atari punk color organ

[MrDEB]

curious if this has ever been done or even possible.
Am playing around building an Atari Punk Console but thinking of adding LEDs that are controlled by 3 band pass filters (low, mid high)
this is for another project for grandson to drive his parents nut with the sound and amuse him with the LEDs.

 

[For The Popcorn]

Yes? No? Maybe? I don't know. Shrug. Huh?

Now that that's cleared up.

Any bets on upside-down mosfets?

 

[Nigel Goodwin]

It's like every other thread he's ever posted, he ignores all the answers and just makes completely random changes all the time.

 

[MrDEB]

I try and follow all the suggestions and going with post#29

 

[For The Popcorn]

I try and follow all the suggestions and going with post#29

For the record, the circuit in post #29 is not my creation. It is merely a schematic for the circuit described in post #12. And the circuit that several people have suggested you follow since then.

But none of the schematics you have posted since post #12 have correctly followed the simple suggested ADD-ON of post #12. If you had, we wouldn't be on post #44 now.

It's my morbid curiosity to wonder about what your schematic looks like currently based on the gibberish since post #29.

 

[audioguru]

I did a frequency response simulation of the "3kHz Treble Bandpass Filter" from the color organ kit in post #10.
It is not a 3kHz Treble Bandpass Filter, Instead it passes only a 4.8kHz whistle sound.
This filter should pass 3kHz to 20kHz frequencies.

The other two filters are also wrong. The mid filter should pass ALL middle frequencies and the low filter should pass ALL low frequencies, not just a couple of frequencies.

 

[MrDEB]

If I am understanding correctly
You need to use P-channel MOSFETs (or PNP transistors) driven from the collectors of the 2N3904s in the original circuit.
is this what the schematic in post@29 doing?

 

[rjenkinsgb]

You need to use P-channel MOSFETs (or PNP transistors) driven from the collectors of the 2N3904s in the original circuit.
is this what the schematic in post@29 doing?

Yes.

 

[tumbleweed]

It is not a 3kHz Treble Bandpass Filter, Instead it passes only a 4.8kHz whistle sound.

With that much gain it seems to me the "bandwidth" is sort of meaningless. The filter's probably going to rail, so if you took the bandwidth at the 20dB gain level it'd probably work ok for this simple circuit.

 

[MrDEB]

Referring to post#45, how to improve the filter etc?
here is the present schematic asked for

 

[For The Popcorn]

If I am understanding correctly
You need to use P-channel MOSFETs (or PNP transistors) driven from the collectors of the 2N3904s in the original circuit.
is this what the schematic in post@29 doing?

OMG.

 

[MrDEB]

here is same but with the mosfet marked

 

[audioguru]

Jameco and you are using slow 1N4002 Rectifier diodes that are used ONLY at 50Hz and 60Hz. I do not know if anybody tested them at audio frequencies. 1N4148 Signal diodes are usually used for audio.

Here is the schematic of 3-way filters that do the filtering you need:

 

[For The Popcorn]

Maybe it's best not to redesign the filter stage.

> MrDEB has a video (way back in post #4 I believe) showing the operation of the circuit and he's happy with it.

> Consider the difficulty that "drive the mosfets from the collectors of the pnp transistors" has caused.

 

[MrDEB]

Thanks audioguru. I looked at the schematic but I see very few component values. Assuming use same as original circuit?

 

[audioguru]

Usually, resistors and capacitors in a filter are calculated for the frequencies you want. In the 3-way filters the frequencies are 300Hz and 3kHz. Here are their components:

 

[MrDEB]

thanks

 

[MrDEB]

Think I located the p channel mosfets

https://www.panjit.com.tw/upload/datasheet/PJD16P04.pdf

 

[MrDEB]

this youtube video explains a mosfet selection pretty good

 

[audioguru]

I do not trust the specs for no-name-brand parts.
I have never used such a tiny package with your high current.
I think that Mosfet will overheat.

 

[MrDEB]

thats my concern
will look for a t220 package