Interesting reading - Old issues of Vacuum Tube Valley magazine

heiney9

http://groupdiy.com/index.php?topic=54889.0

Fascinating to read, always wanted to read this excellent publication that was only around for a few years. Very, very well written and researched articles. I learned a lot and it's an interesting window into the mid-90's when tubes manufacturing was making a quasi-come back.

H9

[Deleted User]

Agree, it was an excellent publication, I've tried getting all the issues but have a few to go. The editor was a perfectionist and tried to get everything exactly right. He, unfortunately, passed away a number of years ago.

heiney9

I was aware of the publication and have seen quotes from it, but this is the first time I've read one cover to cover. I remember hearing the name Kittleson.

That's the kind of "meat and bones" that I enjoy reading. A lot of great audio history revisited in many of the issues, as well as modern views too (atleast on the tubes).

H9

mhardy6647

I reckon the OP knows this, but lots of other good stuff (old magazine scans, e.g.) at www.americanradiohistory.com

... and also, of course, Pete Millett's tremendous resource at www.tubebooks.org

Besides VTV, the other tremendously influential magazine of the 'tube resurgence' was "Sound Practices. Joe Roberts makes the entire back catalog of his magazine available via eBAY on CD basically at his cost of reproducing & distributing the disc. Required reading for anyone interested in vacuum tube hifi, I'd opine.

FWIW, Joe Roberts is a member at AK, and he's fairly active there. I have a feeling most folks at AK have no idea who he is, though.

mhardy6647

Speaking of Sound Practices -- There's a Flikr group called "A Tribute to Sound Practices" that is... well... just that (in spirit, at least): https://flic.kr/g/dfaMf

The "group" is curated by Joseph Esmilla, himself no stranger to the fleapower amplification/high sensitivity hall of fame.

http://jelabs.blogspot.com/
http://jelabsarch.blogspot.com/

Indeed, he's something of a Renaissance man.

http://www.grantorbeta.com/joseph-esmilla-a-musician-and-his-leicas/

He also -- ahem -- designed the amplifier I use; I think it's fair to say that there are quite a few of his "Simple 2A3/Simple 45" amps floatin' around out there :- )

sorry for the somewhat off-topic interjection!

[Deleted User]

I just found a really good copy of Norman Crowhurst and George Cooper's book "High Fidelity Circuit Design".

mhardy6647

Nice.

vcwatkins

Great stuff. Thanks guys!

mhardy6647

Sadly, Charlie Kittelson was a suicide. :- (

VTV turned a lot of once-relatively inexpensive tubes and hifi components into highly-sought after commodities. Not sure if that's a good thing or not, tell you the truth.
That said, it's still a fine resource for certain information & well worth grabbing them whilst they're available. They seem to come and go in terms of web availability; I suspect there might be some dispute about the copyright status and/or ownership of the content (but I am not certain of that).

I downloaded them all a few years ago when they first popped up on line (not that I am 100% sure where those files are at the moment).

[Deleted User]

I'm also getting a lot out of Morgan Jones' "Valve Amplifiers" it's challenging reading but worthwhile. Makes my brain squeal.

mhardy6647

That's "200-level course" material, Ken ;-)

[Deleted User]

The chapter on resistors and capacitors is really excellent. He explains that a model of a capacitor is really a series of parallel sub-capacitors with series resistors between each one. When there is a musical pulse and the capacitor stores the charge and then discharges it only the first few sub-capacitors completely release the stored charge. Because of the isolating internal resistors the other sub-capacitors further away still store some of the original charge and pass it back to the "front" sub-capacitors giving a time smeared version of the original pulse. This is called dielectric absorption or "capacitor memory".

Nightfall

KennethSwauger wrote: »

The chapter on resistors and capacitors is really excellent. He explains that a model of a capacitor is really a series of parallel sub-capacitors with series resistors between each one. When there is a musical pulse and the capacitor stores the charge and then discharges it only the first few sub-capacitors completely release the stored charge. Because of the isolating internal resistors the other sub-capacitors further away still store some of the original charge and pass it back to the "front" sub-capacitors giving a time smeared version of the original pulse. This is called dielectric absorption or "capacitor memory".

That is interesting. Are all types of capacitors susceptible to this? (eg electrolytic, film, etc) To the same degree?

[Deleted User]

While all capacitors exhibit some amount of dielectric absorption it is the ratio of the total resistive component of the capacitor to the reactive component at a specified frequency (this is called "d") that seems to correlate with the perceived sound quality. The lower the "d" the better the sound. PTFE (Teflon) being the lowest with polystyrene next lowest followed by polypropylene and polycarbonate and polyester having higher "d".
He also talks about some plastics are "polar" (not to be confused with polarized capacitors) at a molecular level. This means there are permanently charged electric dipoles similar to magnetic dipoles in a magnet in the dialectric. These polar plastics have difficulty storing an outside electric field and as such are not suitable for audio uses.