zobel circuit

[smokingmachine]

I have a question!

If I have a preamp(bass) do I need a zobel circuit(to correct the impedance of woofer) or I don`t?

[anatech]

I'm lost. It appears you don't have an amplifier connected. There is nowhere to connect a zobel network in that case.

If you have a powered sub, the zobel has been taken care of in the design already. So no, in that case.

-Chris

[lineup]

Originally posted by anatech
I'm lost. It appears you don't have an amplifier connected. There is nowhere to connect a zobel network in that case.

If you have a powered sub, the zobel has been taken care of in the design already. So no, in that case.

-Chris

Zobel Network Filter
is to be seen as a part of LOUDSPEAKER or Woofer.

This filter is in loudspeaker design known as
Impedance Equalizer Link or Impedance Correction Filter
It is used to achieve a flat impedance across major frequency span.

If a load does not have a rise in Inductance at higher frequency
there is no need for Amplifier to have a Zobel network at output.

Because most loudspeakers does not include
an impedance equalizing filter,
most sensible amplifier designers add this at amplifier output
just for protection.

Some brands of speakers have an almost flat impedance
across the upper audio frequency
because manufacturer as a standard correct impedance curve.

Even if your amplifier works good without Zobel now,
if you or somebody else at some time change loudspeakers
you can get your trouble.

[myhrrhleine]

Zobel networks were developed for the phone company to equalise the phase of very long phone lines (by Mr. Zobel).

More recently, Zobel networks have been applied to phase correction in loudspeakers.

You'd need to know what specifically you're correcting.

[Bazukaz]

Hi,
As far as i know,
R-C filters in loadspeakers are sometimes used to equalise impedance between speaker and passive crossover.Other type is a L-C-R filter to equalize impedance peak at driver's resonant frequency.The last one needs a huge coil and is rarely used.


Lukas

[drdagor]

Ah yes. Metalic facilities... What the phone company called their copper. Since some of the wires were longish without repeaters (like 40 miles), compensating networks were designed to deal with the resistance, capacitance, and even the inductance of those long lines.

Regarding matching networks... The good Mr. Zobel is reported to have said something to the effect... "If there's a frog in the line there better be a frog in the network."

[AndrewT]

Smoking has gone kind of quiet!

Can we guess what he has in mind?

[thanh]

A long wire(1.5m) is used connect my pre-amp to my power amp. So should I add zobel circuit for my pre amp ?
Thanks !

[Jan Dupont]

thanh

No

[thanh]

@ACD: thanks!