Used a Light bulb limiter with no speaker plugged in did I do any damage?

[rakkassan34]

I've searched the forum and the web and can't find the answer. When I finished my amp build I used a light bulb limiter to power up the amp without tubes in it once I saw the bulb go dim I powered it off put the tubes in and powered it up again. Light bulb went dim and the tubes had a soft glow and I started taking voltage readings. I did all of this without a speaker plugged in. As some of you have read the amp works great on lower volumes but breaks up bad at higher volumes. I found that my B+ voltages are a tad high and I haven't biased it yet. I'm still troubleshooting and was wondering if I caused some sort of damage by plugging it in without a speaker plugged into it. I had nothing plugged into the inputs and had my light bulb limiter with a 75w bulb in it.

[kagliostro]

I think that without an input signal there are good probabilities you didn't damaged the tubes


K

[sluckey]

I think that without an input signal there are good probabilities you didn't damaged the tubes

I agree.

[rakkassan34]

Thank you thank you. I was thinking and hoping I didn't. Like I said it sounds great at low levels. To me that sounds like a voltage or single component issue and not damage to the whole amp but I had to ask because I don't know what damage plugging one in without a speaker could do

[labb]

If you play a tube amp for very long with out a load on the OT you will destroy the OT.

[sluckey]

If you play a tube amp for very long with out a load on the OT you will destroy the OT.

That's usually true. Heck, just slamming one power chord in a dimed big amp without a speaker can destroy the OT, output tubes and sockets.

But you can safely run an amp for days on end without a speaker if you don't feed a signal into it. I'm not recommending anyone intentionally do that.

[Jack1962]

As others have already stated without a input signal running the amp (with a light bulb limiter) probably didn't do any damage . However , I wouldn't do that without the limiter and with a input signal applied , it will not only damage your OT and tubes it can burn up grid resistors as well and possibly you PT .

[PRR]

> The resistance will climb as the element gets hotter.

I tried that long-long ago.

The cold resistance rises SO fast that a p-p 6V6 amp is basically un-loaded.

Iron fence-wire may be a better bet, though spread it out (zig-zag around nails in a board) instead of wrapping a broomstick.