Questions on preamps and pedals

[dacaumodo]

OK I'm a bit confused about some things. So here's three questions

Is there a fundamental difference between an OD or distortion pedal and a guitar preamp ? Could you, for instance, drive a power amp with, say, a tube screamer?

With some pedals (ex: my TDX9) you can record straight into a mixer, with others you'll need a DI. Why is that?

Some of the projects at ROG (ex. the mouth watering English Channel) interest me very much. Yet I wonder if I could use those pedals (Supreaux, English Channel, Flipster, Matchbox, etc.)via a cab sim and then straight into a PA for instance, or a mixer for recording? Bit like my Sansamp Tri-ac actually...

Thanks folks...
Guillaume

[markm]

Some of the projects at ROG (ex. the mouth watering English Channel) interest me very much. Yet I wonder if I could use those pedals (Supreaux, English Channel, Flipster, Matchbox, etc.)via a cab sim and then straight into a PA for instance, or a mixer for recording? Bit like my Sansamp Tri-ac actually...

Thanks folks...
Guillaume

I recall reading from someone on here that they ran one of the ROG pedals into a Cab Sim and straight to a PA.
For the life of me I don't recall who it was but, I do remember reading it.

[Mark Hammer]

There's only a couple of things needed for a power amp to be driven by something:

1) The output impedance of the driving device should be somewhere in the ballpark of what the power amp expects.  Many will prefer to have something in the 600-ohm range but will settle for things a bit higher.

2) There should be some protection against stray DC voltages, either on the power amp, the driving device, or both.

3) The signal level should be somewhere in the line level range.  Less than line is tolerable, but the S/N ratio may not be as good as it could be, and the output power may be less than what the amp is rated at.  Of course even "proper" signals produce milliwatt and single-digit wattage outputs from large power amps (people DO whisper into mics occasionally), so the issue is really whether the highest possible input signal level is one that exceeds or falls far short of the expected input level for rated wattage.

4) The output of the driving device should be of the same type as the input of the power amp.  So, unbalanced out drives unbalanced input, and balanced input is driven by balanced output.

Meet those requirements and you're in fine shape.  My nephew had a rig that involved some name-brand dual 50W MOSFET power amp, and a Digitech digital multi-FX unit.  One time, while visiting, I plugged my guitar directly into a booster/overdrive pedal and into the power amp input.   Worked just fine.  Most of the ROG amp emulator circuits work no differently than what I used.  So yeah, they should work.

[dacaumodo]

Thanks Mark & Mark.