Anyone here into loudspeakers?

[blakeyboy]

Oh wow- really???

Oh that's useful.

I never understood why the 66 was always preferred over the 88 by the hifi boys....just better specs?

Or was the 88 pushed in power at the expense of something else?

[ozjohn]

I had a look into the difference between the KT 66 and KT 88 tubes. The KT 88 was an older tube and of a higher power rating than the KT 66. KT 66s were probably used  in domestic HiFi amps as 20 watts output power was deemed sufficient as the dynamic range of vinyl LPs was about 45 dB and with an average listening level of about 0.5 w to 1 w the headroom was sufficient to prevent excessive distortion. There were also a lot of power amps based on the Wireless World Williamson amplifier that delivered 10 w output power using EL 84 tubes in push pull. Most modern domestic HiFi amps are in excess of 50 w output power to accomodate the much increased potential dynamic range of 100 dB offered by CD and other digital streaming as the dynamic range is determined by the number of quantisation levels during digitisation  rather than a voltage level or the distance a stylus can travel on a vinyl record.

Edited April 8, 2021 by ozjohn
More info

[blakeyboy]

...but you need more power when the speakers can handle it, but have to nowadays because people want smaller

'better' sounding speakers, which has made efficiency drop, so you need to give them more.....

A good big 'un always beats a good little'un....

 

[ozjohn]

That's right  I suspect the magnetic materials used in modern speakers is much improved over that used in the 1960s also large speakers were always better for good bass response.

I've always liked the idea of electrostatic speakers from the point of view they are linear because the dielectric stays the same with different voltages applied where as magnetic materials change as the current exciting it is changed. Quad brought out some in the late 1950s and still make them to this day along with Vacuum tube amps. They are probably expensive and may be limited in their power handling.

[ozjohn]

6 hours ago, ozjohn said:

That's right  I suspect the magnetic materials used in modern speakers is much improved over that used in the 1960s also large speakers were always better for good bass response.

I've always liked the idea of electrostatic speakers from the point of view they are linear because the dielectric stays the same with different voltages applied where as magnetic materials change as the current exciting it is changed. Quad brought out some in the late 1950s and still make them to this day along with Vacuum tube amps. They are probably expensive and may be limited in their power handling.

That is the permeability constant ur of magnetic materials change with the current exciting it where as the permittivity of a dielectric remains constant.

[blakeyboy]

yep!

all of the above ( I think...at the limits of my physics)

Small speakers particularly sound good these days, but boy you have to pump some power in.

The contrast to this is all too apparent -I'm in the Marshall factory, and I can have my main 4-way active monitors

on, and the four  drivers on the two lower bands can't 400w peaks into them quite often-

the whole system will draw 8 amps from the mains if I push it-

yet if you stick 30w into an open backed light frame cab, containing a 12" speaker with, crucially, a small coil and magnet,

so it's not over damped, the sound blows your head off!!!!!!

 

I know that my monitors have huge headroom before clipping- my treble unit amplifiers will drive them at 310W rms before clipping etc etc,

and a guitar amp is deliberately made to overload, but the difference in efficiency is stark.

 

Ask Jerry about Quad ESL speakers!!

After the ballon goes up I'm want to go to  Herefordshire for a listen.

Last pair I heard was 43 years ago, and I still remember the experience like it was yesterday....