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SP-1a Speech Processor

No, I never have. I've always been a big fan of simpler is better. if the radio has a viable AMC circuit, work with it. You can almost always modify the AMC (timing) and mic preamp circuit to achieve the sound you want. However, The SP-1A would probably work superbly in any radio.

A thought strikes me - if anyone has one of the DSP's from CB City, stick it in a box with a 9-v battery, a couple 1/4 inch jacks, and make yourself a home-made fuzz box for your guitar.
 
Well if you really want to roll your own, you might try the SSM2166 which contains all of the goodies you would want (and some you don't want, noise gates NEVER sound good) in one package. Here is a link to the data sheet, complete with artwork to for the evaluation board:

http://www.analog.com/UploadedFiles/Data_Sheets/83095497SSM2166_b_.pdf

I seem to recall a few years back some HAMs using this chip built into their Yaesu mic's on the FT 817's. Google is your friend. :)

73

riq165
 
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A thought strikes me - if anyone has one of the DSP's from CB City, stick it in a box with a 9-v battery, a couple 1/4 inch jacks, and make yourself a home-made fuzz box for your guitar.[/quote]

LOL-- its very close to a distortion pedal-- back to back diodes with a op amp same as a simple distortion pedal
 
The SP1-A can be made to work fantastically well. I have used them off and on since 1991 when I first got to play around with an AR3500. My mentor owned a few of them and that is the radio that made it possible for the RCI2950 to come to market years latter. The problem I think with a lot of users today is that they are into HIFI and eSSB and for the most part 99% of compression devices kill the hi fidelity and audio bandwidth. You could make a hi fidelity compression device but you have to add a lot more complexity to it. So they are just not that popular today. If you can ignore that though it is a really good way to increase average talk power to the point that your approaching the same amount of improvement you would get with a 100w external amplifier. Combine the two (100-200W amp) and compression or band pass rf clipping and some compression it is in practical terms a lot like having 500-600 watts.

I have some devices that do audio compression alone some that use all pass network and they convert the audio to rf before filtering, clipping, compression and converting it back to audio. and some that have 8 band eq+compression. All of them can sound decent to fantastic on AM and kick butt on SSB. On AM often less is more!

A Ten-Tec 715 can sound really good better than a lot of radio's built in processing.

None of this stuff is idiot approved you can mess anything up if you do not know what your doing.

You can still buy circuits based on the early industry Symetra System from early broadcast days. If you feed your audio through that alone you can improve effective talk power. Feeding it through that before feeding into a compressor also works great. AKA Phase Rotating Asymmetry Eliminator! http://www.w3am.com/8poleapf.html
 
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Agreed. The SP1-A can indeed sound really good if you set it up properly and not overdrive the radio. I had one on a 2950DX and it sounded awesome. I also had another wired into a small project box and used in conjunction with a Urie EQ and fed with a Seinheisser MD-421 microphone through an RDL stick-on preamp to run my old Heath AM station. It sounded awesome as well and had just the right amount of punch.
 
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i have one nib never used it.
never needed it so it sits in the box. bought it from bobs years ago
 
I like a properly working mod limiter. Most factory mod limiters really suck at doing their job.
 
Captain Kilowatt said:
Agreed. The SP1-A can indeed sound really good if you set it up properly and not overdrive the radio. I had one on a 2950DX and it sounded awesome. I also had another wired into a small project box and used in conjunction with a Urie EQ and fed with a Seinheisser MD-421 microphone through an RDL stick-on preamp to run my old Heath AM station. It sounded awesome as well and had just the right amount of punch.
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All 100% on the money. I also think this hobby attracts people that are a little bit OCD or Extreme to the point where "If a little bit is good a lot must be even better!" and usually that is not a true statement. It does not matter if we are talking about machines, people, religion, medicine, politics often when you swing to far to any extreme you end up getting less results not better results. I think it has always been hard to know when to stop for some people. This is even true of cooking too little spice the food is bland! Too much spice and hardly anyone can eat it! Just the right amount of spices, sweetness, sour, tangy etc...and it is incredible!

I use my Ten-Tec715 on my base gear that does not have any form of processing at all and it is fantastic especially on SSB. Since the SP1-a can easily be mounted inside a radio I use that for mobile applications. Since I am on SSB more than AM I really appreciate having some processing on hand.
 
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I talked to a guy a week ago that was a pretty far distance from me. He had a SP-1 I could not really hear any difference with it off or on. The guy does have a very clean and well tuned radio.
 
Low_Boy said:
I talked to a guy a week ago that was a pretty far distance from me. He had a SP-1 I could not really hear any difference with it off or on. The guy does have a very clean and well tuned radio.
Click to expand...

He may not have it set up properly. There are two adjustments on the SP1-A and you need to set each one for best results. VR-1 adjusts the compression level while VR-2 adjusts the input sensitivity. Mine has a very noticeable punch to it yet it does not sound distorted or cause splatter but then again I set mine up watching an oscilloscope as well as listening to it off-air.
 
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