From: louis@tronix.SignalPath.on.ca (Louis Bertrand)
Subject: Re: Blade Amplifiers?
Newsgroups: rec.audio.car
Date: 16 Apr 92 03:22:40 GMT
Distribution: world
Organization: Signal Path Designs

biancol@bullet.ecf.toronto.edu (BIANCOLIN  FABIO S) writes:
>   Hello all, 
>     I remember there being a recent discussion on Blade Amplifiers around
> here, so while i was at the most recent IASCA sanctioned event, i picked 
> up some literature on Blade amps.  It was slightly technical and they
> describe how their amps work to accomodate musical transients and 
> do not overly waste power. 
>   
>    It said something like this:
>   
>    There are 2 types of amps currently on the market.  1) Amplifiers which
> whose power supplies are always at full power (ie. ready to produce the 
> loudest sound that the amp is rated for), and 2) amps whose power supplies 
> change with the music (and whose reproduction lags behind).
>   
>   Drawbacks are 1) too much power consumption, and 2) inaccurate sound
> reproduction.
>   
>    So, along comes Blade.  What they (claim to) do is process the sound 
> as it comes into the amplifier, and delay it so the power supply can 
> adjust accordingly, and then reproduce the required sound.  So, the power supply
> is always operating near maximum efficiency, and this means
> less heat sink, accurate sound, and basically the "Next generation of 
> amplifiers".  
>     Now when i read this, i thought it was a neat idea, and if it truly works,
> its a great idea.  However, Does this mean that your entire system MUST
> consist of Blade amps to sound proper?  (because if there is a delay in 
> the low end reproduction, and none in the high end, ????????)
>   
>     So, could someone who knows, please tell me how exactly one is supposed
> to integrate Blade amplifiers into an audio system? 
>   
[Pardon the long quote, but Fabio did a good summary of the product lit.]

Having been to the same event in Toronto (Apr.12), I picked up some
litterature from Blade, and had to chance to speak to one of their
engineers.

Basically, a lot of the marketing stuff is not exactly correct.
In fact, I seriously doubt that the signal is delayed, as audio
delay devices are either noisy, expensive and, sometimes, both.
The BASH technology they talk about is a name the marketroids 
came up with (it doesn't stand for anything).  I didn't 
specifically ask about the delay part (I simply dismissed it
as I read it).

PWM controllers attempt to keep the power supply output voltage 
constant, and monitor this level against a fixed reference.
The Blade amps do not use a fixed reference.  The reference is derived
from the signal level and the output voltage has enough headroom
to compensate for momentary peaks (twangs, cymbals, etc.).
I don't think the output voltage is compared to the music
reference, for that would imply that the PWM controller's
bandwidth was better than the amplifier's.  If you can already
do that, you can simply build a PWM amplifier.

Integrating them in a system shouldn't be a problem, of course
unless the delay is really there, after all I've said...

The amps are cute, though.  This may work against them in a 
market where "heavy metal" rules.

Have fun!
 -- Louis
--
Louis Bertrand   *   Lynden, Ontario, Canada   *   (416) 648-8066
Signal Path Designs (Analog - Digital - Audio - Embedded uCs)
louis@SignalPath.on.ca (new -- may not work yet)
louis%tronix@maccs.dcss.mcmaster.ca (old -- still works fine)
From: rcm@col.hp.com (Rick Myers)
Date: Fri, 3 Apr 1992 23:06:14 GMT
Subject: Re: How much do you REALLY know? :-)
Organization: Home For Aging Computer Geeks