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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. |
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17th Nov 2015, 4:08 pm | #1 | |
Rest in Peace
Join Date: May 2003
Location: Harlaxton, Lincolnshire, UK.
Posts: 3,944
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42E Valve
In this wanted thread Andy (radioman) stated:
Quote:
I have never knowingly seen this electrode configuration before and would be interested to know what effect it has on the characteristic curves for the valve and in what application(s) it would be used. |
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17th Nov 2015, 4:43 pm | #2 |
Dekatron
Join Date: Sep 2005
Location: Seaford, East Sussex, UK.
Posts: 5,997
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Re: 42E Valve
There is (was) a discussion here: http://www.radiomuseum.org/tubes/tube_6f6eg.html
This suggests that it was said to give "higher amplification" but I would guess that as it was not common practice it probably did nothing or worse. |
17th Nov 2015, 4:46 pm | #3 |
Dekatron
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,385
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Re: 42E Valve
How odd! Sort of goes against the whole idea of screening anode from grid in the first place, RM also lists the similarly-configured 6F6EG.
The mischievous section of my mind wonders if they were in batch production as pentodes when a patent infringement notice from Philips' lawyers plopped onto the doormat and the base wiring was hastily re-configured... I expect that there's a less exciting but more worthy technical explanation though. |
17th Nov 2015, 8:39 pm | #4 |
Dekatron
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,953
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Re: 42E Valve
You may be right: certain US-made Philco radios in the 1930s used pentodes with separate connections (and signal-feeds) to g1 and g3 (usually in the IF amp stages I must admit) and called this a "dual-contriol amplifier" stage.
This could have been a way to get rould Philips patents on 'conventional' pentodes. |
17th Nov 2015, 8:51 pm | #5 |
Rest in Peace
Join Date: May 2003
Location: Harlaxton, Lincolnshire, UK.
Posts: 3,944
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Re: 42E Valve
Thanks for the link Peter; it would be interesting to find an output pentode with a separate pin-out for G3 and compare its curves for normal G3 connection and this G3-G1 configuration.
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17th Nov 2015, 10:30 pm | #6 |
Octode
Join Date: Apr 2009
Location: Aylesbury, Buckinghamshire, UK.
Posts: 1,522
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Re: 42E Valve
6cl6?
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