Goldpoint SA4M-47 passive 'preamp' winging its way to Marco Towers...

[awkwardbydesign]

Interesting, Paul. And thanks for your input. I guess we'll see whether that's the case in my system or not. I have to say that the LDR of Chris' I heard in Anthony TD's system recently sounded superb, and nothing like you've described...

Anyway, as ever the proof of the pudding is in the listening, so we shall see!
Marco.

It may be worth considering the "map" that is already in your brain. What you hear is often nothing like what the measurements show. For example I have just been listening to Dylan's "Masters of War" sung by Julia Easterlin (https://vieuxfarkatourjuliaeasterlin...lbum/touristes), and it sounds haunting and moving to me. But my wife can hear Dylan's own version in her head as she listens, and doesn't agree with me. I don't like Dylan's voice at all, so my "map" is different; I HEAR differently as a consequence!
So all the comparisons between measured and heard are often* a red herring IMO.
*I said OFTEN, not always, so don't start!

[anubisgrau]

Funnily enogh I was discussing these with Nick at Whittlebury the other day. A good passive is the dogs dangles, in fact my Art Audio VPL is,mwhen in passive mode, a passive followed by a buffer stage, which in turn matches it to following equipment, i.e. The power amp, headphone energiser etc. The problem with LDRs is that they are not passive devices like a good quality resistor (my favs are Vishay Z foils, as used in my own passive pre design).

LDRs are semi conductors, albeit two tailed ones. The are, depending on how they are conected, companding, this is why they are the heart of the classic Joe Meek optical compressor, which gives the amazing squashed sound to the organ in the Tornadoes track, Telstar. When wired as expanders, they artificialy enhance dynamic range at the expepnse of some pretty awful "pumping". They are useful in the studio, (I have four channels of Joe Meek compression), but crap in true HiFi systems, they aren't known as suck and blow compressors for nothing.

There was either some development in LDRs in the recent year or two or there are different "truths" out there. AFAIK semi conductors are used to control LDRs and are definitely not on the signal path, unless as in in or output buffers used to reduce impedance.

[lurcher]

From Wiki:

"A photoresistor is made of a high resistance semiconductor. In the dark, a photoresistor can have a resistance as high as several megohms (MΩ), while in the light, a photoresistor can have a resistance as low as a few hundred ohms."

[PaulStewart]

From Wiki:

"A photoresistor is made of a high resistance semiconductor. In the dark, a photoresistor can have a resistance as high as several megohms (MΩ), while in the light, a photoresistor can have a resistance as low as a few hundred ohms."

Indeed, but you can lead a horse to water........

[struth]

It may be worth considering the "map" that is already in your brain. What you hear is often nothing like what the measurements show. For example I have just been listening to Dylan's "Masters of War" sung by Julia Easterlin (https://vieuxfarkatourjuliaeasterlin...lbum/touristes), and it sounds haunting and moving to me. But my wife can hear Dylan's own version in her head as she listens, and doesn't agree with me. I don't like Dylan's voice at all, so my "map" is different; I HEAR differently as a consequence!
So all the comparisons between measured and heard are often* a red herring IMO.
*I said OFTEN, not always, so don't start!

Sure id agree. Its like a book v film. Depending what you saw/read first as to whether you like it...often

[Joe]

It may be worth considering the "map" that is already in your brain.

In my case, it's more of a roughly drawn scribble on the back of a fag packet than one of the Ordnance Survey's efforts.

[tubehunter]

I was recently reading Valve Amplifiers Third Edition by Morgan Jones again and his thoughts on LDR

"

"

[anubisgrau]

From Wiki:

"A photoresistor is made of a high resistance semiconductor. In the dark, a photoresistor can have a resistance as high as several megohms (MΩ), while in the light, a photoresistor can have a resistance as low as a few hundred ohms."

yes what do you actually have on the signal path?

[awkwardbydesign]

yes what do you actually have on the signal path?

A photoresistor.

[lurcher]

yes what do you actually have on the signal path?

To paraphrase:

The photoresistor is made of a high resistance semiconductor. In the dark, the photoresistor can have a resistance as high as several megohms (MΩ), while in the light, the photoresistor can have a resistance as low as a few hundred ohms. The photoresistor (or normally two) is in the signal path.