RF Modulators and Bad Audio

[Penthode]

I have noticed a number of TV Channel 3/ Channel 4 modulators (particularly the ones built into the recent coupon DTV set top boxes) produce moderate to poor sound quality FM sound. The modulation level is low and the aural RF I have measured low on a spectrum analyser on some boxes.

To overcome the problem, I have resorted to putting an old (and known good) modulator from an old VHS machine in a separate box which I power from a "Wall Wart". I have also acquired a "professional" unit made by Blonder Tongue on the bay which works well.

The boxes with poor RF modulated audio include Zenith, RCA and Magnavox. The baseband audio fed to my outboard modulators work much better.

Have anyone else out there noticed the indifferent RF modulated audio from the DTV boxes?

[Phil Nelson]

Yah, when I used my Zenith DTV box, the audio was definitely low. You could increase it a bit by switching from stereo to mono, but not enough to make it seem normal.

Not a big issue because I eventually gave on DTV and pitched the converter in a bin somewhere. We're in a lousy reception area and the local channels are included with cable, so why bother?

Phil Nelson

[Penthode]

Well... I like free over the air for the vintage TVs since when they were made that is how they got their signals: over the air.

But I also like over the air because generally the picture quality is better. Satellite transcodes and cable rate shapes which reduces quality.

[bandersen]

Yes, I've noticed some of my sets don't like the the RF audio from my Access DTA1010 box. One solution I've used is to take the composite output from the DTA1010 and feed it into a separate, higher quality RF modulator.

[kvflyer]

I have used several of the Radio Shack jobs. Both the pass through and the earlier one that did not have pass through. While I could get about adequate audio, it had substantial hiss or white noise if you have it down low and use the TV for volume. I really don't like that. I guess that I am lucky because I have several BT agile modulators that I have accumulated from the auction site. Only got one bad one and that was simply the voltage regulator in the power supply. While I was there, I replaced the filter cap as well.

[stromberg6]

My daughter has a Zenith box in LA and the audio leaves much to be desired. Not too bad quality wise, but the levels aren't what they should be. She has to crank up the volume on her TV, and sometimes forgets to turn it down when switching to a DVD.