Yet another LCR phono EQ

Greetings all,

I finally took the plunge and bought 4 Hashimito 20k:600Ω and 2 Sowter 1280 RIAA!! My searches around the web got me settled on this design (cf. attachement). I'd like to have your insight on 4 aspects (since I modified the original schematic)

--- Is the 600Ω attenuator in the right place? (before the line ouput trans)
--- Is the mono switch ok in this area?
--- the 600Ω resistor after the line input trans necessary?
--- And last, does a headphone output jack a good idea? Does this phono/preamp have enough gain/power? (ie 80Ω headphone)

Thank you so much for your consideration,

All the best,

Olivier
 

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  • Impression Schématique2.pdf
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The LCR should be terminated with single 600ohm load, and present to input as 600ohm so no need another 600 after the IT.
I would recommend to use best pentode circuit and IT for first stage (gain of 40+).
 

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  • 6j49p.jpg
    6j49p.jpg
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Actually any pentode works, 6j49p-dru is bit low on gain just personal preference over e810f/d3a/6j51p etc.
You have 600ohm attenuator, I believe don't need extra 600ohm termination for the LCR.
Since you are making LCR yourself, I think also need to consider the DCR of the coils, there's a spreadsheet tool but I wasn't able to use it correctly.
For second stage IT output, a friend is using single 6am4+ll1692a with excellent result.
 
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