Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

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Belbo
 
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Default Bias Current for SONY TA-F246E

All,

I would really appreciate your help on this. I've had this amplifier
for quite a while in storage and I have just started using it. I am
really under the impression that the Bias Current is all wrong, however
I really don't know what the correct setting is: could someone help me
out on this? If the setting is not know, how can I figure it out???

many thx in advance

Panos

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Mark D. Zacharias
 
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Default Bias Current for SONY TA-F246E


"Belbo" wrote in message
oups.com...
All,

I would really appreciate your help on this. I've had this amplifier
for quite a while in storage and I have just started using it. I am
really under the impression that the Bias Current is all wrong, however
I really don't know what the correct setting is: could someone help me
out on this? If the setting is not know, how can I figure it out???

many thx in advance

Panos


9 millivolts across the emitter resistor pair. Supposed to be done within 15
seconds of power-on.

Mark Z.


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Posted to sci.electronics.repair
Belbo
 
Posts: n/a
Default Bias Current for SONY Amplifier

Mark,

Many thx for your reply, a couple of clarification questions:
1) I've noticed by browsing around that there seems to be a learning
that factory Bias current settings are low and there is an opportunity
to increase the current (by as much as 200%!) without harming the
amplifier, while enjoying superior performance. Is this true and should
I try something like it with this amplifier based on your experience?
2) I assume that you have the service manual. In that case would you be
kind enough to let me know the current (mA) for the 9mV setting?

again, really really appreciate your help on this,

Panos


Mark D. Zacharias wrote:
"Belbo" wrote in message
oups.com...
All,

I would really appreciate your help on this. I've had this amplifier
for quite a while in storage and I have just started using it. I am
really under the impression that the Bias Current is all wrong, however
I really don't know what the correct setting is: could someone help me
out on this? If the setting is not know, how can I figure it out???

many thx in advance

Panos


9 millivolts across the emitter resistor pair. Supposed to be done within 15
seconds of power-on.

Mark Z.


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Posted to sci.electronics.repair
Mark D. Zacharias
 
Posts: n/a
Default Bias Current for SONY Amplifier


"Belbo" wrote in message
oups.com...
Mark,

Many thx for your reply, a couple of clarification questions:
1) I've noticed by browsing around that there seems to be a learning
that factory Bias current settings are low and there is an opportunity
to increase the current (by as much as 200%!) without harming the
amplifier, while enjoying superior performance. Is this true and should
I try something like it with this amplifier based on your experience?
2) I assume that you have the service manual. In that case would you be
kind enough to let me know the current (mA) for the 9mV setting?

again, really really appreciate your help on this,

Panos


Mark D. Zacharias wrote:
"Belbo" wrote in message
oups.com...
All,

I would really appreciate your help on this. I've had this amplifier
for quite a while in storage and I have just started using it. I am
really under the impression that the Bias Current is all wrong, however
I really don't know what the correct setting is: could someone help me
out on this? If the setting is not know, how can I figure it out???

many thx in advance

Panos


9 millivolts across the emitter resistor pair. Supposed to be done within
15
seconds of power-on.

Mark Z.



I just temporarily downloaded the manual and looked it up. Don't have the
model number any more, so could you re-post with the model number?

Generally speaking, you can increase bias at least about 25 to 50% without
really excessive heating - though this would not apply to some exotic or
Class A designs.

It's important to remember that solid state amps should not be allowed to
run really hot. If you can't comfortably keep your hand in contact with the
heat-sink indefinitely, it's too hot.


Mark Z.


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Posted to sci.electronics.repair
Belbo
 
Posts: n/a
Default Bias Current for SONY Amplifier

Model number is TA-F246E. Would really appreciate if you could forward
me the Service Manual to my personal email address,

many thx again for your help on this,

Panos

Mark D. Zacharias wrote:
"Belbo" wrote in message
oups.com...
Mark,

Many thx for your reply, a couple of clarification questions:
1) I've noticed by browsing around that there seems to be a learning
that factory Bias current settings are low and there is an opportunity
to increase the current (by as much as 200%!) without harming the
amplifier, while enjoying superior performance. Is this true and should
I try something like it with this amplifier based on your experience?
2) I assume that you have the service manual. In that case would you be
kind enough to let me know the current (mA) for the 9mV setting?

again, really really appreciate your help on this,

Panos


Mark D. Zacharias wrote:
"Belbo" wrote in message
oups.com...
All,

I would really appreciate your help on this. I've had this amplifier
for quite a while in storage and I have just started using it. I am
really under the impression that the Bias Current is all wrong, however
I really don't know what the correct setting is: could someone help me
out on this? If the setting is not know, how can I figure it out???

many thx in advance

Panos


9 millivolts across the emitter resistor pair. Supposed to be done within
15
seconds of power-on.

Mark Z.



I just temporarily downloaded the manual and looked it up. Don't have the
model number any more, so could you re-post with the model number?

Generally speaking, you can increase bias at least about 25 to 50% without
really excessive heating - though this would not apply to some exotic or
Class A designs.

It's important to remember that solid state amps should not be allowed to
run really hot. If you can't comfortably keep your hand in contact with the
heat-sink indefinitely, it's too hot.


Mark Z.


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