04-03-2022, 10:07 PM
(This post was last modified: 04-03-2022, 10:07 PM by Geordie McBoyne.)
I was surprised to learn that the EL34 was first introduced in 1949. A development of the rare EL60 which had a B9G base. MO valve company came up with their version of the EL34, the KT77.
The Mullard EL37 is similar. https://www.radiomuseum.org/tubes/tube_el37.html
Before WW2 Mullard developed a similar valve the AL60 which has the old B7 base and a 4volt heater. More than ten years ago the AL60 or CV9 could be bought for a few pounds but the Audiophools discovered it and now, like many other audio power valves commands a high price.
https://www.radiomuseum.org/tubes/tube_al60.html
Never seen the Alba radiogram with the single EL34 in the output stage.
The Pye Mozart delivers 10watts with a total harmonic distortion of 0.3 per cent @ 1Kc/s. Has three negative feedback loops.
Geordie McBoyne.
The Mullard EL37 is similar. https://www.radiomuseum.org/tubes/tube_el37.html
Before WW2 Mullard developed a similar valve the AL60 which has the old B7 base and a 4volt heater. More than ten years ago the AL60 or CV9 could be bought for a few pounds but the Audiophools discovered it and now, like many other audio power valves commands a high price.
https://www.radiomuseum.org/tubes/tube_al60.html
Never seen the Alba radiogram with the single EL34 in the output stage.
The Pye Mozart delivers 10watts with a total harmonic distortion of 0.3 per cent @ 1Kc/s. Has three negative feedback loops.
Geordie McBoyne.
