of current, which then (by ohms law) sets the voltage, but then the current isn't really floating, it is limited.  I also think it is a bit odd as most current limiters are made as safety features.

As to the 6L6s, you will need an adapter to use as a 6L6 as it is an octal pentode.  I guess you are saying you can triode strap the pentode and use an octal to ux adapter built to strap it as a triode?  I have to think about how that would work.  If that were the case, you could also use 807s (just need a different adapter as the plate/anode pin is the top cap).

[wisnon]

Shawn, I have even less of a clue than you, but could it be that the resistance is variable and changes to accommodate max voltage/currents per setting?

For example for the higher setting, ie 6.5w, with the max voltage allowed at 5v, then you have a 5v setting with up to 1.3amps allowed? This would mean that a 6A3 is underheated as it ideally needs 6.3v @1amp, but operates here at 5vx1amp, whereas the 300b is 5vx1.2 amp specced and the circuit will allow up to 5vx1.3amps (if needed).

This suggests to me that there could be a logic that is switching resistance on a stepped ladder?

Again, no clue, just speculation.

Regarding the 6L6, Lukasz said they will work with adapters, so I am looking for some cheap ones to try out.

[sfox7076]

I suppose you could put another resistor in the series, but then things are the same as discussed before.  Instead of a filament resistance of 1 Ohm, you have filament resistance of 1 ohm + additional resistance= the R in the equation.  Then still have to have floating voltage or floating current.  Even if 5 is the max, if it floats, how does a 2.5 volt 2.5 Amp tube filament not have the filament voltage float to 5v at 1.25A? I just don't get it in the context of ohms law.  Something else has to be fixed or you will operate tubes outside their rated voltage or current draw.

[sfox7076]

Your best bet would be to buy these and wire it up yourself:  http://www.ebay.com/itm/4-Pin-Bottom-To-8-Pin-Octal-Top-Tube-Adapter-Kit-for-Tube-Substitution-Project-/371046888165?hash=item56641e32e5

finding an A08 to UX4 adapter is not going to end well.  Most octal to UX adapters will be made to be 274A tube to 274B socket.  That is guaranteed not to work. 

[wisnon]

Your best bet would be to buy these and wire it up yourself:  http://www.ebay.com/itm/4-Pin-Bottom-To-8-Pin-Octal-Top-Tube-Adapter-Kit-for-Tube-Substitution-Project-/371046888165?hash=item56641e32e5

finding an A08 to UX4 adapter is not going to end well.  Most octal to UX adapters will be made to be 274A tube to 274B socket.  That is guaranteed not to work.

What about the adapter that convert the 6b4g to 6a3 (ux4 base)? I have a set of those and they work as advertised....

[sfox7076]

No.  The 6b4g is really a 6A3 in an octal socket.  The 6L6 has things like a screen connection.  It uses 6 pins instead of 4 (like the 6A3 and the 6B4G).  2 for the filament.  1 for the Cathode, two for grids (ok, so one is called the screen) and 1 for the anode. 

It is indirectly heated, so I am not 100% sure how one goes about triode strapping the tube to work with 4 pins.  I think you need to leave the cathode pin not connected, but I am not sure .  I would then assume that Grid #2 (the screen) would be strapped to the plate.  That would link them up this way:

6L6 Pin           UX4 Pin
1                    Not connected
2                    Pin 1
3                    Pin 2
4                    Pin 2
5                    Pin 3
6 (if there)     Not connected
7                    Pin 4
8                    Not connected?

I am not 100% sure on this, but I think that is how it would be done.

[wisnon]

Thanks,

Kinda complicated then...

[sfox7076]

Yes, and not worth the effort with the other tubes that are out there.

[sfox7076]

As an aside, the 2A5 could potentially work if you triode strapped it, and those are basically $15 a pair.