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Little Dot Tube Amps: Vacuum Tube Rolling Guide - Page 297

post #4441 of 10574

if its the voskhods mentioned on page 1 then i'd say no good deal.You apparently don't need them matched and then they go for 3$ a piece plus postage!

post #4442 of 10574
Quote:
Originally Posted by mojorisin35 View Post

Is 20$a tube a good deal for 1975 Voskhod's?

 

I assume you mean the double triodes? 6N23P? No, $20 a tube is not a good deal. I have paid $3 to $6 each for these....

post #4443 of 10574

yes the  double triodes 6N23P, do you mind pm'ing ,me a link?

post #4444 of 10574

I have received my first 6SN7GT this morning. A National Union, dated 5108. It lights up and sounds very musical. However, I have put it aside for now. The Western Electric 396A is next in line. And before that, some R&R for me. :)

 

 

Edit: Oh, I took some measurements:

 

National Union 6SN7GT 1951 (LD 1+)

 

Plate R 81.2

        L 81.2

 

Grid   R 3.1

        L 3.4

 

Looks pretty good. :)


Edited by gibosi - 12/21/13 at 10:41am
post #4445 of 10574

Hi mojorisin35,

 

I bought 4 Voskhod 6N23P used tubes (supposedly 100 hours or less on them - saves you the trouble of burning them in) for under $4 each including shipping.

 

Here is a link - this seller probably has many more:

 

http://www.ebay.com/itm/USSR-6N23P-6DJ8-6922-DOUBLE-TRIODE-LITTLE-USED-QTY-20pcs-/221338600574?pt=Vintage_Electronics_R2&hash=item3388cf047e

 

The trick is communication. This seller's English is not the best, and I used Google translate to send my questions and wants in Russian printed out in the Cyrillic alphabet.

 

http://translate.google.com/#en/ru/The%20trick%20is%20to%20communicate.

 

I wanted an octal tube as well to save on shipping. This worked out very well, and the seller made a special buy it now listing for me, which I responded to right away. He also sent me an extra octal tube for free!

 

I ended up with four Voskhod 6N23P 1974 tubes with wire getter, a 1981 Saratov 6N9S (was supposed to be 1961) and another octal tube without any markings except OTK1 which just means Quality Control checker #1 and nothing else. It looks like an old  6N9S tube and sounds fine once I dusted it off.

 

Good luck!

post #4446 of 10574

Late at night on a Saturday in my time zone, but for some obscure reason this seems to be the time when I start browsing Google because I'm curious about something and end up getting new ideas.

 

So, here it goes, two new ideas, or basically tube types to test - notice how I'm only suggesting frame grid types:

 

The E80CC/6085, double triode, frame grid construction, center tappable 12V heaters, mu=27, cathode bias resistor needed 920 ohms (LD amps have 680), and very linear. Basically, a cool double triode that's like a 12AU7 but more interesting. Crack addicts... I mean users have tried it instead in the position of a 12AU7 in their amps with great success. Anyway, I have virtually no doubt it would work in our LD amps and sound at least pretty good with the same adapters we used for 12Ax7 tubes!

 

The C3G, single pentode, frame grid construction, 6.3V heater, mu=40, linear like crazy! But (l)octal base and 180 ohm cathode resistor needed (not that it's ever been an issue up to here, the 2C51 needs a 240 ohms resistor and it worked fine). Basically, a "super critical" pentode made for telecommunication signal repeating - amplification - with ultra low noise and ultra high linearity. Now that's interesting! They'd need custom adapters, but at least we'd be back to using a single tube per channel, which could more esthetically pleasing.

 

Anyway, just a few ideas. The E80CC is only supposed to be an excellent frame grid double triode, but the C3G are supposed to be some - if not the - best small signal tubes ever made, or so the web says. Then again, the fact that whole amps are built around that tube says a lot about their quality. Anyone who already has octal sockets willing to try it? Testing a E80CC is even easier, barely even a challenge at this point...

 

Edit: Bonus tube, the D3A, frame grid pentode, noval, 6.3V heater, mu=77, cathode resistor=470 ohms, ultra linear. Great fun!


Edited by Audiofanboy - 12/21/13 at 5:11pm
post #4447 of 10574
post #4448 of 10574
Quote:
Originally Posted by mordy View Post

Hi mojorisin35,

I bought 4 Voskhod 6N23P used tubes (supposedly 100 hours or less on them - saves you the trouble of burning them in) for under $4 each including shipping.

Here is a link - this seller probably has many more:

http://www.ebay.com/itm/USSR-6N23P-6DJ8-6922-DOUBLE-TRIODE-LITTLE-USED-QTY-20pcs-/221338600574?pt=Vintage_Electronics_R2&hash=item3388cf047e

The trick is communication. This seller's English is not the best, and I used Google translate to send my questions and wants in Russian printed out in the Cyrillic alphabet.

http://translate.google.com/#en/ru/The%20trick%20is%20to%20communicate.

