Valve base problems - UK Vintage Radio Repair and Restoration Discussion Forum

Canleykid · 18th Feb 2014, 7:01 pm

Having mounted a number of B9A bases and finding the valves move about with a small amount of pressure I am not impressed. Does anybody know of a better quality valve base than those available from Rs spares? or a way of making the bases rigid ( I had thought of using some kind of padding i.e. a thin heat resistant O ring between valve base and fixing plate ). Any Ideas

GrimJosef · 18th Feb 2014, 8:33 pm

Are they ceramic valve bases ? It's hard to fabricate ceramics with the same tight dimensional tolerances that the better plastics can achieve. So the metal connectors which grip the valve pins are free to move much further in ceramic bases than they are in plastic ones. This does allow the valve to move quite a lot. But it shouldn't degrade the performance significantly.

If the movement offends you though then you can still buy plastic bases from e.g. Hot Rox http://www.hotroxuk.com/valve-socket-9pinpl.html, http://www.hotroxuk.com/belton-9pin-...r-vt9-st2.html or eBay. Be a little wary of used ones. Many will be fine. But if they have been subject to a lot of use or over-enthusiastic application of a soldering iron then the grip of the plastic on the metal connectors can be loose. This can cause them to open up and make poor contact with the valve pins and there's little that can be done about it if you want long-term good connections.

Cheers,

GJ

Canleykid · 18th Feb 2014, 11:15 pm

Thanks for your help GJ as you assumed the valve bases are ceramic, I will get hold of some new plastic bases and give those try. I have seen in Hong Kong (one of my sons lives there so I get out there at least once a year) bases that appear to be brass, I assume with pin insets to allow good contact. I wondered if these were available in the UK as the visual affect is very good. ATB Canleykid

Herald1360 · 19th Feb 2014, 1:15 am

You could just use a spring retainer to hold the valves in place. Simplest sort uses a couple of bent solder tags retained by the base screws, and a bit of doubled heat resistant string with a couple of knots either side of the valve pip and two small springs hooked onto the solder tags to tension it. For low power valves you can get bayonet fit screening cans with an internal spring that presses down on the top of the valve.

Some pics here:

http://www.hificollective.co.uk/valves/valve_bases.html

of the can type and some bent springy wire ones as well..

Peter.N. · 19th Feb 2014, 2:17 pm

If you grind a small screwdriver to a fine point you should be able to get it between the contacts and the base and squeeze them up a bit.

Peter

Herald1360 · 19th Feb 2014, 6:22 pm

Won't that potentially just make them rattle around even more inside the ceramic base insulator? I don't think the original problem was poor contact.

Peter.N. · 20th Feb 2014, 10:53 am

Sorry, misunderstood - again.

MrElectronicman · 21st Feb 2014, 1:14 am

I have a number of valve bases both plastic and ceramic from Japan that I bought recently. I prefer the plastic bases as the they are tighter as GJ said.

The connectors in some of the ceramic ones are quite tight, so much in fact that I broke one of the valve pins trying to remove a valve. Overall the ceramic holders appear to be quite sloppy, but that is due to the size of the holes into which the connectors mount not the connectors themselves.

Canleykid · 21st Feb 2014, 2:25 pm

The initial concern was with the movement or more specifically the rigidity of the valve rather than the flexibility or poor engineering of the pin connectors. From my own observations I have concluded that a, the tolerances of manufacture could be tightened up and b, the fixing ring could be made slightly thicker so that they do not bend when reasonable screw driver pressure is applied. The Triumph Herald (had a few of those in the distant past) has suggested springs and thanks for your help its just I don't think spring clamps look so good on the finished object. No offense is intended in this reply so please all don't take any.

G8HQP Dave · 21st Feb 2014, 6:25 pm

Isn't the valve supposed to be able to move about a little? Rigid sockets in a rigid base meeting rigid pins in a brittle base are a recipe for problems unless precision engineering is used.

Modern valveholders do not seem to be as well made as NOS ones.

Phil G4SPZ · 21st Feb 2014, 6:48 pm

Quote:

Originally Posted by Canleykid

...I wondered if these were available in the UK as the visual affect is very good...

But you can't really see the valveholder when the valve is in place, so why worry?

