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December 18, 2018, 01:27:06 pm

Author Topic: Input Impedance Question  (Read 307 times)

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Offline audiomaniac

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Input Impedance Question
« on: October 08, 2018, 11:10:29 am »
I'm trying out a new integrated amp that lists an input impedance of 47k. My old amp had an input impedance of 100k and I read that my Reduction/Integration was designed to work with an input impedance of 50k and higher. My new amp sounds great with digital but not so much with vinyl. Kind of dull sounding. Is it possibly a system matching issue and can I tweak the Reduction to be a better match? Thanks.
John
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Crack, Reduction + Integration

Offline Paul Birkeland

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Re: Input Impedance Question
« Reply #1 on: October 08, 2018, 01:16:25 pm »
47K isn't too low of a load for a Reduction.  It does happen sometimes that the actual DC resistance portion of the input impedance isn't an accurate representation of the dynamic input impedance of an amp, and in those instances you can end up with some problems.

Paul "PB" Birkeland

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Offline audiomaniac

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Re: Input Impedance Question
« Reply #2 on: October 08, 2018, 02:30:13 pm »
47K isn't too low of a load for a Reduction.  It does happen sometimes that the actual DC resistance portion of the input impedance isn't an accurate representation of the dynamic input impedance of an amp, and in those instances you can end up with some problems.

OK, good to know. Would there be any audible difference between 47k vs 100k equipment with all other things being equal? Thanks
John
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Crack, Reduction + Integration

Offline Paul Birkeland

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Re: Input Impedance Question
« Reply #3 on: October 08, 2018, 04:24:57 pm »
When you go too low with your loading impedance, you'll produce more distortion with the source components trying to drive it.  We mention 15K as being the low limit for the Reduction and Eros, and I certainly wouldn't go down to 10K.

With 47K and 100K, I don't think you're going to hear any major differences from the Reduction.  I would say that I helped a local friend build up a stereo power amp and advised him that the input impedance dropped all the way down to 8K at 20kHz.  This would not sound so great without a stout pre-amp feeding it!
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline audiomaniac

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Re: Input Impedance Question
« Reply #4 on: October 08, 2018, 08:07:25 pm »
OK, thanks very much. Must be something else I'm dealing with.
John
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Crack, Reduction + Integration