I wanted an octal tube as well to save on shipping. This worked out very well, and the seller made a special buy it now listing for me, which I responded to right away. He also sent me an extra octal tube for free!

I ended up with four Voskhod 6N23P 1974 tubes with wire getter, a 1981 Saratov 6N9S (was supposed to be 1961) and another octal tube without any markings except OTK1 which just means Quality Control checker #1 and nothing else. It looks like an old  6N9S tube and sounds fine once I dusted it off.

Good luck!

Mordy
Thank you soo much for your link and advice. I have sent off a message and am waiting on a reply ! I cannot wait

Gary
post #4449 of 10574

Am I the only one listening to 2C51/396A/5670 through a LD?

 

Anyway, my curiosity was just too much for me to resist, and accordingly, I decided to compare the Western Electric 396A to my best 6DJ8-types: 1961 US-Amperex 6922/E88CC, 1960 Heerlen 7308/E188CC and 1975 (October) Voskhod 6N32P.

 

 

In my opinion, the Western Electric 396A compares extremely well with these tubes. It is most similar to the Heerlen E188CC. That is, the US 6922 has a bit more bass and more treble, the Voskhod has more bass presence with laid back mids, and the Heerlen, with that lush midrange, is almost an exact match. Given my ears and gear, the differences between the Heerlen and the Western Electric are too subtle to be revealed easily ... It will take more time...

 

That said, I rate the Western Electric 396A as a great tube and a relative bargain, not nearly as expensive as the premium 6DJ8-types. I picked up my Western Electric 396A for around $17/shipped. Highly recommended.

 

~~~~~~~~~~~~~~~~~~

 

How to use:

 

If you have a breadboard 9-pin socket, the right triode connections are the same as for the 6DJ8, but the left triode and heater connections are different:

 

http://www.head-fi.org/t/563884/little-dot-tube-amps-vacuum-tube-rolling-guide/4110#post_10021890

 

However, I am using a 2C51 to 6DJ8 adapter, which makes rolling these tubes much easier:

 

http://www.ebay.com/itm/260723522614?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

(Although this listing is for two adapters, the vendor agreed to send me only one adapter and accordingly reduced the price by half.)


Edited by gibosi - 12/22/13 at 11:00am
post #4450 of 10574

Hi Gibosi,

 

I have two breadboards with Vector adapters, one for 12AX7 that I can also use with an adapter for octal tubes. The second breadboard is set up for 6DJ8 type tubes.

 

Instead of switching in and out the two different breadboard contraptions, could I plug in the Vectors on top of each other and leave out one of the tubes? Would the amp think that I am only using one breadboard?

 

Next, to use the Western Electric 396A, could I make up a fifth Vector and attach it to the second screw fitting available for each of the breadboard leads while unplugging the Vector adapter that is different for the 6DJ8?

 

Hope I am making myself clear....

post #4451 of 10574
Don't mean to interject here, but you could just run parallel wires to the other breadboard hooked up for which ever tube you want. If you only plug in one tube at a time and power down allowing for the caps to discharge before changing tubes it should be a lot easier than stacking Vectors.... eek.gif

Put both bread boards side by side and just run the wires that you need from one to the other. If it doesn't present any hum doing this it would be a grand solution.
beerchug.gif
post #4452 of 10574

Mordy,

 

What you are proposing will probably work (I think). However, the more complicated your connections (5 Vectors and 2 sockets), the more likely it is that one or more of these connections may fail. Of course, completely swapping out the Vectors and the attached socket each and every time you want to switch between 6DJ8 to 12AX7 would seem to me to be a real hassle, so I certainly understand your motivation. But while your proposal would make it simpler to switch tubes, unfortunately, it would add considerable complexity to the circuitry, and thus, more connections that can go flaky and even fail.

 

Personally, I find it easy to have only one socket. With only three wiring changes required to switch between 6DJ8 to 12AX7, swapping tubes can be done in just a few minutes, while keeping the number of connections to a minimum. And again, using an adapter for 2C51 tubes is easy and it also helps to keep things simple.

 

But if you are comfortable with your proposed arrangement, then go for it. I can't see any reason it wouldn't work. :)

post #4453 of 10574

Now Everybody Sing!

"Oh Christmas Tube, Oh Christmas Tube, Your glow is sure enticing."

 

Built in light...

 

It makes a perfect ornament and an even better tree topper, but "She who must be obeyed" quickly put the kaibosh to that action. :(

 

Oh well, on my desk it will stay...

One more time, with feeling!

"Oh Christmas Tube, Oh Christmas Tube, Your glow is sure enticing."

post #4454 of 10574
What. A. Beautiful. Tube!
post #4455 of 10574

Voltage measurements for a 1951 Western Electric 396A (LD 1+)
 
Plate R 98.1
        L 98.1
 
Grid   R 1.8
        L 1.7

 

Interestingly, the plate voltage is quite a bit higher than a 6SN7 (81.2) or a 6N23P (85.2)

 

And the grid voltage is lower than a 6SN7 (3.2) or a 6N23P (2.6)

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