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Old 26th July 2008, 12:41 AM   #1
Brit01 is offline Brit01  United Kingdom
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Default Class AB or H???

I'd like to know which class of amp sounds better or how they differ?

I'm in the process of choosing a new power amp and 2 of my options include a class AB amp (2 x 160W) and a class H amp(2 x 260W).

There's a lot of technical info about but side my side which would be more suitable to run my pair of Klipsch F-1, 93db, 8 ohm, 2-way speakers?

Cheers
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Old 26th July 2008, 01:26 AM   #2
jaycee is offline jaycee  United Kingdom
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Class H is pretty much Class AB, but the difference is that Class H has whats called a tracking power supply. Basically, the Class H amp adjusts its power supply voltages according to the amount of power its being asked to supply

Typically Class G/H is only seen in PA amps where efficiency becomes important as higher output wattages are required. For domestic use, its usually not warranted.

93dB speakers are very sensitive. You'd be fine with the 160W amp. In fact looking at Klipsch's specs for those speakers, 260W would be too much and likely to damage the speakers should you crank it too much.
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Old 26th July 2008, 01:43 AM   #3
Brit01 is offline Brit01  United Kingdom
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Hi jaycee,

I'm looking for the best soundstage, separation and control. I never crank up the volume. My living conditions don't permit it.

I heard many times the more power I have the better separation and open feel I will get back. The guys from the Carver forum said the TFM-55 would sound great with 375 watts per channel!!!

The 2 amps I am looking at are the Europower A500 and EP1500. Yes pro amps, one more suited for the studio(A500) and the other powerhouse EP1500.
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Old 26th July 2008, 04:23 AM   #4
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Quote:
Originally posted by Brit01

I heard many times the more power I have the better separation and open feel I will get back.
Somebody should tell all those guys running flea tube amps...

No, seriously I don't agree with this, but I do agree with jaycee, 160W is plenty.

-Justin
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Old 26th July 2008, 05:04 AM   #5
lineup is offline lineup  Sweden
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Why not Class A.

www.firstwatt.com F4 and F5
They are very much great sounding Class A amplifiers
for higher effiency speakers, like 93 dB.

93 dB was something like Nelson Pass himself used for these amplifiers.

http://www.firstwatt.com/products.htm

They are also very easy to build with good instructions of Master Pass.
Of course you will need a nice Tube Pre Amplifier or Op-Amp frontend
as voltage amp to feed those firstwatt power followers.
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Old 26th July 2008, 07:45 AM   #6
Nordic is offline Nordic  South Africa
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Yep, with 93db speakers, I'd rather settle for a quality class A or small valve amp... In my opinion 10W would be enough.
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Old 26th July 2008, 07:48 AM   #7
jaycee is offline jaycee  United Kingdom
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Depends really, I know the UK is cold and wet, but its not cold enough to want to run a Class A amp!!
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Old 26th July 2008, 03:20 PM   #8
Brit01 is offline Brit01  United Kingdom
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Quote:
Of course you will need a nice Tube Pre Amplifier
Funny you should say. I'm planning to build an Aikido line stage amp. Just trying to get the parts together. Haven't found any valve suppliers yet here in Uruguay.

I wanted to use the valve pre-amp with a good SS power amp.

Considering the cost of the A500 power amp I could buy 2 and bi-amp my speakers: Would this make an audible difference in the sound quality or is it not worth it??

Cheers
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Old 26th July 2008, 04:11 PM   #9
lineup is offline lineup  Sweden
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hey.

I am also very fond of Aikido ... the 24 Volt version
There are good PCB to order for Aikido 24 Volt Tube amplifier.
I would try to get 6GM8 / ECC86 low voltage tubes.
This would be my first Tube Amplifier Project.
( I feel better not going into those 300-400 Volt hazards, from start )

If biamping is worth while. Yes it is
The load on each amplifier will be less (50%) = less distortion.

If you would build active crossovers, and use one amplifier for each speaker Woofer and Tweeter,
then would be much greater improvement in sound quality.
But this is a very big project .. even for Two Way speakers.

You can read Rod Elliott ESP articles on biamping and active systems:
Benefits of Bi-Amping (Not Quite Magic, But Close) - Part 1
http://sound.westhost.com/bi-amp.htm


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Old 26th July 2008, 04:51 PM   #10
Brit01 is offline Brit01  United Kingdom
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Quote:
If you would build active crossovers, and use one amplifier for each speaker Woofer and Tweeter,

Hi lineup,

Great information thks.

Looks like electronic active crossover is the way to go then.
So from what I understand I would use an electronic crossover with the signal input feeding into 2 power amps. One to handle the lower frequencies, remove the speakers crossover connection, and connect these wires to the lower frequency input.
The second amp that handles the higher frequencies will be connect to the high frequency speaker connection for these.

Also I was advised to buy the Aikido Octal valve amp. You are suggesting to build a 24 volt version? Just using a AC 230v-24v transformer to feed the power supply board that is adapted to 24V?

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