18th Feb 2014, 7:01 pm	#1
Canleykid Retired Dormant Member Join Date: Jan 2014 Location: Birmingham, West Midlands, UK. Posts: 60	Valve base problems Having mounted a number of B9A bases and finding the valves move about with a small amount of pressure I am not impressed. Does anybody know of a better quality valve base than those available from Rs spares? or a way of making the bases rigid ( I had thought of using some kind of padding i.e. a thin heat resistant O ring between valve base and fixing plate ). Any Ideas

18th Feb 2014, 8:33 pm	#2
GrimJosef Dekatron Join Date: Sep 2007 Location: Oxfordshire, UK. Posts: 4,311	Re: Valve base problems Are they ceramic valve bases ? It's hard to fabricate ceramics with the same tight dimensional tolerances that the better plastics can achieve. So the metal connectors which grip the valve pins are free to move much further in ceramic bases than they are in plastic ones. This does allow the valve to move quite a lot. But it shouldn't degrade the performance significantly. If the movement offends you though then you can still buy plastic bases from e.g. Hot Rox http://www.hotroxuk.com/valve-socket-9pinpl.html, http://www.hotroxuk.com/belton-9pin-...r-vt9-st2.html or eBay. Be a little wary of used ones. Many will be fine. But if they have been subject to a lot of use or over-enthusiastic application of a soldering iron then the grip of the plastic on the metal connectors can be loose. This can cause them to open up and make poor contact with the valve pins and there's little that can be done about it if you want long-term good connections. Cheers, GJ

18th Feb 2014, 11:15 pm	#3
Canleykid Retired Dormant Member Join Date: Jan 2014 Location: Birmingham, West Midlands, UK. Posts: 60	Re: Valve base problems Thanks for your help GJ as you assumed the valve bases are ceramic, I will get hold of some new plastic bases and give those try. I have seen in Hong Kong (one of my sons lives there so I get out there at least once a year) bases that appear to be brass, I assume with pin insets to allow good contact. I wondered if these were available in the UK as the visual affect is very good. ATB Canleykid

19th Feb 2014, 1:15 am	#4
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: Valve base problems You could just use a spring retainer to hold the valves in place. Simplest sort uses a couple of bent solder tags retained by the base screws, and a bit of doubled heat resistant string with a couple of knots either side of the valve pip and two small springs hooked onto the solder tags to tension it. For low power valves you can get bayonet fit screening cans with an internal spring that presses down on the top of the valve. Some pics here: http://www.hificollective.co.uk/valves/valve_bases.html of the can type and some bent springy wire ones as well.. __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

19th Feb 2014, 2:17 pm	#5
Peter.N. Dekatron Join Date: Jul 2008 Location: Charmouth, Dorset, UK. Posts: 3,601	Re: Valve base problems If you grind a small screwdriver to a fine point you should be able to get it between the contacts and the base and squeeze them up a bit. Peter

19th Feb 2014, 6:22 pm	#6
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: Valve base problems Won't that potentially just make them rattle around even more inside the ceramic base insulator? I don't think the original problem was poor contact. __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

20th Feb 2014, 10:53 am	#7
Peter.N. Dekatron Join Date: Jul 2008 Location: Charmouth, Dorset, UK. Posts: 3,601	Re: Valve base problems Sorry, misunderstood - again.

21st Feb 2014, 1:14 am	#8
MrElectronicman Heptode Join Date: Feb 2011 Location: Washington DC, USA Posts: 619	Re: Valve base problems I have a number of valve bases both plastic and ceramic from Japan that I bought recently. I prefer the plastic bases as the they are tighter as GJ said. The connectors in some of the ceramic ones are quite tight, so much in fact that I broke one of the valve pins trying to remove a valve. Overall the ceramic holders appear to be quite sloppy, but that is due to the size of the holes into which the connectors mount not the connectors themselves. __________________ David

21st Feb 2014, 2:25 pm	#9
Canleykid Retired Dormant Member Join Date: Jan 2014 Location: Birmingham, West Midlands, UK. Posts: 60	Re: Valve base problems The initial concern was with the movement or more specifically the rigidity of the valve rather than the flexibility or poor engineering of the pin connectors. From my own observations I have concluded that a, the tolerances of manufacture could be tightened up and b, the fixing ring could be made slightly thicker so that they do not bend when reasonable screw driver pressure is applied. The Triumph Herald (had a few of those in the distant past) has suggested springs and thanks for your help its just I don't think spring clamps look so good on the finished object. No offense is intended in this reply so please all don't take any.

21st Feb 2014, 6:25 pm	#10
G8HQP Dave Rest in Peace Join Date: Sep 2008 Location: Solihull, West Midlands, UK. Posts: 4,872	Re: Valve base problems Isn't the valve supposed to be able to move about a little? Rigid sockets in a rigid base meeting rigid pins in a brittle base are a recipe for problems unless precision engineering is used. Modern valveholders do not seem to be as well made as NOS ones.