Quick circuit testing question...

[Colonel_Sanders]

Hi again guys,

I'm finally ready to put some signal through my build but I'm not 100% confident in my design. So I'm wondering if it will cause any damage if I fit just the preamp tubes first and trouble shoot from there?

I can't see why not, but it doesn't hurt to check eh?

Thanks,
C_S

[Bruce / Mission Amps]

Hi again guys,

I'm finally ready to put some signal through my build but I'm not 100% confident in my design. So I'm wondering if it will cause any damage if I fit just the preamp tubes first and trouble shoot from there?

I can't see why not, but it doesn't hurt to check eh?

Thanks,
C_S

I do this all the time but I use a solid state rectifier plug and a variac to bring up the power supply slowly.
I find that with the line voltage around 80vac-90vac (at the PT primary), the preamp tubes have enough heater voltage and they are amping just fine for checking.

[Colonel_Sanders]

Thanks Bruce! I don't have a variac though, so will it be alright at full tilt? Or is there a quick way to DIY a variac?

Cheers,
C_S

[Colonel_Sanders]

Well, I've got it on full voltage and nothings blown up yet . Tubes are amplifying and my relays are switching. All geezy!

Cheers,
C_S

[olddawg]

An old troubleshooting trick is to put a 100 watt light bulb in series with the AC mains. It was called a suicide cord. You would usually make one out of a short extension cord. You plug it all in and the turn the amp on. If the bulb glows bright you are drawing excessive current and you immediately jerk the plug from the wall socket. It's an old trick, especially in TV. Its much better to have a variac and an isolation transformer.

[Enzo]

And a current meter.

[Albert Kreuzer]

Here is my lightbulb limiter. I can switch between 1, 2 or 3 lightbulbs (for small/medium/big amps) and test jacks for a current meter. It has a mains fuse and a bypass switch.

Cheers,
Albert

[Enzo]

Cool.

[booj]

Sounds like a good plan! (Pardon the pun)