[Heathkit] How much capacitance

[Tom NØJMY]

Back to the 180 uF @ 500V replacements that I sell for replacement of 
the 125 @ 450V (say, in a Hunter Bandit, for example).

As far as re-engineering the designs of yesteryear being dangerous, well 
lets take a look:

Mike M. brings up the good point of tolerance on the older 
electrolytics.  These old circuits were designed around those wide 
tolerances, so with the old -20 +80 standard, a 125 uF cap could 
actually be anywhere from 100 to 225 uF and be acceptable for that circuit.

Even if more expensive electrolytics with a -10 +60 tolerance were used, 
they could still fall anywhere from 112.5 to 200 uF.

Today's electrolytics are -10 +10.  That puts the 180 uF unit between 
162 and 198 uF.  You can see my reasoning; is it faulty?

As for the 500V rating, that's an increase of about 11%.  Depending on 
the year that the rig was designed, your line-voltage might have 
increased by that much.

I add a little more protection by selling only cans rated at 105C.

As far and it goes, I still like the soft-start and other forms of 
protection from in-rush (and whatever you call the opposite - when you 
shut down and the caps discharge).

And, quite frankly, if it were my Heathkit or Drake amp or p.s., I would 
use Mike Bryce's retrofit kit: www.theheathkitshop.com .  Now, those 
boards are available for the most popular models, but not the widest 
*range* of models, so there still seems to be a demand for these 180 uF 
@ 500V caps and given the forgoing, I feel pretty safe in offering them.

All the best,
Tom - NØJMY
Hayseed Hamfest Co.

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