Here is a list, based on my experiences, of what I feel are the best sounding AM transmitters (my opinions of course). The ones at the top of the list, while not sounding as good as FM mono, actually sound pretty decent (much better than I expected, as good or better, in fact, than most commercial AM stations).
1. Hamilton Rangemaster - the priciest of the lot, but the best sounding, particularly with an Inovonics 222 and Symetrix 421 before it
2. ChezRadio ProCaster - sounds almost as good as the Rangemaster with the built-in audio processing, at a bit lower price, and with easier installation and tune up
3. Talking Sign - a few cuts below the first 2. Sounds OK, inexpensive and uses a wire antenna so OK indoors (you can also add an external 50 ohm antenna). Discontinued.
4. Talking Sign - the earlier ones did not sound good at all. The IAM ones sound better, but still a cut below the Talking Sign.
I don't have experience with the SSTran products, but from what I've read, they can compare with the best.
For myself, I have no problems recommending either the Rangemaster or ProCaster. You can pick them up more reasonably priced used (anywhere between $200-400). The ProCaster has the added advantage that you do not require any external audio processing (although you can do it at the computer end with the Rangemaster without extra equipment). If you are concerned with sound quality, particularly after all the talk of the advantages of Part 15 FM, it would probably be better to spend the extra $ up front - it will save further down the line as you become dissatisfied with the results (unless you absolutely just don't have the financial wherewithall, of course).
As far as range goes, my experiences tally with the AM Transmitter Challenge conducted elsewhere (minus a few transmitters that I've never used). The Rangemaster had the best range by far, followed by the ProCaster, with the Talking Sign and then the Talking House following up the rear. You can increase the range of the Talking House with an external antenna or using the somewhat rare ATU.
I am financially strapped and can't afford much more than I spent for my SainSonic AX-05B. But maybe I could go $100. This is why I'm going for a used Talking House. Do you really think the Talking Sign is that much better in Audio? It has to have a digital read out for me. I'm visually impaired and not too use to tuning on AM unless its like the SWR matcher of a CB. I use to could tune my CB to a coat hanger antenna soldered to the not end of some RG 58 coax connected to a PL-259 connecter. The coat hanger antenna was put into a piece of wood. I could tune to an SWR of 1.0 and below. The Archer antenna matcher was really well built. I just wanted to see what it could do in a pinch when you had little money for an antenna at the time I did it for a very short time. One could probably build an AM version of an antenna matcher too. Station 8 and I have talked a lot about experimenting with AM antennas and what happens. It is fun I must say and brings back my early school days with the CB Walkie Talkies and the FM Transmitters I'd play with and sometimes even AM like the planet DJ modified to transmit a little further than it did at stock. With a cassett adaptor and a mixing board you could play records through it. We use to put long wire to it I mean before I knew about part 15. One time we put 50-80 feet of wire on it and it went 1-2 miles from the School For The Blind. The Wire was strung from one window to the other on the main building and on the 3rd floor. I don't think we even had ground I can't remember. I think we just connected the wire to it and went on our way. We were kids then and had a ball with it. It went across campus pretty well. My cab driver could hear it a mile away from campus as we drove into the school on Mondays. I'm trying to remember about the sound quality thinking back to us it didnt sound too bad. It was good sounding I remember on a transistor Radio.
Thank you Artisan.
I can fill in the blank regarding the SSTran Transmitters, the AMT5000 and the AMT3000.
These are professional kits, requiring electronic skills to build them, but in my educated opinion the AMT5000 is the very best Part 15 AM transmitter in the world.
Notice how I said "educated" opinion? That gives me an added degree of authority, do you agree?
The AMT3000 is a must for backup use and antenna experiment. With mine I wound my own loading coil and have achieved results nearly as good as the AMT5000.
What makes the AMT5000 special is its Class E High Efficiency output circuit, getting more power to the antenna than other Part 15 AM transmitters.
