Hot Plate ohms question

[wrd]

I have a Marshall 1987X (50 watt Plexie reissue head) and a Mesa 2x12 cabinet. The cab is rated at 8 ohms. I can set the Marshall to 8 ohms.

My question is- I have a 16 ohm Hot Plate. I bought it for another project unrelated to this situation. Can I use this 16 ohm Hot Plate with the 8 ohm cab and 8 ohm amp setup without any damage?

Thank you for any comments or suggestions.

[surlybastard]

I have absolutely no expertise or real insight backed up by knowledge (other than that I have a Weber MASS lite that works with anything between 4-16 ohms), but IMO (and it is just an opinion) this strikes me as very very dangerous and I *would not* recommend it. Those things are rated for a reason, and I believe any variance in resistance is bound to cause problems, maybe not right away but you never know.

I typically live by the rule that the only truly safe match is when all the ohms are the same.

Now perhaps someone with actual real facts can back me up on this.

[Beston1]

Hi, I also have a 1987x (& a Vintage Modern 2266) and use a THD hotplate rated at 16 ohms through a 16ohms 1960ax 4x12, I wouldn`t risk using anything other than the correct/matched ohm`s with a hot plate.
Hope this helps, let us know what happens.....

[surfnorthwest]

Why not rewire your 2x12 for 16ohms.

[Machine Head]

Never use a smaller Ohm value than the required minimum! Using a bigger value (resistance) will affect a change in the produced sound by the speaker/s but won't harm the amp. 4, 8 or 16 Ohm indicates the resistance of an input.

To say it simple: If you attach a 4 Ohm cab input to a 8 Ohm amp output the speaker will "suck" double so much electric current at higher volume settings than the output device is intended for. Among other things this will provoke a overheating of the components and that's why it can cause component damage.

[aristotle]

Well... Per THD at least, so long as " the impedance of the speakers is equal to or greater than the amplifier, AND
the impedance of the Hot Plate is equal to or greater than the amplifier" it's OK. The amp only cares about the load that it's hooked up to. To the extent that an underloaded Hot Plate output isn't bringing the load that the Hot Plate presents to the amp down below what the amp is set to, it'll be OK (and per the documentation on the Hot Plate, evidently an 8 ohm load on the output of 16 Ohm Hot plate doesn't drop the input impedance below 8 ohms by design.) They do claim that it affects the tone controls though if the cab isn't at the same impedance as the Hotplate.

Surf's idea would be ideal, but since your 2x12 is an 8 Ohm cab, it's going to be two 16 Ohm speakers wired in parallel (or less likely two 4 Ohm speakers in series.) No way to wire the cab to 16 Ohms in either case without getting different speakers.