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RIAA preamps

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While we're talking about pickups, here's a scanned circuit diagram of a Fidelity record player using a crystal pickup, note the complete lack of any RIAA equalisation.
 

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I just simulated that amplifier, assuming: 470K pickup resistance, 'tone' control at 10% (5K) and volume at 50%.

Rolloff begins at 100 Hz instead of 20; but after that, the curve is within about 5 db of the RIAA curve. Volume control has a big influence due to C6; it's a lot brighter at high and low settings.
 
Just buy one of these and be done with it ;)

**broken link removed**

I've seen similar ones selling for around £49 if you shop around .....
 
A turntable should have audio spec's. This one lists only its weight.
 
Just buy one of these and be done with it ;)

**broken link removed**

I've seen similar ones selling for around £49 if you shop around .....

why should I buy that piece of crap when my dad has one of the best quality record decks made it cost 500 £ 20 years ago ! those "things" are just cheap rubbish
 
the advert also takes the p!ss - included cover - wow so what have record decks been sold with ever since they were brought into this word some came with a whole peice of furniture, it features a tape input too unique to their exclusive model what a carry on what the hec is the line in on every pc if not a tape input all they are doing is wireing it through or if the sound goes via usb then they just put the so called tape input straight into the usb soundcard and bypass the preamp really its time retailers and producers were made to have "technical spec" apart from the advertising clap trap
 
the advert also takes the p!ss - included cover - wow
At the risk of sounding like a dumb consumer, I bought an earlier version that surprisingly did not include a cover. I'm still upset.
 
Cheap junk sounds like hell!
Good stuff sounds wonderful and some cost less than the cheap junk.
 
well i get the impression that its just another one of those cheapo decks like the ones that used to come with music centres which were invariably not goo, I'd rather build my own preamp and stick with my dads state of the art deck (of the time and I'm sure they didn't get much better than that)
 
At the risk of sounding like a dumb consumer, I bought an earlier version that surprisingly did not include a cover. I'm still upset.

yea well that lack of cover probably saved them a quid ? what record player ever came with out a lid ? its almost essential, they are playing on the fact that people now think the world of anything to do with computers or are too young to know what playing records was about
 
I think they are more relying on the fact that most people who buy them will use them once to transfer all their vinyl over to digital then pack the deck up in the attic for the rest of its life.
 
quite I doubt very much the quality of the cartridge and mechanism can even slightly rival an older but very high quality machine
 
While we're talking about pickups, here's a scanned circuit diagram of a Fidelity record player using a crystal pickup, note the complete lack of any RIAA equalisation.

What could "gram motor" mean, on the xformer secondary?
 
What could "gram motor" mean, on the xformer secondary?

It's a second winding on the AC deck motor, used as a transformer to power the amplifier - crude but efficient! :p

I was trying to find an even older Fidelity example, which used a crystal pickup and a single EL84 valve - but couldn't find it.
 
A record player was also called a gramophone. So it uses a gram motor.
 
Hi Audioguru,

For my 12th birthday I was given a wind up Gramophone Decca 10. It had a variable speed control, so I could slow down and speed up the record, I got some interesting rhythms on it.

The reason I replied, is that I also had an electric record player with 78, 45, 33 1/3, and 16, Perhaps for LP, or maybe voice?, I didn't have any records.
 
16RPM was used for what we now call "audiobooks".

Nigel: Your post #35 reminds me of the loudspeakers with a coil instead of the perm mag. These sets allways hummed (I guess they did not know the words (sorry)). E
 
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