Hello,
I've read some posts about 600 ohm LCR implementation in this circut.
As wrote It's anoter circuit but what do you think about this:
http://emisukeaudio.sakura.ne.jp/EM-TUBE_EQ3_Ver2_KAI.pdf
Can be used a similar solution in the valve-itch-phono
Redards
Guglielmo
I've read some posts about 600 ohm LCR implementation in this circut.
As wrote It's anoter circuit but what do you think about this:
http://emisukeaudio.sakura.ne.jp/EM-TUBE_EQ3_Ver2_KAI.pdf
Can be used a similar solution in the valve-itch-phono
Redards
Guglielmo
Hmm it uses a Mosfet follower to provide the drive and back to back 2200uF couplers because of 600 Ohm impedance network. Certainly adaptable but it would need that Mosfet and big lytic caps in the signal too. Also remeasuring curve compliance of course.
It doesn't thrill me, but if you want to try adapt it and listen nothing's stopping you.
It doesn't thrill me, but if you want to try adapt it and listen nothing's stopping you.
So now that I've added a LOMC to my turntable, I'm planning to integrate a SUT into my Valve Itch. My Benz Micro Wood SL has an output of .57ma, so I'm leaning toward a Partridge 977 1:6 SUT. I'm not concerned about wiring the SUT into the signal chain, but I am concerned about grounding. See, I'm using a Rega tonearm, which does not have a dedicated ground wire. With all Rega tables, the tonearm is shielded through the left channel return.
Without the tonearm shielded to the chassis, am I likely to induce hum if I ground the Partridge cans to the chassis? If so, should I shield the cans through audio ground?
Thanks
Without the tonearm shielded to the chassis, am I likely to induce hum if I ground the Partridge cans to the chassis? If so, should I shield the cans through audio ground?
Thanks
Okay — now the SUT is up and running. Ended up going with a pair of Cinemag CM-1254. Integrated into this little box with four switchable step up ratios between 1:10 and 1:40. Signal grounds are floating and this little guy adds no additional noise to the system. Now ready for a UFSP shootout with my Benz Wood SL.
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Curious - if you had no 6N2P’s (I don’t) but had 6J9P a.k.a. russian E180F (I do) what would the circuit have looked like ?
Secondly, did you or anybody else ever compare (I have a dejavu feeling I asked you this before) with Diego Nardi phono as I had an itch to build his Mono Phono many years ago and it would be nice to do so from a Nostalgia perspective, but if your Itch is simply so much better why bother
Lastly, if doing mono only with your Itch, any benefit in paralleling ‘unused’ triodes in the same bottle since a single channel build will still use the same number of bottles to keep the elevated heaters ?
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It would have looked same topology input stage but with passive parts values sized as to bias alternative valves correctly. With caution to how much plate current for optimal noise. Not theoretically, but on FFT. I don't think that E180F has enough gm to do what I had in mind when I mentioned E810F connected as triode though.
Never had hands on experience with Nardi's phono, thus no comment.
About paralleling it may prove 3dB noise beneficial but Miller will double, so if interested in direct MM use, that mode would be problematic.
Never had hands on experience with Nardi's phono, thus no comment.
About paralleling it may prove 3dB noise beneficial but Miller will double, so if interested in direct MM use, that mode would be problematic.
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According to LCR-RIAA, "the output impedance of which should be 600 ohms, is important for adhering to the target curve."
In the posted design, Ecc81 output impedance is 267, so there is 330 in series to match up.
With 6N2P-EV in valve itch, the output impedance is 1000/2.25=444, does that mean it's good enough to drive the LCR directly?
By the way I just built the phono with K72 teflons no other fancy components, initial impression is a bit better than Bench's RIAA5 (with premium parts).
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