Powering up amp after replacing caps

[louderock]

Just replaced the filter caps and bias caps on my 1974 Marshall 50 watt. Hooked up my Amp-Head bias tester and let the amp warm up for 5 minutes on standby. When I switched the amp on, I felt like I was getting too much noise out of my speaker (volume was at 0) so I switched everything off. Is there a power up procedure that needs to be followed when powering up for the first time after replacing caps? I have checked and re-checked all polarities. Do I need to make one of the light bulb current testers?

[WaltC]

If the caps are all good and the work is done correctly then nothing special is required. That said <G> I always bring mine up on a variac "just in case" and it's saved my bacon more than once. In lieu of a variac the light bulb current limiters work just fine.

[louderock]

Just wondering about these JJ can caps. They aren't marked for polarity. The caps that came out had 3 lugs. The center lug was unmarked and was ground while the other 2 lugs were red and yellow. Would I be correct in assuming that the JJ caps are configured in the same way? Middle lug is ground and the 2 outside lugs are + ??

Edit: After closer inspection, I can see that the JJ caps are marked on the lugs. The are scribed on the bottom of the lugs instead of colored with red or yellow. There is a crude + and - on the base of the lug and they are arranged as I had suspected. Center is ground just like on the previous caps.

[Rosewood]

If the caps are all good and the work is done correctly then nothing special is required. That said <G> I always bring mine up on a variac "just in case" and it's saved my bacon more than once. In lieu of a variac the light bulb current limiters work just fine.
That's the only reason I use a variac after a cap job, just to make sure my brain didn't go to the Bahamas for a moment while soldering.

[louderock]

Turns out one of my new JJ power tubes is bad!!! :FM That was the hum. I went ahead and built a dim bulb tester. Neat how that works. I couldn't get a good steady current reading on the JJ tubes and out of curiosity I put the old Sovteks back in. Steady reading! So, one by one I swapped the JJ's and one of them is no good. This was my first total cap job on an amp so you can imagine that I wasn't exactly happy when I powered up and had a nasty hum out of the speaker. Glad it was a bad tube and not me!

[WaltC]

well at least it was a fairly easy and relatively cheap fix!! <G>

[ohmslaw]

Turns out one of my new JJ power tubes is bad!!! :FM That was the hum. I went ahead and built a dim bulb tester. Neat how that works. I couldn't get a good steady current reading on the JJ tubes and out of curiosity I put the old Sovteks back in. Steady reading! So, one by one I swapped the JJ's and one of them is no good. This was my first total cap job on an amp so you can imagine that I wasn't exactly happy when I powered up and had a nasty hum out of the speaker. Glad it was a bad tube and not me!

I have had a couple of the JJ power tubes go bad straightaway. Had a 6L6GC start sizzling on me the first day I put it in; a real sparker, that one. They are a great-sounding tube for the dough but like any tube they have a few rejects now and again.

[donnyjaguar]

I generally charge the caps up before I install. This to make sure there is no internal resistance that drains them. Be careful to discharge them before soldering, of course!!