John Curl's Blowtorch preamplifier part II

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Has everyone looked at 'Stereophile' Apr. 2013 ? On the cover is Nelson Pass's XP-30 triple-decker preamp, that weighs as much a CTC Blowtorch (75 lb) and is just as expensive. I almost forgot that Nelson was part of our 'hi end' club. Go Nelson, and let no one go after me again on the case fabrication issue, without giving Nelson an equally hard time. It is only fair! '-)
 
So how about my B&K true rms voltmeter and my Clio test setup. and LCR meter, etc. What level of equipment do we need? I supposedly have the first Solid State Burr-Brown selectable tone generator ever made, a friend who passed away was friends with Mr. Brown and I got the unit. How many toys do I have to add to join the club as a junior member or an associate? I'll need a new oscilloscope, I think mine has been sitting so long the electrolytic's are toast by now.
 
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Where metal mass pays off

George
 

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Then I can't trade you my P6042? How about a wide band 500A clamp-on current probe? CT's? Ground -as in Earth- impedance tester?
No? Then, might as well join us. :)

Who else is in The Test Equipment Club?

-RNM

I can only do current to 100 Amps and have actually had that clipping on the output of an audio power amplifier!

Safety ground test equipment I have. I am strong in sound level meters, microphones, calibrators and standards! (I actually gave away a spare pistonphone.)

Now we should limit this to test equipment, not tools. I think I will win on tools. (Anybody else have a turret press? Jacco still got yours?)

I did have a flood in 2004 and lost pretty much everything. So eBay was required to help out. Among other gear I picked up a Chinese copy of a Tek scope and use that often as it came with software to download images. I didn't buy that with my Tek scope.

I am still weak in video test equipment, (particularly digital) RF signal generators and RF network analyzers. I only buy equipment when I actually need it and will use it enough to pay for itself.

My rule for tools is that I have to buy more material than the tool costs.

Demian,

I use eBay reciprocity for equipment calibration. Buy three units, if they all agree, sell two of them as calibrated!
 
Yes,
Simon I have the mills, drills, lathes and other sundry equipment. 450 lb. per minute reaction injection molding machine, but you say tools don't count. I got many beat in that area.

There is a very nice electronic surplus store nearby that has things by the bushel load, whatever you could possibly use. I'll have to pay them a visit and see about a new oscilloscope, just not sure what I should get for audio only use.
 
Tools, did you say? This is a small fraction- you name it, we got it. Mills, lathes, swiss screw, EDM, molding, extrusion... Did I mention our SEM/EDX? And we do own Instron (not just the machine, the company) as well...
 

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Is all that in your garage Sy.......:D

I would love to have access to an Instron, I could really use that for materials properties. I did have access while in aerospace but not for few years now. Nice optical comparator it looks like in that picture. I would feel right at home there.

Just had to turn down a job at an aerospace fasteners company when I asked the supposedly best machinist what tolerance he was working to and he looked at me funny and couldn't speak a word of proper English. Turns out they were working to +/- 0.001" and thought that was tight tolerance.
 
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I can only do current to 100 Amps and have actually had that clipping on the output of an audio power amplifier!

Demian,

I use eBay reciprocity for equipment calibration. Buy three units, if they all agree, sell two of them as calibrated!

Works to a point. I try to get different views of the same thing. If two different instruments from different manufacturers agree then I can have confidence. And calibration doesn't necessarily bring confidence. I had a bunch of stuff calibrated. I came to learn that the calibrators used were not adequate (my instruments are higher resolution and accuracy than the calibrators they used, if they actually used them).

I can handle something like 10,000 amps peak current on the current probes I have. Needed for surge testing. Its one area where no amount of theorizing will substitute for hands on (OFF!) testing.
 
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If its what I think it is I played with one at IBM research Almaden about 7 years ago. I moved a few atoms around. The researcher showed me the process of building a one atom flip flop. It was slow. A fair portion of the equipment to run it looked like it came from my storage locker. Even IBM doesn't waste money casually on new stuff if not necessary.
 
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But what bandwidth do I really need to use? No reason to get something that goes to the Ghz range I would think, but someone have a recommendation of bandwidth I would really need to use?
100MHz, with a 20MHz switchable bandwidth reduction, has worked well for me over the years on almost everything audio and related. EDIT: for an analog scope. For a sampled one a very high sampling rate will produce a nicer display. Used to drive me up the wall when JA would show time-domain waveforms with early sampled scopes and there would be all this noise in the waveforms, which I suspect many believed actually were in the signal. Things are much better now.
 
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SY,

I didn't realize you owned all that.

All,

Attached is the output of my test power supply. One FFT is with just a 2200 uF filter cap and 50 ohm load. The other is a CRC filter with 1000 uf through 1 ohm to another 1000 uF.

I am flumoxed as to why the CRC is actually noisier. I will repeat this experiment to confirm and examine what is going om.

ES
 

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