audioguru

Ceramic capacitors might have a tolerance of +80%, -50%. You need 5% poly ones.

What is a TILT unit?

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Uncle $crooge

Ubergeek63

I think Y5Us are generally 10% but vary that much over temperature and again over voltage.

Anything starting with an X in the material designation is much better, usually only 10%. COGs or NPOs, on the other hand, are very stable.

MrDEB

instead of cutting it into sections
http://headwize.com/projects/showfil...=equal_prj.htm
a different more modern approach than different frequency bands, as I understand it.

audioguru

I don't like "TILT".
I think you should not try to fix how you hear.
If my ear canal resonates then leave it like that because it is normal.
If the bass is not strong when the level is low then that is how things sound so don't "fix" it.

TILT is not modern, it was used in the 70's. May it rest in pieces.

I worked for a Pro Sound manufacturer. They devepoped a speaker with a diffuser for high frequencies but the diffuser messed up its frequency response. I made an equalizer for it that made it sound fantastic. Only 4 frequencies needed cuts and boosts.

My home stereo doesn't have equalization except for a +10dB boost at 35Hz so my little 8" woofers sound and feel like huge sub-woofers.

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Uncle $crooge

MrDEB

just go with the 10 band equalizer?
any thoughts on running the audio as well as the display through same circuit ?
I even contemplated using 20 lm3916 or 3914's?
but then one must still add filters to each 39xx
I found where I can procure 3914's for $1.25 each

MrDEB

I might have done this route before??
hopefully able to input audio into 10 filters (20 = stereo), do the matrix displays AND use the same filters for audio out to a 25w amp.
Adding diodes might do it?
I changed the circuit flow for left to right and peak detector cap.

Attached Images

audio out redo.GIF (56.6 KB, 4 views)

audioguru

Audio does not pass through a diode.
The peak detector does not work when it is fed from the volume control. The detector's capacitor must charge quickly from the high output current of a new opamp that must be added to each filter.

The peak detector's capacitor must have a resistor across it to discharge it. 100k?

Attached Images

MrDEB's circuit.PNG (14.0 KB, 4 views)

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Uncle $crooge

MrDEB

refering back to the oriential circuit, It has the cap going to ground and the diode feeds it.
I can maybe see why the second op amp but the resistor??
As I am not to proficent in this audio stuff I have to take your knowledable input.
What should I look for in a TINA simulation?

MrDEB

I put the circuit into TINA and not knowing what I am really looking at??

Attached Images

peak detector1.GIF (62.9 KB, 3 views)

audioguru

A resistor is needed to discharge each peak detector capacitor.

The switching transistor discharges the capacitor into the 10k volume control at the input to the LM3914 in the Oriental circuit. The time constant is 10ms but the multiplexing does not allow the capacitor to discharge much so it remains charged and the displayed level of its frequency is wrong.

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Uncle $crooge

audioguru

Your first opamp reduces the level of the input signal instead of amplifying it.
Your 1m resistor has a value of only 0.001 ohms. It is supposed to be 1M which is 1 million ohms.
I don't think Tina was told what the circuit is supposed to do.

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Uncle $crooge

MrDEB

being a women she wouldn't listen anyways--lol
I never realized I needed a capital M. Was going by what happens when I use a capital K - error message.
On the first op amp?? I think I go it wired right??
will insert a resistor across the cap.
what woulds happen If I inserted the resistor across the transistor in such a way that the transistor drains the cap through a resistor??

MrDEB

?? see no difference? must be doing something wrong.
I now have the resistor going across the cap when transistor is on???
weather this is kosher??

Attached Images

peak1.GIF (62.5 KB, 4 views)

audioguru

The voltage loss of your first opamp is 0.2 times. If the resistors are swapped then the gain is 5 times.

The transistor following the peak detector capacitor is a switch and 10 transistors will be connected together. So the 100k resistor must be across the capacitor before the transistor.

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Uncle $crooge

MrDEB

changed the resistors on input. swaped the op amp inputs back (+ to ground)
moved resistor across the cap
wave forms look different but really don't know what I am looking for.
why does the gain on the input op amp (vf3) go from just below 0 gain before switching resistors to -200 and proceeding towards -100 after switching the resistoprs around. Isn't this going backwards?

Attached Images

peak2.GIF (99.5 KB, 5 views)