Poor power supply knocks out OTB

[Happy Jack]

I played a pub two months ago where my OTB kept screwing up - either suddenly disintegrating into bursts of static or simply dropping out altogether. After the first (much shortened) set I had to hastily re-rig and DI through the PA.

Played the same pub last night and as we were setting up I could see from my power conditioner that the pub's power supply was poor. The display on the conditioner is in coloured LEDs (rather than a voltage reading) and we were getting all the reds lit, plus the occasional orange. I'd interpret that as being maybe 160V - 180V rather than an all-green-LED rating of 240V.

As soon as I started testing my OTB I started to get the same problems as last time. Game over. Unplug the amp, and dig out the DI box.

Is this a valve amp thing? Do pre-amp valves need a minimum voltage before they just stop working?

Or is there something else I should be investigating?

[icastle]

[quote name='Happy Jack' post='1360916' date='Sep 3 2011, 01:13 PM']I played a pub two months ago where my OTB kept screwing up - either suddenly disintegrating into bursts of static or simply dropping out altogether. After the first (much shortened) set I had to hastily re-rig and DI through the PA.

Played the same pub last night and as we were setting up I could see from my power conditioner that the pub's power supply was poor. The display on the conditioner is in coloured LEDs (rather than a voltage reading) and we were getting all the reds lit, plus the occasional orange. I'd interpret that as being maybe 160V - 180V rather than an all-green-LED rating of 240V.

As soon as I started testing my OTB I started to get the same problems as last time. Game over. Unplug the amp, and dig out the DI box.

Is this a valve amp thing? Do pre-amp valves need a minimum voltage before they just stop working?

Or is there something else I should be investigating?[/quote]

There is a minmum voltage that valves need before they'll work properly.

Valves run at less than mains voltage and usually have power supplies that provide a constant voltage.
Your amp would have been designed to work on 220V +/- the usual 10% with a bit added for luck.

It *could* be that the power supply on the amp isn't able to deal with a 30% + input loss.

As far as the record for voltage losses is concerned, I reckon you might be giving Dood a run for his money...