UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > General Vintage Technology > Components and Circuits

Notices

Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets.

Closed Thread
 
Thread Tools
Old 5th Jul 2022, 7:28 am   #1
joebog1
Banned
 
Join Date: Jun 2015
Location: Mareeba, North Queensland, Australia
Posts: 2,704
Default 1/2 12ax7

So I have a quick question. Does anybody know of a single triode similar to the 6AV6.
Its so close to half a 12AX7 that apart from heater voltage, it doesnt matter.
I dont care about the diodes, but I am looking for low noise, and preferably in seven pin minature. I already know about the 6AT6, which is close, but more like a half of a 12AY7.

Joe
joebog1 is offline  
Old 5th Jul 2022, 7:47 am   #2
radiomobile
Pentode
 
Join Date: Nov 2020
Location: Bristol, UK.
Posts: 131
Default Re: 1/2 12ax7

Mullard EBC91 ?
radiomobile is online now  
Old 5th Jul 2022, 8:46 am   #3
kalee20
Dekatron
 
Join Date: Feb 2007
Location: Lynton, N. Devon, UK.
Posts: 7,061
Default Re: 1/2 12ax7

6AV6 (may be the same as radiomobile's EBC91).

But you'd have two unused anodes... if you don't like unused sections it's a toss-up between an unused anode and grid (12AX7) or these two anodes.
kalee20 is offline  
Old 5th Jul 2022, 10:29 am   #4
joebog1
Banned
 
Join Date: Jun 2015
Location: Mareeba, North Queensland, Australia
Posts: 2,704
Default Re: 1/2 12ax7

Yes I have two unused diodes with a 6AV6 too, But I can just tie them to cathode ( I think ). I was hoping for some perhaps obscure CV series ( yes its Common Valve ) but not in Australia. Here CV is 99% military issue. I have quite a few 6AV6 and, 6AT6 for that matter, but I thought I would pick the brain of the trust of brainz and see what surfaces. I am inventing more problems for myself probably, but there is no such thing as too much correct information.

Thanks guys

Joe
joebog1 is offline  
Old 5th Jul 2022, 11:29 am   #5
turretslug
Dekatron
 
turretslug's Avatar
 
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,385
Default Re: 1/2 12ax7

6C4 / EC90 is essentially one half of 12AU7 / ECC82 (which I daresay you knew already Joe) but I'm stumped over an unadorned 12AX7 / ECC83 half.

Colin
turretslug is offline  
Old 5th Jul 2022, 1:17 pm   #6
Radio Wrangler
Moderator
 
Radio Wrangler's Avatar
 
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,801
Default Re: 1/2 12ax7

Apart from their whomped-up prices, why not use half a 12AX7? You can save the heater power on the unused side. 9 pin is a bit bigger than 7 pin, but not greatly so.

David
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
Radio Wrangler is offline  
Old 5th Jul 2022, 2:35 pm   #7
Marconi_MPT4
Heptode
 
Marconi_MPT4's Avatar
 
Join Date: Mar 2011
Location: Dorset, UK.
Posts: 519
Default Re: 1/2 12ax7

Two possible seven pin miniature base single triodes that have the same characteristic as 12AX7 are Tung-Sol 6DR4, Tung-Sol and Sylvania 6BK6 / 12BK6 with double diodes.

No equivalents so may be hard to find!

Rich
__________________
To an optimist a glass is half full; a pessimist half empty; an engineer twice as big as need be!
Marconi_MPT4 is offline  
Old 5th Jul 2022, 8:56 pm   #8
bikerhifinut
Octode
 
Join Date: Nov 2013
Location: Penrith, Cumbria, UK
Posts: 1,993
Default Re: 1/2 12ax7

I think you answered your own question Joe.
I'd be perfectly happy to use a 6AV6/EBC91 (same valve as we all know) in a situation that required half an ECC83, as you say, electrically its pretty much identical.
Strap the anodes to the cathode and away you go. I am assuming its for an Audio application? These double diode triodes were often used as Audio preamplifiers back in the day.
You've got a stash so what have you to lose?
RW comment about using half an ECC83 is valid but his comment about the cost of them these days is even more valid. I'd even think about using a couple of EBC91 where an ECC83 would be specified in a homebrew project on the basis that theres lots around and they're cheap.
I noticed your comment about "apart from heater voltage they're identical" and wondered if you are using 12.6V Heater supply? If so then theres the 12AV6 and probably even cheaper if you can find some.
Just my pennyworth Joe for what its worth.

Andy.

Last edited by bikerhifinut; 5th Jul 2022 at 9:00 pm. Reason: remembered summat
bikerhifinut is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 10:21 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.