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Integrated phono pre-amp for Thorens TD160B

Purl

Member
Well .. I recently changed to a Naim NAC252 pre-amp which does not have an in-built phono stage and now need to find a decent phono pre-amp so I can get back to my vinyl.

Of course, any number of boxed phono stages would do, but with my Naim Fraim full, and adding more levels a complete health and safety no-no, I need to find something which I can integrate into the Thorens TD160B (a la Naim Prefix, Linn Urika) . Ideally I would want to power this from the Naim 24V DC. .. I have a Linn K9 (MM).. wondered if anyone has solved this problem previously, or might have a bright idea?

I also wondered if anyone has re-purposed any of the standard Naim phono boards (522, 322 etc.) and integrated them into a TT? With careful attention to shielding, might this work?

Open to all DIY and off-the-shelf solutions ... budget .. ideally south of £250.
 
Well .. I recently changed to a Naim NAC252 pre-amp which does not have an in-built phono stage and now need to find a decent phono pre-amp so I can get back to my vinyl.

Of course, any number of boxed phono stages would do, but with my Naim Fraim full, and adding more levels a complete health and safety no-no, I need to find something which I can integrate into the Thorens TD160B (a la Naim Prefix, Linn Urika) . Ideally I would want to power this from the Naim 24V DC. .. I have a Linn K9 (MM).. wondered if anyone has solved this problem previously, or might have a bright idea?

I also wondered if anyone has re-purposed any of the standard Naim phono boards (522, 322 etc.) and integrated them into a TT? With careful attention to shielding, might this work?

Open to all DIY and off-the-shelf solutions ... budget .. ideally south of £250.

Yes, I ran 323 cards under my LP12's plinth for a while, before moving to a valve phono stage. But you really need a dual 24v PSU to power it (I guess a single would work, not sure of SQ though) - nice if you have a hicap available, or a DIY similar.
 
Yes, I ran 323 cards under my LP12's plinth for a while, before moving to a valve phono stage. But you really need a dual 24v PSU to power it (I guess a single would work, not sure of SQ though) - nice if you have a hicap available, or a DIY similar.
That’s interesting .. definitely worth considering..
 
Thanks for that link .. hadn’t spotted that one before .. excellent spec on paper, and cheap as chips.. Have messaged the seller to see if they have a MM version..
The specifications suggest that this is the MM version.

Input sensitivity: 2-3mV
Gain: 40db​

My concerns would be that it runs directly from 220-240VAC combined with how to locate it within the confines of TD160B without issue.

Also, the input capacitance is unspecified. You'll want a maximum of 100pF to get the best out of K9. Hard to tell what the input capacitance is supposed to be from looking at this...

s-l1600.jpg
 
Looking at the board, I would guess the input capacitance is probably C1, which you should be able to pick your own value for. 47K is typical input resistance for a MM stage.
 
Looking at the board, I would guess the input capacitance is probably C1, which you should be able to pick your own value for. 47K is typical input resistance for a MM stage.
Upon further inspection, I'm inclined to think that it is the unmarked (but for bold outline) empty holes that appear to allow a bridge between signal and ground on either channel.
 
Thanks for your comments..
The seller of this board was pretty unhelpful and knew nothing about it technically.. so I side-stepped that one ..
Currently working on a solution using a couple of Naim NA522 boards .. will post a pic when complete..
 
Thanks for your comments..
The seller of this board was pretty unhelpful and knew nothing about it technically.. so I side-stepped that one ..
Currently working on a solution using a couple of Naim NA522 boards .. will post a pic when complete..
If you do end up with NA522 boards it is the 470pF polystyrene cap on each that can be usefully replaced with the same type in values as low as 47 or 68pF; these in order to get the capacitive load (tonearm wires plus the of phono input) down into the recommended 100 - 200pF range for the audio-technica derived K9 cartridge. Perhaps go as high as 100pF caps should you be intent upon mounting these boards within the deck, i.e. omitting a meter of external lead plus RCAs.

2613882-d3096d73-naim-522-mm-phono-boards.jpg
 
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Thank you Craig B.. yep .. will definitely swap these out.. I have a selection of polystyrene caps on order.. will try the 68pF first..

First test power-up (with original caps) went ok .. but there was some audible background noise at reasonable volume so will double check the earthing and shielding of the die-cast box..
 


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