[bcowen]

I found this forum through Google search, and was wondering if any of you had interest in purchasing any National Electronics 6AS7G tubes (have several) made in USSR? If this isnt appropriate, please let me know and I'll either put in the the classifieds section or Ebay.

How to I insert picture without url?

The classifieds section here is the best place to post for sale ads. You can insert a picture by pasting a screenshot if you don't have a URL.

Kind of like this:

 

[johnston21]

I heard a radio article on CBC just this week on this subject…shortages / hoarding / desire of sound distortion.

 

[Thaddy]

I was about to roll these 1951 RCA’s into my WA22 until I realized two things with this tube. The getter appears broke, and there is a brownish material that looks to be between the base and tube. I’ve listened to these in the past but never noticed if these issues were always present. For now this tube is on the bench. Is this tube a goner or should it be ok to use?

 

[bcowen]

I was about to roll these 1951 RCA’s into my WA22 until I realized two things with this tube. The getter appears broke, and there is a brownish material that looks to be between the base and tube. I’ve listened to these in the past but never noticed if these issues were always present. For now this tube is on the bench. Is this tube a goner or should it be ok to use?

The brownish stuff between the base and glass is likely just glue or adhesive that has oozed out. Nothing to worry about. If the getter (holder) is broken off, due caution is needed. If you can assure the broken getter piece is resting only on glass and not potentially bridging two of the element leads, then it should still work fine. Once the getter has been flashed during manufacture, the getter support and pieces are no longer needed or used. If, however, there's a chance it could connect between any of the leads, best not to use it as you'd create a short that could damage the amp.

Pulled this one out of a tube tester. The loose piece bridged a couple of the elements and shorted, taking out several resistors and a couple potentiometers in the process:

 

[Thaddy]

Thanks for the reply @bcowen. The getter looks to be holding on so it should be ok.

 

[mordy]

The brownish stuff between the base and glass is likely just glue or adhesive that has oozed out. Nothing to worry about. If the getter (holder) is broken off, due caution is needed. If you can assure the broken getter piece is resting only on glass and not potentially bridging two of the element leads, then it should still work fine. Once the getter has been flashed during manufacture, the getter support and pieces are no longer needed or used. If, however, there's a chance it could connect between any of the leads, best not to use it as you'd create a short that could damage the amp.

Pulled this one out of a tube tester. The loose piece bridged a couple of the elements and shorted, taking out several resistors and a couple potentiometers in the process:

I have a Tung Sol 12SN7 BGRP tube where the little clip (heat radiator) above the top mica came lose and wasn't attached any more. I was afraid that it might short something. What to do?
I turned the tube upside down so that the clip rested inside the top of the glass. Then I took a little round magnet 4mm and taped it to the top of the tube to hold the lose clip in place - worked just fine.
As an added bonus somehow this contraption diffused the tube glow for a nice effect.

 

[bcowen]

I have a Tung Sol 12SN7 BGRP tube where the little clip (heat radiator) above the top mica came lose and wasn't attached any more. I was afraid that it might short something. What to do?
I turned the tube upside down so that the clip rested inside the top of the glass. Then I took a little round magnet 4mm and taped it to the top of the tube to hold the lose clip in place - worked just fine.
As an added bonus somehow this contraption diffused the tube glow for a nice effect.

Yes, but the imposed magnetic field will disrupt the quantum flow in the flux tunnel. If conditions are just right, it could result in the genesis of a black hole. Pretty risky.

 

[CAJames]

Yes, but the imposed magnetic field will disrupt the quantum flow in the flux tunnel. If conditions are just right, it could result in the genesis of a black worm hole. Pretty risky.

FIFY. Black glass tubes create worm holes, clear glass creates black holes. Don’t ask why.

 

[bcowen]

FIFY. Black glass tubes create worm holes, clear glass creates black holes. Don’t ask why.

Why?

Oh, wait. Failed to read the instructions. Sorry.

 

[No Deal]

Is this really a 421a or was I deceived? I have forgotten what the rectangular pieces are at the top but they are not the same shape that I see on other 421a tubes. I have convinced myself that if this tube is a 5998/421a which makes me wonder if it can be paired with a 421a.

 

[raindownthunda]

Is this really a 421a or was I deceived? I have forgotten what the rectangular pieces are at the top but they are not the same shape that I see on other 421a tubes.

That is a 421a. Clear top and bottom D getters. The shape of top mica supports may have changed throughout the decades of production for these tubes.

 

[Monsterzero]

Is this really a 421a or was I deceived? I have forgotten what the rectangular pieces are at the top but they are not the same shape that I see on other 421a tubes.

That's the real deal, as @raindownthunda said.

 

[No Deal]

That's the real deal, as @raindownthunda said.

Thanks to all. So many things to know about these tubes and sometimes a short window to buy.

 

[Velozity]

I have a few Chathams and RCAs left. https://www.head-fi.org/classifieds/various-6as7g-tubes.28185/

 

[g0ldl10n]

Hey, I came across this RCA 7236 on ebay and have been trying to find information on it, but have been quite unsuccessful. I do like the Tung-Sol 7236 I have for my DV, so decided to purchase one of these, was only $12.00 so I thought wth? However, if anyone has any info on these that would be appreciated!

Also, there is still one left on ebay for $12.00 for anyone that may be interested.