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[Daniel Martini]

Hello all! I have a quick question I can't seem to get a solid answer on. Basically I run sound for a lot of "on the fly" underground shows where the power is less than desirable. I have four Meyer Sound DS4P mid bass cabs that require 240v 20amp circuits and when I request said receptacle at the "venue" I see a lot of blank stairs... I've also requested a 50a range outlet to run to my spider box which of course takes care of this but that's met with more confusion and a strong no as well. So I'm left with 120v Edisons and generators (which aren't something a lot of these guys are willing to pay for).
So a solution in my mind would be a step up transformer but I wanted to get your opinions. Is that a good solution to lug around? If I did get one I'm not even sure where to look. All the transformers on eBay are for small electronics and are all euro plugs ...

Thank you in advance - Dan

[Steve-White]

Run them on 120V.

[John Roberts {JR}]

You will need robust 115v service

JR

[Brian Jojade]

I have four Meyer Sound DS4P mid bass cabs that require 240v 20amp circuits
....
So a solution in my mind would be a step up transformer but I wanted to get your opinions. Is that a good solution to lug around? If I did get one I'm not even sure where to look. All the transformers on eBay are for small electronics and are all euro plugs ...

Thank you in advance - Dan

As Steve posted, you can run those speakers off of a 120v service.  You should under most scenarios be able to drive 2 speakers off of  a single 20 amp circuit, unless you're driving the subs stupid hard.  In that case, one per circuit would be perfectly OK.

Since you can run them off of 120v a step up transformer gains you exactly nothing. In fact, there will be a percentage loss in available power because transformers are typically only about 95% efficient.  You'd need 1 step up transformer for each speaker, as running 2 off of a single 20 amp circuit would be putting you pretty close to capacity even at continuous RMS, let alone peak. 

It is pretty mind blowing that anything that considers itself a venue doesn't have some sort of higher current power available, but that's another discussion completely.

[Daniel Martini]

D'oh! God I must have read that spec sheet 100 times and missed that they were switching amps ha. Thank you guys! Will be running two per 20a circuit and i usually don't ever push them (they get honky quite easily).

And Brian in regards to your venue comment I wouldn't consider a lot of these places venues either haha. More like office spaces/warehouses real down n dirty stuff .

Appreciate the help all!

[Steve-White]

That's ok Dan, we all have our "Moments" which is what makes this site such a nice resource.

As far as what John referred to as source power in watts.  A transformer would actually worsen the situation with parasitic loss from heat in the process of the voltage conversion.

A couple of good 20A 120V circuits and you should be able to rock the house - maybe not full power for your rig, but enough to get paid and called back.

[Daniel Martini]

As far as what John referred to as source power in watts.  A transformer would actually worsen the situation with parasitic loss from heat in the process of the voltage conversion.

That really is interesting and completely makes sense, it would just be extra work since there's a transformer in the amp anyway.

[Jim McKeveny]

".. and missed that they were switching amps"

Most regard Class D amps "switchers". Meyer clearly states these are Class AB/H, with a universal power supply.

[Erik Jerde]

It is pretty mind blowing that anything that considers itself a venue doesn't have some sort of higher current power available, but that's another discussion completely.

I have a feeling since the events were labeled as “underground” that these aren’t exactly performance venues that he’s working at.

[John Roberts {JR}]

Most regard Class D amps "switchers". Meyer clearly states these are Class AB/H, with a universal power supply.

A perhaps confusing distinction...

Class D amplifiers use saturated switching output stages. These generally deliver higher efficiency.

Amplifiers with switching power supplies use high clock frequency saturated switching stages to replace heavy iron power transformers with smaller HF transformers. A switching PS saves size, weight, and cost(?) vs conventional PS.

A class D amplifier can deliver slightly higher efficiency than a well executed class G/H multi rail amp, but not enough to write home about.

I have been out of this game for a while so Class D amps may be cheaper now too....

JR   

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