Identifying Russian tube pinout

[Bunkey]

Apologies if this is a tired question; I have a couple of these 6N17B tubes to play around with - I have the datasheet yes but unfortunately I'm not clued up on the finer points of tube construction and can't for the life of me work out which pin is which...

Any help would be much appreciated 

[bluebunny]

You should find that there's a slightly bigger gap between pins 1 and 8.

[Ben N]

vigilante397 knows these buggers well. He may have a tip for you. ( I should, but alas the two project boards I got from Nathan who-knows-how-long-ago are still in queue.)

[bluebunny]

You should find that there's a slightly bigger gap between pins 1 and 8.

My bad.  I think in this case it's a dot, not a gap:

[Bunkey]

Thanks for the contributions. That's the sheet I have also.
http://www.tubeclinic.com/6N17B.pdf

I've had a message back from the vendor and apparently that line on the base points to the two anodes.
I can only assume the rest of the pins match the diagram for the dotted case.

Hopefully that covers the possibilities; maybe with some choice buzzwords like: 6N17B, 6N16B, subminiature, valve, triode, 6H17b & 6H16b (for the cyrillic-impaired), orientation and pinout - this thread might turn up in the search form next time! 

If anyone has anything else to add I'd love to hear it.

Thanks again.

[duck_arse]

there is only two pins that will show any resistance reading, and they are the heater connections. find some resistance and you have found pins 8 and 4. [I think, difficult to make out on that dia.] from that the anodes, grids and cathodes follow in sequence.

[Marcos - Munky]

Duck is correct. Pins 4 and 8 are the heaters. Put your meter on continuity mode and find two pins which will give you continuity - iirc they're the ones with the line pointed at them, but I may be wrong on that. Call one of them pin 4 and the other one pin 8. Then the rest is easy, despite the very confusing diagram. They follows a sequence.

I have some 6N17B tubes at home, some of them soldered into IC sockets (to make them easier to be plugged in/out). I can check the exact pinout for heaters and each triode for you, but the thing is I won't be at home today. If you don't get the pinouts until tomorrow, I'll get them for you.

[vigilante397]

I second checking resistance between pins to find the heater. I also agree with the vendor, on your second pic that lovely line inside the glass on the bottom points to the two anodes/plates (pins 1 and 5). Which one you put where doesn't matter, they're designed to be rotationally symmetrical, so if you install it 180 degrees turned around the plates, grids, cathodes, and heaters will all still line up.

Anytime a question comes up about Russian subminis I try to jump in

[Bunkey]

It's alright Marcos, thank you.

The diagram is correct as it's shown there and as I mentioned above the line denotes the anode of each triode.

I've had a few coffees now and my eyes are working a little better...


Looking at the valve assembly I can see it's split into two distinct parts, which are the individual triodes. It's quite easy to seperate one bank from the other as the pins beneath correspond to the triode above despite the maze printed in the datasheet.

The anode pin(s) - as denoted by the line on the valve base - goes to one end of its respective assembly and this pin is located directly beneath the part to which it attaches; the other pins use flying leads.
Each heater pin adjacent to the anode attaches to a 'U' arrangement that loops around the bottom of the triode assembly and extends up into the tip of the valve on one leg of each 'U' - From this U there is a small loop of wire running up the center of each triode block. The filament has a resistance of ~6.9ohms cold confirming this is the heater; I assume this value will rise as they get hot else the current consumption is going to be twice what the datasheet suggests. It might be worth accounting for this warm-up if current capability of the power supply is marginal; I'm already dissipating ~2.5W of heat in an LM317 with the heaters at their nominal current, dropping to the required voltage from a regulated 12v supply - This is fine of course but I'm definitely going to be using a decent TO-220 heatsink on the regulator for piece-of-mind.
The other two pins for grid and cathode attach to their respective triodes at points closer to the middle of each triode assembly. Interestingly, the cathode is physically situated in the centre as a sleeve over the heater filaments mentioned above; the grid is offset from the centre.

I'm confident this is correct as comparing the construction with an ECC82 of identifiable pinout, the construction and location of its elements is identical.


Edit: Thanks Nathan, I was busy writing an essay there!

[Bunkey]

Beeeautiful...

But WOW I'm gonna need a bigger sink on that regulator!



Plate voltages, for those worried about the integrity of my breadboard, are an experimental 25v.

[vigilante397]

If you're running a pair of them you can run the two sets of heaters in series off a 12V supply so each tube gets 6V, saves tou a handful of components and A LOT of heat.

[Bunkey]

 

[Marcos - Munky]

Just in case somebody needs the pinout of the 6N16B and 6N17B:

- the lines indeed marks the anodes.
- think of the pin numbers as if you're putting it on a 8 pin IC socket, looking at the tube from above, not from the bottom. Pick any one anode to be pin 1.
- then you have for triode 1 the anode on pin 1, grid on pin 7 and cathode on pin 6. For triode 2, the anode is on pin 5, the grid on pin 3 and cathode on pin 2. Pins 4 and 8 are for the heaters.
- as pointed out by Nathan, those tubes have their pinout in a such way you can rotate them in 180º. That's why it doesn't matter which anode is "pin 1".

[MetalGuy]

I've played with these tubes a lot. They work well in 12AX7 circuits but for high gain the heaters must be rectified. Downside is heaters current hungry and tubes get hot.

[Ben N]

In Soviet Russia, tube pinout identifies you.

[Bunkey]

They work well in 12AX7 circuits but for high gain the heaters must be rectified.

Discovering the importance of a good smooth heater supply whilst attempting to use rectified SMPS DC atm - It does sound good, beneath the underwater bzzzzzzz... imparts an interesting choppy quality that makes me feel physically nauseous actually. One for the 'steal my idea' thread.

[vigilante397]

For single tube designs with subminis I always used a 7806 regulator, they did well for clean heater supply. For more than one tube I either ran the whole thing on 12V and ran heaters in series or I used an LMZ12003. They're a little pricey (ended up just doing a bulk buy for a nice discount) but they're an SMPS with integrated FET and integrated inductor, just add a couple passive and good to go, and they supply nice clean power up to 3A.

[Bunkey]

I said rectified, I meant regulated.

Will check those out Nathan. I'm using a 230v AC - 15v DC SMPS wall wart from a wifi router, run through two LM317's (15v-11.5v-6.4v) and a few decoupling stages. It'll power an oscilloscope and signal generator fine from the first regulator but seems to cause all sorts of problems with audio amplifiers, especially this.

Unless running the heaters off a totally separate supply to the rest of the amp (or something else) is causing the issue... everything is double insulated though so I can't see a ground loop forming.

[PRR]

> heaters off a totally separate supply

Most tube amps "want" the heater circuit connected to the audio circuits. Conventionally one end, or the center-tap, of the heater supply is connected to audio common.