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[Steven 10+ year member]

I have designed a circuit board, and wrote program that automatically adjusts the GAIN on my amplifier if it detects a clippped signal.

I'd just like to know whether you guys think it is a good idea.

The board uses an L-pad design so as not to alter the impedance of your load on the amplifier. Determined by hooking up a 4-Ohm speaker and measuring the impedance at the input side of the board

The board needs 9 connections:

4 for the speaker - One (+) off amp, One (+) to speaker, one (-) off amp, and one (-) off the speaker

2 for gain control on the amplifier, you have to disable the on-board gain control and wire the board in its place - Voids the warranty but works.

1 connects to the USB port on a PC/Laptop.

2 for power/ground

The board takes the signal from the amplifier and converts it to a digital signal. This digital signal is then processed by the computer. The computer then tells the board too either increase/decrease the gain to maintain an unclipped signal.

The only problem I had while testig the board was once the volume reached a certain level (about where it normally started to clip), the volume will not increase any farther but this is due to the limitation of the amplifier itself.

Using a 'scope the board introduces a little noise (not even audible, seeing as how I had to use a scope to find it) into the system, but hey, every amplifier / HU / EQ / Signal processor introduces noise into the system

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[Alaxan 5,000+ posts]

WHy not make an attachment on this board for those amps with a remote gain control as well?? Might make it a little more efficient and save warranties. A lot of people doing a DIY install for the first time that may want something like this need as much warranty as they can get LOL. Over all tho I think it is a good idea and if it works well enough would be a nice addition to caraudio.

 

[ss3079 5,000+ posts]

Can I see your PCB layout and parts list?

- Steve

 

[Steven 10+ year member]

I'm sorry but I won't give out my board designs until I get the patent.

But I was thinking what if I designed the board to attach to the RCA inputs instead of the gain. That way you set the gain to max and the board will lower the voltage of the RCA's when it finds a clipped signal, the way I understand it lowering the input voltage would be essentially the same as lowering the gain

 

[cooldoctorb 10+ year member]

Good idea, you should sell the idea and make a percent on it. maby you'll get rich.//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

 

[chris229 10+ year member]

Originally posted by cooldoctorb Good idea, you should sell the idea and make a percent on it. maby you'll get rich.//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

guys--------clipping isn't bad and really you want a little

 

[ss3079 5,000+ posts]

Originally posted by chris229 guys--------clipping isn't bad and really you want a little

True, I never really have it loud enough to hear it clip anyways....only once in a while.

- Steve

 

[Heresy 10+ year member]

It's a great idea and even better that you can make it yourself. Just a little curious, what kind of educational background do you have?

 

[Steven 10+ year member]

Heresy

I dropped out after grade 11. I haven't set foot in a school since, that was 5 years ago. Almost everythging I know about electronics, computers, stereos, I taught myself. I write programs in C++.

I do plan to one day go to college/university and get a degree in computer programming or electronics but I can't afford it yet. Until then I'll continue to make my money building and selling computers, and putting together stereos for friends.

 

[Steven 10+ year member]

Well i'm in the process of getting the patent, cool.

I talked to a bunch of head honchoes at various car audio companies. Jensen is going to buy my designs off me. They offered $500 for my original design + 35% of all sales of the product. Sounds good, so long as they hold up their end.

 

[dopey 10+ year member]

I was wondering bout the part of measuring impedence. You said that it measures impedence to control clipping, but the problem with a woofer is that it's not a constant impedence. Depending on the enclosure, resonance and frequency the woofer is playing will change the impedence. Is this a typo, or can you clarify this.. Other than that it's a great idea.

 

[Steven 10+ year member]

It doesn't measure impedance. I used an L-Pad to ensure that the device, when installed, won't effect the load on the amplifier.

If you use 4-ohm speakers the load on the amp is normally 4-ohms. Without an L-pad my board once attached would radically change this load, thus change the performance of the stereo.

With my current set-up (4-ohm subs), I built an L-pad onto my board to maintain the 4-ohm impedance. As the subwoofers impedance changes the L-pads Impedance changes (because they are being driven evenly) so that the Amp always sees the Impedance of the Sub

 

[dopey 10+ year member]

Does this function in the same manner as the JL amps. Where as they have a constant wattage at any impedence/voltage? I understand that yours does clipping.

 

[Steven 10+ year member]

That sounds like a limitation of the amplifier. JL probably designed some limiting hardware for their amps to help prevent overheating/Overloading.