[ARC5] [BoatAnchors] TCS: Better Speaker "Ear Popping" Cure.

[Arden Allen]

Actually, Don, I was referring to **forward recovery time.**  But it all 
seems ridiculous because zeners aren't that slow and recovery times should 
be no more than a few microseconds.  So perhaps the back to back 
configuration needs resistors in parallel with each zener diode.  Science?

Arden Allen
KB6NAX

He who is cruel to animals becomes
hard also in his dealings with men.
We can judge the heart of a man by
his treatment of animals.
—Immanuel Kant

-----Original Message----- 
From: don davis
Sent: Friday, February 12, 2016 2:17 AM
To: 'Arden Allen' ; 'David Stinson' ; 'Old Tube Radios (new)'
Cc: Arc5 at mailman.qth.net
Subject: RE: [BoatAnchors] TCS: Better Speaker "Ear Popping" Cure.

OK, got it now.  Yes, in theory all of these "should" work but clippers are 
more difficult than they look.  Most of these are made to work empirically. 
What Arden refers to is reverse recovery time (trr) which sets a limit for 
the time to suck all of the energy out of the junction so it is ready to 
switch again.  As an example 1n5811 (high speed switching device) has trr = 
30nsec.  May or may not be relevant since this is rated and measured at high 
power, but yours' is at low level signal.  I looked at the 1n4004 and it 
doesn't spec this.  For space use we used to spec the amount of energy that 
had to be dumped as well as trr.  When we modeled Zeners in SPICE we would 
always put a 10 Meg resistor across to get them to  "work right" or they 
would frequently fail to initialize for initial values.  Maybe try this in 
actual circuit?

Either config should work (series back to back or parallel with blocking 
diodes) but with the zeners in series with a high impedance into a high 
impedance circuit I can see why it might not work.

73 de don ad6pb

-----Original Message-----
From: BoatAnchors [mailto:boatanchors-bounces at theporch.com] On Behalf Of 
Arden Allen via BoatAnchors
Sent: Thursday, February 11, 2016 6:42 PM
To: David Stinson <arc5 at ix.netcom.com>; 'Old Tube Radios (new)' 
<boatanchors at minime.theporch.com>
Cc: Arc5 at mailman.qth.net
Subject: Re: [BoatAnchors] TCS: Better Speaker "Ear Popping" Cure.

> ......That's correct, Don.  Arden's idea is a good one-
connecting the Zeners cathode-to-cathode *should* work just like the circuit 
with the steering power diodes.  But it doesn't.  Not a bit.  Speaker still 
pops with keying.  I have no idea why what I drew works and what Arden 
suggests doesn't.
Makes no sense to me.  I just stuck with what worked.

CORRECTION:  That effect says to me the zener diodes you're using have a 
much longer forward conduction delay.  After all they were NOT designed to 
operate in the forward mode.  I wonder if a spec sheet could tell us.  I'll 
try to find out, not that it's necessary for Dave's functioning clipper.

Back to the Demo destruction derby...

Arden Allen
KB6NAX

He who is cruel to animals becomes
hard also in his dealings with men.
We can judge the heart of a man by
his treatment of animals.
—Immanuel Kant

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