Shock mount tube sockets? Yet another thing I didn't know...

King Fan

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So, pointing out EF80s may be microphonic, our amazing friend @robrob notes on his Micro Bassman page it may help to build them in heads more than combos, and to use "rubber insulated sockets." I've seen some such; the 'bay currently lists exactly one (1) 1956 socket-isolation plate that mounts on 4 little bolts with rubber washers above and below.

1647962049933.png

Then, searching 'shock mount tube socket' I found this TGP thread (from our friend @mabinogeon ) where he notes TubeDepot sells their ¼" rubber grommets to cushion a standard socket, like so -- apparently you drill out the mounting holes to ¼".

1647961073014.png

But *then* I read the thorough answer to that TGP question, where a smart person points out that *Fender did this* on Tweed amps, which partly explains the famous green or pink thread locker. Me: "I did not know that."

1647961405091.png


And then he goes on to point out they also explicitly grounded the output sockets.

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So, my friends: I'm sure some of you knew about the vintage tweeds. Did you know this modern ¼" grommet trick? More to the point: Anyone done it?

Could you use neoprene washers instead, at least on the socket side of the chassis, or perhaps under both screw head and nut, on a longer bolt?

And would you need to ground the socket? Just on the output tubes? Was that somehow for metal-jacket tubes, or am I overlooking the obvious safety/function reason?
 
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D'tar

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should be plenty of left over ST Patricks day nail polish! If youre in to kelly green!

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King Fan

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Heh, nah, I'm thinking Bianchi bicycle touch-up paint. It has that pale green almost sparkle thing going on. IIRC TDPRI used to have a smart member named Celeste; in Italian: "che-LES-tay."
 

printer2

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There is not enough mass on the tube side to do much isolating with the washers. I used them with a 12AU6 as the input tube on a 6V6 Bassman type of build. The amp sings on its own if you turn the volume up enough. But as long as you keep playing it is rather interesting. Really tough to keep the tube from vibrating in a combo. Mind you it was also a high efficient speaker, years away from seeing live bands I forgot how loud things can be.
 

muscmp

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i've used grommets on v1 of my 5e3 builds. i've not had any problems with vibration and/or microphonic problems but they are cheap and easy to do.

play music!
 

frankenxtein

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I've scraped worn out old internal computer CD/dvd roms and found silicon rubber grommets holding the transport. The smaller ones are from laptop cd/dvd drives.

I used the shockmount from a Voice of Music VM730 reel to reel on my ef86. Maybe it wasn't necessary but , that was my first time using the tube.
Also , my ef86 is "V2" in a Matchless Clubman 35 (ef86)

If you use to stiff of wire or mount a resistor to the chassis from the socket. The vibration will just get in there that way.
Any way it goes those worn out drives have some small grommets in them.
IMGP0243.JPG
 

printer2

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I've scraped worn out old internal computer CD/dvd roms and found silicon rubber grommets holding the transport. The smaller ones are from laptop cd/dvd drives.

I used the shockmount from a Voice of Music VM730 reel to reel on my ef86. Maybe it wasn't necessary but , that was my first time using the tube.
Also , my ef86 is "V2" in a Matchless Clubman 35 (ef86)

If you use to stiff of wire or mount a resistor to the chassis from the socket. The vibration will just get in there that way.
Any way it goes those worn out drives have some small grommets in them.
View attachment 964714
I have some around here somewhere.
 

King Fan

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Cool info, thanks, all. FWIW, I'm planning to put mine in a head unit, and I will use silicone damper rings as Rob suggests, but if the head sits on the speaker cab, or, heaven forbid, in front or back, I figure more isolation may not be too much.

Anybody put sound-dampening feet on the head unit? Suggestions? I used to have some underneath my stereo turntable -- ah, the memories.

For those who've done it, I'm seeing you used grommets? Has anybody else done this? Has anyone tried neoprene washers?

Do we think Fender used washers? or grommets?

And can anyone tell me why they grounded the output sockets?
 

dougsta

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Cool info, thanks, all. FWIW, I'm planning to put mine in a head unit, and I will use silicone damper rings as Rob suggests, but if the head sits on the speaker cab, or, heaven forbid, in front or back, I figure more isolation may not be too much.

Anybody put sound-dampening feet on the head unit? Suggestions? I used to have some underneath my stereo turntable -- ah, the memories.

For those who've done it, I'm seeing you used grommets? Has anybody else done this? Has anyone tried neoprene washers?

Do we think Fender used washers? or grommets?

And can anyone tell me why they grounded the output sockets?

I used 5 x EF80 valves in my EF80 pp amp head, 2 for the pre amp, 1 for PI and 2 for the pp output stage. I used McMurdo skirted sockets £4 each from here:

Didn't notice any microphonic issues, ran them at full volume put quite a few recordings put up on soundcloud.

Doug
 

King Fan

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Speaking of EF80s, I also simplistically figured you might be able to use spring-loaded tube shields like you do for 12A_7 tubes. But I shoulda known there was a reason Rob suggested damper rings -- I'm now noticing EF80s are taller than 12A... tubes.
 

muscmp

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Cool info, thanks, all. FWIW, I'm planning to put mine in a head unit, and I will use silicone damper rings as Rob suggests, but if the head sits on the speaker cab, or, heaven forbid, in front or back, I figure more isolation may not be too much.

Anybody put sound-dampening feet on the head unit? Suggestions? I used to have some underneath my stereo turntable -- ah, the memories.

For those who've done it, I'm seeing you used grommets? Has anybody else done this? Has anyone tried neoprene washers?

Do we think Fender used washers? or grommets?

And can anyone tell me why they grounded the output sockets?
i've used the neoprene washers on the speaker screws for isolation purposes so i guess the same could be done for sockets. i got mine at home depot and i remember that they did have larger sizes. here is a link on amazon. of course this is probably not the size you need nor the number of pieces. well, won't let me add the link so here are a couple pics.


Screen Shot 2022-03-22 at 2.52.31 PM.png Screen Shot 2022-03-22 at 2.52.22 PM.png


i would think that you could relatively easily find some solid rubber feet to attach to the bottom.

play music!
 
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