New to me Pedersen W-15

[diamondsouled]

Interesting! Nice mono set up BTW! There are a few different versions of the W-15. Like yours with both power tranny and choke oriented the same, like mine with the choke mounted sideways to yours and a third with a different choke, potted if I remember right. They sure built them solid!

Hard to believe it's been five years since this was posted originally. Time flies! Holy crap I just passed 8K!

Cheers

Lar

 

[tcdriver]

One thing that I have noted, on my unit, is that the three first filter capacitors have no markings to indicate the voltage ratings. I was not sure how high a voltage to use when I formed the capacitors. Initially, I formed them to 450V, however; I noted that on turn on the B+ would surge to greater than 500V. In communications with member fthedj, he informed me that on his W-15, the second can capacitors where rated at 500VDC. So, I then reformed the first three filter capacitors to 500V. However; this did not answer the question as to just how high a voltage the B+ would go to at startup. One factor is the AC line voltage. The amplifier is marked "115 V, 60 CPS" on top of the chassis. The AC line voltage at my house measures about 123V. I was a little concerned that the extra line voltage could cause a problem for the capacitors, so, I installed a bucking transformer to buck the line voltage down to about 113V.

Below is a plot of the B+ voltage at startup for the first three filter capacitors and the output tube cathodes.