Running LMT500 without a cab

[scalpy]

Hi folks, quick question. I'm playing in a show and just found out the sound guy is planning on everybody in the pit using headphones. Can I use my markbass Little mark tube 500 as a preamp without hitching up a cabinet?

Thank you in advance

Harry

[discreet]

In short, yes.

[chrismuzz]

Yep!

Apparently you can't if your amp has a valve power stage, but I don't know why

[Bill Fitzmaurice]

[quote name='chrismuzz' timestamp='1429046239' post='2747434']
Apparently you can't if your amp has a valve power stage, but I don't know why
[/quote]With SS if there's no speaker no current flows from the output devices, so no harm. With tubes current flows from the tubes to the output transformer primary windings whether there's a speaker or not. As current can't flow from the transformer secondary windings if there is no speaker bad things happen.

[chrismuzz]

[quote name='Bill Fitzmaurice' timestamp='1429050172' post='2747561']
bad things happen.
[/quote]

Thanks for that! Im guessing risk of fire or electrocution of something??

[discreet]

[quote name='chrismuzz' timestamp='1429052543' post='2747593']
Thanks for that! Im guessing risk of fire or electrocution of something??
[/quote]

Arcing inside (and outside) your output transformer and possibly valves and valve bases, leading to one or more valves going kaput and fusing the windings in the output transformer causing no (or reduced, or distorted) output. So maybe not that dangerous for you, but certainly dangerous for your valve amp.

Edited April 15, 2015 by discreet

[scalpy]

Thank you for your replies. No cab it is!

Harry