John Curl's Blowtorch preamplifier part II - Page 436 - diyAudio
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Old 14th May 2010, 06:43 PM   #4351
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I don't think so, you'll get nothing new from that.
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Old 14th May 2010, 08:57 PM   #4352
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I agree with PMA, group delay is important in filters, very important, but not in amplifiers to any significant degree that I know. It is interesting that the late Richard Heyser had the examples of delay: group delay, phase delay, and REAL delay (?). Talk about confusing.
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Old 14th May 2010, 09:18 PM   #4353
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You might be right or not.
Here you have the group delay in two different amps.
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Old 14th May 2010, 09:37 PM   #4354
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Group delay and phase delay - Wikipedia, the free encyclopedia
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Old 15th May 2010, 06:06 AM   #4355
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In any case, I can't tell you much about group delay, relative to amplifiers.
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Old 15th May 2010, 11:38 AM   #4356
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Amplifiers are usually minimum phase so when they have a wide bandwidth, say more then 200kHz -3dB, group delay is flat in the audible range but that is trivial, isnīt it ?
The same is true for bass extention.
Following Blauert that identified 1msec of delay as the audible threshold at some frequencies, constructing an amp with more delay then that whould need spectacular incompetence or a purposely designed additional allpass. Still a lot of German designers go for wide frequency response and claim gains in soundstage depth and resolution in micro detail.
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Old 15th May 2010, 05:06 PM   #4357
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Quote:
Originally Posted by Joachim Gerhard View Post
Still a lot of German designers go for wide frequency response and claim gains in soundstage depth and resolution in micro detail.
Absolutely! You heard my amp with a bandwidth of circa 250kHz, open loop - lots of soundstage depth and accuracy.

That's the first thing to vanish if the bandwidth gets closed down - well well before any perceivable loss of treble information.

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Old 15th May 2010, 05:16 PM   #4358
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Still i wish you could try some feedback, at least a little. I am not in the position to critisise your decissions on the other hand. Your amp sounded wonderfull in my system.
The most natural so far that i heard.
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Old 15th May 2010, 05:25 PM   #4359
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I agree there are big differences between amps in soundstage, details, space, even for those with BW above 200kHz. But I am absolutely sure that group delay is not any issue in this case. Follow another tracks, like dynamic spectra and dynamic noise modulation.
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Old 15th May 2010, 05:35 PM   #4360
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Still i wish you could try some feedback, at least a little. I am not in the position to critisise your decissions on the other hand. Your amp sounded wonderfull in my system.
The most natural so far that i heard.
Absolutely NOT interested. But I've tried adding NFB to every previous amp, and they all lose space, microdynamics, and most importantly, the soul of the music. I'll listen for two hours or even up to two days, then the NFB comes out and I let out a big sigh of relief, and get back to the music, rather than the (more sterile) sound of the amp.

Regards, Allen
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