GU50 socket blues - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 10th June 2012, 10:25 AM   #1
diyAudio Member
 
Globulator's Avatar
 
Join Date: Aug 2004
Location: Cambridge, England.
Default GU50 socket blues

I'm having real trouble with tube sockets for these tubes.

First I buy some with little flimsy aluminium cages on, these I find difficult to get the tube in (no wiggle room) and impossible to remove.

Second I buy some flat disc like chinese ceramic sockets with three slots around the perimeter. These seem fine and to grip the tubes well, but after a moving the chassis about these have now broken the glass at the base in 3 GU50 tubes so I've now had to order more tubes .
The first tube they broke I thought was unlucky, but today I returned to the workshop to see two more gone. Obviously they put huge sideways pressure on the pins - useless.

My original Sweet Peach sockets are lovely but I cannot seem to find those for sale separately - so any ideas on what to try next? Does it have to be a move to the big russian ones that look like water towers?

It's also a pain as hours of metal work also goes down the tubes with this - I was so close to getting the mechanicals done
  Reply With Quote
Old 10th June 2012, 10:33 AM   #2
diyAudio Member
 
Join Date: Aug 2008
I have the original soviet steel ones. They make it very difficult to remove the valves, but you can easily remove the ceramic part (the base) and use it exactly the same way as the chnese ones you bought. It's maybe possible to do that with the cages you have already.

BUT, you have to be raaly careful, because the pins on the GU 50 may seem to be equal angles, but they re really not . This is not very easy to see. The soviet bases are aligned properly. Is there any chance that the chinese bases have all the pins in the same angles, causing strain?
  Reply With Quote
Old 10th June 2012, 10:49 AM   #3
diyAudio Member
 
Globulator's Avatar
 
Join Date: Aug 2004
Location: Cambridge, England.
The spacing of the chinese socket sockets seems to match the key for pin #1 and the tube pins. I think the pressure in in or out from the centre TBH - not side to side.

I.e putting them in bends the pins toward the tube centre and sets up a tension on the glass, that cracks near the base shortly after.

Maybe I need to source the original bases then, or maybe chop the towers off the ali ones I have so I can use the base and bolt cradle but still be able to rock the tubes as they go in or out.
  Reply With Quote
Old 10th June 2012, 01:12 PM   #4
diyAudio Member
 
Globulator's Avatar
 
Join Date: Aug 2004
Location: Cambridge, England.
I've tried the bases of the flimsy aluminium towers and can't seem to get a GU50 into that without undue force so I guess I need to get the originals.

Or the copies that they use in the Sweet Peach, because those ones actually work...
  Reply With Quote
Old 10th June 2012, 01:17 PM   #5
EssB is offline EssB  United Kingdom
diyAudio Member
 
Join Date: Jan 2009
If you have this type BEST SOCKET FOR GU-50 LS-50 5C9S / 4 NEW NOS !!! | eBay you might find that bending back the spring clips makes it easier - it still needs a strong steady pull though.
I think I'll probably remove the ears and spring clips from mine to get a better grip on the top cap and still retain the polarisation groove in the top ring.

I would have thought that rocking the tube in the socket could also cause the same cracking ?

Do all Russian sockets have very high insertion force ? I have some B9A bases that can't be used at all unless I 'exercise' the contacts first. I use a dead tube with most of its pins cut off for that.
  Reply With Quote
Old 10th June 2012, 01:22 PM   #6
EssB is offline EssB  United Kingdom
diyAudio Member
 
Join Date: Jan 2009
Just seen your last message, try exercising them with a suitable size drill shank or something, filed to a point/rounded.
  Reply With Quote
Old 10th June 2012, 02:11 PM   #7
diyAudio Member
 
Globulator's Avatar
 
Join Date: Aug 2004
Location: Cambridge, England.
Quote:
Originally Posted by EssB View Post
If you have this type BEST SOCKET FOR GU-50 LS-50 5C9S / 4 NEW NOS !!! | eBay you might find that bending back the spring clips makes it easier - it still needs a strong steady pull though.
I think I'll probably remove the ears and spring clips from mine to get a better grip on the top cap and still retain the polarisation groove in the top ring.

I would have thought that rocking the tube in the socket could also cause the same cracking ?

