diytube.com

Hi,
Maybe I am not understanding the diagram right, but if you look at the manual (downloaded from http://www.dynakitparts.com/store/manuals/DYNA-mark3.pdf), it looks like the choke is wired to lug 2 of can cap and pin 8 of GZ-34. Shouldn't one of the wires go to lug 1, since you need 30uF/525vdc-choke-20uF/525vdc? I am looking at the pictograms at last two pages. Thanks.[/url]

Its wired just like in a ST70 (the same part). The cap is 20-30-20-20 so the second section IS the 30mf section (half-moon symbol).
BTW a MkIII should never be powered up full without the output tubes. I know someone who was reforming the caps in his MkIII without power tubes and when he got up to like 90% AC voltage...kaboom went the can cap.

I went scurrying around in the attic and found my thread on bringing up an amp. It's posted on 101; hope it helps those who are a little unsure of the process. And thanks, Mike, for reminding folks about the danger of not monitoring the potential applied to filter caps.

SDS-PAGE wrote:Hi,
Maybe I am not understanding the diagram right, but if you look at the manual (downloaded from http://www.dynakitparts.com/store/manuals/DYNA-mark3.pdf), it looks like the choke is wired to lug 2 of can cap and pin 8 of GZ-34. Shouldn't one of the wires go to lug 1, since you need 30uF/525vdc-choke-20uF/525vdc? I am looking at the pictograms at last two pages. Thanks.[/url]

I thought the same thing myself, when I first inspected the wiring. Then I realized that pin 8 of the GZ-34 is wired to lug 1 of the can cap. So, effectively the choke IS wired to lug 1, just not in the way that you thought it would be. Since pin 8 and lug 1 are wired together, it doesn't matter if the choke is connected to pin 8, or to lug 1. Electrically, they're the same.

mesherm wrote:Its wired just like in a ST70 (the same part). The cap is 20-30-20-20 so the second section IS the 30mf section (half-moon symbol).

I dunno about the ST70, but the stock schematic for the Mark III absolutely DOES NOT go 20-30-20-20. The 30 uF section goes first, right up against the rectifier.

I never said that it didn't.