Headphone Tones?

[Ham]

Has anybody ever used a small battery operated equalizer on their md in order to change the tone(s) and/or the frequency response? Is it possible to add components to a headphone to accomplish the above?

[SVEN1]

Ever hear of the VTS RATPHONES, these headphones had a frequency control to adjust the tone to your liking.
Had a pair and loved them, sold them and regretted it. Not many were made by Ratphones.
Looked for months on a way to build a pair without using any external battery source as the VTS used no batteries.
A circuit board was built in the earcup. The closest I could get to building one was getting a few pictures of what the PCB looked like.
The Ic chip ID was wiped off. Rick Viola was no longer making the standard Ratphones and would not make anymore VTS units. So I was crap out of luck.

Good news is that since Rick has not been making headphones anymore he just decided to give up the schematics to built the VTS unit. Rick is known as GOODRAT on Geotech.

I will post the schematic here as well as the pictures I have.

Yikes, after previewing noticed the pictures are pretty large, decided not to resize to give you a better look at whats inside.

You could probably make a add on PCB inside the detector your building..........

[bklein]

For some ideas I suppose you could go to one of the many guitar effects sites.
Several passive circuits for frequency cut/boost. Could also use an active approach - perhaps a gyratron type cut/boost equalizer. Radio Shack and others sell powered speakers for use with MP3 players that I think have equalization capabilities as well. I was going to try one of these with my GP Extreme but haven't gotten around to it.

[johnandles]

zsct1555 availability or substitute?

Hello I am finding hard to source Zetec zsct1555.
It appears to be a very low powered 555 timer.
would a lmc555cn be a suitable substitute?
Cheers
john

[SVEN1]

There are a number of easy to acquire substitutes that are an exact match. I beleive the one you listed is one of them. I am out of town and can't check my list for you.

[johnandles]

There are a number of easy to acquire substitutes that are an exact match. I beleive the one you listed is one of them. I am out of town and can't check my list for you.

Thanks SVEN1,I guess all I can do is build the circuit and see.
Regards
John

[nickel_n]

Hi johnandles
did you build the circuit?was the lmc555cn the exact match?
kind regards
Nikel

[johnandles]

At this stage I have got the parts but not built yet.I was hoping SVEN1 would have replied with a match.
I also find I dont have the exact resistor values .
I suppose a close value would work.
It is still on my to do list
Regards
John

[SVEN1]

Found this:
THE 7555
7555 is a CMOS version of the 555. It is exactly the same as the 555 but consumes less power. The 555 consumes 10mA, while the 7555 consumes 80uA (1/120th). The CMOS version comes with different identifications according to the manufacturer.
LMC555 or LM555CN is made by National Semiconductors, TLC555 is made by Texas Instruments, ICM7555 is supplied by Philips, ZSCT1555 comes from Zetex and ICM7555 is made by Maxim. The main feature to note is the inclusion of the number "7" or the letter "C" to identify the CMOS version.
They use less power than the older (555, NE555, LM555) versions and don't require a capacitor on the control pin. Although pin and functionally compatible, the component values differ between the low-power CMOS and older versions.
The Exar XR-L555 timer is a micro-power version of the standard 555 offering a direct, pin-for-pin substitute with the advantage of lower power operation. It is capable of operation from 2.7v to 18v. At 5v, the L555 will consume about 900 microwatts, making it ideally suitable for battery operated circuits. The internal schematic of the L555 is similar to the standard 555 but with current-spiking filtering, lower output drive capability, higher nodal impedances, and better noise reduction system.

http://www.talkingelectronics.com/pr...Page1-555.html

[johnandles]

Thanks SVEN1

[golfnut]

I think why not play music thru headphones from Ipod.

When det gets a decent bang, the ipod player chanel gets cut and the det tone plays though.

bit of SW and a couple of cmos switches...

S

[6666]

Is there an audio clip that gives an example of what this does ? thanks