Do all Russian sockets have very high insertion force ? I have some B9A bases that can't be used at all unless I 'exercise' the contacts first. I use a dead tube with most of its pins cut off for that.
Yes I have 4 of those ones - but they are not the ones that did the damage, this chinese type shown below are when cracked the glass:

I can only think that these sockets do not allow the whole tube to 'float' in the socket like the normal case, but force the pins in with a constant pressure that eventually cracks the glass near the base.
Attached Images
File Type: jpg GU50-destroyers.jpg (6.0 KB, 236 views)
  Reply With Quote
Old 10th June 2012, 02:56 PM   #8
Funker is offline Funker  Germany
diyAudio Member
 
Join Date: Feb 2009
Location: Hamburg, Germany
Default GU-50 sockets

Hi ,
I had the same problem whith my homebrew 400W Bassamp. Im still gathering the parts . I alrady have the GU50s, the driver valves , and I had wound my opt . Now I come to the thing with the sockets. I got 6 original russian military sockets like the one in the ebay link. But the russian sockets looking awful strange like a missile launcher. I found another twelve in my workshop ,salvaged from scraped mil. radios. They probably made in former east germany . These are not that rugged like the russian ones. But they also have a ceramic pin plate with milled contacts which can easily remove separately for cleaning or rapair. On the top there are spring loaded retainer to secure the valves in their position.
I prefer these GDR "light" sockets and after the modification I will use them in may amp.

Pics of socket and valve down below.

Im not in need to secure the tube, because I woulnt install my amp in an HGV or tank, , I will cut the three strips slightly above the mounting flange. So in this way it keeps the guide notch for safe insertion of the valve. Another point to mention is the black knob at the top fo the GU50. Many valves come without it. This knob is just a handle to pull the tube out of the socket. I find it is a quite useful detail. The thread fit a metric M3 screw.

These GDR sockets come up from time to time in ebay or on german ham radio sites.

There is a guy in Germany who selling special made , high quality sockets for GU50s and many more old fashioned WW2 / cold war valves .

Here are the link:

Spezialfassungen

scroll down to the bottom where you find the GU50 sockets. a short description in english are available.

He will ship to EU and worldwide on request.

Good luck with your project!

73
Wolfgang
Attached Images
File Type: jpg DSCF0001.JPG (364.0 KB, 223 views)
File Type: jpg DSCF0002.JPG (73.2 KB, 217 views)
File Type: jpg DSCF0003.JPG (72.0 KB, 215 views)
File Type: jpg DSCF0004.JPG (71.2 KB, 214 views)
File Type: jpg DSCF0005.JPG (72.8 KB, 54 views)
File Type: jpg DSCF0006.JPG (72.6 KB, 67 views)
__________________
Ground your devices before they ground you
  Reply With Quote
Old 10th June 2012, 04:25 PM   #9
es345 is offline es345  Germany
diyAudio Member
 
Join Date: Jan 2012
Location: Ulm
Quote:
Originally Posted by Globulator View Post
I'm having real trouble with tube sockets for these tubes.

First I buy some with little flimsy aluminium cages on, these I find difficult to get the tube in (no wiggle room) and impossible to remove.

Does it have to be a move to the big russian ones that look like water towers?

It's also a pain as hours of metal work also goes down the tubes with this - I was so close to getting the mechanicals done
I am using the russian sockets since 6 month now in my 300W bassamp. They have a high reliabiliy, no broken tube.
I also have no problems to remove when reusing the knob again, just a little bit of patience during that step.

BR Hans- Georg
Attached Images
File Type: jpg GU50+Sockel 2.jpg (118.1 KB, 82 views)
File Type: jpg GU50+Sockel 3.jpg (128.6 KB, 73 views)
  Reply With Quote
Old 10th June 2012, 09:02 PM   #10
diyAudio Member
 
Globulator's Avatar
 
Join Date: Aug 2004
Location: Cambridge, England.
Thanks for the links and recommendations.
It looks like the socket is going to cost rather more than the tube!!

And the Russian one designed for it looks the best, no surprise I guess but it's a shame the chinese ones are too dangerous to use - I've never had an issue like this before.

I wonder where I can get the russian closed bases on their own from? Time for more research!
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
GU50 Prototypes matejsirk Instruments and Amps 12 14th May 2013 06:03 PM
My little SE with GU50 matejsirk Tubes / Valves 20 28th January 2012 03:27 PM
GU50 compared with EL84 eeyore Tubes / Valves 2 13th May 2010 11:07 PM
Gu50 cristelu2006 Tubes / Valves 13 18th November 2009 10:29 PM
Gu50 Set ? pwan Tubes / Valves 3 22nd April 2007 04:15 PM


New To Site? Need Help?

All times are GMT. The time now is 12:32 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2