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Dynaco PAS2 can cap questions

M

MaggieMaggie

Active Member
Lots of schematics out there, show the symbols to hook it up. And several replacement caps all with different values. I have seen 20-20-20-20, 30-20-20-20, 30-20-2010. Someone did some Dynakit mods, the can was wired 20-40-20-20. And then there are the electrolytic boards. And of course those folks don't give away the schematic. My question is, looking at the assembly manual schematic ( which refers to lug numbers) from left to right, should it be 20-40-20-20 or 20-30-20-10??? Thanks in advance.
 
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I've never needed a schematic for a cap can. All the ones have ever replaced state on the can the uF and next to it a symbol (triangle, square, circle, D) and the leads on the bottom are marked with the same symbols. Take pictures of the wiring connections before unsoldering. I also hand draw how all the different wires connect to each cap/symbol.
 
MaggieMaggie said:
Lots of schematics out there, show the symbols to hook it up. And several replacement caps all with different values. I have seen 20-20-20-20, 30-20-20-20, 30-20-2010. Someone did some Dynakit mods, the can was wired 20-40-20-20. And then there are the electrolytic boards. And of course those folks don't give away the schematic. My question is, looking at the assembly manual schematic ( which refers to lug numbers) from left to right, should it be 20-40-20-20 or 20-30-20-10??? Thanks in advance.
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I would not even think of replacing the can cap in a PAS. Instead i would install a power board
that replaces all of the filter caps with modern "industry type" caps mounted on a board.
There is several available , one is
z-psu from erhard-audio
 
BmWr75 said:
I've never needed a schematic for a cap can. All the ones have ever replaced state on the can the uF and next to it a symbol (triangle, square, circle, D) and the leads on the bottom are marked with the same symbols. Take pictures of the wiring connections before unsoldering. I also hand draw how all the different wires connect to each cap/symbol.
Click to expand...
The problem is, the original schematic doesn't have any cap values on it, so you're left to wonder what the values actually are supposed to be. And, there doesn't seem to be a schematic with the values floating around the web. The original can cap is supposed to be 30,20,20,10, which seems like the reverse order to the schem. to me. Looks like you would hook it up as 10,20,20,30, so that C1 (10uf) would be for the 12x4 rectifier, etc.

jeff
 
Don't think the order of the cap values in the can (or printed on the can) has anything to do with how they are connected to the rest of the circuit. Have replaced many multi-cap cans and have never assumed the order of the uF values meant anything.
 
It does seem strange that the Dynaco PAS manual schematic doesn't list the uF values for the can. (And I checked a ST-70 manual and same for that one.)
I believe the original PAS was 30-20-20-10 @450v.
And whatever can you think is a good replacement, watch out for the height (around 2") if you want the PAS cover to still fit.
 
Thanks all. I would have to say I'm likely the third person to do um, surgery on it. It's not as full of afterthoughts as a Voice Of Music I made the mistake of buying on Ebay. That I can't identify....I have been to several websites that all claim to sell Dynaco or say this is used for Dynaco and they all do something different. I have something meant for a Hallicrafters to try. What I did see from someone is that the first section should not be over 30 if it's ss rectified. Tubed not so likely to cook with inrush. After I posted this I did find some sites who did a low value, next section highest value. As for separates boards, what I see is installed where someone put in a very heavy duty filament supply. I mean this thing plays for a minute after I shut it off so I'm leaving that alone. PS Tone control bypassed made it killer.
 
PS The instructions I think where meant to be idiot proof, like playing a Magnus Chord Organ, triangle goes here, ect. PS I would kill for one of those to play with, Fleabay pushed them through the roof.
 
So, lesson learned. I finally had some time to get back to it. I neglected to check if the power transformer roached and yes it did. Googled it and I get dotcoms out of stock.
 
I have new production PA522 transformers ( 230 volt only) available in sweden . Where do you live ?
 
Couldn't get the link to go, but if you look at the build guide on the AK data base schematic, it's 20-20-30-10 from left to right. You can also try searching Dynaco Tube Audio Forum, there is a Pass 3 schematic with values there.
 
Just wrap this up, like a dummy forgot to check the Transformer, and Bumblebee is dead. And eternally out of stock at Dynakit, did find one custom wound from Greece for your local wall voltage for $$$
peterh said:
I have new production PA522 transformers ( 230 volt only) available in sweden . Where do you live ?
Click to expand...
USA 120v. It's what I get for not reading enough here at AK to find install a 1/4 amp fuse. As much as I like it, I almost have my Marantz receiver fixed, I'll go back to that for it's phono. Once I flip some speakers I'll get back to it.
 
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