Valve (Tube) Sockets with shield

[grapefruit]

I'm planning a project using a 12AX7. A local supplier has Chassis sockets with shield....

Base "B9A" "NOVEL" - Chassis + Shield.
9 Pin valve socket with ceramic base to solder tags. Includes optional shield cap that fits only the smaller tubes. eg 12AX7.

My quesition is, is the shield cap secure enough to keep the tube from getting broken if mounted externally, or are they just for shielding? The one I'm looking at is from Wes Components in Sydney. Part# VS912

Cheers,
Stew.

[JonFrum]

The shield is thin metal. If the unit drops to the ground, I wouldn't rely on it holding up without damage, but maybe you'd get lucky. If you grabbed it and pulled/twisted, you could probably tear it off, or at least do a lot of damage. For real protection, you'd need something like a cage. Personally, I wouldn't leave shielded tubes exposed unless I was keeping the unit in a home studio, and I'd only do I because I have no kids.

[brett]

Hi
With a shield it won't look like a valve, so there's no aesthetic benefit of leaving it outside.  It also contains potentially lethal voltages.
For my real McTube, I used a large diecast box and cut out a hole, covered with an open mesh, so the tube could be seen glowing.  But after ten minutes, I didn't look at it again
cheers

[JonFrum]

On the other hand, exposed tubes can be cool.   

[grapefruit]

Thanks for the replies.

I think I'll just keep it inside the box, mounting the socket on a piece of aluminium angle. I'll need a fairly large box to fit the tranny anyway. I'm using the 12AC wallwort to a mains trannie wired backwards approach. Something like 12V (haven't worked it out yet) to 240V transformer. (I'm in Australia).

If this works ok I'll use PCB mount sockets.

Cheers,
Stew.

[JonFrum]

Have you seen this build?

http://www.frontiernet.net/~jff/af2b/Dual_Channel_Blackface-style_Preamp_for_Bass_Guitar.html

[grapefruit]

Thanks for that link. It provided a few more usefull links too.

I think I'll start off basing it on a Mesa overdrive circuit, also keeping in mid the circuits of the Westbury W20 and Real Mc Tube. Not sure If I'll get enough gain out of two stages but I'll see how it goes.

I've ordered the shielded socket anyway. It may help reduce potential hum caused by having the traanny and circuit in a relatively small box. I'll use a regulated heater supply too.

Cheers,
Stew.

[bancika]

I made one preamp with tubes sticking out from chassis, here's link
http://storm-software.co.yu/diy/index.php?project=tube_reactor
I don't know if shields would help if someone stomps on tubes directly really hard, but as far as I'm concerned, they do good job

[grapefruit]

Thanks Bancika,

The method you used of pad per hole soldered on top side seems like the best method for a tube based build. I usually go straight from breadboard to PCB but this one is going straight to pad per hole proto board.

Cheers,
Stew.

[bancika]

yeah, it's very nice when you want to experiment. I have made maybe dozen changes to plate resistors, snubbers, tone stack resistors and caps, etc. until I got tone I was looking for. Perfboard made those changes really easy