I have made a simulation for you. Remember that the pot will have influence. Worst case is when it is at 5k + 5k.
I suggest
1 uF, 47 k + 470R, 1n
The simulation is done with LTSpice.
http://www.linear.com/company/software.jsp
I suggest
1 uF, 47 k + 470R, 1n
The simulation is done with LTSpice.
http://www.linear.com/company/software.jsp
Put in the values and see what you get. No need to solve any equations but it's good to know a little
Wynand,
Let me explain what I meant.
The small caps (c4/c6) can get some ~2mm closer to the opamps, right?
Then do that.
But most important, each electrolythic must be right next to the small caps, and not at the beginning of the board.
So, move C3 closer to C4, and C5 right next to C6 (to the right).
There's space on the board to rearrange this.
Actually, there's too much space, you can make a much tighter layout, the board can be smaller.
If you do this, in the future you can try better opamps on that circuit, results will be much better.
Let me explain what I meant.
The small caps (c4/c6) can get some ~2mm closer to the opamps, right?
Then do that.
But most important, each electrolythic must be right next to the small caps, and not at the beginning of the board.
So, move C3 closer to C4, and C5 right next to C6 (to the right).
There's space on the board to rearrange this.
Actually, there's too much space, you can make a much tighter layout, the board can be smaller.
If you do this, in the future you can try better opamps on that circuit, results will be much better.
thalis said:It’s a ‘zen’ kind of phono circuit which if implemented with care can give pleasure
Hello Thalis,
You are absolutely right, it sounds fantastic.
The RIAA component values on your schematic are close, I have just made slight adjustments.
But I have used much lower value resistors on the Jfets, and I give much more gain on the first stage. Allows me to have much lower output impedance on the second stage.
The rest is layout, grounding arrangement, component choices, etc.
This thing is very, very silent.
I'm still waiting for some parts to settle on the final thing (I feel that 2SK369 may be an even better choice for the first stage, gonna try it), but this thing is already singin' like a bird.
1000 thanks to you, and also to your friend Salas for insisting.
(Sorry to not respond – I didn’t see these comments earlier)
I’m very pleased to hear about that dear Carlos, and I thank you for your kind words ;-)
From what I also understand, you proceeded with appropriate adjustments for your setup and preferences, and I’m glad you did it
The 369 is good, I remember it having somewhat greater input capacitance though, but you can try it nevertheless – I would be also pleased to hear your impressions regarding it.
Regards.
Thalis
I’m very pleased to hear about that dear Carlos, and I thank you for your kind words ;-)
From what I also understand, you proceeded with appropriate adjustments for your setup and preferences, and I’m glad you did it
The 369 is good, I remember it having somewhat greater input capacitance though, but you can try it nevertheless – I would be also pleased to hear your impressions regarding it.
Regards.
Thalis
thalis said:
Thalis, I have just tried the 2SK369 today, on the input stage.
I'm not worried with the input capacitance, as this is an MM phono pre, so the input cap to ground may not be needed, the jfet does it's job.
I'm not using any cap on the input, anyway.
Btw the 2Sk369, after all, is not a good idea on this circuit.
Unless you use a CCS, it has much lower gain than the 2SK170, on this circuit and with the values I'm using (which I prefer not to change).
That's a shame, because the 2SK369 costs 1/3 the price of the 2SK170...
jfet phonostage power supply
Hi Carlos,
Could you post a schematic of the power supply you used with the phono stage.
Thank you,
Ray Simmons
carlosfm said:
Hello Thalis,
You are absolutely right, it sounds fantastic.
The RIAA component values on your schematic are close, I have just made slight adjustments.
But I have used much lower value resistors on the Jfets, and I give much more gain on the first stage. Allows me to have much lower output impedance on the second stage.
The rest is layout, grounding arrangement, component choices, etc.
This thing is very, very silent.
I'm still waiting for some parts to settle on the final thing (I feel that 2SK369 may be an even better choice for the first stage, gonna try it), but this thing is already singin' like a bird.
1000 thanks to you, and also to your friend Salas for insisting.
Hi Carlos,
Could you post a schematic of the power supply you used with the phono stage.
Thank you,
Ray Simmons
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