Signals confusion

[randrohe]

Hello everyone,
If an active instrument outputs a line level signal, wouldn’t this be compromised going into the front of an amp as the amp is expecting to see an instrument level?
And if not, then plugging a synth or a mixing board straight would be acceptable?
Isn’t re-amping necessary to convert ?
How am I still unsure about this?

[Nick Sevilla]

Hello everyone,
If an active instrument outputs a line level signal, wouldn’t this be compromised going into the front of an amp as the amp is expecting to see an instrument level?
And if not, then plugging a synth or a mixing board straight would be acceptable?
Isn’t re-amping necessary to convert ?
How am I still unsure about this?

Yes. Guitar amps need instrument level input. Here is a simple primer, not too technical:

https://support.focusrite.com/hc/en-gb/ ... ment-level

That is why they make "reamp" boxes. So you can plug in a console's line output to a guitar amp. Been done for decades, the guy who made all that reamp stuff up, John Cuniberti, is a cool dude, engineered and produced a lot of Joe Satriani's records.

Now, as to an active guitar or an active bass, that is only for the way the pickups are electronically processed, most still will output a guitar level signal. Some have both a line level output and a guitar level output on them, but those are rare. As an example, I have a Music Man JP6 that has a battery operated (aka "active") piezo pickup under the bridge. The output is still guitar level.

[winky dinglehoffer]

If an active instrument outputs a line level signal, wouldn’t this be compromised going into the front of an amp as the amp is expecting to see an instrument level?

Guitar amp inputs are high impedance; a passive guitar pickup needs to see a high input impedance so as not to sound bad. As to "level", a guitar can put out a surprisingly high voltage; level can be an issue, but you undoubtedly have ways to adjust that.

A synth into an amp will sound like a synth into an amp. I happen to like that sound, but is it "true" to the synth's sound? Of course not. You can plug straight into a mixer or interface & get a much fuller-frequency and often less distorted sound. But if that's what you want, why go into a guitar amp in the first place?

If you're reamping a guitar, simulating a pickup's impedance makes sense in that it will cause the input signal to interact with the amp in a more guitar-like way. But a guitar amp will continue functioning with lower impedance signals (disregarding low impedance mic outputs here); whether a particular source sounds better at a high or low impedance is up to you to determine.

[digitaldrummer]

They now make quite a few FRFR (full range, flat response) amps that generally have a combo line/instrument jack on them. Those are meant for plugging modeling devices into (like the Fractal and Kemper's) but should work equally fine with a synth/keyboard. I know a lot of keyboard players that just use a powered monitor (like what you'd use for a pa main or monitor) for their keyboard amp (whereas they used to have big old heavy "keyboard" amps). but all depends on what kind of sound you are trying to get.

And speaking of mixers, a lot of portable mixers have line/high impedance switches on one or more inputs (like an interface) so you can choose the correct matching level/impedance. Their outputs would generally be line level (if its unpowered).