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Has anybody measured/calculated the voltage of B+1 rail on the kit 2 amp? I seem to remember seeing it was aroung 560v.I have got my hands on some very nice Black Gate VKs caps, but they're only rated at 350v, giving me a 700v od in series. The standard caps are 450v rated, which means I'm 200v down on OEM.
Am I heading to tears or is 700v cap rating safe for the B+1 rail?
thanks
Paul
Edits: 12/28/07 01/01/08
Hi,
It is ok to wire 2 x BG VK 22uf 350v at the C1 position after the rectifier. But you will not have enough capacitance for smoothing. If your speakers are sensitive you will hear hum. You will need to increase the C2 to more than 300uf - use a Elna Cerafine 330uf 500v if you can still get one.
I use Mundorf Tubecap 20uf in that position. The Mundorf is rated 1200v. For C2 I use a BG Wkz 100+100. The amp is very very powerful after the cap mod.
Regards
Vi
the b+ voltage should not really be more than 440V in kit 1, otherwise the 450V caps would be out of spec.
the instructions say 425V but i find mine runs higher than that in the UK
if you connect the caps in series you should connect an equal resistor in paralel accross each. this acts as a potential divider and ensures you get an equal voltage accross each cap, so you don't have the danger of getting the whole lot accross one of them and it blowing
C1 and C2, the caps between the rectifier valve and choke are connected in this way. the resistors also act as bleeders so when the amp is switched off the B+ drains away after a minute or so. for resistor values you could use the same as these or a bit higher
Richard, the 450v caps in the Kit2 PS are all used in series wired pairs - giving a rated 900v.However I do recall seeing somewhere that the voltage is 560v max - but I cannot seem to find where I saw that before. If I can confirm that I know I can swap out the stock caps with some BGs I have rated at 350v.
Regards
Paul
Suggestion : measure voltage out of the rectifier, and also at the OPT
Hey Pauly,
In your first post, you mention the Kit 1. In your subject and last post you mention the Kit 2.
If you have the manual, you should have the B+ voltages mentioned in the "Testing" section towards the end.
Bill"Build your system for yourself not the critics"
My bad, I meant kit2 (6550 SE kit). My manual is long gone - I think I built the kit sometime in 2005.I'll measure the voltage at the rectifier as GTCharly suggests - I was just being a bit lazy.
Paul