Electret pre-amp / mixer for an accordeon mic system - Page 2 - Electronic Circuits Projects Diagrams Free

Wilf · 1st February 2009, 07:09 PM

Oooops...
i think I was a bit tired when I drew that...
That was meant to be a 5534 op-amp. I just got the number mixed up with a different power amp circuit.
Mixing resistors, yep, need them...
Oh dear, sorry, it´s been a few years...
The resistors below the trims are so that the trims adjust between 66% and 100% of the output voltage... I thought that bit at least made sense when i drew it. I guess the capacitors at the bottom are totally wrong though.
ah well

**Nigel Goodwin** · 1st February 2009, 07:12 PM

Quote:

Originally Posted by Wilf

Oooops...
i think I was a bit tired when I drew that...
That was meant to be a 5534 op-amp. I just got the number mixed up with a different power amp circuit.
Mixing resistors, yep, need them...
Oh dear, sorry, it´s been a few years...
The resistors below the trims are so that the trims adjust between 66% and 100% of the output voltage... I thought that bit at least made sense when i drew it. I guess the capacitors at the bottom are totally wrong though.

The resistors are as well, sound is logarithmic so the pots will do nothing.

flat5 · 1st February 2009, 09:19 PM

I would try my circuit with another 50k pot facing the other way to the mixer to adjust the overall level. If it does not work well enough then add a dual low current/low noise op-amp.
Maybe the TL072CP is a good choice.

rotava · 12th June 2009, 04:37 PM

Hello,

did anyone had results with this attempt?

I want to make something like this in my accordion and i want to know if this is a good circuit.

thank you

Wilf · 12th June 2009, 05:03 PM

Hm, sorry, I've put this project on the back burner for a while, so I haven't tested any of these circuits yet. I'll try and remember to post something up here again when I get going with it...

flat5 · 12th June 2009, 07:07 PM

If you mail order to get the trimmers and caps and 10k resistors it will be cheap to try. See post #5.
The resistive value of the 50k log trimmers (upside down and backwards) are a guess (there will be three, not two).
I think from Futurlec the parts may cost about $10. Their shipping cost is very little and no min. order.
If you are really interested I could put together a Futurlec parts list for you.
Futurlec, The Electronic Components and Semiconductor Superstore

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1st February 2009, 07:09 PM	#16
Wilf	Oooops... i think I was a bit tired when I drew that... That was meant to be a 5534 op-amp. I just got the number mixed up with a different power amp circuit. Mixing resistors, yep, need them... Oh dear, sorry, it´s been a few years... The resistors below the trims are so that the trims adjust between 66% and 100% of the output voltage... I thought that bit at least made sense when i drew it. I guess the capacitors at the bottom are totally wrong though. ah well

1st February 2009, 09:19 PM	#18
flat5	I would try my circuit with another 50k pot facing the other way to the mixer to adjust the overall level. If it does not work well enough then add a dual low current/low noise op-amp. Maybe the TL072CP is a good choice.

12th June 2009, 04:37 PM	#19
rotava	Hello, did anyone had results with this attempt? I want to make something like this in my accordion and i want to know if this is a good circuit. thank you

12th June 2009, 05:03 PM	#20
Wilf	on hold Hm, sorry, I've put this project on the back burner for a while, so I haven't tested any of these circuits yet. I'll try and remember to post something up here again when I get going with it...

12th June 2009, 07:07 PM	#21
flat5	If you mail order to get the trimmers and caps and 10k resistors it will be cheap to try. See post #5. The resistive value of the 50k log trimmers (upside down and backwards) are a guess (there will be three, not two). I think from Futurlec the parts may cost about $10. Their shipping cost is very little and no min. order. If you are really interested I could put together a Futurlec parts list for you. Futurlec, The Electronic Components and Semiconductor Superstore Last edited by flat5; 12th June 2009 at 07:22 PM.