Got my battery powered NIGC running over the weekend. Quite impressed with the sound, (1mv and 11mv offset.)
However, I built it to use with an active pre and it is TOO LOUD. I have a TVC output on my pre (does not fully attenuate the signal) and 93dB speakers. I used the same values as on Peter's monoblock schema. Just a 220R input series resistor to + and a 22K to ground.
I read here that the feedback resistors set the gain. How much attenuation can I expect by increasing the 680R from (-) to 1K or more?
I did try different values on the input series resistor - I happened to have a 3.6K Caddock and I thought it may have sounded better overall (?) , but didn't reduce the gain much. Any caveats I should consider, e.g., ratios of the input resistors?
Thanks
Mike
However, I built it to use with an active pre and it is TOO LOUD. I have a TVC output on my pre (does not fully attenuate the signal) and 93dB speakers. I used the same values as on Peter's monoblock schema. Just a 220R input series resistor to + and a 22K to ground.
I read here that the feedback resistors set the gain. How much attenuation can I expect by increasing the 680R from (-) to 1K or more?
I did try different values on the input series resistor - I happened to have a 3.6K Caddock and I thought it may have sounded better overall (?) , but didn't reduce the gain much. Any caveats I should consider, e.g., ratios of the input resistors?
Thanks
Mike
if u are using not inverted gc then:
take the value of the resistor connected between the output of the chip to the negative input and divide it by the value of the resistor connected between the negative input and ground
if u will show a schematic it will be much easier to explain
take the value of the resistor connected between the output of the chip to the negative input and divide it by the value of the resistor connected between the negative input and ground
if u will show a schematic it will be much easier to explain
Hi, Thanks for the reply.
I am using the schema here:
http://www.diyaudio.com/forums/showthread.php?postid=265546#post265546
I am using the schema here:
http://www.diyaudio.com/forums/showthread.php?postid=265546#post265546
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I am open to other suggestions - althought I hve found several references from those who have apparently used 1K and 22K in the feedback loop with no problems.
I was thinking of rigging up an 1 step "attenuator" like a 10K series resistor and a shunt resistor to halve the gain. Any suggestions on values to accomplish this?
Mike
I was thinking of rigging up an 1 step "attenuator" like a 10K series resistor and a shunt resistor to halve the gain. Any suggestions on values to accomplish this?
Mike
sss said:its better to lower the gain of an amp then to use input attenuator , lower gain = better performance , anyways imho changing the gain from 30 to 20 or 10 wount do nothing to stability
In your opinion stability is not affected ?
Opinion doesn't come into it. Gain margin and phase margin do.
sreten.
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