Hi Joachim
I think R12 can be omitted. Perhaps it would also be better to remove C4 and R4, and take feedback direct from the output of the 2'nd opamp. Output impedance will then be a consistent 100R. I don't know if this would be better or worse but it would be simpler.
It may be nice to put an ultrasonic filter between the first and second stages to compensate for the zero in the first stage, but this is difficult if the load is unknown. Adjusting P1 will also shift the frequency of that zero, making it more difficult.
Regards - Godfrey
Yes, i understand. Just made a quick calculation on a RIAA with more gain. If we kepp the 600 Ohm to ground the resistor values in the RIAA get quite high and the cap values are rather odd. We could again ad the servo and do the line stage as a buffer, Curl style.
I whould rather prefer a buffer then a passive solution but i wait what John has to say.
I whould rather prefer a buffer then a passive solution but i wait what John has to say.
Pavel, i asked John if i could draw the schematics and he leads me the way. I can draw fast. That is the only reason.
For the rest of you, to keep you pleasantly diverted, we will 'tart up' our VW with a foxtail on the radio antenna, flames or flowers, your choice, painted on the exterior, a name for it, 'Miss Lemon' was stenciled on my '54 Chevy, for example, " 4 carburetors, 2 straight exhausts, full Murphy bed in my back seat, TV and a phone, got to talk to my 'baby' when I'm driving alone." Thanks to Chuck Berry for the inspiration. ;-)
For you 'insiders: Cigarette lighters and coffee holders in the back seat, heated and air conditioned front seats, all electric adjust, everywhere.
For you 'insiders: Cigarette lighters and coffee holders in the back seat, heated and air conditioned front seats, all electric adjust, everywhere.
Won't R3 unnecessarily load down the volume control wiper connection?
Isn't the gain of the line stage too low? I'd think the non-linear capacitance of the JFET input stage would be a significant contributor to distortion.
Buffers at the opamp outputs would help, too, but may not fit into the design goals.
Isn't the gain of the line stage too low? I'd think the non-linear capacitance of the JFET input stage would be a significant contributor to distortion.
Buffers at the opamp outputs would help, too, but may not fit into the design goals.
Thanks, Joachim, now what must we do to make this a practical, rather than an 'idealized' design?
Don't the 'Folk' deserve a taste of moving coil? For the price of a little K369, shunt cascode?
I've successfully removed R3 entirely in this sort of application without a problem. However, I understand why somebody might feel the need to retain it for safety reasons. Still, Mouser has 10M non-magnetic Dale resistors in stock and PartsConnexion has 10M PRP parts, too. Not as good as the Gigohms of the opamp input, but may have to do.
Again, if you want to stick with this opamp, then higher gain is merited to keep the common mode voltage low. (For those who aren't familiar with this, look at page 9 of the data sheet.)
A single LSK389 is undoubtedly better for a line stage, but once you start down that path...
Again, if you want to stick with this opamp, then higher gain is merited to keep the common mode voltage low. (For those who aren't familiar with this, look at page 9 of the data sheet.)
A single LSK389 is undoubtedly better for a line stage, but once you start down that path...
The MM stage could have too much DC offset. If we asume 1mV input offset the output could reach 500mV.
CG, please go back and look at #7253. 1 Meg is OK, 10Meg is overkill. What else is wrong with this design, as shown?
I won't argue. I suppose we are supposed to be getting used to Austerity, in Europe. But I had imagined the DL-103 to be a kind of Voelkstonabnehmer, or pick-up.
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