[sdiy] Re: crystal clear

[Forbes, William - EE - UK/Leamington]

But aren't inductors and capacitors reactive components and therefore will
only have imaginary impedances.
Losses will be due to resistive components (copper losses in inductors
etc.).

I agree that there will be some loss in a passive network but what sort of
magnitude are we talking about?
Remember loudness is measured in dB. Therefore 3dB means 2x the power!

Bill.

> -----Original Message-----
> From: Magnus Danielson [mailto:cfmd at swipnet.se] 
> Sent: 08 May 2003 14:12
> To: don at till.com
> Cc: synth-diy at dropmix.xs4all.nl
> Subject: [sdiy] Re: crystal clear
> 
> 
> From: Don Tillman <don at till.com>
> Subject: Re: crystal clear
> Date: Wed, 7 May 2003 16:51:59 -0700
> 
> >    > Date: Wed, 07 May 2003 21:44:21 +0200 (CEST)
> >    > From: Magnus Danielson <cfmd at swipnet.se>
> >    > 
> >    > I think you fool yourself on the simplicity of a 
> common amplifier
> >    > and passive cross-over filters. You need a much bigger 
> amplifier
> >    > than if you had two smaller amplifiers.
> > 
> > What, no equations to back this up?  :-)  
> > Y'r slipping, Magnus!
> 
> I'm trying to convince people with a more common sense type 
> of arguments, but I
> could really back it up with formulas if I really wanted. 
> There is a summation
> of powers which really isn't very interesting and fairly 
> apparent, so I made it
> implicit... but here it is for the necessary bordercase:
> 
> Pbigamp = Ptotal = Ptop + Pmid + Pbas + Pcrossover
> 
> Ptopamp = Ptop
> Pmidamp = Pmid
> Pbasamp = Pbas
> Ptotalamp = Ptopamp + Pmidamp + Pbasamp
> 
> => Pbigamp > Ptotalamp
> 
> Also, the more complex stuff you want to do in the passive 
> crossover, the
> bigger loss you tend to get unless you spend quality time on 
> the loss issue.
> 
> > (It's really true.  And plugging in typical numbers shows that it's
> > far more of an effect than one would assume.)
> 
> Indeed. I just didn't have any real numbers at hand.
> 
> It's easier to make a few smaller amp than a big 
> motherfucking amp, and I find
> that a good argument in many different senses. It is easier 
> to find transistors
> which can work with even the worst-case reactance if you make 
> smaller amps than
> if you make a big amp.
> 
> Cheers,
> Magnus
>