How to figure out max voltage of an amp

[jimbo7]

I'm trying to find out how many volts my amp puts out to see if I can run 2 T24's on it. The manual doesn't have voltage and I'm not sure of the formula I found (√(watts x ohms)). This would be: √(1000x4)=63.24v max. For each channel it would be: √(225x8)=42.42v per channel. Since I'm using a BP102 (35v max), this amp would be fine, correct?

The amp is a Carvin DCM1000 and here the manual: http://www.google.com/url?sa=t&rct=j&q= ... Wc&cad=rja

I guess I could put my meter on it and see, but I don't like that idea without a speaker load attached. Forgive me for my noobness.

[billkatz]

I'm trying to find out how many volts my amp puts out to see if I can run 2 T24's on it. The manual doesn't have voltage and I'm not sure of the formula I found (√(watts x ohms)). This would be: √(1000x4)=63.24v max. For each channel it would be: √(225x8)=42.42v per channel. Since I'm using a BP102 (35v max), this amp would be fine, correct?

The amp is a Carvin DCM1000 and here the manual: http://www.google.com/url?sa=t&rct=j&q= ... Wc&cad=rja

I guess I could put my meter on it and see, but I don't like that idea without a speaker load attached. Forgive me for my noobness.

SInce you are not going to use it bridged, the 100W calculation is not useful. The 42.4 V at 8 Ohms is correct (single ended it is rated at 37.4V into 4 Ohms. If your driver requires a limit of 35V, this will be fine.

[SoundInMotionDJ]

I guess I could put my meter on it and see,

+1

Solid state amps can be run without a load. Provide an input signal, turn the input gains up all the way, measure across the terminals.

[jimbo7]

I guess I could put my meter on it and see,

+1

Solid state amps can be run without a load. Provide an input signal, turn the input gains up all the way, measure across the terminals.

Ah, I see. I'm use to the valve amp approach to things.

[Grant Bunter]

If you're using a DCX and have an output of 42 odd volts, you will find about 6dB of limiting is required to get 35V. Adjust accordingly dependant on your signal path and strength...

[Rich4349]

Tube-newb question: Would the output of any given amp be a higher voltage when fed with a preamp, compared to without?

[jimbo7]

I don't think it works that way. Otherwise you could get electrocuted by connection the terminals together.

[Grant Bunter]

Tube-newb question: Would the output of any given amp be a higher voltage when fed with a preamp, compared to without?

A simple definition of a preamplifier:
"an electronic device that amplifies a very weak signal, for example from a microphone or pickup, and transmits it to a main amplifier"

The "weakness" of the signal in the definition above means if you didn't use a preamp and hooked the source straight to your amplifier, regardless of what you do, you won't get it that loud.

That's quite different from the components making up the amplifier itself, with it's various input and output stages etc. The output in volts is determined by those components and the amps design.
You can't magically increase that voltage per se...

[Rich4349]

Oh. I was under the impression that an amplifier with a value (power, rating, whatever) of "100" would take an input of say ".5" and make it "50". But a preamp would take that .5 and make it say 1.5. Then the amp could do its thing and turn the 1.5 into 150 (watts, presumably). But apparently this just ain't so.

[Grant Bunter]

Oh. I was under the impression that an amplifier with a value (power, rating, whatever) of "100" would take an input of say ".5" and make it "50". But a preamp would take that .5 and make it say 1.5. Then the amp could do its thing and turn the 1.5 into 150 (watts, presumably). But apparently this just ain't so.

Well if we take your analogy, look at it like this:
Say your amp does in fact take an input of .5 and makes it an output of 50.

But the "thing" you attach to the amp doesn't put out .5, it puts out only .2.
The amp can't make it 50 in that case.
So you add a preamp, that takes the .2 and makes it .5.
Because you've added the preamp, your amp puts out 50 again.
50 is the most the amp will ever put out.

Actually, that's not quite true. Transient peaks, as Bill says in most sub plans, can be up to 10x the rated output. But those transients are extremely short in duration, as in milliseconds. So your 50 can be 500 for a brief instant.
The amplifer can't tolerate putting out that amount of power on a continuous basis without blowing up, or failing in some way...

[byacey]

A preamp will only increase the sensitivity of the amount of signal required to drive the amp to full output power. The output power is strictly limited to the capabilities of the power amp.

I've heard many musicians bragging about how powerful their guitar amps are, because the only have to turn the input gain to "2" to be loud; this is a naive thinking.

Not the norm, but solid state amps can be damaged by running without a load if it has an output transformer. Some amps designed for permanent installations have an output transformer for driving 25 or 70V loads, but they also have terminals for driving 4 and 8 ohm loads.