RCA 12AX7 Clear-top Side Getter

[jgab]

Hi,
I am interested to know if clear top side getter tubes sound different than regular top getters? I have a chance to buy a RCA clear top 12AX7 long plate, but I would like to know if it will have any difference in sound compared to a normal RCA long plate? Are clear tops usually more expensive?

Any experience with clear top 12AX7 tubes?

Why would a tube manufacture even make a side getter?

Thanks,
J

[krx]

The getter doesn't do anything to the sound. It's just there to get rid of stray gas molecules in the vacuum. If it works, it works.

If they are otherwise identical in construction, I would expect them to sound similar (no two tubes ever sound exactly the same, of course). Wouldn't surprise me if there's some difference besides the getter though. Generally they would change things like that either to improve reliability/microphonics or reduce cost.

[dotfret]

I've seen only four side getter 12AX7 in over forty years of staring at the things - all from ambiguous European re-labellers. They sounded like a lot of European NOS valves - better than new stuff, but nothing special about them.

I've seen a lot of RCA 12AX7, but never a clear top. Remember, RCA designed the 12AX7 - why would they change to a different design, then change back later? It is vaguely possible that RCA bought some in and relabelled them - RCA did buy from outside suppliers occasionally.

Whatever, consider that if the valve does make your amp sound exceptional - where do you go for another? The well is dry as a bone ...

[goattech]

i just found a rca 12au7 clear top side getter at a swap meet and picked it up dirt cheap, the guy even tested it for me while i was there.

[Phil_S]

RCA made a clear top 12AU7 and it seems to have a following. Nice tube. I own 3 or 4 of them. I think they are NOS. I'm still looking for a place to put them. I think the 12AX7 is a totally different story.