Hi .
Can anyone help with a question that's puzzled me for some time - the RCA type 59, seemingly a IDH version of the 46 triple grid pentode of 1930s is never seen used in any amp (that I can find on the web) I've used these in SE amps successfully for some time. Being in the UK there is little info and so the question - why are they not used? after all, most others of that period are used frequently. Any thoughts appreciated.
Thanks.
David.
Can anyone help with a question that's puzzled me for some time - the RCA type 59, seemingly a IDH version of the 46 triple grid pentode of 1930s is never seen used in any amp (that I can find on the web) I've used these in SE amps successfully for some time. Being in the UK there is little info and so the question - why are they not used? after all, most others of that period are used frequently. Any thoughts appreciated.
Thanks.
David.
Coast to Coast Radio use a pair in their 1932 amplifier and Lafayette used three in their 1938 model. Three ...
As a matter of interest all Pentodes have three grids; G1 control grid, G2 screen grid and G3 suppressor grid. Along with one Anode and one Cathode (or Filament in the old days) makes five elements hence Pentode.
It would seem that the 59 uses zero voltage bias; this is the 100a from Lafayette
It would appear that the symbol M means k Ohms.
As a matter of interest all Pentodes have three grids; G1 control grid, G2 screen grid and G3 suppressor grid. Along with one Anode and one Cathode (or Filament in the old days) makes five elements hence Pentode.
It would seem that the 59 uses zero voltage bias; this is the 100a from Lafayette
It would appear that the symbol M means k Ohms.
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I have a large shoe box full of 59 tubes bought years ago. Probably the primary reason the 59 has never been popular is the seven pin socket. Until the emergence of ebay and inexpensive sockets from China, the seven pin socket was about extinct. Another reason is that the 2A3 is just more practical because of the socket and because it is still being produced. The 2A3 gives slightly more power.
Post # 3.
That is only the second time I have seen the suppressor grid tied to the plate.
But it also has the input stage with the suppressor to ground.
And the driver stage ties both the suppressor and screen to the plate.
And the output stage ties the control grid and screen together; and the suppressor to the plate.
Some like to try a little bit of everything.
The first time was the SE EL34 Randall amplifier project in San Francisco (a group project that was done at the Randall Museum).
The Randall amplifier tied both the Suppressor and the Screen to the Plate.
That is only the second time I have seen the suppressor grid tied to the plate.
But it also has the input stage with the suppressor to ground.
And the driver stage ties both the suppressor and screen to the plate.
And the output stage ties the control grid and screen together; and the suppressor to the plate.
Some like to try a little bit of everything.
The first time was the SE EL34 Randall amplifier project in San Francisco (a group project that was done at the Randall Museum).
The Randall amplifier tied both the Suppressor and the Screen to the Plate.
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I have 22 schematics (including the Randall you mentioned, and only counting output stages) where the supressor grid or the beam forming plates and the screen grid are tied to the plate. Here are 8 of them (I use the term 'supertriode' in my database of schematics for the situation that both the screen grid and the suppressor/beam plates are tied to the plate):
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0,5 x 6H3P + 6H6P dc-coupled + 2 x GU50 supertriode pp.gif -
0,5 x 6N2 + 6P15 supertriode se.jpg -
6AU6 supertriode + ECC85 + PL509 supertriode parafeed se.jpg -
6DJ8 dc-coupled + 2 x 5A6 supertriode pp.pdf
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6J8P + FU50 supertriode + FU13 supertriode se.jpg -
7W7 supertriode parafeed transformer-coupled + 2 x 7W7 + 2 x 307A supertriode pp + GZ37.pdf
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6J5 + ML6 transformer-coupled + PT15 supertriode se + 5AR4.jpg -
ECC81 + 4 x C3m supertriode pp.pdf
RCA 59
Thanks All
That was really my point - why is the 46 often recommended and used whilst the 59 is not as they are so similar except for their heater/filament arrangements. SE 46 amps are plentiful but nothing for the 59 apart from use in class B as per the makers data sheet.
Thanks for your thoughts.
David
Thanks All
That was really my point - why is the 46 often recommended and used whilst the 59 is not as they are so similar except for their heater/filament arrangements. SE 46 amps are plentiful but nothing for the 59 apart from use in class B as per the makers data sheet.
Thanks for your thoughts.
David
> is never seen used in any amp (that I can find on the web)
?? RadioMuseum shows it was used in like 320 different models, 189 in 1933, including the iconic RCA 280.
> seemingly a IDH version of the 46
I don't have a 1932 price-list here, but an indirect cathode may have cost significantly more.
?? RadioMuseum shows it was used in like 320 different models, 189 in 1933, including the iconic RCA 280.
> seemingly a IDH version of the 46
I don't have a 1932 price-list here, but an indirect cathode may have cost significantly more.
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