Looking for recommendation for Phono Stage

What people are working on at the moment
RhythMick
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#46 Re: Looking for recommendation for Phono Stage

Post by RhythMick »

Thanks. So obviously looking for the squareness of the wave, but even that is a very visual judgement.

Totally agree ears are the final arbiter but if I'm going to try half a dozen options it will get quite difficult to compare I reckon. Still, if that's the best way I'm good. Perhaps 2 breadboards, winner stays on, keep trying to improve...
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Nick
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#47 Re: Looking for recommendation for Phono Stage

Post by Nick »

Well, other than ears, the best way is you spend £15k-£20k on up to date audio analyser from AP, R&S or Keysight. You will be surprised how good a first step a square wave is though.
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RhythMick
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#48 Re: Looking for recommendation for Phono Stage

Post by RhythMick »

Nick wrote: Mon Jan 21, 2019 6:13 pm Well, other than ears, the best way is you spend £15k-£20k on up to date audio analyser from AP, R&S or Keysight. You will be surprised how good a first step a square wave is though.
Fair point, thanks.
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izzy wizzy
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#49 Re: Looking for recommendation for Phono Stage

Post by izzy wizzy »

RhythMick wrote: Mon Jan 21, 2019 6:09 pm Perhaps 2 breadboards, winner stays on, keep trying to improve...
I do something similar on the one I use. Mono the input and output with a combining connector and then modify one channel - swap back and forth.

Cheers,
Stephen
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#50 Re: Looking for recommendation for Phono Stage

Post by RhythMick »

Today's location for audio circuit thinking...
1548191055022356.jpg
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IslandPink
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#51 Re: Looking for recommendation for Phono Stage

Post by IslandPink »

That's all very well, but have you got a toilet where you can sit with a pad of paper, a pencil and a calculator ?
"Once you find out ... the Circumstances ; then you can go out"
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pre65
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#52 Re: Looking for recommendation for Phono Stage

Post by pre65 »

Sitting on the toilet, working it out with a pencil ? :shock: :lol:
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RhythMick
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#53 Re: Looking for recommendation for Phono Stage

Post by RhythMick »

pre65 wrote: Tue Jan 22, 2019 9:09 pm Sitting on the toilet, working it out with a pencil ? :shock: :lol:
Someone help that men tuck his stool in...
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Nick
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#54 Re: Looking for recommendation for Phono Stage

Post by Nick »

I thought Rudolf was back for a moment then.
Whenever an honest man discovers that he's mistaken, he will either cease to be mistaken or he will cease to be honest.
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shane
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#55 Re: Looking for recommendation for Phono Stage

Post by shane »

Careful! Say his name three times and he’ll appear.
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#56 Re: Looking for recommendation for Phono Stage

Post by Lee S »

Strictly speaking Shane, the Duck-billed Platypus is not the only egg laying mammal in the world... there is another called an Echidna... :P :P :lol:
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shane
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#57 Re: Looking for recommendation for Phono Stage

Post by shane »

This is true, but whoever heard of an echidna that ate custard?
The world looks so different after learning science. For example, trees are made of air, primarily. When they are burned, they go back to air, and in their flaming heat is released the flaming heat of the Sun which was bound in to convert air into tree.
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pre65
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#58 Re: Looking for recommendation for Phono Stage

Post by pre65 »

shane wrote: Wed Jan 23, 2019 5:37 pm This is true, but whoever heard of an echidna that ate custard?
Eric does. :lol:
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Mike H
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#59 Re: Looking for recommendation for Phono Stage

Post by Mike H »

Image

IslandPink wrote: Tue Jan 22, 2019 9:08 pm That's all very well, but have you got a toilet where you can sit with a pad of paper, a pencil and a calculator ?
Or even, just the toilet...
 
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#60 Re: Looking for recommendation for Phono Stage

Post by RhythMick »

Ooh that was a good week skiing. No snow since Dec 22 - pistes in remarkably good nick considering.

Now back to the important stuff. No not work, the next amp design.

Thomas Mayer also likes the D3A - http://vinylsavor.blogspot.com/2012/12/ ... h-d3a.html

"The low plate resistance makes this tube very suitable for transformer coupling. With a step down transformer, for example Lundahl LL1692A in 3.5:1 configuration or LL1660 in 4.5:1 the tube is perfect to drive a 600 Ohm LCR RIAA network. In such a configuration there would even be some gain left after the EQ network. With a step up transformer after the RIAA, for example Lundahl LL7903 in 1:4 confguration this could be boosted up for further amplification in a second D3a stage using another step down transformer for low output impedance. With a Lundahl LL2745 wired 2.8:1 at the output such a 2 stage phono preamplifier would have a MM gain of about 46 dB with an output impedance of less than 300 Ohms. This gain can be brought up to suitable levels for moving coil cartridges with a MC step up transformer."
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