UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Multi-Channel VHF Modulator Design

oldeurope · 24th Feb 2005, 6:04 pm

Good evening David,

"The problem with your circuit with the stereo mix to mono directly on the input, is if the source device (in my case a set top box) also feeds other places (my stereo amp). The mixer may reduce stereo separation on all destinations due to the output impedance of the source. I put the pot right on the input so that the system can't be overloaded."

I don't hope you use this boxes with 5 scart sockets or more to split the
signal...
Normally in the set top box and DVD's it is made in the way I showed
it in the picture.
Do you loose signal at scart when you make a short a RCA?
Don't think so.

I ever try to use less components as possible in the sound stage.
Every bit damages the signal.

"True, but think about what the diode detector in the average vintage TV will do to the signal if it reaches 100% mod!"

100% is standard at 405. Michael toled me he had problems with a set
when he made less than 100%.
Maybe?!?
I tried less than 100% and I had no trouble.
I think the IC makes this to make intercarrier FM sound possible.

What kind of converter do you use?

Kind regards
Darius

24th Feb 2005, 6:04 pm	#11
oldeurope Retired Dormant Member Join Date: Dec 2003 Location: Solingen, Germany Posts: 727	Re: VHF Modulator wanted Good evening David, "The problem with your circuit with the stereo mix to mono directly on the input, is if the source device (in my case a set top box) also feeds other places (my stereo amp). The mixer may reduce stereo separation on all destinations due to the output impedance of the source. I put the pot right on the input so that the system can't be overloaded." I don't hope you use this boxes with 5 scart sockets or more to split the signal... Normally in the set top box and DVD's it is made in the way I showed it in the picture. Do you loose signal at scart when you make a short a RCA? Don't think so. I ever try to use less components as possible in the sound stage. Every bit damages the signal. "True, but think about what the diode detector in the average vintage TV will do to the signal if it reaches 100% mod!" 100% is standard at 405. Michael toled me he had problems with a set when he made less than 100%. Maybe?!? I tried less than 100% and I had no trouble. I think the IC makes this to make intercarrier FM sound possible. What kind of converter do you use? Kind regards Darius Attached Thumbnails