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Old 18th January 2005, 10:42 PM   #1
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Default How important is channel separation in amp design?

Hi folks,
just a general question - How important a factor is it to take into account when designing an amp.

lets say that the frequency response is ideal, and the only thing that is below what i want is channel separation.

If you were aiming for ~100dB below 400Hz, but only resulted in ~85dB up to 1kHz or so for this region - would this have a great bearing on the sound?

Sorry if I sound like a novice - but that's what I am!
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Old 18th January 2005, 11:06 PM   #2
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Consider that vinyl fans put up with 30db at 1K, 80db seems quite sufficient.
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Old 19th January 2005, 07:17 PM   #3
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thanks very much for the answer

But in the scheme of things - how important is it to the overall design?
are frequency response and distortion levels more important?
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Old 19th January 2005, 11:06 PM   #4
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Originally posted by Commited

are frequency response and distortion levels more important?
Absolutely!
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Old 19th January 2005, 11:11 PM   #5
AKSA is offline AKSA  Australia
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Bill is correct. 30dB is fine for vinyl, and imaging is usually very, very good.

However, with SS amplifiers, imaging is often compromised. I find that a separate power supply for each channel seems to really help with imaging. Every little bit helps with SS; not so much with tubes, which often share the same ps for two channels and seem to have brilliant imaging nonetheless.

Cheers,

Hugh
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Old 20th January 2005, 04:40 PM   #6
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What is adequate for a CD player source then?

Everything looks VERY good except for this part (which to be honest looks good - but not amazing )

Cheers for the info much much much appreciated
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Old 20th January 2005, 06:19 PM   #7
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Quote:
Originally posted by AKSA

However, with SS amplifiers, imaging is often compromised. I find that a separate power supply for each channel seems to really help with imaging. Every little bit helps with SS; not so much with tubes, which often share the same ps for two channels and seem to have brilliant imaging nonetheless.
That is really interesting. Do you have an explanation as to why this is so?
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Old 20th January 2005, 06:39 PM   #8
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As far as imaging is concerned, channel separation is fairly important. Even something as simple as individual rectifiers and capacitors for each channel gives a big improvement. The next step would be totally independant transformers.

On a Carver amp I once tested, I hooked both chanels up to speakers, but only one to a source. Even at modest levels the music could be heard through the undriven chanel.

Tube amps are more forgiving of sloppy layouts because of higher voltage and thus lower current. There's less chance of magnetic coupling.
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Old 21st January 2005, 05:50 AM   #9
GregD is offline GregD  United States
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Quote:
Originally posted by Bill Fitzpatrick
Consider that vinyl fans put up with 30db at 1K, 80db seems quite sufficient.
That's one of the things I always found frustrating about vinyl. By playing around with various things over the years, I've found it takes 60-65db of channel separation before I'm happy, but I don't find much difference with more than that.
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Old 9th February 2005, 10:14 AM   #10
AKSA is offline AKSA  Australia
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Bill,

I have many thoughts on the matter, but won't air them here as they are unproven, folklorish, and possibly laughable........

I think imaging is related to phase shifts and intermodulation effects in the 1KHz-5KHz range.

Much also depends on the room and the speaker crossovers. It's all a bit like seduction, everything has to be right.......

Cheers,

Hugh
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