Klaas Robers wrote:There is nothing wrong with a mono cartridge for your aplication. Keep that, it might even be better than a stereo one.
Testing the mono i think its bandwidth gos up to 9 khz ,the stereo one i know for sure is still going strong on 10 khz and above ...just hearing the results the stereo one does do better hearing the frequency sweep on the higher end i would say 4 khz up it beats the mono ...but for SSTV i agree the mono would be ok still...
Think the mono stylus is a bit worn which might cause problems on tracking as well as play back ..so love to use it just have to see if it still works as far as the stylus gos .
When i start doing recording again i can check the recording with the scope more accurate than my old ears !
I was mainly interested to see since i only have the ceramic type what would be the result if i used it to do the embossing ,i will be getting a magnetic type as well as i think those would be less power hungry to work .
No, the point is that you can sometimes use a stereo amplifier as a mono amplifier that gives the double output voltage. That is what I wrote about the bridge amplifier. But sometimes each channel of a stereo amplifier is already a bridge amplifier, and then the trick will not run.
OH i see ...
I know this trick as NXP has an integrated stereo amplifier chip TDA1519, which contains two amplifiers. It is designed for car-stereo. One amplifier inverts the input signal. In a carradio you want to run the output amplifier on the voltage of 13.8 volt. That limits the output voltage to 13.8 volt peak-peak, 6.9 volt peak. The designer can use the chip as a stereo amplifier, then he should connect one of the speakers in "reverse". But he can also use the chip as a single bridge amplifier by simply joining the two inputs and connect the loudspeaker in between the two outputs. That will give an output voltage of 27.6 volt peak-peak or 13.8 volt peak. And yes, then he will need a second chip for the other channel. I once used this chip as a bridge amplifier, so I know it.
70 % volume seems fine on the mono 70 to 80% on the stereo cartridge i think there will be distortion running them much higher .
I am still thinking how you could check if your amplifier can be used as a bridge amplifier, or that it will not bring you the extra output voltage.....
I could i suppose try both L R input channels and outputs left right to cartridge same result to either side of the cartridge ,you would think you would need half the amount of volume to drive it then ...but its not a problem at all for a recording as is it would work now just with that one channel .
I still have a bit of work on play back placing play back arm and for correct tracking ,bit limited to placement of it but i will have to do some play back tests to see all is fine here before moving on ...
Edit ....having played around with the 2 tone play back arms from the 50s i am not very happy with them due to their mechanical construction on the the 2 pivot points i think i can do better , i also need this to be more adjustable to the new play back area on the case ..pretty much worked out what i will use a old broken lap top HD and again here a voice coil arm from and older HD these will give me finer movements in the two axis movements the arm idea so far is a metal drinking straw need some thing hollow to carry the wires from the stylus cartridge ....so thats what i am up to .