First start of new build

[dmartn149]

I'll be finishing my first home built amp soon, and I'm a little worried about turning it on for the first time. When the time comes should I just plug it in and turn it on, or is there some procedure I should follow?

[AudioMan]

The procedure can vary depending on whether the amp is a solid-state power amp, a preamp, or a tube amp.

When I built a power amp, I would test the low-level stages first with a DC voltmeter, and with no power output stage connected. Then as it appeared good, I would use an audio tone to check if there was a linear response, or premature clipping of the low-level circuits. When all these preliminary checks appeared normal I would attach the power devices with no output load for a solid state amp and use a variac to slowly raise the AC input power voltage and check for abnormal current flow. After all the check look good would I apply a dummy load and then apply an audio signal for the final tests.

A power tube amplifier I would use a dummy load to ensure that the output transformer functions properly and the output tubes don't draw excessive current. Again, a variac is what I would use to slowly bring up the voltage.

[g1]

As you may not have a variac, at least use a light bulb limiter the first time you start it up.
In case of problems, it can save parts from damage.

[Enzo]

Agree, a light bulb limiter (google it) is simple and cheap, and will do the job of protecting your amp.

Assuming it is a tube amp, once it is built, I would remove all tubes, and power up on the bulb. if the bulb glows bright, there is trouble in the amp. if the bulb lights only dim, then we can proceed. I'd go to each tube socket and measure voltages at the pins. verify you have heater voltage on the proper pins at each socket. If there is a tube rectifier, it will have 5vAC on its heater, instead of 6.3v. If that is all OK, we step up to installing the rectifier tube only. And power back up.

Look for B+ voltage on all plate pins. Assuming fixed bias, is there bias voltage on each power tube grid? If that is OK, I'd install all the small tubes. Now do we have B+ on their plate pins? It will be lower than it was with empty sockets. Also is there now voltage on the cathode pins? Do both heaters in each tube light up?

If that works, I connect a load, then I install power tubes. See what happens.

[dmartn149]

It is a tube amp, and I don't have a variac. Enzo, your procedure was just what I was looking for. I'll print it out, build the lbl and proceed as recommended.
Thanks