Hi Pals,
I have an amp with input sensitivity 1.2V amp with 26dB gain,that will drive an 8Ohm speaker with 100Watts.
My stepped attenuator is 10K with 23 steps starting at 46 dB down to 1db attenuation in 3dB STEPS.
My full range speaker is only 50W peak power rated and I do not want to overdrive it even if someone inadvertently turn the dial up to 1dB attenuation.
Will it be possible to use a fixed attenuation stage before stepped attenuator?
Will it affect input device by any means as I assume the impedance of attenuation stage will be halved ?
I have an amp with input sensitivity 1.2V amp with 26dB gain,that will drive an 8Ohm speaker with 100Watts.
My stepped attenuator is 10K with 23 steps starting at 46 dB down to 1db attenuation in 3dB STEPS.
My full range speaker is only 50W peak power rated and I do not want to overdrive it even if someone inadvertently turn the dial up to 1dB attenuation.
Will it be possible to use a fixed attenuation stage before stepped attenuator?
Will it affect input device by any means as I assume the impedance of attenuation stage will be halved ?
Yes, that's fine. Just make the value of the fixed attenuator compatible with the source.
Usually 10k is fine, except for tubes. In fact, just a resistor in series with the input could work.
What is the output level of your source?
However this will work best if using a source with a defined maximum output, like a CD player
or computer. A turntable, tape deck, or tuner, not so much. The tweeters can still be damaged
with the lower power, though.
Usually 10k is fine, except for tubes. In fact, just a resistor in series with the input could work.
What is the output level of your source?
However this will work best if using a source with a defined maximum output, like a CD player
or computer. A turntable, tape deck, or tuner, not so much. The tweeters can still be damaged
with the lower power, though.
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Thanks!
It’s a CD player with output spec 2.1V.
Amp is powering a full range speaker FF125W Fostex .
Input impedence of amp is 100K.
Any benefit of using an attenuator stage before stepped Attenuator over a fixed resistor?
It’s a CD player with output spec 2.1V.
Amp is powering a full range speaker FF125W Fostex .
Input impedence of amp is 100K.
Any benefit of using an attenuator stage before stepped Attenuator over a fixed resistor?
The data sheet says the rated input is 16W. To reduce 100W to 16W at 8R,
reduce the maximum output voltage level from 28V to 11V, so reduce the input from 1.2V to 0.48V.
To get 0.48V from the 2.1V CD, reduce it by a factor of 0.23 times.
A series resistor of about 33.5k before the 10k stepped volume control will do this.
The total input impedance will then be 43.5k.
For an input impedance of 10k, a two resistor input attenuator can be used.
The series resistor is then 7.7k, and the shunt resistor is 3k.
reduce the maximum output voltage level from 28V to 11V, so reduce the input from 1.2V to 0.48V.
To get 0.48V from the 2.1V CD, reduce it by a factor of 0.23 times.
A series resistor of about 33.5k before the 10k stepped volume control will do this.
The total input impedance will then be 43.5k.
For an input impedance of 10k, a two resistor input attenuator can be used.
The series resistor is then 7.7k, and the shunt resistor is 3k.
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Awesome Rayma! Thanks for correcting the power rating for speaker , it is rated 16W!
Which one will you choose? A series resistor or series + shunt resistor ? Advantages and disadvantages of both ?
Which one will you choose? A series resistor or series + shunt resistor ? Advantages and disadvantages of both ?