Medium Frequency Amp

[moicez]

Hello to you all, thanks for reading, so here is my question:

What can I use to amplify frequencies from 500kHz to 3MHz?

The reason is that I am going to multiplex and then demultiplex and in between amplify the sound using AM. So after the AM signals get amplified I will filter then demodulate (probably going to use an envelope detector) and finally connected to a speaker.

[Jazz P Bass]

I cannot recommend ant one amp.
You did not specify wattage out.
Here are a couple of cool links.
http://www.qsl.net/wa1ion/amp/amptests.pdf
RF Amplifier Basics

[moicez]

Oh of course, very important wattage.
100 watts would do it.

[Enzo]

So you want a wideband RF amp that will handle at least 3MHz. Also Basic video amps have that sort of range.

Your approach as described sounds unnecessarily convoluted.

[moicez]

I have noticed that there is some sarcasm around the forums, but I dont agree with that.

Thank you all very very much, I see the flaws now. Using AM was the first idea that came to mind to achieve so many channels, besides the obvious one (a lot of amplifiers); I guess I never though of the power and amplifier needed.

Back to the drawing board...

[moicez]

I did manage to find some amps: RF Amplifiers.Com - twt amplifiers,microwave twt amplifiers,rf tube amplifiers,traveling wave tube amplifiers,for MIL-STD-461/462,high power high frequency microwave amplifiers,RTCA/DO-160, SAE Specifications, and Bellcore Testing

[Enzo]

No sarcasm intented in my post, can't speak for the others. REreading, you wanted a power amp to do this. Nah.

A video amp has to have at least 3.5MHz bandwidth, which would cover your range, but finding one that puts out 100 watts, I don;t think so.

An AM radio operates between 500KHz and 1.7MHz, so an AM radio RF amp could be had or built. But that leaves the MAJOR problem of trying to skim audio channels off it and directly into speakers.

Taking the envelope off an AM signal is called "detection."

If you really want to multiplex audio channels, my first thought would be digital, since systems that do exactly that already exits. Even inexpensive mixers these days include a USB interface. You still have to amplify the individual signal for the speakers. But if all you want is 100 watts distributed among a bunch of speakers, what is that per speaker? Plenty of small single chip amps are out there. Create or buy powered speakers. Then all you do is put the demux at teh speaker end and send line level signals to each powered speaker.

[J M Fahey]

Dear moicez.
To begin with, this board is not sarcasm-based or powered, like many others.
We all try to help our fellows, in good faith.
We have also *been helped*many times, and I'm particularly grateful for that.
That said, please understand that what you are asking *sounds*, on first impression (which of course may be absolutely wrong) like you read about AM, RF, modulation and demodulation (so far, so good) and , in a very general way, tried to apply that to guitar amplification, which is physically possible but both more complex (and expensive) and less efficient than other, more popular technologies.
Ironically, there *is* an amplification technology starting to be used by many which:
a) uses way over audio frequencies (think 40 to 300 KHz and beyond) Maybe not yet "RF" but quite in the ballpark.
And the interference it causes lies definitely in the RF band.
b) uses modulation and demodulation to achieve very high powers, in a very efficient way.
c) Unfortunately does not use AM (sorry) but pulse-width modulation, in some of its flavors , called by some "Digital" modulation.
d) it's called "Class D" in its basic form, there are some variations such as so-called "Class T" (Tripath), Delta-Sigma modulation and others.
e) so in a way, you were quite close to the jackpot.
Good luck.