Ah, I think an input buffer WOULD be a really good idea.

-Colin

I added an input buffer before splitting the signals Hold on just finishing up...

OK check it out: www.geocities.com/smoguzbenjamin/stereo.html
That should work right?

Don't forget output caps and 2.2 meg resistors to ground.

Make sure you're giving the op amps 4.5v at the + input instead of ground if you're going to use a single supply.

I'm not sure if the lowpass will work, I'll  have to spend a bit of time staring at it.

You didn't lable the +9v pin on the MN3102 (should be 1).

Same with the MN3207, should be pin 5.

The end of the pot should go to pin 7, not before the cap, I believe.

-Colin

QuotePin 7 connected to the end of a 22pf capacitor connected to pin 5
Pin 6 connected to the end of a 5k resistor connected to a 10k pot connected to pin 5

The schematic was drawn according to that

The power amp stages have 0.1uF input caps. Putting two caps in series didn't sound like a good idea so I omitted the output caps here. 2M2 resistors to ground, whoops forgot about that :lol: I'll edit the schemmo.

The active filter, I calculated the values, the lowest passing freq is 15Hz and the highest would be 10kHz with the cap being 1600 pF, but since that ain't a standard value I decided to use 3 470pF caps in series. That's a total of 1410 pF. Close enough, if the clock noise still gets through I'll have to tweak it a bit.

Quote from: smoguzbenjamin

QuotePin 7 connected to the end of a 22pf capacitor connected to pin 5
Pin 6 connected to the end of a 5k resistor connected to a 10k pot connected to pin 5

The schematic was drawn according to that

The power amp stages have 0.1uF input caps. Putting two caps in series didn't sound like a good idea so I omitted the output caps here. 2M2 resistors to ground, whoops forgot about that :lol: I'll edit the schemmo.

The active filter, I calculated the values, the lowest passing freq is 15Hz and the highest would be 10kHz with the cap being 1600 pF, but since that ain't a standard value I decided to use 3 470pF caps in series. That's a total of 1410 pF. Close enough, if the clock noise still gets through I'll have to tweak it a bit.

The caps wouldn't be in series.  The 3x470 is inside the feedback loop, a capacitor outside of the feedback loop won't effect it.

You're using a bandpass filter, then?  That's quite interesting, I would have chosen a lowpass at about 8khz.

Try this circuit:


  Active Low-Pass Filter
        +---------+--------+
        |         |        |
        R2        C2       |
        |         |   |\   |
IN--R1--+---R3----+---|-\  |
        |             |  >-+--- OUT
        |         +---|+/
        C1        |   |/
        |         |
 -------+---------+--------------


R1= 13  ohms
R2= 14  Kohms
R3= 13  ohms
C1= 2042  nF
C2=  1  nF

I got that from http://www.vwlowen.demon.co.uk/java/audio.htm

I think I described it wrong.  It should be "A 22pf capacitor connected to pin 5 and pin 7.  A 5k resistor and a 10k in series connected from pin 6 to pin 7".  Look at the datasheet on my site, that should clear things up.

-Colin

P.S.-thanks for the credit!  [/code]

Thanks for the help! Credit where credit is due in my opinion I edited the pin numbers for the MN3201, they're correct now I hope Now to de-lazyfy myself and re-draw that low pass filter :lol:

I was referring to the output caps of this circuit interacting with the input caps of the power amp stage, since each power amp has got a 0.1uF cap at its input before anything else, I decided to leave output caps out here.

Quote from: smoguzbenjaminThanks for the help! Credit where credit is due in my opinion I edited the pin numbers for the MN3201, they're correct now I hope Now to de-lazyfy myself and re-draw that low pass filter :lol:

I was referring to the output caps of this circuit interacting with the input caps of the power amp stage, since each power amp has got a 0.1uF cap at its input before anything else, I decided to leave output caps out here.

Ah, I've never heard of that.  You learn something new every day!

Let me know how it turns out. The schem is a nice building block for a chorus/flanger with the addition of an LFO to modulate that pot.

-Colin

Right! Now to absolutely finalize the plans for the preamp, get the parts I need and build. Thing is I have an important school week from the 8th till the 12th march and after that I'm in London for a week. Damn.

Oh well. I'll amuse meself in the meantime :mrgreen: lol

Quote from: smoguzbenjamin Right! Now to absolutely finalize the plans for the preamp, get the parts I need and build. Thing is I have an important school week from the 8th till the 12th march and after that I'm in London for a week. Damn.

Oh well. I'll amuse meself in the meantime :mrgreen: lol

Waiting for parts sucks so much.  I've been waiting for 2 weeks for this big order from futurlec, a few days for some sample orders (3 or so) and a while for an order from Smallbear.

-Colin

My TI samples shipped pretty fast 3 days or so to Holland. I'm not gonna start this next week though since I'll be occupied for the coming 2 weeks. Dang life has a way of kicking you in the ass and occupying you when you just get ready to start something relatively big! :x Drat.

Oh well I'll just hang out here and survive for a week or two