This thread has made me think and I am tempted to recall my 205CIIL from it's holiday in Norway to try it out. I've got a range of MMs from 2mV to 12mV so the MM stage I am curently playing with has gain to incorporate that but I never worried about whether the noise would get too high at max gain. I need to check those sums. There is a neat circuit Hans Polak simulated a couple of years ago as an MM front end for digital interfaces (think focusrite scarlet) which would do the job.
But given we are only talking an extra 6dB in my case I doubt I would need it. But I do like making life difficult for myself for lolz
But given we are only talking an extra 6dB in my case I doubt I would need it. But I do like making life difficult for myself for lolz
Has anyone tried or considered the Cordell VinylTrak Phono?
http://www.cordellaudio.com/preamplifiers/vinyltrak.shtml
http://www.cordellaudio.com/preamplifiers/vinyltrak.shtml
At least one person has built that, but no PCBs are available. Scott Wurcer did a very interesting simplified version of this and EUVL was looking at producing some PCBs for that. I haven't chased recently to see if they came to fruition as I'm a couple of years behind on projects.
The damped RIAA Bob uses is a very interesting (if slightly alien to most) concept but I think it could be an interesting leveller for MM users.
I copied the circuit from my Kenwood KX-A36, which uses 5532/6556, and made a pre amp using the TL072.
I used a 12 volt wall wart, and had to change the input and output resistors. The linear wart gave about 17 volts at that low load, good as the output is proportional to supply volts.
A Thorens TD 309 fed a Philips set with 2030 on one channel and 1875 on the other, both were Chinese branded chips.
The listener had Sony speakers in rose wood finish from his college days in the 1970s, and was satisfied.
A ground had to be made, and connected to turn table ground, or noise was a problem.
The AD 797 looks good on the spec sheet, in real life this forum will have experienced users to give their opinion.
I used a 12 volt wall wart, and had to change the input and output resistors. The linear wart gave about 17 volts at that low load, good as the output is proportional to supply volts.
A Thorens TD 309 fed a Philips set with 2030 on one channel and 1875 on the other, both were Chinese branded chips.
The listener had Sony speakers in rose wood finish from his college days in the 1970s, and was satisfied.
A ground had to be made, and connected to turn table ground, or noise was a problem.
The AD 797 looks good on the spec sheet, in real life this forum will have experienced users to give their opinion.
akitika phono
Only MM but this designer claims:
Phono Preamp
"Electronic Termination for Lowest Noise
For minimum noise, the preamp uses an electronic termination scheme. You'll recall that the standard loading resistance is 47 K Ohms. If you do this with a 47 K Ohm resistor, you get significant amounts of noise. Instead, you can terminate with a 1 Meg resistor in a controlled gain Miller loop that makes it look just like 47K Ohms, but it has (ideally) 13 dB less noise. This, along with the rest of the careful design choices makes this an extremely low noise preamplifier. You can read more about the technique here"
https://www.akitika.com/documents/ElectronicCooling.pdf
Does this mean the gain can be increased further without noise issues?
Only MM but this designer claims:
Phono Preamp
"Electronic Termination for Lowest Noise
For minimum noise, the preamp uses an electronic termination scheme. You'll recall that the standard loading resistance is 47 K Ohms. If you do this with a 47 K Ohm resistor, you get significant amounts of noise. Instead, you can terminate with a 1 Meg resistor in a controlled gain Miller loop that makes it look just like 47K Ohms, but it has (ideally) 13 dB less noise. This, along with the rest of the careful design choices makes this an extremely low noise preamplifier. You can read more about the technique here"
https://www.akitika.com/documents/ElectronicCooling.pdf
Does this mean the gain can be increased further without noise issues?
Electronic cooling can reduce the noise a bit with high-inductance cartridges (hundreds of mH), although even then the difference is usually only noticeable in between records and not when there is a record playing. For a low-inductance cartridge like yours (33 mH), the effect is negligible with or without record playing.
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No one
PM hans Polak, ask him questions build the boards you have and listen. Worry about other designs and option later would be my advice. Trust me on this Been there and got the piles of unfinished projects to show for it
Hans had already made a provision for an MM version. He provides instructions and values. This is the one I am about to start building. For me, the downside was the inability to have a single phono stage that is switchable between MC and MM. So it would have to be two versions of this built into the same box, with an MM/MC switch. I suppose that would work OK as well, yes?
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