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hydebee hydebee is offline
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Default help setting bias for a sound valve amp

help setting bias for a sound valve amp please tell me how


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philo philo is offline
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Default help setting bias for a sound valve amp


"hydebee" wrote in message
...
help setting bias for a sound valve amp please tell me how



apply a sine wave input
then watch the output on a scope,,,

adjust until there is no "clipping" and least distortion



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Patrick Turner Patrick Turner is offline
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Default help setting bias for a sound valve amp



philo wrote:

"hydebee" wrote in message
...
help setting bias for a sound valve amp please tell me how



apply a sine wave input
then watch the output on a scope,,,

adjust until there is no "clipping" and least distortion


I have to disagree with this over simplistic advice.

The bias setting wanted is most likely the setting for output tube idle
current.

The biasing is the adjustment of the grid dc voltage without any signal
present and this controls the anode current within the tube such as
EL84, 6L6, 6V6, EL34, JT66, KT88, 6550
or whatever output tubes are in the amp.
Bias setting is different for all the tube types, and some amps have
one bias setting adjust pot for 2 or 4 output tubes, some have
individual
bias adjust pots.

If the bias is not set correctly the tubes couls melt down and cause
damage, maybe even burn the house down.

The biasing method should be described in the owner manual for that amp.

But we need to know what amp you have before we offer any firm advice.

Patrick Turner.
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philo philo is offline
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Default help setting bias for a sound valve amp


"Patrick Turner" wrote in message
...


philo wrote:

"hydebee" wrote in message
...
help setting bias for a sound valve amp please tell me how



apply a sine wave input
then watch the output on a scope,,,

adjust until there is no "clipping" and least distortion


I have to disagree with this over simplistic advice.

The bias setting wanted is most likely the setting for output tube idle
current.



snip

Yep...you are probably right but
I think you've read a bit too much into the very sketchy question


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Patrick Turner Patrick Turner is offline
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Default help setting bias for a sound valve amp



philo wrote:

"Patrick Turner" wrote in message
...


philo wrote:

"hydebee" wrote in message
...
help setting bias for a sound valve amp please tell me how



apply a sine wave input
then watch the output on a scope,,,

adjust until there is no "clipping" and least distortion


I have to disagree with this over simplistic advice.

The bias setting wanted is most likely the setting for output tube idle
current.


snip

Yep...you are probably right but
I think you've read a bit too much into the very sketchy question


Indeed the OP question was sketchy.

I a smoke avoiding person though.

Patrick Turner.


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philo philo is offline
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Default help setting bias for a sound valve amp


snip

Yep...you are probably right but
I think you've read a bit too much into the very sketchy question


Indeed the OP question was sketchy.

I a smoke avoiding person though.



Always best to err on the side of caution...
I've sure gotten a few plates red-hot from time to time...
but never had a melt-down yet!


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Patrick Turner Patrick Turner is offline
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Default help setting bias for a sound valve amp



philo wrote:

snip

Yep...you are probably right but
I think you've read a bit too much into the very sketchy question


Indeed the OP question was sketchy.

I a smoke avoiding person though.


Always best to err on the side of caution...
I've sure gotten a few plates red-hot from time to time...
but never had a melt-down yet!


If ever a BJT gets that hot, its waaaaayyyy tooooo late, we have
silence.

Then the tube recovers after cool down, and that's the upside of some
hot things,,,

Patrick Turner.
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philo philo is offline
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Posts: 13
Default help setting bias for a sound valve amp




Always best to err on the side of caution...
I've sure gotten a few plates red-hot from time to time...
but never had a melt-down yet!


If ever a BJT gets that hot, its waaaaayyyy tooooo late, we have
silence.

Then the tube recovers after cool down, and that's the upside of some
hot things,,,




I think the red-hot plates were back in the old days when I used an 807 fed
by a 6AG7
on my ham transmitter...
I don't think there was any way you could kill an 807 !


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west west is offline
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Default help setting bias for a sound valve amp


"hydebee" wrote in message
...
help setting bias for a sound valve amp please tell me how

Doesn't your Sound Valve have 2 pairs of LEDs with an adjustment in between
on the front panel?

west



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