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Amplifier power
John Phillips wrote: Jim Lesurf wrote: Eeyore wrote: Jim Lesurf wrote: I also still have my natty copy of the 'sliderule' he had sent out with one issue of HFN. This seems to imply I should change to a more powerful amp. I confess seeing this was one of the things that prompted my curiosity and lead to the HFN article I mentioned. Like yourself, I suspect, I've spent far more hours than any sane person should watching a scope display, etc, of power amp output whilst playing music to see what demands the music waveforms place on the amp and speakers. Some time ago John Crabbe reported published work in which listeners' perception of the same absolute loudness was rather different when they were listening in a large concert hall compared to a domestic listening room. This would suggest you do indeed need less in SPL terms at home than you get in the auditorium. Because the nearfield and farfield are closer at home. Graham |
Amplifier power
tony sayer wrote: Eeyore scribeth thus Did you check the spec of the LME49720 ? http://www.national.com/pf/LM/LME49720.html They had to devise a special method to measure the THD without the noise dominating. They're not even that shockingly expensive. Shockingly enough in small quantities;!... From the likes of Farnell maybe £4 seems a lot but compare that to a $400 wooden volume control knob ! http://uk.farnell.com/1367613/semico...questid=131459 That's only £2 per divine op-amp ! Wonder what Doc Martin would have to say;?... You lost me Graham |
Amplifier power
Marky P wrote: tony sayer wrote: I Wonder how may pro recording bits of gear are around with 5532's;).. Just about most of it in current use. Are they at all similar to 5534's? Sure I used them in a phono pre-amp in the 80's, copied out of a R. A. Penfold book. Yes, they're the dual version and about 3dB noisier although not quite sure why. Graham |
Amplifier power
GregS wrote: Eeyore wrote: Rob wrote: Eeyore wrote: Once only wrote: wrote in message If all (properly designed) amps sound the same, how do I decide which amp to buy? Is it just a case of choosing one with sufficient power output and how do I determine this? No, thats not true - the myth of long wire with gain. Amplifiers can have very similar specs but have different sonic characters and abilities. Bandwidth and an amps ability to pump out the amperes when fronted with an awkward load etc etc etc. If I were you the first thing is to not pay too much attention to the big girls blouses of this group. Do yourself a favour, don't heed mag reviewers advice either. Try the pre-owned market, plenty of stereo bargains to be had. This is just one example, the Pioneer A400 was a huge success because of it ultra wide stable bandwidth (5 - 100) and it's impressive ability to drive any loudspeaker and remain stable - thats the ability to churn out amperes! It sold by the truck load and often crops up in the for sale ads, and it is proven to be a rugged longstander, can be picked up for less than £100. But then there are others, Nad, and even Sony from the late 80's and early 90's. First port of call believe it or not would be Cash Converters, then the specialist pre-owned dealers, then the small ads. Once you've found a model, look it up! Don't bother with Naim or Arcam, over-priced and nothing special. But don't buy antiques. No matter how well they were supposed to sound. All the electrolytic caps will need replacing and standards weren't as high then. Modern amplifiers are much better on the whole. cross-posted intentionally to rec.audio tech I have a 20 year old (at least) NAD 3020 - works perfectly but sounds distinctly soft/mellow compared to a newish SS amp, and indeed an even older Pioneer receiver. Is this a symptom of old caps, and/or poor design? I know the 3020 moderately well. It was very well regarded (and designed - I fact I met the designer) and should still sound at least decent today. At that age, recapping the electrolytic caps specifically is likely to be a good move. Especially if you're competent with a soldering iron yourself or have a friend who is. The parts won't cost much. I have gone over many amps, and its really rare that I would need to replace the main caps. Many times the smaller caps will go bad. If I were really going over an amp in every detail, if I had plenty of time, then I might check the main caps, or even buffer them. Its likely an amp will sound just fine if not driven hard with lossy main caps. If it can obtain max power with resonable distortion then I would not touch the main caps. I'd avoid over over-generalising. The lifetime / ripple current rating etc of reservoir caps varies hugely. Any sign of a bulge or white/yellow deposits around the base and out it comes. Graham |
Amplifier power
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Amplifier power
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Amplifier power
"Eeyore" wrote ...
tony sayer wrote: Eeyore scribeth thus Did you check the spec of the LME49720 ? http://www.national.com/pf/LM/LME49720.html They had to devise a special method to measure the THD without the noise dominating. They're not even that shockingly expensive. Shockingly enough in small quantities;!... From the likes of Farnell maybe £4 seems a lot but compare that to a $400 wooden volume control knob ! http://uk.farnell.com/1367613/semico...questid=131459 That's only £2 per divine op-amp ! I can't remember the last time (or ever?) I've seen a chip that was concurrently available in a package as new as SOIC and still in an antique metal-can, 8-pin TO-99! Is there some sort of continuing demand for those old metal cans? Military? |
Amplifier power
Robert Orban wrote: says... Seems to be tricky to find anything actually. This mic has a max input SPL of 134dB which receives the comment "Hi-SPL handling is perfect for suspension over choirs and orchestras" http://www.dv247.com/invt/11582/ Try this: Dynamic-Range Requirement for Subjectively Noise-Free Reproduction of Music JAES Volume 30 Issue 7/8 pp. 504-511; August 1982 A dynamic range of up to 118 dB is determined necessary for subjectively noise-free reproeuction of music in an audio recorder with a white-noise floor. Maximum peak sound-pressure levels in music are compared to the minimum discernible level of white noise in a quiet listening situation. Microphone noise limitations, monitoring loudspeaker capabilities, and performance environment noise levels are also considered. Author: Fielder, Louis D. Affiliation: Ampex Corporation, Redwood City, CA Well, I never imagined I'd have Bob Orban backing me up on a technical issue ! Thanks Bob ! Graham |
Amplifier power
Richard Crowley wrote: "Eeyore" wrote ... tony sayer wrote: Eeyore scribeth thus Did you check the spec of the LME49720 ? http://www.national.com/pf/LM/LME49720.html They had to devise a special method to measure the THD without the noise dominating. They're not even that shockingly expensive. Shockingly enough in small quantities;!... From the likes of Farnell maybe £4 seems a lot but compare that to a $400 wooden volume control knob ! http://uk.farnell.com/1367613/semico...questid=131459 That's only £2 per divine op-amp ! I can't remember the last time (or ever?) I've seen a chip that was concurrently available in a package as new as SOIC and still in an antique metal-can, 8-pin TO-99! Is there some sort of continuing demand for those old metal cans? Military? Audiophools ? Graham |
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