Toys not play nice, why?

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Toys not play nice, why?

Postby Scott DeVarenne » Tue Aug 24, 2010 9:20 pm

Tweaker guitar amplifier, into effects loop I introduce Zoom G2.
Signal is attenuated significantly even with all modules bypassed and output of G2 cranked. With high gain Tweaker preamp setting I get digital clip, there are no indicators but I know that sound, oh how I know that sound. But well before clip, trouble too. Why?
Relevant specs:

Zoom G2
Rated Input Level -20dBm
Input Impedence 1 megaohm
Maximum Output Level +5dBm
(output load impedance 10 kilo ohms or more)

Tweaker
Effects Loop Send Impedance 600 ohms
Effects Loop Return Impedance 220 kilo ohms

Shed light, please.
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Postby Malcolm Boyce » Wed Aug 25, 2010 12:45 am

First thing I notice is the TRS Stereo output of the Zoom unit.
"Once again, it is NEVER the gear that makes a good record.
It just fills Forum pages..." --compasspnt

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Postby macrae11 » Wed Aug 25, 2010 2:57 pm

Specs say the Tweaker has a 220kohm impedance on the effects return, which seems quite high. I don't know what the normal impedance for an effects return is, but some amps have switchable loop imedance. If you plug the pedal in before the amp, does that get rid of the volume issues?
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Postby Malcolm Boyce » Wed Aug 25, 2010 3:19 pm

As well, the "Zoom" appears to be designed to be fed by an instrument and not the out of a device such as the amp FX loop. Even if the Zoom unit is set to "unity", if it's output is scaled to a low level I/O, it will clip on input and not output a level corresponding to it's input.

Think of an outboard FX device in a console situation. If a desk outputting a +4 level is patched through a device set to -20, it will clip the device on input, and return a much attenuated signal.
"Once again, it is NEVER the gear that makes a good record.
It just fills Forum pages..." --compasspnt

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