M-125 : Socket screws

It appears the base of the KT88’s are touching the heads of the socket mounting screws. This makes me unhappy. Anyone have a quick solution, maybe a felt ring or something? Currently don’t have the time to disassemble the lot and fit countersunk screws.

Pete

Does anyone use 'socket savers ?'. They may be a temporary solution. Any experience ? Bad idea ?

I just push my tubes into the sockets as far as the screw heads allow. I know it seems less than aesthetically pleasing, but it has never caused a functional problem.
People have discussed tube savers before, mostly in the context of tube rolling.

You may want to look that these. I have used them on other projects. While these are Metric Torx, I am sure you could find SAE in the head drive you want.

https://www.fastenright.com/general-fixings/TX-drive-micro-profile-head-screws/mph03

jwb474 wrote:You may want to look that these. I have used them on other projects. While these are Metric Torx, I am sure you could find SAE in the head drive you want.

Good thing you mentioned the SAE thing. I'm in Europe, I just default to metric.

Are these UNF ?

Edit : aren't these metal ring sockets, so bolt and nut ? I which case it wouldn't really matter with other nuts.

No, The Metric screws I referenced are ISO 724 - Metric Threads like M3, M4 etc.
UNF, Unified National Fine Threads, is a more specialized machine screw spec to ANSI B1.1 like 4-48, 6-40 etc.
UNC, Unified Coarse Threads, is the standard machine screw mostly used spec to ANSI B1.1 like 4-40-, 6-32 etc
SAE, Society of Automotive Engineers, has the same pitch as UNC.

The only other way that I can think of to fix your issue, especially without any disassembly is to a little southern engineering and get the keyway replacement and cut off the center keyway and use them as spacers.
Note: you may need to trim the edges for screw head clearance.

https://www.tubedepot.com/products/octal-tube-keyway-replacement

Thanks,

I've looked at the pictures on the VTA website, and from what I can see it's a bolt and nut affair, and fairly easily accessible when taking the bottom panel off the amp.

I'll just open the amp up, remove the screws and use a countersink. I'll use metric to reinstall. I'll even try not to get shavings in the amp !

SixOhms wrote:Thanks,

I've looked at the pictures on the VTA website, and from what I can see it's a bolt and nut affair, and fairly easily accessible when taking the bottom panel off the amp.

I'll just open the amp up, remove the screws and use a countersink. I'll use metric to reinstall. I'll even try not to get shavings in the amp !

When you countersink, I would would use a 100 Degree Undercut profile screw so you lessen the possibility of having to add clearance washers because of an extended bevel .

https://www.mcmaster.com/products/100-degree-flat-head-screws/metric-316-stainless-steel-hex-drive-flat-head-screws/

jwb474 wrote:

SixOhms wrote:Thanks,

I've looked at the pictures on the VTA website, and from what I can see it's a bolt and nut affair, and fairly easily accessible when taking the bottom panel off the amp.

I'll just open the amp up, remove the screws and use a countersink. I'll use metric to reinstall. I'll even try not to get shavings in the amp !

When you countersink, I would would use a 100 Degree Undercut profile screw so you lessen the possibility of having to add clearance washers because of an extended bevel .

Capital ! However, I'm now considering a chassis upgrade. And a tube roll...and...and...and...

A felt 'dot' cut in half and positioned fore and aft works a charm.

If you are going to the trouble of rebuilding, use ceramic sockets. The Celanex can have short life if soldering is not perfect.

As far as rolling, see Tube Rolling Mythology.

Seamus wrote:
A felt 'dot' cut in half and positioned fore and aft works a charm.

If you are going to the trouble of rebuilding, use ceramic sockets. The Celanex can have short life if soldering is not perfect.

As far as rolling, see Tube Rolling Mythology.

I've been looking for 'higher' ceramic sockets as an alternative to having to modify the top plate for countersunk screws. Haven't found anything yet, though. If I do that'll kind of catch two birds...

worst case, could you mount them on top of the chassis?

My ST120 has the VTA supplied ones and I've had zero problems as-is...

IMO, top mount are hideous.



These work well when mounted below:




https://www.ebay.com/itm/334699259507

Reputable US vendor.

Slightly smaller than the holes, but perfectly serviceable.