Down here that device (Stinger brand) sells for the equivalent of 50 dolars. A bit too much for a couple of transformers.
I'll look for small audio transformers from old transistor radios on my junk drawers, I should have a few of them. Thanks for the suggestion.
I'll look for small audio transformers from old transistor radios on my junk drawers, I should have a few of them. Thanks for the suggestion.
Small audio transformers from transistor radios probably can't handle the voltage swings from a power amp. They'll likely saturate.
That sucks, I think I bought four of them for about 6USD each.
If you're not in a hurry I would be willing to send you one. Probably wouldn't get it until mid January. Not sure how strict/corrupt customs is in your country; hopefully not anything like Brazil.
It's not like Brazil, it's worse, hehe.
Thanks a lot for your offer, (really!) but right not all the customs situation is a nightmare. Goverment will change soon, so we hope the situation will improve. In the meantime I'll try to get some local solution with the valuable information on this thread.
Can't you tap the input of the amp chip? Unless this is one of those amps that adjust volume by changing gain, or the volume control is built in the chip itself.
I would just do it the way I use to measure class D amps. (A USB audio interface) Ok we can't use that, but all you need is a balanced to single ended input converter that has an attenuator at the input. A transformer solution is being discussed, but op amps work as well without breaking the bank for a good quality transformer. Then also add a 5W resistor as a dummy load for the amp's filter to work properly.
I would just do it the way I use to measure class D amps. (A USB audio interface) Ok we can't use that, but all you need is a balanced to single ended input converter that has an attenuator at the input. A transformer solution is being discussed, but op amps work as well without breaking the bank for a good quality transformer. Then also add a 5W resistor as a dummy load for the amp's filter to work properly.
This new digital world is nice but also very restrictive. In this case all the audio processing plus amplification is done inside one chip from a Korean company (NeoFidelity NTP7112). Couln't get the datasheet for that particular chip or the schematic of the tv set.
How is done? A direct digital feed at the input of the chip and 2 or 3 channels of speaker level output. That's all. In the middle (DSP processing, EQ, volume level and D/A) is done inside this chip, no place to tap anything that I'm aware off.
Well there's a Headphone/line out but not affected by the volume control or DSP processing, both needed in my case. That is something that I'll investigate by accesing the factory menu to see if I can change something in software. Some sets let you do that but the option is hidden here or do not exists. Sony tv sets lets you choose line audio out affected by Remote Control volume.
How is done? A direct digital feed at the input of the chip and 2 or 3 channels of speaker level output. That's all. In the middle (DSP processing, EQ, volume level and D/A) is done inside this chip, no place to tap anything that I'm aware off.
Well there's a Headphone/line out but not affected by the volume control or DSP processing, both needed in my case. That is something that I'll investigate by accesing the factory menu to see if I can change something in software. Some sets let you do that but the option is hidden here or do not exists. Sony tv sets lets you choose line audio out affected by Remote Control volume.
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