Halve the diamond, double the performance!!!

Elvee · 11th March 2011, 12:36 PM

Hi,

Here is what is basically a Taylor half-diamond follower, but with a twist: Q4 and Q5 take care of the positive part of the signal, ensuring symetrical performance, and smooth class B operation:

jam · 11th March 2011, 04:06 PM

Holding the input constant what is the worst case oamffset (drift)?
It does look like a novel idea.

Jam

Elvee · 11th March 2011, 04:41 PM

Quote:

Originally Posted by jam

Holding the input constant what is the worst case oamffset (drift)?

In this example, it is approximately 50mV (Q1 and Q3 held at the same temperature).

It depends on the matching of the current densities in Q1 and Q3. If the currents are scaled in the same proportion as the junction areas, a first order cancellation occurs, both statically and dynamically.

AKSA · 18th September 2011, 01:59 PM

Brilliant, Elvee!

Have you built and auditioned it?

Hugh

Elvee · 18th September 2011, 05:20 PM

Quote:

Originally Posted by AKSA

Have you built and auditioned it?

Yes, I have built it, tested it with real audio too: no obvious flaw.
I won't comment further in that direction since I have tin ears, but it sounds OK.

It is not a topology for the faint hearted though: the input impedance is negative, which can be disconcerting to the novice.

kenpeter · 18th September 2011, 11:21 PM

You know the base current of 2n3055 is wildly not a linear load.
Somehow need to add or subtract that drive current back into
the equation that will hold Q1's emitter drop constant.

Bigun · 19th September 2011, 12:01 AM

I like it !

reminds me a little bit of this: Amplifier Variations.

kenpeter · 19th September 2011, 12:02 AM

Easier way to hold half diamond emitters at constant voltage drop...
Taylor still worth knowing, please keep exploring the original circuit.

kenpeter · 01:05 AM

Or this way too, could hold those two emitters constant.
You might ask, why not a simple mirror across the top?
Yeah, but a mirror isn't so easy to bootstrap. Or is it???
M2 might want gate swing a few volts above the rail.

I keep trying to throw a gratuitous Taylor in there,
other weird solutions just keep popping in my head.
At least we are watching a collector and bouncing
that info as current to an active load on the emitter...

18th September 2011, 01:59 PM	#4
AKSA diyAudio Member Join Date: Sep 2001 Location: Melbourne, Australia	Brilliant, Elvee! Have you built and auditioned it? Hugh __________________ Aspen Amplifiers P/L (Australia) www.aksaonline.com

19th September 2011, 12:01 AM	#7
Bigun diyAudio Member Join Date: Jan 2009 Location: K-W Ontario Blog Entries: 2	I like it ! reminds me a little bit of this: Amplifier Variations. __________________ "The test of the machine is the satisfaction it gives you. There isn't any other test. If the machine produces tranquility it's right. If it disturbs you it's wrong until either the machine or your mind is changed." Robert M Pirsig.

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11th March 2011, 04:06 PM	#2
jam diyAudio Member Join Date: May 2001 Location: Charlotte,NC,USA	Holding the input constant what is the worst case oamffset (drift)? It does look like a novel idea. Jam

18th September 2011, 11:21 PM	#6
kenpeter diyAudio Member Join Date: Nov 2007 Location: Dallas	You know the base current of 2n3055 is wildly not a linear load. Somehow need to add or subtract that drive current back into the equation that will hold Q1's emitter drop constant.

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