John Curl's Blowtorch preamplifier part II

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#80,502
john curl said:
I did very little in the design of the WAMM, except that my technician supplied standard OPamp replacements with a hybrid jfet input, 5534 output on a minidip socket. However, the WAMM was one of the most fantastic speaker systems I have ever had the chance to hear. I used to visit Dave Wilson on occasion in the '80's and listen all evening on his WAMM system. It was a wonderful experience.
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But Dave certainly liked to link you to it for that extra cred 🙂. Don't blame him either.
 
#80,505
Whereas in my case experience of the Wamm set-up was limited to a pair in Italy which was driven by Spectral amps with a Spectral MC front-end. That system sounded dreadful....but, to be fair, they had recently been delivered, were only a half dozen hours in use...and were waiting for Mr Wilson to come over to set them up properly. The main problem was a lack of coherence/intregation. I had previously heard the same front-end with big Jadis amps and Sound Lab A-3 electrostatic panels and that was so bland. (different location). Yet the same speakers (A-3) with JC Levinsons sounded very very good indeed.

(Of course the multi $K cables had not yet 'run-in'!!!!)
 
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#80,507
given relative standardized input level the higher power amp for the same load Z will have higher gain - which amplifies its input stage noise more than a lower gain device with similar input device noise

this effect is most obvious in the headphone world with sensitive IEM - some with 130 dB re 1 V sensitivity - you will hear hiss with a high gain amp driving them
 
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#80,515
Derfnofred said:
If they're both in their linear regions (not clipping), then how is this possible?

Does the extra zero on faceplate do the trick? Surely that's common knowledge.
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Because they are not in the linear regions! 1 watt average level for recorded music probably needs 100 watts. For a live classical concert more like 1,000 watts. Of course if you are listening to vinyl on headphones with such margins, DON'T DROP THE NEEDLE!

(Do you really think the OP was measuring the actual levels?)
 
#80,518
Well lets think about that. Removing the edge cases
Scott (listens quietly)
Richard (likes it loud)
Ed (likes to deafen thousands at a time).

If we calibrate according to THX spec (std) then -20dBFS is 85dB at the listening position or 1W for a pair of std speakers and 2m listening distance, lets say 2W for 4m. 0dBFS is 17dB above that for a sinusoid so 100W and 103dB. This seems to be loud enough for most men and all wives!

Go active and immediately you drop to 2x50W. You don't have to throw away power for baffle step so you could even argue 50W and 25W would be perfect.

With modern recordings needing more headroom than that is just damaging your hearing and annoying the neighbours.

Or have I missed something?
 
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