Alternatives to 7R7 valves - UK Vintage Radio Repair and Restoration Discussion Forum

telstar · 19th Nov 2018, 2:45 pm

Are there any unofficial but obtainable alternatives to the 7R7 valve other than the CV900 one? I was just thinking on the same lines that 10P13 = UL41 is a typical example of unofficial comparison, without modifying the base?
Any ideas?
Cheers

Herald1360 · 19th Nov 2018, 11:25 pm

It looks a bit unique.....

Characteristics wise you might get away with an EBF80 in an adaptor. Or there's the 14R7/CV3937 with 12.6V heater

There's a few offered on Ebay.

tri-comp · 24th Nov 2018, 11:18 pm

If you need a NOS 7R7 you can buy one here for $3.- ex. P&P:
http://www.esrcvacuumtubes.com/vacuu..._7a4-11y9.html
or here:
http://www.abcvacuumtubes.com/vacuum..._7a4-11y9.html
or here:
http://www.thetubecenter.com/vacuumt..._7a4-11y9.html

That doesn't seem a very high price for a NOS valve.

I've done business with all companies in the past and allways been 100% satisfied. Actually it's one company marketed as 3 afaik.

Herald1360 · 25th Nov 2018, 4:37 pm

The valve prices are fine, but how much do they pile on for international postage?

ukcol · 25th Nov 2018, 5:56 pm

Equivalents listed in my G C Arnold book that you haven't mentioned:

7E7 and CV892.

Herald1360 · 26th Nov 2018, 12:23 am

If you compare the data for each in here:

https://frank.pocnet.net/other/Sylva...istics1945.pdf

They're pin compatible but rather different in terms of the pentode characteristics.

Probably rarer too.

19th Nov 2018, 2:45 pm	#1
telstar Octode Join Date: Dec 2003 Location: Leeds, West Yorkshire, UK. Posts: 1,593	Alternatives to 7R7 valves Are there any unofficial but obtainable alternatives to the 7R7 valve other than the CV900 one? I was just thinking on the same lines that 10P13 = UL41 is a typical example of unofficial comparison, without modifying the base? Any ideas? Cheers

19th Nov 2018, 11:25 pm	#2
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,536	Re: Alternatives to 7R7 valves It looks a bit unique..... Characteristics wise you might get away with an EBF80 in an adaptor. Or there's the 14R7/CV3937 with 12.6V heater There's a few offered on Ebay. __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O Last edited by Herald1360; 19th Nov 2018 at 11:36 pm.

24th Nov 2018, 11:18 pm	#3
tri-comp Heptode Join Date: Oct 2008 Location: Aalborg, Denmark Posts: 903	Re: Alternatives to 7R7 valves If you need a NOS 7R7 you can buy one here for $3.- ex. P&P: http://www.esrcvacuumtubes.com/vacuu..._7a4-11y9.html or here: http://www.abcvacuumtubes.com/vacuum..._7a4-11y9.html or here: http://www.thetubecenter.com/vacuumt..._7a4-11y9.html That doesn't seem a very high price for a NOS valve. I've done business with all companies in the past and allways been 100% satisfied. Actually it's one company marketed as 3 afaik.

25th Nov 2018, 4:37 pm	#4
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,536	Re: Alternatives to 7R7 valves The valve prices are fine, but how much do they pile on for international postage? __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

25th Nov 2018, 5:56 pm	#5
ukcol Rest in Peace Join Date: May 2003 Location: Harlaxton, Lincolnshire, UK. Posts: 3,944	Re: Alternatives to 7R7 valves Equivalents listed in my G C Arnold book that you haven't mentioned: 7E7 and CV892.

26th Nov 2018, 12:23 am	#6
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,536	Re: Alternatives to 7R7 valves If you compare the data for each in here: https://frank.pocnet.net/other/Sylva...istics1945.pdf They're pin compatible but rather different in terms of the pentode characteristics. Probably rarer too. __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O