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Speech Processor??? Anyone Have Info
- Thread starter Mudfoot
- Start date
The same guy I bought the CP Antenna plans from sells an component assembled DSP board and an unassembled board that comes with instructions.
www.cbcintl.com
http://www.cbcintl.com/DSP.htm
I purchased the DSP board along with the instructions.
I also have the circuit schematic for it. In order to set it up right you need an O-Scope but a modulation meter can be used in a pinch.
http://www.worldwidedx.com/tuners-m...ies/35198-cbc-dynamic-speech-processor-3.html
I'm thinking that the Telstar voice max is the one I would want
http://www.telstar-electronics.com/VoiceMax B.pdf
http://youtu.be/-3DKpCEhW6g
www.cbcintl.com
http://www.cbcintl.com/DSP.htm
I purchased the DSP board along with the instructions.
I also have the circuit schematic for it. In order to set it up right you need an O-Scope but a modulation meter can be used in a pinch.
http://www.worldwidedx.com/tuners-m...ies/35198-cbc-dynamic-speech-processor-3.html
I'm thinking that the Telstar voice max is the one I would want
http://www.telstar-electronics.com/VoiceMax B.pdf
http://youtu.be/-3DKpCEhW6g
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DSP
Hey, Duster, I have one already built w/all original paperwork I would sell for $20.00 + ship if you're interested.
Geoff S. KB9KQU
Hey, Duster, I have one already built w/all original paperwork I would sell for $20.00 + ship if you're interested.
Geoff S. KB9KQU
I was only curious about it. I overhead a local saying he ordered one. I don't have a need for one, just educating myself.
It's been my experience that most communications grade speech processors leave noticeable artifacts behind in the audio. They usually have limited bandwidth that ruins any Hi-Fi attempts. Often having the unnatural sound heard in many TV commercials although, not as loud as them.
The type of filtering used after the clipping makes a big difference here. Some appear to have no filtering. Better sounding boards use active low pass filters to provide a wider bandwidth while still having a sharp cutoff frequency to remove harmonics from the clipped waveform.
If you want to bring the majority of your audio content towards 100% modulation and still sound clean, this link will get you on track: COMPRESSOR LIMITER FOR AM TRANSMITTER BROADCAST - jpl995
The board shown here is assembled and relatively inexpensive at around $40 shipped. It's designed to pass broadcast fidelity and can be set to give more compression and clipping than you'll ever need. Set conservatively, it's not even detectable to the ear until you bypass it and the average modulation level drops below 70% as the peaks hit 100%.
One last thing to consider is this type of board works with line level audio. That means you'll either have to use a mic with a strong pre-amp or insert the board in the existing audio chain after the internal pre-amp stages. If you don't have enough drive to the board, it's useless because it won't go into clipping.
The type of filtering used after the clipping makes a big difference here. Some appear to have no filtering. Better sounding boards use active low pass filters to provide a wider bandwidth while still having a sharp cutoff frequency to remove harmonics from the clipped waveform.
If you want to bring the majority of your audio content towards 100% modulation and still sound clean, this link will get you on track: COMPRESSOR LIMITER FOR AM TRANSMITTER BROADCAST - jpl995
The board shown here is assembled and relatively inexpensive at around $40 shipped. It's designed to pass broadcast fidelity and can be set to give more compression and clipping than you'll ever need. Set conservatively, it's not even detectable to the ear until you bypass it and the average modulation level drops below 70% as the peaks hit 100%.
One last thing to consider is this type of board works with line level audio. That means you'll either have to use a mic with a strong pre-amp or insert the board in the existing audio chain after the internal pre-amp stages. If you don't have enough drive to the board, it's useless because it won't go into clipping.
I use the W2IHY EQplus.
Buildt in compressor and limitter do quite nice as well low and high tone equaliser, don't need more as the FT 2000 - D has enough internal settings to get good audio.
Always get excellent audio reports, being very loud but no distortion and cutting through the noise or other stations.
Worked C37UN this week on 18 with 200 watts on the inverted L for 160 ( tuned by the MFJ 998 autotuner) and had no problems getting through the gaggle of kilowatt+ beams using callers.
Didn't need the Heathkit SB-1000 to make more power as well.
In the last 37 years made lots of own build compressors/limiters, Julius his EQplus does very fine, no R.F. to be detected in the audio and excellent service.
Just put in my callsign generator and added the on/off switch and LED to the front of the EQplus, mirroring the on/off switch and LED on the bottom of the EQplus, but then to the left hand top.
Just looks natural, same switch same LED just flashes every 3 minutes in my callsign.
The switch enables me to switch it on/off and an extra potentiometer on the back regulates the level of the callsign generator to the output of the EQplus.
That way the generator's output is outside the compressor and other stuff.
Buildt in compressor and limitter do quite nice as well low and high tone equaliser, don't need more as the FT 2000 - D has enough internal settings to get good audio.
Always get excellent audio reports, being very loud but no distortion and cutting through the noise or other stations.
Worked C37UN this week on 18 with 200 watts on the inverted L for 160 ( tuned by the MFJ 998 autotuner) and had no problems getting through the gaggle of kilowatt+ beams using callers.
Didn't need the Heathkit SB-1000 to make more power as well.
In the last 37 years made lots of own build compressors/limiters, Julius his EQplus does very fine, no R.F. to be detected in the audio and excellent service.
Just put in my callsign generator and added the on/off switch and LED to the front of the EQplus, mirroring the on/off switch and LED on the bottom of the EQplus, but then to the left hand top.
Just looks natural, same switch same LED just flashes every 3 minutes in my callsign.
The switch enables me to switch it on/off and an extra potentiometer on the back regulates the level of the callsign generator to the output of the EQplus.
That way the generator's output is outside the compressor and other stuff.
K40 Speech Processor mic circuit reuse
I'm thinking about I still have my K40 Speech Processor mic. Even thought the mic element is shot,I think that I can remove the circuit board and install it in one if my radios. If I can figure out how to impedance match it for the new mic.
I have four candidates;
1. TRC-428 Nine Scan
2. Uniden PRO-505XL
3. Galaxy DX-959
4. CRE-8900
The TRC-428 needs to be sent to DTB to get a diagnosis of it's condition plus some old pots need replaced as well as R90 needs cut out or replaced with a different value resistor. It's stock except for a friend of mine tuned it 25 years ago. Stock modulation is 70 percent and that's whistling into it.
op:
I'm thinking about I still have my K40 Speech Processor mic. Even thought the mic element is shot,I think that I can remove the circuit board and install it in one if my radios. If I can figure out how to impedance match it for the new mic.
I have four candidates;
1. TRC-428 Nine Scan
2. Uniden PRO-505XL
3. Galaxy DX-959
4. CRE-8900
The TRC-428 needs to be sent to DTB to get a diagnosis of it's condition plus some old pots need replaced as well as R90 needs cut out or replaced with a different value resistor. It's stock except for a friend of mine tuned it 25 years ago. Stock modulation is 70 percent and that's whistling into it.
op:
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