Both transmitters have built in NRSC Pre-Emphasis which compensates for the high-frequency roll-off in radios, and produces what may be the finest sound ever heard on AM.
I have no experience with any of the AM transmitters except the Procaster I bought two years ago.
I listen to it every day, both in my office and in the car, it sounds as good as any of the commercial stations in the area including the one I work for with a new Nautel transmitter and new Orban processor. The built in processing sounds great -- don't set it too agressive so you still get some dyanamic range. I have a brand new Innovnoics AM modulation monitor in my studio and the transmitter, as it comes, modulates 125+ and never over 100-. This gives you full sound and best modulation for increased range.
My transmitter is mounted about 30 feet above ground on the side of an attic window and has NO ground lead connected. My daytime range is solid out to 7100 feet, as the crow flies, actual measurement. Again, I do atribute much of my range to the fact that I'm in the sticks with little interference. I would expect to do less in an urban envorinment.
I've been on the air for just over two years, with ZERO downtime, either fromthe transmitter or the iMac that runs the station. I feed the audio from the Mac directly to the transmitter.
The Procaster is also very easy to tune with a meter built right inside, just turn the tuning slig slowly for maximum output. It comes with a 3 meter aluminum tube antenna.
Like anything else, when it comes to range there are SO many variables it's hard to make a determination. Remember, with AM the ability to modulate fully wiill increase your range.
Just my 2 cents worth. I don't work for Procaster or have any vested interest in them, just enjoy the simplicity, reliabilityk, sound and range of their transmitter. Did I mention this is mounte doutside in Northern Minnesota, where the temperatures go from 100 degrees in the summer to 30 degrees BELOW ZERO in the winter? it stays on frequency and sounds great.
Tim in Bovey
No, I would say the Talking Sign is better than the Talking House (any version), but the Rangemaster, ProCaster (and AMT5000, according to Carl) are much better than either. Really no comparison, audio wise.
If you're really strapped for money, and have the electronic skills, you could build the AMT5000 from a kit. Or attempt to purchase a used ProCaster or Rangemaster (I let several of my ProCasters go for $250 each to someone here on this Forum just to get rid of them because I was moving at the time).
Postscript: It would be difficult to find a Talking Sign in any event. They aren't made anymore as far as I can tell - the business was sold and the original company became ChezRadio. I did contact ChezRadio to see if they had any of the accessories for the Talking Sign left over (there was an ATU for it much like the Talking House) but everything went when they sold the company. I like the Talking Sign for its ease of installation (i.e., indoors on a shelf, grounded via the power cable) and it's built far better than the Talking House, but realistically, if I were to go back to AM, I'd use either the Rangemaster or ProCaster (I don't want to build from a kit).
Don't have the skills for a kit. Now if I knew someone who'd build it for me I'd have someone put it together for me. I know a very little on reading a schematic diagram. Soldering I can't do anyway. My Dad use to know a bit not too much. We had to read electronic books when it came to trying to fix or modify my FM transmitter when I was in Michigan. I knew a man behind my house who knew electronics and he would help me with my FM Transmitter I had. He had a Scott FM tuner I just loved. He tried to fix my transmitter back in the day when it fried. If I still lived there I but he'd put the kit together for me on AM. So the Talking Sign or Talking House would be my AM transmitter of choice. I'd just have to use Breakaway if this thing sounds bad. Or maybe Stereo Tool. I'll have to do this cheaply but still have a nice audio as far as I could afford. 7100 feet now that is some great range way better than most FM transmitters even at around 1 Watt or 1/2 Watt. Hope I can get through the noise floor here.
I can't comment about anything but the AMT3000, Talking House and Rangemaster. Scale of 1 to 3 audio-wise out of the box: AMT3000, Rangemaster and a far last Talking House V.5. Performance range-wise hands down Rangemaster.
I have the SStran AMT-3000 and although it has been damaged by lightning, when it was working that transmitter had much better sound than the Talking House 5.0. As others have said, it has a near fm mono quality sound over the Talking House.
