please help~ express clone, low B+, loss of volume

[reroe]

i've finally finished express DIY.
anyway it does work but some problems I have

1. B+ ok when tube uninstalled (~405V for B+1~B+5)
2. when all tube installed, HV isn't high enough
volume's so low and distorted sound even when set for clean operation(vol 1~2)
3. so i checked tube by tube(actually i don't know the right procedure to debug my amps, lol), and the result is...
when power tubes installed, HV's ok (that is, B+1 395V, B+2 380V)
when V3 (PI) installed, HV drop (~315V)
4. i realized that V3's contact isn't good because i inserted V3 tube to socket by a half (by some reason, iron flew to pin4 hole and V3 can't be inserted as much as it should be)
5. from all above things, i suspect there's PI problem..

but how can i fix it? and is there any possible cause that makes my amp not work?

please help me.

[Phil_S]

Jammed pin hole? Run a thin rod through it to see if you can un-jam it, or change the socket.

[soma_hero]

yeah make sure your socket pins aren't shorting somehow. Was it like shavings from drilling holes in the chassis? You could have provided just enough connection between to pins that one shorted to the other. Do you see any scorch marks on the socket?

What PT did you use? Initially thought you didn't have enough current in the PT, but if it's fine when you have the power tubes in and then gets messed up when you insert the PI tube that sounds like a local problem and not something to do with your PT.

If the voltage is fine with output tubes, and V1/V2 in their sockets, then you know the problem is around V3. Check all wires, make sure you have the right connections.

[dartanion]

You could very well have soldered the pin hole shut. It's pretty easy to have this happen if you are not careful with the amount of solder you use while wiring the sockets.

If the socket is suspect, replace it.

[reroe]

thank you all...
i'll try the new socket.

[Cliff Schecht]

On my Express build one of the sockets wasn't seating because I flowed too much solder on it too many times. A drill bit the size of a 12AX7 pin and either a power drill or an Exacto blade holder can be used to simply drill out the excess solder. This is nice because you don't have to change the socket or whip out the solder sucker/solder braid.