UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - New Aurora converter

ppppenguin · 4th Jul 2006, 10:54 am

I think that Darryl should answer these questions but here is my opinion.

The output stage is a simple NPN emitter follower. The emitter resistor is 200R. The base is biased slightly positive.

I measured the minimum vision modulation as 10% at sync tip. I did not look at the manual or the data sheet. It does not matter if the sync tip is anywhere between 0% and 10% provided it is reasonably stable.

I did not measure the audio modulator in detail. If it can only reach 90% modulation I would not regard this as a problem. This is equivalent to 1dB down from the maximum possible. A 1dB difference is just audible by direct comparison

4th Jul 2006, 10:54 am	#15
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: New Aurora converter - help wanted with review I think that Darryl should answer these questions but here is my opinion. The output stage is a simple NPN emitter follower. The emitter resistor is 200R. The base is biased slightly positive. I measured the minimum vision modulation as 10% at sync tip. I did not look at the manual or the data sheet. It does not matter if the sync tip is anywhere between 0% and 10% provided it is reasonably stable. I did not measure the audio modulator in detail. If it can only reach 90% modulation I would not regard this as a problem. This is equivalent to 1dB down from the maximum possible. A 1dB difference is just audible by direct comparison