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ECC83/12AX7 vs 12BH7
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RanMaFan
May 18, 2000, 3:00:00 AM5/18/00
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I have a circuit currently using ECC83 tubes, but the designer says that a
12BH7 would give lower distortion. Is it correct and is the 12BH7 a drop-in
replacement for the ECC83?
Thanks!
12BH7 would give lower distortion. Is it correct and is the 12BH7 a drop-in
replacement for the ECC83?
Thanks!
Henry Pasternack
May 18, 2000, 3:00:00 AM5/18/00
to
RanMaFan wrote in message <8g0m7c$gb9$1...@clematis.singnet.com.sg>...
>I have a circuit currently using ECC83 tubes, but the designer says that a
>12BH7 would give lower distortion. Is it correct and is the 12BH7 a drop-in
>replacement for the ECC83?
>I have a circuit currently using ECC83 tubes, but the designer says that a
>12BH7 would give lower distortion. Is it correct and is the 12BH7 a drop-in
>replacement for the ECC83?
The 12BH7 is a very different tube from the 12AX7. But if the designer
says it will work in THIS application, you should assume it's OK to make
the substitution.
-Henry
Michael Appelt
May 19, 2000, 3:00:00 AM5/19/00
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The 12BH7 compares more to ECC81/12AU7, not to ECC83/12AX7.
If I recall correctly it basically is higher dissipation.
If I recall correctly it basically is higher dissipation.
Michael
Henry Pasternack <eat_...@spam.com> wrote in message
news:8g0moq$l9b$1...@slb3.atl.mindspring.net...
OvrReactor
May 19, 2000, 3:00:00 AM5/19/00
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I certainly wouldn't just "drop in" a 12BH7 into a circuit optimized for a
12AX7. Depending on the circuit, the 12BH7 will be drawing more current (which
will have an effect on all the other circuits), or will be operating in a
non-linear area of it's characteristic curve. To operate correctly, you will
need to change the plate and cathode resistors, and also reduce the value of
the dropping resistor in the power supply to ensure that all voltages remain
the same everywhere else in the circuit.
12AX7. Depending on the circuit, the 12BH7 will be drawing more current (which
will have an effect on all the other circuits), or will be operating in a
non-linear area of it's characteristic curve. To operate correctly, you will
need to change the plate and cathode resistors, and also reduce the value of
the dropping resistor in the power supply to ensure that all voltages remain
the same everywhere else in the circuit.
In any event, you WILL get reduced gain, but improved headroom. Perhaps a
12AY7/6072A would be a better "upgrade", though.
Regards,
Tom Mitchell
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