connecting a preamp to a 2 channel power amp

[HertzWhenIPlay]

when connecting a preamp to a 2 channel power amp, is a 2 channel preamp required?

the power amp is not bridgeable.

thanks.

[runmikeyrun]

no, it's not required. Plug into channel 1 and use the speaker out for that channel. Keep the volume at 0 on the channel 2. Make sure to check the amp for DIP switches on the back panel, my QSC has some that allow you to select stereo or parallel inputs. Make sure it's set to stereo, if it's parallel the amp is going to try to drive channel 2 along with channel 1. Most amps have protection built in if there's no load on a channel, but why take chances?

[Jazzdogg]

Originally Posted by HertzWhenIPlay

when connecting a preamp to a 2 channel power amp, is a 2 channel preamp required?

the power amp is not bridgeable.

thanks.

Depends.

Do you want to be able to control each cab's level and EQ separately? Or are you trying to feed both cabs the same signal?

Not all power amps have the ability to drive both input channels from a single input; some are switchable. Not all power amps can have their outputs bridged, which can be dangerous to the operator and his gear if done unadvisedly.

[nashvillebill]

Let's clarify--there is a difference between bridgeable (bridging outputs) and parallel (dual) mono or bridging inputs. Unfortunately amp manufacturers do not always standardize on their terminology.

The parallel mono, or dual mono, is when some amps have a switch which internally connects inputs of the two power amps, sorta like a Y-cable, so that both power amps can run off of a single signal. Each power amp is connected to its own speaker. If the amp has independent gain controls, each power amp and its corresponding speaker can have its volume adjusted independently. The key is that the inputs are connected, sometimes called bridged--but it's the inputs.

Some people prefer to use the word bridging with respect to the outputs, when the two power amps are connected on their outputs and used to power a single load, typically one speaker (which must be twice the nominal impedance of the speaker load rating of the separate power amp). This is how I tend to think when somebody says "run the amp bridged".

[T-Bird]

Hi.

+1 for not required.

Almost without exeption I run all my PA stacks mono. I feed the (oldish) amps with a balanced XLR feed, and use TRS patch cables to "transfer" the signal to the other channel if needed. If Your pre has only a phone output, a XLR patch cable can be used.

This is obviously assuming the amp has both XLR and TRS inputs.
And also assuming that You want to run both the amp channels simultaneously .

Regards
Sam