21-08-2012, 10:12 AM
Hi David,
Those aren't too bad - I've seen plenty be high by 25-30%. Interesting that the 330K is spot-on. I have a massive tub of those particular resistors, and find them to be excellent - I use them as replacements in vintage transistor radios as they look reasonably "period". Quad used them in their amplifiers (certainly the ones I've seen), so they must have been reasonably OK...
Whenever I measure a vintage electrolytic, if it's basically working, the value is always well-over the stated value. Not so with modern caps. I guess that back then, they erred on the side of caution. IIRC, the tolerances were always unequal - e.g. -10%, +50%.
Regarding IFTs, my experience agrees with you. I rarely tweak undisturbed IF cores, and if I do, any improvements are always marginal. But I generally need to adjust the oscillator - however I suspect this probably has more to do with the trimmer capacitors than the coil...
If you haven't already seen it, some of my DIY can be seen on my website:
http://www.markhennessy.co.uk/electronics.htm
http://www.markhennessy.co.uk/audio.htm
All the best,
Mark
Those aren't too bad - I've seen plenty be high by 25-30%. Interesting that the 330K is spot-on. I have a massive tub of those particular resistors, and find them to be excellent - I use them as replacements in vintage transistor radios as they look reasonably "period". Quad used them in their amplifiers (certainly the ones I've seen), so they must have been reasonably OK...
Whenever I measure a vintage electrolytic, if it's basically working, the value is always well-over the stated value. Not so with modern caps. I guess that back then, they erred on the side of caution. IIRC, the tolerances were always unequal - e.g. -10%, +50%.
Regarding IFTs, my experience agrees with you. I rarely tweak undisturbed IF cores, and if I do, any improvements are always marginal. But I generally need to adjust the oscillator - however I suspect this probably has more to do with the trimmer capacitors than the coil...
If you haven't already seen it, some of my DIY can be seen on my website:
http://www.markhennessy.co.uk/electronics.htm
http://www.markhennessy.co.uk/audio.htm
All the best,
Mark
