The Boogie Man Posted May 11, 2008 Share Posted May 11, 2008 Hi Troops, I've got a feeling this has been covered before, but I just wondered, Is there a way to simulate a system running flat out to measure the wattage/ampre draw at the wall/distro/meter without sound at the stacks. I'd just like to confirm the draw in a real world situation without moving to the country to set up a field in the middle of nowhere. CheersBaz Link to comment Share on other sites More sharing options...
mackerr Posted May 11, 2008 Share Posted May 11, 2008 Depending on how many watts you think you need to dissipate you may need a pretty big dummy load. IIRC a couple of electric water heater elements either in series or in parallel get near 8 ohms, and can handle very high power. Just remember to put them in a big bucket of water to keep them cool. Mac Link to comment Share on other sites More sharing options...
cfmonk Posted May 11, 2008 Share Posted May 11, 2008 Depending on how many watts you think you need to dissipate you may need a pretty big dummy load. IIRC a couple of electric water heater elements either in series or in parallel get near 8 ohms, and can handle very high power. Just remember to put them in a big bucket of water to keep them cool. Mac This is definitely a joke right? Or are you actually suggesting putting them in water? Link to comment Share on other sites More sharing options...
J Pearce Posted May 11, 2008 Share Posted May 11, 2008 Well they are water heater elements... Link to comment Share on other sites More sharing options...
mackerr Posted May 11, 2008 Share Posted May 11, 2008 They are designed to be submerged in water with fairly high voltage running through them at high current. They are heating elements, so they may get red hot if they are not cooled in water. Mac Link to comment Share on other sites More sharing options...
cfmonk Posted May 11, 2008 Share Posted May 11, 2008 Sincere apologies! Did not read the post properly! Thought the suggestion was to put normal heater elements in water ;) Link to comment Share on other sites More sharing options...
Simon Lewis Posted May 11, 2008 Share Posted May 11, 2008 We've used electric fire elements with some success. The drawback is that when they get hot, the connecting cables can get pretty warm too... so you need crimped connections, not soldered ones! Ben Duncan gives details in his book on high power amplifiers. Link to comment Share on other sites More sharing options...
Jivemaster Posted May 11, 2008 Share Posted May 11, 2008 RS part number RS components 252-3038 HSW600 wirewound resistor,4R7 600W A project based on this would be a dummy load for a 4 ohm system, or based on two in series for an 8 ohm system. They do however need good heatsinks and flowing water through the bore to prevent them expiring. However note please that under full level white noise or sine wave an amp will draw full power from the supply. BUT with typical music repro the power drawn will be round a quarter of the rated output. Link to comment Share on other sites More sharing options...
The Boogie Man Posted May 11, 2008 Author Share Posted May 11, 2008 Cheers Troops.baz Link to comment Share on other sites More sharing options...
Simon Lewis Posted May 11, 2008 Share Posted May 11, 2008 Although probably OK for short term use, it's worth noting that wirewound resitors can present an inductive load to the amplifier. Link to comment Share on other sites More sharing options...
Stuart91 Posted May 11, 2008 Share Posted May 11, 2008 We recently "torture tested" an amp. A quick dig round our warehouse turned up some old security floods, which had a 9 ohm resistance. Served the purpose quite happily. Link to comment Share on other sites More sharing options...
ceecrb1 Posted May 17, 2008 Share Posted May 17, 2008 Ok..During todays job, an amp stopped working after a GOOD 30mins of use. (however turned on but silent for about 3 hours before hand).This amp did the same thing 2 months ago, but when I got back to the warehouse and tested, it worked fine without changing a fuse etc...... it worked all WEEK in my workshop supplying the techs with radio without a problem (at a relatively low "radio" volume).However I cant test it for long periods with a "decent" volume as it disturbs the office and the next door TV studio (who are currently recording a series...). Does anyone know of any "DIY" test rigs I can setup where I can test the amp with a decent load but not with a speaker. i.e. Silent. Surely it cant be as simple as a high wattage resistor (thinking that technically the speaker has inductance as well being a coil). ??? edited fro dab spelin Link to comment Share on other sites More sharing options...
Brian Posted May 18, 2008 Share Posted May 18, 2008 Surely it cant be as simple as a high wattage resistor (thinking that technically the speaker has inductance as well being a coil).For most general day-to-day testing a resistive dummy load is fine. However, if you really want to stress the amp, and I'm thinking of things like its SOA protection here, then you will need a 'proper' dummy load. The is an international standard for it, have a Google for 'DIN dummy speaker load'. Link to comment Share on other sites More sharing options...
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