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Klaas Robers wrote:And, what is more, it is a stereo amplifier. If you feed-in the input signal in normal polarity for left and upside down polarity for right, you can connect the cartridge between the left and the right outputs. That is called a "bridge" amplifier.
But first measure if the black sockets of the outputs are interconnected to the internal "ground". It is not impossible that the amplifier internaly is already a bridge amplifier, and then this trick does not work. The internal ground can be found on the input sockets.
Good luck.
I see four outputs for speakers. And then I know:
- a 100 watts stereo amplifier, that is 50 watts per channel.
- if you have 4 loudspeaker outputs, that may be 25 watts per output,
- and thus 12.5 watts per channel.
I don't thrust that 4 loudspeaker outputs.....
And who told you that the amplifier was 100 watts?
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.
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.
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.
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.....
Klaas Robers wrote:I think that for cutting, the monocartridge is better than the stereo cartridge.
In a stereo cartridge the "needle" should have vertical movement too, and for cutting you need a much larger needle pressure. A mono cartridge can bear that much better than a stereo cartridge.
Then I observed that playing back the 78 rpm record, there was a lack of low tones. I experienced that when I played back a 78 rpm record with the proper low up and high down characteristic that the sound reproduction is quite good. But if you played back using a small loudspeaker, then this could also be the manco.
The SSTV-play back was sounding quit well..... However I did not try to feed it into my SSTV monitor.
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