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Old 26th June 2013, 06:26 AM   #1131
dvv is offline dvv  Serbia
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Originally Posted by Bob Cordell View Post
Thank you so very much for these kind words. I'll try to stay on that track in the second edition, while improving the existing material and adding new material.

Suggestions from the DIY community help a lot, and I try to listen to all of them (I'm keeping a list that is getting quite lengthy).

Cheers,
Bob
Not at all, Bob, my words merely reflect my feelings.

To me, quality is quality, never mind whether I completely agree with it or not. In a sense, I'm from "the other camp", i.e. I like small amounts of global NFB, in the mould of Otala, Harman/Kardon, etc. However, I recognize the fact that there are many ways to go about it, each with its ups and downs.

I also reognize a paradox I've been observing for at least 30 years. Put 3 TV sets on a table, assemble a jury presumed to be qualfied and have them choose the best one. It may take i little time, but chances are they will eventuall agree on one model.

Repeat the same with any audio device, and chances are they will never agree. Especially regarding amps and loudspeakers.

The paradox is that as (medical) doctors tell me, our sense of hearing is thought of as less acute than our sense of sight.

My only suggestion would be that you take a little time and space in your bext edition to cover the two (most?) opposing trends overall, the little local much overll NFB vs much local, little global NFB approaches. To put it in prespective. Assuming your current edition describes the approach you prefer personally, the challenge is writing objectively about the other approach.
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Old 26th June 2013, 06:47 AM   #1132
jcx is online now jcx  United States
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Repeat the same with any audio device, and chances are they will never agree. Especially regarding amps and loudspeakers.
conflating 2 very different cases there

amps don't vary anything like loudspeakers, in fact many "good" amplifiers could be made to "sound the same" with little tweaking, output impedance padding to give >60 dB nulls between them – should be effective pretty much up to their respective power rating

but with loudspeakers even EQ-ing the on axis response - they still won't sound "the same" if they use different drivers of different sizes on differently shaped boxes and they could each be from major different schools of directivity - omni, controlled, line source, mono/di-pole...

good amps don't have to – and probably shouldn't sound different

for loudspeakers we really don't even have a single target corresponding to the "wire with gain" goal for amps
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Old 26th June 2013, 07:04 AM   #1133
dvv is offline dvv  Serbia
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I'm sorry, JCX, but amps DO sound differently.

I only have to look at what I have at home, I need go no further. Marantz, Sansui, Harman/Kardon and Karan Acoustics - 4 amps, 4 different results on any of my 3 pairs of loudspeakers, in 3 different rooms. With fairly consistent differences across the board.

I agree that the differences in sound are most likely to be greater with speakers than with amps (almost always so).
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Old 26th June 2013, 07:38 AM   #1134
Mooly is online now Mooly  United Kingdom
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Just preordered my copy this morning. 9th to 12th August estimated delivery.

(Amazon keep asking me if I want to trade in Bobs book Geez, talk about depreciation )
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Old 26th June 2013, 09:38 AM   #1135
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Originally Posted by Mooly View Post
Just preordered my copy this morning. 9th to 12th August estimated delivery.

(Amazon keep asking me if I want to trade in Bobs book Geez, talk about depreciation )

Lets keep this tread going with with trivia . I will get my copy and we all can have a party of sorts .

Last edited by nigel pearson; 26th June 2013 at 09:41 AM.
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Old 26th June 2013, 11:08 AM   #1136
Bonsai is offline Bonsai  Taiwan
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Originally Posted by djoffe View Post
Gentlemen,

I sent Johan Huijsing an email this weekend asking "who designed the 5534"?

He responded:

Dan,



Theo van Kessel designed it at Philips / Signetics in about 1990.



Regards

,

Johan

I thought the first exemplars were sold in the late 1970's (78 or 79)

Philips version may have been done in 1990' but it was certainly out before that.

It was DOD'd by Philips in about 2003. I asked the PL Manager (who was based in the valley) why. Answer: we dont make enough money on it.
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Old 26th June 2013, 04:18 PM   #1137
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Originally Posted by dvv View Post
I'm sorry, JCX, but amps DO sound differently.

I only have to look at what I have at home, I need go no further. Marantz, Sansui, Harman/Kardon and Karan Acoustics - 4 amps, 4 different results on any of my 3 pairs of loudspeakers, in 3 different rooms. With fairly consistent differences across the board.

I agree that the differences in sound are most likely to be greater with speakers than with amps (almost always so).
Dvv . A challenge for anyone who has bits in the shed . Find a chip amp with a circuit reasonably like the blameless design in the handbook . Build three amps all identical . Three power supplies . One , the minimum required , Next the best you can with lets say 200% spare current . The third a switch mode . I bet they all measure the same ? And the next question is , do they sound the same ?
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Old 26th June 2013, 04:58 PM   #1138
AndrewT is offline AndrewT  Scotland
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Originally Posted by nigel pearson View Post
....................... Build three amps all identical . Three power supplies . One , the minimum required , Next the best you can with lets say 200% spare current . The third a switch mode . .................
Give a hint for some values.

Say 60VA & 4700uF+4700uF for a 60W amplifier, then 180VA & 15mF+15mF (for 3times the current for the same 60W amplifier and finally a pair of 180W SMPS, or should that be a pair of 30W smps for the dual polarity supply?

Is that what you mean?
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Old 26th June 2013, 05:04 PM   #1139
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Originally Posted by Struth View Post
Amazon.com (usa) says "in stock, 18 left" but their price is higher than at amazon.ca (Canada) which still says "arriving July 13". I'll take the lower price in exchange for a few more days.

As usual, suppliers pander to USA demand in priority of availability. Just because they're the biggest consumers.... the best customers... really nice people....
Bought a copy today, paid extra for quick delivery tomorrow. Screen shot below.
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Old 26th June 2013, 05:23 PM   #1140
jcx is online now jcx  United States
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I bet they all measure the same ?
not if you're half competent, know what to measure - even a good US$150 sound card could "see" the various capacity PS differing loaded ripple through a LM3886 ~100 dB -PSRR with fc rignt at mains frequency

and that's just if you restrict "measurement" to audio input test signals, look at audio output under load

Last edited by jcx; 26th June 2013 at 05:45 PM.
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