kasperbergholt Messages: 47 Registered: August 2021 Location: Copenhagen, Denmark
Baron
Hi!
I'm considering buying a Parasound A23 or A23+. Several places it's mentioned that it runs in class A up till a certain point.
I've tried finding the threshold for this without success.
Does anyone here know.
Related, any one who have done measurements / knows an equation for establishing watts used in relation to DB sensitivity for specific speakers (I'm using Harbeth M301's).
Wayne Parham Messages: 18978 Registered: January 2001
Illuminati (33rd Degree)
Speaker manufacturers often publish a specification that tells you SPL at one watt measured at one meter distance. Sometimes it is listed as SPL at 2.83v, which is the same if the speaker presents an 8Ω load.
Rusty Messages: 1415 Registered: May 2018 Location: Kansas City Missouri
Illuminati (3rd Degree)
Doesn't the correlation between your speakers sensitivity and the number of A-watts you are concerned with come down to your listening level and program material? Do you feel that the purity of the A class will be diminished by switching into class A/B? Your speakers being of a lower sensitivity would require more watts wouldn't they to get the sound pressure level of a higher sensitivity speaker? Depending on the source say vinyl or digital, and the type of music you listen to.
kasperbergholt Messages: 47 Registered: August 2021 Location: Copenhagen, Denmark
Baron
Rusty wrote on Sat, 23 October 2021 11:31
Doesn't the correlation between your speakers sensitivity and the number of A-watts you are concerned with come down to your listening level and program material? Do you feel that the purity of the A class will be diminished by switching into class A/B? Your speakers being of a lower sensitivity would require more watts wouldn't they to get the sound pressure level of a higher sensitivity speaker? Depending on the source say vinyl or digital, and the type of music you listen to.
Regarding 1) It will - but I don't think I can calculate when the shift from A to A/B happens if I don't know when the amp switches - e.g. at 2 watts or 6 or 10 (or higher).
I'll follow the suggestion of contacting the manufacturer directly
Regadring 2) purity of class A. Many people do it seems. I have very limited listening experiences of pure class A (and that's primarily been tube amplifiers (Audio Note P1SE and P2SE).
John Curl answers the question in an interview in the following manner:
"All else being equal the more Class A you have the better. We don't need a
full Class A amplifier, because people don't listen to full power levels all
the time. They really need only 10 Watts or so because that is where most
of our listening is done. However, getting that 10 Watts of Class A is really
quite a feat considering of the all other constraints of having 200 Watts
Class AB in reserve. The Class A portion is always smoother and better,
while the Class AB is always a bit rougher because it is against the law of
physics. It breaks the music into positive and negative cycles and then
splices them back together."
Rusty Messages: 1415 Registered: May 2018 Location: Kansas City Missouri
Illuminati (3rd Degree)
Here's some more information on using class A from the Pass Labs you might find interest in Kasperbergholt. https://www.passlabs.com/technical_article/leaving-class-a/
I can understand you're interest in this mode of operation and it's effect on quality. I was the same about OTL tube operation. I went that route but made a commitment also with my loudspeakers and went from mid sensitivity like yours to high sensitivity to better engage with the lower wattage of tubes in general and specifically OTL tube amps. You'll probably be just fine with your choice of Parasound amp you choose. They get great user reviews. And your equally well praised speakers will need those extra A/B watts for when you turn the volume up.
P.S. I have an older 90's vintage Parasound amp I've used with home theater.
kasperbergholt Messages: 47 Registered: August 2021 Location: Copenhagen, Denmark
Baron
It's funny you mention tube amplifiers. My interest was sparked after listening to two tube power amplifiers from Audio Note (P1SE and P2), which sounded beautifully, so I considered taking that path.
Then I found out that it takes the doubling of watts to achieve an increase of 3db (if I understand the mechanisms correctly).
I downloaded a measurement app yesterday (Spectrum for iPhone). My normal listening level is around 55db measured 1 meter from the speakers on axis - with peaks up to 92db.
I'm not sure it measures correctly / is correctly calibrated. Will look more into this in the following days.
Rusty Messages: 1415 Registered: May 2018 Location: Kansas City Missouri
Illuminati (3rd Degree)
Never heard of Dorothy Ashby and her jazz harp interpretations. Nice kind of cocktail hour smooth jazz. Interesting to hear that instrument used that way. Harpo Marx would have approved. Here's something for you if you like a bit of funk jazz and haven't taken in Tokyo Groove Jyoshi. Asian funk with a traditional twist.
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