About a phono preamp

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rsavas

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That is a good history lesson thx
And yes, slew rate is critical for a phono preamp. The demands on the feedback loop are enormous.
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If you run multiple gain stages then this takes that burden away. This is what Doug Self suggests when using the NE5534 in a MM app.
But I still think the jfet is the best choice for a MM IPS, look at Bob Cordell's vinyl trak design or the LSK489 app note. The LM4562 should be fast enough.
I think the final touches could be a DC servo and get rid of C5, if you are bothered by ecaps in the FB.
 

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rsavas

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Joined 2012
stocktrader200 said:
low noise npn transistor for front stage into op amp RIAA at lower gain works great.
the jfets may be more noisy then(than) just the op amp in this config.
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When you say maybe, that means to me that you are not sure. Read the paper, it explains why the jfets were used and not a bjt. If you look, many better receivers/amps used this same jfet ips configuration. You are free to do as you wish and show us your designs. Maybe you are a fan of Doug Self design's, one of my first phono amps I built, used a NE5533, which is a dual 5534 in a 16-pin dip.
 
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keilau

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Joined 2013
rsavas said:
That is a good history lesson thx

If you run multiple gain stages then this takes that burden away. This is what Doug Self suggests when using the NE5534 in a MM app.
But I still think the jfet is the best choice for a MM IPS, look at Bob Cordell's vinyl trak design or the LSK489 app note. The LM4562 should be fast enough.
I think the final touches could be a DC servo and get rid of C5, if you are bothered by ecaps in the FB.
Click to expand...

The old (1984) Kenwood Basic C2 preamplifier uses the JFET + op-amp topology for both MM and MC. It worked quite well with LOMC cartridge (Dynavector) for me too. I first got the C2 thinking of temporary use, but ended up keeping it for many years. At 70dB with 0.25mV input, the noise performance is acceptable.
kenwood_basic_c2_phono_schematic.jpg

I switched to a NAD 1600 later when I want the remote control function. It has a all discrete phono stage MM/MC. But I did not like the sound of the NAD and replaced it with a Harman Kardon AP2500. No remote, but the sound is excellent.

The modern op-amp has made the JFET IPS optional. Take a look at Wyn Palmer's new design with DC servo.
 
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