Lamp Holder question

[crunchman]

The lamp holder I used is polarized, I ran the 120v from the PT to the + end is this right or backwards, this new build is blowing fuses with power up, pretty sure its power supply related, I make some stupid mistakes sometimes!

[Jazz P Bass]

Lamp Holder

What kind of lamp holder is it?
Brand, model?
I do not think 120Vac can be polarized.
Volts dc maybe.
Most older amps ran a 6Vac lamp off of the heater winding.

[crunchman]

its an L-110 from aes, I bypassed it and its still blowing fuses, next question is are fuse holders polarized??, i have the typical fender style with the brass nut and using the rear tab for the hot.I hate this, I know its something simple!

[Jazz P Bass]

I think you are confusing things with this "polarizy" statement.
The lamp holder, L-110, is good for 110Volts.
What matters is the lamp.
The fuse is a series item.
Voltage in, voltage out.
No polarity.

[loudthud]

Typically that type lamp holder is used with a #47 bulb that runs on 6.3V. There are 120V bulbs available that could be used in that holder, they are probably neon. What type bulb do you have?

There is no polarity as such because the lamps almost always run on AC, but there may be a Safety reason for a "polarity" meaning one side may be easier to short to the chassis if the bulb is removed with the power on.

You should be using a "current limiter" to power up your amp. It's simply an incandescent 120V light bulb wired in series with the amp. If there is a fault in your amp, the light glows brightly and prevents the fuse from blowing. You should be able to find info on this doing a search or in just about any text on amp building. You have probably mis-wired something or have a bad transformer.

[crunchman]

Thanks LT, I have something mis-wired (not sure what). I wired like this, L-terminal to fuse, out fuse to power switch, switch to 120v PT, 0v PT to N-terminal.

I'm sure its blatantly obvious, but I can't see it ??......Thanks

I'll chime in on the bulb issue once I get the wiring switched !

[loudthud]

From another thread your transformer has a 100V tap. That wire should not be connected to anything. It should be connected to an unused terminal lug or insulated with heat shrink tubing and tucked out of the way somewhere. Any kind of tape will eventually come off so it's not good to use it.

[crunchman]

only using the 120v and the 0v on the PT primary, just want to know if my wiring is correct ?? Thanks

[loudthud]

I wired like this, L-terminal to fuse, out fuse to power switch, switch to 120v PT, 0v PT to N-terminal.

That sounds correct. There must be a problem with one of the other wires to the transformer or possibly elsewhere in the amp. If there are three yellow wires, one with a (usually) black stripe, do not ground it or connect it to anything. Insulate and stow. There should be 3 red wires, one with a stripe, and two or three green wires, the third one would have a stripe. Any other wires coming out of the transformer? Where are they connected? What is this amp? Did you follow any kind of wiring diagram or layout?

[crunchman]

I found the problem, I had 2-wires going to the 0v on the PT primary, because I was by passing the lamp it screwed me up! Its a Dirty 18 and I was following the posted layout on the Brownnote forum, haven't had a chance to crank'er up yet with the wife and kids lurking.The power scaling kit (London power) should arrive this week and that should be doable, I chose his version cause it regulates both the plate and screen voltage for better low-volume tones, same kit in the Badger, mini-plex and Reeves amps......Anyway, thanks for the help L.T.! I found the problem just before leaving for the weekend and just returned.

I'm gonna add the NE51 bulb when I do the scaling, AES says its meant for 120v, we'll see Thanks again.