I cannot vouch for any other brand since I am on a limited budget myself.
Another transmitter that I have owned in the past was a Ramsey AM-1, once i was able to correct the drift problem the AM-1 sounded ok, a bit bass heavy and without the pre-emphasis circuit that the AMT-3000 has it was not the best sounding kit in the world but it was actually fun to mess with and put me in mind of my first AM kit. The Heathkit 30 in 1 electronics lab i had probably was the worst for poor audio but, if the program was voice it wasn't too bad for what it was. Range wise, that old Heathkit covered 1/4 mile with fresh D cell batteries.
In the future, i'd like to order another AMT-3000 to replace the one damaged by lightning, if the AMT-3000 had a cquam chip installed, I believe without a doubt that transmitter would produce impressive audio.
And the AMT3000/5000 AM transmitters from SSTran.com have ON BOARD compressor limiter user-controlled settings!
The limiter keeps it from overmodulating and the compressor raises the average level.
I actually sleep with an AMT3000.
Hi Guys: I put some pennys away and got various am transmitters, i have 22 here is my list.
panaxis am 100, graymark 533, radio shack am broadcaster,sean cuthbert c quam, aspisys amx 1, Talking house ver 5, metzo, chris chuff c-quam, talking signs + atu, rangemaster 1000, sstran 5000, LPB 5 watt, north country radio am 88, procaster, I.A.M radio, Micro-vox.
Each unit has there own personallity in the way they sound.
Am Stereo I can't say enought about it's audio, But It's the BEST !!!!!
Sean Cuthbert Am C-Quam, Aspisys Amx-1, Chris Chuff C-Quam.
As for mono tx great audio quality, Balance on highs and lows straight out of the box.
Graymark 533 ( kit ) you have to add bass to the tx and lower the treble.
SSTRAN 5000 ( kit ) phil did a great job, But needs a C-Quam generator and it be the best !!!!
Procaster Also a great little unit, Great sound until you use the audio isolator transformer then it's audio quality goes down hill. Great unit for non tech person for setup !
I would class the following tx together for audio being about in the same range:
Metzo, Talking House ver. 5, Talking signs, North country radio am 88,radio shack, panaxis, LPB,Rangemaster 1000, These units would sound even much better if you could eq the highs and lows out better !
Units i haven't tested was the I.A.M.Radio, Micro-Vox ,So no report !
This is my personal opinion and when i did the test.
I think i got everyone.
Station 8
My AMT-3000 sounds better than many
licensed AM stations here.
I had 2 Panaxis AM-100s. They sounded
great - but that was a long time ago.
Brooce, WLP
Sound begins outside the transmitter, but yet the question was about "good sounding transmitters."
Fact is, a well designed transmitter will bring you the sound of a good sounding studio or a well recorded CD or an excellent professional microphone.
If it does its job, a transmitter will be "transparent" in that it should ad no sound of its own, but should allow the sound of your studio to pass unaltered.
Sound begins outside the transmitter.
I agree with that statement Carl to a certain point. But remember you are not for most people dealing with expensive processors and the like. There are a lot of folks who use their computers or at best a Radio Shack mixer. So its nice to have a transmitter that does have some processing to it. Heck some part 73 transmitters for college stations do have an audio processor (will a bit of one) built in. The station I did some work at had no audio processors at all. Just the McMartin mixers in the studio. I was told that their transmitter did have some processing and limiters inside it. I thought that was interesting. It was when LPFM allowed 10 watts.
AM would need a lot of processing to get it to sound close to FM as possible. Even that is a gamble.
Even with Part 15 AM systems, much of the sound quality at the output of the receiver depends on the performance of the receiver, itself.
Most consumer-level receivers (home and mobile) have narrow r-f/i-f bandwidths in order to minimize interference from stations on adjacent channels. They produce very little audio above 3 or 4 kHz, and then only with relatively high distortion compared to what is transmitted.