12bh7 in a Croft

[fiddlemaker]

Anyone know if it’s ok to use a 12bh7 in the 12bh7a positions in Croft amps?
I gather the main difference is that the “a” has a higher maximum anode voltage.
Cheers
John

[Jazid]

I think the only significant difference is the warm up time is defined in 12bh7a, otherwise ratings are identical. Also you're using it as a voltage stabiliser, not as a vertical deflection amp so any uprating to peak anode voltage wouldn't be significant.
Hope this helps.

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[Jimbo]

You can use the 12Bh7 as a substitute for the 12BH7a.

[fiddlemaker]

Thanks for the helpful replies.
Season’s greetings to all !

[Jimbo]

Thanks for the helpful replies.
Season’s greetings to all !

Merry Croftmas John

[basnas]

Is the 12bh7 better than 12bh7a in yours Croft john

[DSJR]

If in any doubt - ASK GLENN!!!

Not saying the above will contradict others' advice here, but Glenn knows all about his circuits and has always been open to tube rolling and should be pretty unbiased in his advice on valve alternatives, whether in the supplies or the signal paths.

[goraman]

Now lets talk about substituting a 6414 for a 12BH7? I have paid less than $20.00 a matched pair.

http://tdsl.duncanamps.com/show.php?des=6414

A far better 10,000 hour computer tube.
https://www.tubesrule.com/product_p/vtu009b-.htm

[snowman_al]

Not really the same thing...

Plus the 6414 has limited anode (plate) volts of 200 max. Where you might fit a 12BH7 for a 6414, do not assume it works the other way.

Alan

[fiddlemaker]

If in any doubt - ASK GLENN!!!

Not saying the above will contradict others' advice here, but Glenn knows all about his circuits and has always been open to tube rolling and should be pretty unbiased in his advice on valve alternatives, whether in the supplies or the signal paths.

Hi Dave, I'd just rather not bother Glenn with stuff that might be common knowledge amongst those that are better informed than I am!

Is the 12bh7 better than 12bh7a in yours Croft john

Hi Jan, I'm not expecting a 12bh7 to be better than a 12bh7a per se, its just that I found a very nice mid fifties NOS 12bh7 available at a very good price and wanted to check equivalence/compatibility.