Double triode ID? - UK Vintage Radio Repair and Restoration Discussion Forum

Station X · 4th Dec 2020, 12:52 pm

The pinout of this valve appears to be the same as that of ECC83's etc. but it's taller. Total heater resistance is about 8R cold. Only writing visible is "BRIMAR" and "MADE IN".

Anyone know what it might be?

Thanks.

Cobaltblue · 4th Dec 2020, 12:53 pm

Is this another example of a 12BH7 ?

http://www.r-type.org/exhib/aaa0177.htm

Cheers

Mike T

Station X · 4th Dec 2020, 12:57 pm

Seems likely, it came from a box of what were largely TV pulls. I'll give it a test.

Station X · 7th Dec 2020, 9:19 pm

Tests perfectly as a 12BH7 so a 12BH7 it is. Now labelled and boxed up in case I ever find a use for it.

Thanks Mike.

Leon Crampin · 8th Dec 2020, 12:05 am

The 12BH7 makes a very meaningful bias/erase oscillator valve for tape recorders. In a circuit originally designed for a 12AU7 (ECC82), with which it is pin compatible, it can provisde a useful increase in erase power at the expense of some HT and heater current.

Leon.

4th Dec 2020, 12:52 pm	#1
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Double triode ID? The pinout of this valve appears to be the same as that of ECC83's etc. but it's taller. Total heater resistance is about 8R cold. Only writing visible is "BRIMAR" and "MADE IN". Anyone know what it might be? Thanks. Attached Thumbnails __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

4th Dec 2020, 12:53 pm	#2
Cobaltblue Moderator Join Date: Dec 2010 Location: Exeter, Devon and Poole, Dorset UK. Posts: 6,875	Re: Double triode ID? Is this another example of a 12BH7 ? http://www.r-type.org/exhib/aaa0177.htm Cheers Mike T __________________ Invisible airwaves crackle with life or at least they used to Mike T BVWS member. www.cossor.co.uk Last edited by Cobaltblue; 4th Dec 2020 at 12:54 pm. Reason: Added Link

4th Dec 2020, 12:57 pm	#3
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Double triode ID? Seems likely, it came from a box of what were largely TV pulls. I'll give it a test. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

7th Dec 2020, 9:19 pm	#4
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Double triode ID? Tests perfectly as a 12BH7 so a 12BH7 it is. Now labelled and boxed up in case I ever find a use for it. Thanks Mike. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

8th Dec 2020, 12:05 am	#5
Leon Crampin Octode Join Date: Nov 2005 Location: Surrey, UK. Posts: 1,874	Re: Double triode ID? The 12BH7 makes a very meaningful bias/erase oscillator valve for tape recorders. In a circuit originally designed for a 12AU7 (ECC82), with which it is pin compatible, it can provisde a useful increase in erase power at the expense of some HT and heater current. Leon.