John Curl's Blowtorch preamplifier part III

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Only special purpose extremely high crest factor ones. xDSL drivers myself but I consulted on some envelope tracking amps for cell phone base stations and a 200V pulser for ultra sound. That was an interesting problem, the same piezo element that made the pulse at 200V had to receive the nV level signal back within msec (human tissue has a very large attenuation at MHz).
Thanks!

Plenty of information if you do a search. I general this is a complex (as usual) problem that does not reduce to a simple one dimensional answer. The current on demand behavior depends on a lot of things like exact composition and design (not all SLA batteries are the same), the diffusion of electrolyte on discharge, temperature, time, etc. a multi-disciplined problem.
There may be plenty of measurement info on each but what I'm talking about is a differential measurement which points towards why an active regulator on LiFePO4 battery output noticeably degrades the perceived sound.

I suspect my 'hammer' is at play - noise floor modulation :)
 
The speed of current delivery is determined by the internal impedance - LiFePO4s are down at ~8mOhm
Supercapacitos may well substitute for these batteries - up around 350Farads about equivalent or lower impedance but they are limited to 2.7V so you would need 10 of them & way of balancing them during charging - of course you would also need to balance the batteries.

IanCanada here is developing a battery or supercap PS pack - don't know what prices it will be?

Maybe you could parallel a number of electro caps to achieve something similar?

I am going to study every word of the above using a technical dictionary before I get back to you - thanks a bazillion!
 
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Your not going to start with "music is a complex waveform full of transients so standard analysis like Fourier etc. don't apply".

If you measure this with a small R -- fast charge time with polar type cap and asymmetrical transient waveform, you will see it.

The total output is composed of the charge from C as well as the charge held in the Cda. Say 90% in C and 10% held in Cda. On initial discharge, only the C is released and not the Cda which is withheld ... and only comes out later.... So, the initial output is low by some 10% initially. Good caps arent necessarily that bad but illustrating... depends on how much is kept in Cda. [Typical might be 1-2%.]

This has been measured with a high speed S//Hon music waveforms and compared with and without a C.


Anyway.... the mention of peak level ear response info reminded me of that.


but, I am not going to go over the results of typical tests and what they show.


THx-RNMarsh
 
Ah, crap, it's terrible when a joke bombs - sorry to 'hear' about you had an accident

No problem the issue comes and goes, it was bad last Saturday but I still enjoyed what I heard and still feel I could tell the difference. It's nice keeping things civil.

BTW I had to put my hands over my ear when one of the participants set the volume at his normal listening level.
 
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No problem the issue comes and goes, it was bad last Saturday but I still enjoyed what I heard and still feel I could tell the difference. It's nice keeping things civil.

BTW I had to put my hands over my ear when one of the participants set the volume at his normal listening level.

Yea, good to be civil.

That sort of volume level is unnecessary & I would leave the room, to be honest - we only have one set of cilia & easily damaged.

I generally stayed away from the mosh pit
 
Actually I was an observer at the time, I was already not physically able to participate in the "full" experience but I did like the energy (second childhood maybe).

I tended to be more interested in experimenting with mind altering substances (but within reason) than the physical bouncing around in the mosh pit

LSD gives a great insight into just how our perceptions are internally generated & experiencing synesthesia directly confirms this
 
That type of music isn't known for it's lucidity, I doubt there's anything wrong with your power supply

After some rumination, I think it maybe it is the cheapo nasty class d bridged mono bus pumping chip amp that is at fault. Solution is to drop the eq by -2b at 50hz. Seems less bothersome now with the newish alnico speaker than the ceramic one before it. Methinks the alnico magnet is buffering the current - perhaps - perhaps not, but the cloth surround and spider after a 100 hundred hours is still breaking in, and is taking at least 30 minutes at the beginning of a session to loosen up.

I don't listen to rock music all that much, but I do like Grotus. Very funny, very political and the singer has a voice like a chainsaw. A band that makes fuzz sound intelligent, like an educated punch to the head.

Sadly, I've given up using emoticons, they're just not funny enough.
 
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