Cheap noise gate

High/Deaf said:

Sorry but that's just not true. Solid state gear loves to run into an open circuit. The higher the impedance, the less current it's supplying and the less work it has to do. Also, the less power (volume) you will get out of it. But it will run forever like that and not even get warm.

If you blew up your PA, it wasn't because you had no load tied to it. Too low of a load was much more likely the cause. Or bridging an amp and running it at even slightly lower load than spec'd - that's a real killer. I've fixed quite a few bridged amps that the band thought they could just run another sub off of. And then put tinfoil around the fuse when it blew. I suppose they didn't notice the smoke coming out of it because of the dry ice machine. The insides were pretty well turned to charcoil.

Click to expand...

I will not argue, but I will humbly disagree. Newer PA's may have some sort of protection, but my 1990's Yorkville 1212 (2 x 600 watts) did not like it when I had a bad cable and one speaker went out. I could be wrong though... (I have been before)...

EDIT: Here is a post from a thread on Gearslutz:

- Some may begin to oscillate without a load and the oscillation can make them fail. It's generally a rarity but there are some examples of amplifiers that may do so.

- Some solid-state amplifiers use output transformers and similar topologies as generic tube amps, some of such designs even run with high voltage power supplies. Particular examples of such designs would be several mid 1960's single-ended class-A SS amps that used an OT and a supply voltage of approximately 150 VDC. These may have similar issues with flyback voltages and arcing as tube amps.

Naturally, it all depends on design. Most SS amps run perfectly happy without a load but simply being solid-state is not enough grounds to assume that an amp can do it. It always depends on the circuit.

https://www.thegearpage.net/board/index.php?threads/do-solid-state-amps-need-a-load.764373/

I suspect it was more likely the cable that perhaps shorted before the speaker went out. Or a bad speaker that shorted. That's what kills PA's with direct (low impedance) outputs.

I've dealt with SS PA's that have OT's - used for 70V line driver systems, like paging systems in a hotel. One amp driving dozens of speakers as constant voltage source and small xformers at each speaker tapping the voltage back down again. There were also 25V systems that allowed by directional comms, like what your school may have had. If the OT is unloaded and doesn't have a problem, I can not see technically how that amp would oscillate itself to death. If the OT has an internal short, sure I can see it happening.

But I doubt you're running a 4/8/16 ohm PA system with line drive taps on an old PA amp. It wouldn't work very well.

Anyways, sorry you blew up your PA. Very unusual situation it if wasn't a bad cable or speaker. Especially as, IME, Yorkville is generally well built stuff.