John Curl's Blowtorch preamplifier part II

Status
Not open for further replies.
Jump to Latest
#79,202
Just for fun
This is an estimation based on the impedance of Watt / Puppy 7 as published by Stereophile
Wilson Audio Specialties WATT/Puppy 7 loudspeaker Measurements | Stereophile.com

I digitized the data using Digitize graphical data with Dagra
Then I spent some hours doing data pairing and then had Excel perform the calculations

According to published sensitivity of 93dB/W/m, 10V rms drive (~25W) would correspond to approx ~96dB spl (midrange I guess) at 5 m with two loudspeakers playing.

For 10 dB spl more (doubling the sense of volume), the drive would need to be approx 30Vrms (~225W)

George
 

Attachments

  • Power for Puppy 7.PNG
    Power for Puppy 7.PNG
    88.3 KB · Views: 279
  • Current for Puppy 7.PNG
    Current for Puppy 7.PNG
    82.9 KB · Views: 281
  • Puppy 7 Impedance.PNG
    Puppy 7 Impedance.PNG
    59.1 KB · Views: 275
Last edited:
#79,205
You are welcome Dejan.
I’ve searched for related work but I have not found much.
The issue has been investigated in the 80ies. I’ve found two papers
http://www.genelec.com/sites/default/files/media/About%20Us/Academic_Papers/11775.pdf
http://www.genelec.com/sites/default/files/media/About%20Us/Academic_Papers/11870.pdf

There are two more papers to which I have no access:
P.J. Baxandall, "A Technique for Displaying the Current and Voltage Output Capability of Amplifiers and Relating this to the Demands of Loudspeakers," presented at the 82nd Convention of the Audio Engineering Society (1987 March). Preprint 2421. J. Aud. Eng. Soc. Vol.36, p.3 (1988 January/February).

E. Benjamin, "Audio Amplifiers for Loudspeaker Loads," presented at the 93rd Convention of the Audio Engineering Society (1992 October). Preprint 3432. J. Aud. Eng. Soc. Vol.42, pp.670-683 (1994 September).

George
 
#79,212
Only when reading in bed 😀

So that's quite a fearsome looking load to drive. Maybe a candidate for a 'sensed' feedback connection at the speaker terminals to take the cable/connection interface out of the equation. You never see that done these days.
 
#79,213
gpapag said:
but I have not found much.
Click to expand...

A very good article
Heavy Load: How Loudspeakers Torture Amplifiers | Stereophile.com

Also D. self has devoted a chapter (Chapter 40 “Cool Audio Power”) in the third edition of his
Self on AudioThe Collected Audio Design Articles of Douglas Self 3rd edition,
https://www.routledge.com/products/9781138854468


scott wurcer said:
You can contact Eric on the Yahoo micbuilders list,
Click to expand...

Thank you Scott. Unfortunately his e-mail address is not visible to me.

billshurv said:
The earlier ones were a lot harder to drive.
Click to expand...

Bill, thanks for the info but I will not devote more time on these speakers.🙂

john curl said:
WATT1. My amps will drive it
Click to expand...

Good for you Mr. Curl

George
 
#79,214
audio purist

Mooly said:
So that's quite a fearsome looking load to drive. Maybe a candidate for a 'sensed' feedback connection at the speaker terminals to take the cable/connection interface out of the equation. You never see that done these days.
Click to expand...
The last I recall was a Kenwood "Audio Purist" product. My father acquired one, I think to tease my audiophile brother. I don't remember if he actually used the sense leads or not, or just strapped things at the amp.

EDIT: His speakers were not difficult loads, and were selected for their suitability as end tables as far as I could tell.
 
Last edited:
#79,216
bcarso said:
The last I recall was a Kenwood "Audio Purist" product. My father acquired one, I think to tease my audiophile brother. I don't remember if he actually used the sense leads or not, or just strapped things at the amp.
Click to expand...

I'm struggling to remember the one I was thinking of. Japanese, yes... can't recall which it was now.

bcarso said:
EDIT: His speakers were not difficult loads, and were selected for their suitability as end tables as far as I could tell.
Click to expand...

🙂 that's a nice story. Things were very different back then.
 
#79,220
waltzingbear said:
I see remote sensing all the time....... in power supplies.

Cheers
Alan
Click to expand...
Sure, very old and quite standard. It's a little more tricky to apply to wide-bandwidth power amps. Actually, considering that cable manufacturers are always looking for new opportunities, including questionable claims for improved data transmission cables, I'm surprised that someone hasn't jumped on yet another bandwagon.
 
Status
Not open for further replies.
Top Bottom