John Curl's Blowtorch preamplifier

[john curl]

Actually, it is, but it is NOT 100% RF tight. Big deal.

 

[bear]

I think I mentioned this some time back, but iirc, Borwick in his book on headphones and speakers has a very clearly written and detailed chapter on the non-linear effects of fuses.

_-_-bear




Mr. Curl, you can email me that tanh paper... tnx.

 

[scott wurcer]

I think I mentioned this some time back, but iirc, Borwick in his book on headphones and speakers has a very clearly written and detailed chapter on the non-linear effects of fuses.

_-_-bear
Mr. Curl, you can email me that tanh paper... tnx.

I usually remove all fuses, but for different reasons. Note: I do not like to listen to music loud and never have had an incident due to a lack of fuse.

But on their non-linearities, yes, they are easily derived. Like most non-linear resistances one would be hard pressed to argue for any effects that were not low order, symmetrical, and most important at an appreciable fraction of their rated use. Most importantly like things analog the effects monotonically decrease with level.

 

[dimitri]

Borwick in his book on headphones and speakers has a very clearly written and detailed chapter on the non-linear effects of fuses

http://books.google.com/books?id=pA...k9WqBg&sa=X&oi=book_result&ct=result&resnum=5

 

[scott wurcer]

Dimitri this plot is unscaled. In general without scales this data is not useful. You can show non-linearity of RN60 resistors at -130dB and blow it up to fill the screen.

Put a fuse in series with a speaker and then replace it with a resistance and look at the difference. Hard since fuses are tiny fractional Ohms. OTOH a four wire measurement on a fuse is easy to do with a good instrumentation amplifier.

 

[john curl]

Not peer reviewed, either.

 

[john curl]

What we should do is find Dr. Greiner's original paper with this graph and put it up.

 

[scott wurcer]

Not peer reviewed, either.

One of your favorite guys, Doug (5534) Self, has this stuff included in his book with real scaled measurements. Of course he recommends the liberal application of feedback. Doug shows the problem mainly at low freqencies (the looping) and at near failure point.

 

[lineup]

is this the DR- Greiner paper you refer to, John:
AES E-Library
Transconductance Power Amplifier Systems for Current-Driven Loudspeakers
JAES Volume 37 Issue 10 pp. 809-822; October 1989

or maybe this is it:
AES E-Library
Amplifier-Loudspeaker Interfacing
JAES Volume 28 Issue 5 pp. 310-315; May 1980

 

[scott wurcer]

I think this is the right one.

Amplifier-Loudspeaker Interfacing
JAES Volume 28 Issue 5 pp. 310-315; May 1980
Loudspeaker cables are investigated to determine if they exhibit transmission-line characteristics. Lumped representations of cables are suggested with consideration of the effects cable parameters might have on the audio signal being transmitted. Interaction of the cable with the amplifier, the loudspeaker, and other elements which may be part of the amplifier-cable-loudspeaker circuit are treated.
Author: Greiner, Richard A.
Affiliation: Department of Electrical Engineering, University of Wisconsin, Madison, WI,

 

[lineup]

Another paper published 1991
by
can be free of charge for anyone be downloaded
from Bruce Coppola website, here

Effects of Cable, Loudspeaker and Amplifier Interactions
Fred E. Davis 1991 June in a magazine
http://bruce.coppola.name/audio/cableInteractions.pdf

10 REFERENCES

[1] R. A. Greiner, "Amplifier-Loudspeaker Interfacing," J. Audio Eng. Soc., vol. 28, pp. 310-315

The Author:

Fred E. Davis is currently a consulting electronics controls, portable instrumentation and tools, computer
engineer, and previously has been director of engi- hardware design and software, and consumer elecneering
for machine vision and optical data storage tronics. Besides a passion for music, his interests incompanies.
He has worked with biomedical electronics, clude photography, books

 

[scott wurcer]

Be careful here lineup, I think the #12 zip cord holds its own in this test.

 

[john curl]

What was good enough for Dr. Greiner is not good enough for Scott Wurcer. Go figure. AND look at that hysteresis!

 

[scott wurcer]

I have no problem with #12 zip cord and no fuses, and that's what I use.

 

[john curl]

This is a hi fi thread? No wonder people don't understand what I am trying to say.

 

[jam]

Nothing has changed....................the moderators shoud split this into two threads. .

http://www.toonio.com/v/10929/two-frogs-food-fight.html

Jam

 

[Wavebourn]

I think this is the right one.

Amplifier-Loudspeaker Interfacing
JAES Volume 28 Issue 5 pp. 310-315; May 1980
Loudspeaker cables are investigated to determine if they exhibit transmission-line characteristics. Lumped representations of cables are suggested with consideration of the effects cable parameters might have on the audio signal being transmitted. Interaction of the cable with the amplifier, the loudspeaker, and other elements which may be part of the amplifier-cable-loudspeaker circuit are treated.
Author: Greiner, Richard A.
Affiliation: Department of Electrical Engineering, University of Wisconsin, Madison, WI,

How many kilometers of cable did he investigate?

 

[scott wurcer]

What's wrong? Lineup posted a paper that concludes that #12 zip cord is totally adequate in many applications. Furthermore the article relies almost completely on concrete actual measurements.

Note to moderators don't act on my account I will start my own threads. Hey Jam, no flies on me.

 

[hitsware]

how about light bulbs as current sources ?

 

[PMA]

HI PMA , the thick Blowtorch alu box isn't for RF ??

Box is quite fine. But connectors are insulated from the box. Electric field component gets easilly inside the box along the wires. Then you have bare wires inside. If I made a similar measurement as I have shown here, on Blowtorch, I would get poor result, speaking in RF terms.