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Old 22nd May 2002, 10:51 PM   #1
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Exclamation Leach amp R37 - R40 resistor change!?

I saw on the Leach web page that some resistors ( R37-R40) have been changed from 470 to 680 ohm to give more current to the load.
My question is: should I do the same thing with Super L each amp?

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Old 22nd May 2002, 11:32 PM   #2
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Dr. Leach said that the change doesn't make a difference, unless you are running low impedence speakers. The superamp is the same as the leach amp in this case (serving the same purpose for the protection circuit). If your speakers are low impedence, then you should make the change, and you will get a decrease in distortion. I just kept the original values for my superamp boards, since i am driving normal speakers

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Old 22nd May 2002, 11:41 PM   #3
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Is 4ohm impedance with some dips into 3ohm critical for this amp with unchanged resistors?
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Old 22nd May 2002, 11:51 PM   #4
BrianGT is offline BrianGT  United States
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The change was originally in place due to someone's comments on the performance change when used with low impedence electrostatic speakers.

Distortion was measured due to the protection circuit.

If you have distortion on your leach amp, I would recommend the change. Otherwise, the design has been working for quite a while as it was before the change. I personally see no reason to change it for my speakers.

If you are still in doubt. Change the resistors on one channel and see if you notice any noticeable difference in quality.

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Old 23rd May 2002, 12:07 AM   #5
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Tell me Brian, could I use 1% MKP caps instead of Mica caps, which I canīt find?
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