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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets.

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Old 1st Dec 2018, 6:36 pm   #21
John10b
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Default Re: Stupid Question?

Thank you all for your considered replies. I was indeed talking in an engineering sense and not trying to explaining Latin.
Lots to ponder over, so if I have a ceramic cartridge and connect to a step up transformer the output Voltage from the the transformer (passive device) will be bigger, it’s Amplfied.
Cheers
John
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Old 1st Dec 2018, 6:40 pm   #22
John10b
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Thank you RadioRangler our posts crossed.
Cheers
John
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Old 1st Dec 2018, 7:48 pm   #23
dave walsh
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As David [RW] said, in that other thread "preamplifier recommendations", all sorts of terminology can be employed to make you think a passive switching device somehow "amplifies".
It might be derived from the fact that a fader in an audio mixer can be passive OR powered [primarily to obtain a better signal quality] or just disingenuous salesmanship. Without going too OT, it reminds me of the time in the sixties when amplifier ratings would be described in a different way [RMS?] [by some companies] to give the impression of a higher output in watts.

John raised a number of issues I hadn't thought of and it all seems to boil down to description. Despite his Philosophical and Mathematical ability Wittgenstien felt that everything started with language-that made me think as well! He once wrote a long piece about how you describe the colour red to a blind man?

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Old 1st Dec 2018, 8:08 pm   #24
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Default Re: Stupid Question?

The audio output of budget amplifiers was approximately four times the truth. Instead of specifying the RMS power per channel, they specified the peak power and combined the channel figures. All a bit naughty, but it must have moved boxes.
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Old 1st Dec 2018, 8:44 pm   #25
Ted Kendall
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Why the term "passive control unit" didn't catch on I don't know. Descriptive and accurate, leaving no room for confusion...on second thoughts, that's probably the reason!
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Old 1st Dec 2018, 9:22 pm   #26
bikerhifinut
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Quote:
Originally Posted by Scimitar View Post
The audio output of budget amplifiers was approximately four times the truth. Instead of specifying the RMS power per channel, they specified the peak power and combined the channel figures. All a bit naughty, but it must have moved boxes.
There is no such thing as an "RMS" watt.

When you think about it it's obvious. A Watt is a Watt. A unit of power. And not restricted to electrical energy.

A.
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Old 1st Dec 2018, 10:14 pm   #27
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Quote: "There is no such thing as an "RMS" watt."

You are unquestionably correct, of course! But in fairness to Scimitar, it was the somewhat misleading use of terms such as 'peak power' and 'music power' in such budget Hi-Fi systems that encouraged us knowledgeable ones to add 'RMS' to make things abundantly clear - even if the term was redundant.
And sometimes, such habits just stick . . .

Al.
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Old 1st Dec 2018, 10:26 pm   #28
bikerhifinut
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True enough Al, forgive me for being a pedant.
And as you say the various and probably mendacious claims of "peak music power" etc etc can confuse folks.
it's when i look at a pair of titchy bluetooth speakers running off a tiny wallwart and the claim of "200W" power, my eyes roll.
A
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Old 1st Dec 2018, 10:35 pm   #29
bikerhifinut
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Anyway, johns original question had me puzzling for a long time when I started out on the hobby.
It was going back to the first principles that saved me.
But i still go boggle eyed when it seems the laws of physics are defied with step up transformers.
As RW states, there are paybacks in terms of impedance and other matching issues.
now this is just my observation, I have no measurements I can show but on balance I prefer listening to a Moving coil low output cartridge via a decent silicon amplifier rather than a transformer step up into a similar moving magnet stage. I suspect there are interactions with an inductive source (the cartridge) into an inductive load (the step up transformer) that I don't understand and possibly never will.
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Old 1st Dec 2018, 11:30 pm   #30
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I think I have said this before, but a repeat will do no harm. Especially as it caused me serious grief 60 years ago when an amplifier circuit was drawn and "explained".
There is no such thing as an amplifier! (Statement from me).
If we ignore conversion (Einstein), we know that energy can be neither created nor destroyed. We also know that matter can be neither created nor destroyed. (OK, the real world we live in, not that of the world of the electron).
Why did the physics lecturer not explain that what he was doing with the valve circuit was making an inverted copy of the original, using an electronic pantograph!
It is always a COPY!
Les
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Old 2nd Dec 2018, 12:25 am   #31
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Default Re: Stupid Question?

Quote:
Originally Posted by John10b View Post
Thank you all for your considered replies. I was indeed talking in an engineering sense and not trying to explaining Latin.
Lots to ponder over, so if I have a ceramic cartridge and connect to a step up transformer the output Voltage from the the transformer (passive device) will be bigger, it’s Amplfied.
Cheers
John
I suspect the design of a step up transformer to work with a source of as high an impedance as a ceramic or crystal cartridge would be slightly non trivial! You would need a primary inductance with a reactance of ten megohms at least at the lowest frequency of interest. The tinny audio resulting from the intervalve step up transformers in a 1920s radio show it's difficult enough at at a few kilohms, let alone a megohm or so.

A moving coil cartridge at least has the grace to be a low impedance source, so the primary inductance requirement is meetable.
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Old 2nd Dec 2018, 1:04 am   #32
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Part of this is just an issue with naming and semantics. As noted for any power amplification a source of energy (the power supply is required).

However, there are "powered voltage amplifiers" where amplifying power was never a design consideration, such as in some pre-amp and low level signal applications, where the intent is to increase the signal voltage.

Obviously, if the input and output impedances are the same, it must also be a power amplifier, to have a higher voltage generated across the same impedance than what you started with.

Yet there are times where the output impedance that the signal loads into is so high as to be near infinite or many meg Ohms. So in these cases it is possible to have voltage amplification with no power gain and no power supply or active amplifier is needed.

The classic example in valve electronics is the inter-stage audio transformer in vintage radios where the transformer feeds a valve's grid, biased into the negative region and there is insignificant grid current, you can get voltage amplification by a factor of 3 to 5 from the transformer.

Since the word "amplification" is associated more commonly with active (and power consuming) devices, I have always tended to name the voltage transformation effect of a transformer "Voltage magnification". A passive circuit with LC & R also demonstrates voltage magnification if the damping is low.
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