[MIKELAP]

I didn't care much for the 6AV6 or 6AT6 way too bright for me.

And don't forget how to count when cutting off the pins with the Dremel...

That's what i liked about them crisp and clean . Still have alot of them but didnt cutoff the pins did that as needed. LD has been gone a few years now

 

[cddc]

It is worth noting that the 6AT6 (and 6AQ6 and 6AV6) are double diode-triodes. That is, there is one triode and two diodes inside each bottle. They are not double triodes so the notion that after some years, you can simply switch the left and right sections and have two new tubes isn't valid. In order to use them in the LD, you have to somehow disconnect those diodes. And while cutting off pins 5 and 6 could be called "butchering", it's cheap, expeditious and it works. lol

Thought 6av6 is a dual triodes and folks cut pins to use half of it.

Anyway feeling bad when I heard snipping tube pins...

 

[MIKELAP]

Thought 6av6 is a dual triodes and folks cut pins to use half of it.

Anyway feeling bad when I heard snipping tube pins...

That's called R&D lol

 

[cddc]

That's called R&D lol

R&D is fine, but don't cut the pins please ...need to R&D some other way to avoid snipping pins

 

[cddc]

I didn't care much for the 6AV6 or 6AT6 way too bright for me.

And don't forget how to count when cutting off the pins with the Dremel...

Thou I hate snipping tube pins, the soldering job in the pic was well done

 

[Datun Walnut]

Can anyone explain to me what the jumpers do when swapping between ef95 and EF91 tubes? As far as I can make out, for EF91 the jumper connects the cathode to the g3. Whereas the jumper is off for EF95 as the connection is already made in the tube. Am I correct?

 

[TrollDragon]

Can anyone explain to me what the jumpers do when swapping between rf91 and EF91 tubes? As far as I can make out, for EF91 the jumper connects the cathode to the g3. Whereas the jumper is off for EF95 as the connection is already made in the tube. Am I correct?

Pins 5 (anode) and 6 (grid) are permanently connected to each other on the board. The jumper bridges pin 7 to that arrangement for EF92 tubes to tie up g3 so it's not floating. The jumper is not installed in EF95 mode as pin 7 is tied to the cathode on pin 2 and bridging that jumper would short the anode to the cathode.

Here is a good read on strapping pentodes as triodes which is what we use in the Little Dot.
http://www.audiodesignguide.com/New2A3/ETF06TS.pdf

 

[triod750]

Only trouble with this reply is that one has to really understand what is written. To some of us that is a problem. Even if we understand every single word we can have difficulties interpreting what they mean together

 

[Datun Walnut]

Only trouble with this reply is that one has to really understand what is written. To some of us that is a problem. Even if we understand every single word we can have difficulties interpreting what they mean together

We're all learning. I'm slow but getting there.

 

[Datun Walnut]

Pins 5 (anode) and 6 (grid) are permanently connected to each other on the board. The jumper bridges pin 7 to that arrangement for EF92 tubes to tie up g3 so it's not floating. The jumper is not installed in EF95 mode as pin 7 is tied to the cathode on pin 2 and bridging that jumper would short the anode to the cathode.

Here is a good read on strapping pentodes as triodes which is what we use in the Little Dot.
http://www.audiodesignguide.com/New2A3/ETF06TS.pdf

I'll DL that and have a read. Thank you. I have a small but useful homebuilt triode tester. I'm wondering I'd I made a box with a 7 pin socket on strapped up like a triode, I could test my pentodes.

 

[TrollDragon]

I'll DL that and have a read. Thank you. I have a small but useful homebuilt triode tester. I'm wondering I'd I made a box with a 7 pin socket on strapped up like a triode, I could test my pentodes.

I can't see why that wouldn't work.

 

[TrollDragon]

Only trouble with this reply is that one has to really understand what is written. To some of us that is a problem. Even if we understand every single word we can have difficulties interpreting what they mean together

I could have included pinouts of EF92 and EF95 tubes to show the difference of how they are wired up internally. The jumper on the board of the LD allows us to use both types of tubes.

 

[triod750]

I could have included pinouts of EF92 and EF95 tubes to show the difference of how they are wired up internally. The jumper on the board of the LD allows us to use both types of tubes.

You did fine. It's difficult to teach blockheads.

 

[lupoal]

my two tungsol 6SN7GTB, are driven by two CV4014 (thank you Datum Walnut!) and... they sound really fine but... the two tubes seems to have (well, I think they have) a quite different operating temperature, I swipped the tubes between the two position and the hotter one is always the same (tube, not position), I've done the same with the CV4014 (thinking could be from differences in those but no, the hotter 6SN7 remain unchanged)...here is a picture, what do you think about? all normal or one of the tubes is fault?

 

[Datun Walnut]

my two tungsol 6SN7GTB, are driven by two CV4014 (thank you Datum Walnut!) and... they sound really fine but... the two tubes seems to have (well, I think they have) a quite different operating temperature, I swipped the tubes between the two position and the hotter one is always the same (tube, not position), I've done the same with the CV4014 (thinking could be from differences in those but no, the hotter 6SN7 remain unchanged)...here is a picture, what do you think about? all normal or one of the tubes is fault?

Do you have a multimeter? Can you check the heater voltages on the sockets. They should be 6.3v or there abouts (mine are 6.5) if it the fault moves with the valve it's probably the valve itself. Sometines the heater wire might be slightly different. You could measure the resistance across the heater pins and see if the is a difference between the two valves. I can send you the pin details if it will help.