John Curl's Blowtorch preamplifier part II

[simon7000]

Originally Posted by cliffforrest

Sharing the same stlye power sockets??

Criminal!

New York City was the first place to get electric service. Edison did it and it was all DC! The standard outlet was designed by Edison and his gang, so it is the Westinghouse and AC folks who just adopted it.

Now Con Edison continued to provide DC until NOVEMBER 2007 to those folks who used it. By then they had provided regulators and rectifiers at each building that still needed DC! There had been electric DC service for 125 years until then.

The issue was not with lighting, but with motors. Until recently virtually all elevators used DC motors for a smoother ride. So there still are buildings that use DC and in NYC they got it direct from the manufacturer. Of course part of the length of service would be that the subways are DC.

[scott wurcer]

Originally Posted by simon7000

New York City was the first place to get electric service. Edison did it and it was all DC! The standard outlet was designed by Edison and his gang, so it is the Westinghouse and AC folks who just adopted it.

My last house was next door to the Wentworth house 1888 (founded Wentworth Institute) as of 1991 or so he (the current owner) still had some tube and open wire in service. Channels were morticed into oversized kickboards.

[Bonsai]

"Sharing the same stlye power sockets??

Criminal!""

Check out my Taiwan Electricians Code experience over in the Musical Fidelity A1-X thread - two identical double 2 pin sockets next to each other. One wired for 110, the other for 220. Only through luck have I not fried more equipment.

Still, not as bad as running a 115V DC line into an Orchestra pit. I hope the facilities manager had his *** kicked straight out of that job.

[enregistree]

Originally Posted by scott wurcer

I repeat this exhaustive survey of excess noise, plenty of choices (if you can sort out the colors ).

https://dcc.ligo.org/public/0002/T09...rent_noise.pdf

Back to resistor noise – for measurments clarification – I sorted graphs on p.10 of article you linked with illustrator. Now we can spend less time guessing… (attached is only cut-out preview, the graphs are here).

[Bonsai]

Well that should make bad resistor avoidance much easier. Thank you

[scott wurcer]

Originally Posted by enregistree

Back to resistor noise – for measurments clarification – I sorted graphs on p.10 of article you linked with illustrator. Now we can spend less time guessing… (attached is only cut-out preview, the graphs are here).

Thanks, that was nice of you.

[Bonsai]

BTW, there is a nice piece in the latest EW about MLCC's. I new they were bad, but not THAT bad.

Avoid them in Audio. Period.

[jcx]

which ceramics? - as we always have to remind people there are different fromulations, NP0/C0G are not piezo, have better DA than some film, mica caps

I have measured distrotion bleow -100 dB in NP0 in a 2nd order fliter at ~ 1/4 fc - such that there was significant dV across the C
Bruce Hofer seemed to think my distortion measurement was unually high for good NP0 - so even better may be expected depending on manufacturer

[Bonsai]

jcx,
NPO/COG are great.
X7Ris the problem. But, I think most people do not realise just how bad.

[simon7000]

I like X7R capacitors. I have one on my engraver table in my shop. It is hooked up to a microphone input. The speaker output is connected to an led on my office desk. When the light goes out I know the machine is finished.