Meitner Floating Charge power supply

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jacco vermeulen

jacco vermeulen

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Joined 2004
I think it may be a switched mode PSU but I can't tell from the descriptions. [/B]
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Yes,

there was an article/interview on the Meitner amplifier in a German audio magazine around the 1990s, with pictures of the powersupply. Even believe Ed Meitner is German by origin.
I've heard the bigger one of the Meitner amps, the 100 watts model. Believe it was the first serious attempt to do a home-use smps style amplifier. The amplifier looked great, covered in polished tropical wood, weighed some 25lbs. Very pricy over here at that time, Krell KSA100 level.
ps: i recall that cooling of the Meitners was also a bit different
 
A

ash_dac

Member
Joined 2005
Eva said:
That's probably a switched capacitor approach, as in voltage doublers, but with a lot of hype around it.
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I'm not sure if it's the right place to post this question.

I've noticed that many bitstream dacs use a switched mode PSU to power the circuits. Meinter used a switched mode PSU with the frequency locked to the input sampling frequency.

Can anyone explain the benefit of this over an RC filter linear regulator in powering a digital circuit?

This was all I could come up with:- http://www.diyaudio.com/forums/showthread.php?postid=845481#post845481
 
tvi

tvi

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Joined 2001
Hope this is of some help

Regards
James
 

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jacco vermeulen

jacco vermeulen

Member
Joined 2004
It's a choke powersupply.

At least i got it half right. I have not seen commercial amplifiers with a choke supply before the Meitners.
All of the Aleph builders here stick the biggest transformers, caps and coils they can find in a case to make a CRC, without calculating it. With a class AB amplifier as the Meitner the coil is used to store energy, not for dropping voltage ripple.

I believe the heatsink is called a passive vent cooler. I've welded something like that from aluminium rods and plates a number of years after i saw the meitner sinks. (argon arc welding)
Efficiency of such heatsinks is much higher than conventional ones, and ideal for DIY(if you know how to weld or crimp aluminium)

The one with the smps supply was from the same period, one day it will come back to me. (i should be silent with a dancing smps expert present)
 
poobah

poobah

Member
Joined 2005
ash_dac,

The frequency lock method you describe can be labeled as cheesy or brilliant. This is done to eliminate errors... or more precisely to ensure that the exact same error appears in every sample of the signal etc...

If the exact same error appears in every sample in the same way... it, by definition, is no longer noise... but an artifact (or inaudible DC bias. One could argue that the noise should be reduced in the first place.

I often take precise measurements on waveforms that are polluted with 60, 120, & 360 "noise". I take samples precisely at 720 Hz. In this way, some samples come out high... some come come out low. When all the samples are averaged together; I get amazingly good results. 10 - 20 millivolt bounce on 540 Volt DC levels with ripple compnenets around 2 or 3 Volts.

;)
 
audiobomber

audiobomber

Member
Joined 2004
Eva said:
I can see a plain 50/60Hz toroid on that picture, and no switching transformers, so there is not likely to be any SMPS stuff in that design.
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I didn't think so. Were switch-mode power supplies even available in 1980? That's when the Meitner stuff was originally designed. I recall he patented his "floating charge" ps, but I've never heard an explanation of how it works.

I have four of his amps (pre and 3 power), and I can tell you they do sound great.
 
Eva

Eva

Member
Joined 2003
audiobomber said:


I didn't think so. Were switch-mode power supplies even available in 1980? That's when the Meitner stuff was originally designed. I recall he patented his "floating charge" ps, but I've never heard an explanation of how it works.

I have four of his amps (pre and 3 power), and I can tell you they do sound great.
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Could you post pictures of the insides of these amplifiers?

Switch-mode power supplies were already being extensively used in areas such as computing during 1970s, and hundreds if not thousands of non-B.S. patents were produced during that decade (that fortunately have now expired). During 1980s SMPS started to slowly enter the consumer market but almost everything was already invented.

I wonder whether Meitner patents were or not B.S. (as the ones we use to see now).
 
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