ibanez,
(The following is either ‘imho’, or correct to the best of my understanding…I always welcome addition input from others.)
So you want to use the loop? Good for you. It’s there to be used, and not the source of all evil that some would make it out to be. Sure it changes your tone, but then you adjust your tone stack and live with the results. For example – if you want your delay to retain your level of distortion on the repeats (not ‘clean up’ with each feedback because of the decreased level to the preamp), placing it in the loop is the only thing that’s going to work. Some effects sound better after the preamp.
In general, a better quality effect unit will sound ‘better’. Your amp is a high quality piece of equipment and has the resolution to reveal a crappy sounding effect for being…crappy.
It's critical that you truly –understand– what the controls are doing for you to have to best benefit from them. Let’s discuss.
First…is the Mesa effects loop ‘instrument level’ or ‘line level’?
The answer is ‘neither’. It’s adjustable via the controls, to handle a variety of situations.
As you most likely know, ‘Output’, ‘Send Level’, and ‘Solo’ are all controls that are placed in the signal chain when the amp is set to ‘Loop System Active’. In order of signal flow…
Send Level – This control affects the signal immediately after the preamp, and controls the level that is output from the ‘Send’ jacks. The purpose of this control is to give the user the ability to provide the appropriate signal level for the particular piece(s) of equipment that they are using in the loop.
Output – This control affects the signal immediately after the ‘Return’ jacks, and controls the level that is being input into the power amp.
As mentioned in the manual, a ‘nice by-product’ of this control is its ability to raise or lower the level of all channels simultaneously…but this is merely a convenience benefit of the control’s true reason for being included on the amp: effect level balancing.
An additional ‘by-product’ of having the Output control is expressed via some users’ quest for tone. By running the amp in a state of ‘not unity gain’ (having a channel ‘Master’ and the ‘Output’ vastly different from one another), users seek a ‘certain tone at a certain volume’. Again… this is merely a convenience benefit of the control’s true reason for being included on the amp: effect level balancing.
Solo – This control is (you guessed it) merely a ‘nice by-product’. Wired in parallel with the ‘Output’ control, it is a ‘non tone affecting’ (in general) volume boost. The mere act of including this control does not alter (degrade) the tone, and the addition of the control was a nice feature. This control is not part of balancing signal levels of the effects loop, and so I won’t be mentioning it below.
Alright, now let’s talk ‘unity gain’. When you don’t have the effects loop active, the amplitude of the signal leaving the preamp is essentially the same amplitude of the signal entering the power amp. Unity gain…not smaller, not larger. (We are ignoring the effects of the reverb circuit in this conversation).
On my amp (RK II), when I engage the loop:
1) with the ‘Output’ and ‘Send Level’ at noon, AND
2) with nothing plugged into the send or return jacks
…I have unity gain with the effects loop activated. I verify this by listening to the level while switching back and forth from ‘bypass’ to ‘loop active’ using the switch on the amp (not by hitting the loop button on the footswitch). So, even with the loop engaged, we have unity gain.
Now, let’s look at examples of how to use the controls (Output and Send Level) with effects in the loop. Your target is unity gain in these examples (you’re welcome to break the rules once you learn them…but let’s learn them first). For simplicity, these examples involve only one pedal.
Remember, since your using the controls with the intent of balancing the effects loop, all the ‘nice by-products’ are secondary.
Example 1 – You have a really sensitive instrument level effect. It clips way to easily when hit too hard with a signal. The effect does not have its own level control on it.
Possible answer - The signal leaving the preamp needs to be reduced to a level that the pedal can handle. You do this with the ‘Send Level’ while listening to the effect. Reduce the send level until the clipping stops. Now the effect sounds good, but the level is so low coming out of the effect that the power amp is not getting a large enough signal for unity gain. You correct this by raising the ‘Output’. You verify by having the effect on, and switching back and forth from ‘bypass’ to ‘loop active’ using the switch on the amp (not by hitting the loop button on the footswitch).
So, using the controls, what have you done….you reduced the amplitude of the signal between the preamp and the effect, and raised the amplitude of the signal between the effect and the power amp. This was to accommodate the effect (the whole purpose of the controls).
Example 2 – The pedal does not have any problem with clipping, but the pedal introduces a amplitude change, louder in this case.
Possibly answer – I’d leave the ‘Send Level’ around noon so the effect receives a sizeable signal (good for signal to noise ratio), and lower the ‘Output’ control for unity gain. You verify by having the effect on, and switching back and forth from ‘bypass’ to ‘loop active’ using the switch on the amp (not by hitting the loop button on the footswitch).
Ok…now think about these examples, and let us know if you have more questions.
One other thing…
Here is what the manual says about setting all your channel ‘Master’ before adjusting your loop:
Dedicate and Dial in your sounds in each of the preamp Channels and adjust Channel MASTER settings for volume balance (this affects send level strength in the LOOPS).
Best of luck.
Strat
