+4 vs -10 effect loop options

[mantis]

If you have the option to go either way so lets say the amp cam change to +4 or -10 and so can the effect or effects , which way would you go and why?
I Choose +4 for both as it's louder but not sure if I'm taking anything away by doing so.

Opinions?

[pianoguyy]

That option isn't there for volume. It is there to match input/output levels.


Even though this is an inaccurate example, I think a good way to describe the difference would be watts and ohms.
You can safely use a 100 watt amp on a 50 watt speaker, just turn the volume down.
But a 16 ohm amp shouldn't be used in an 8ohm cab. Turning the volume down to make sure the speaker doesn't blow isn't the same because you are receiving the 'power' regardless of volume.

[toejam]

They're to match the levels of your effects units. One is for rack effects (line level), the other is for pedals (instrument level).

For example, from the owner's manual of my old Marshall Valvestate 8240 2x12 stereo chorus combo: Effects Level Switch - Selects the level to match your external effects units (0dB for rack units and -20dB for pedals).
Of course, that's a slightly different signal strength ratio for input sensitivity from +4 to -10, but you get the idea.

[Axewielder]

-10 dBV is called "consumer line level" while +4dBu is called "pro audio line level". In a nutshell, the pro level is a bit hotter than the consumer level. Technically there is a subtle impedance difference as well which is largely irrelevant (hence the different units). Instrument level is actually lower than both of those line levels. Most pedals are compatible with line level, which allows them to run in effects loops in unity gain. Sometimes you have to really dig deep to find which level equipment is at. Sometimes there is a switch. My Eventide has an internal jumper than can be moved.