I have a Carvin SX-300 stack. I use Boss effect pedals. I tried running my regular pedal setup and plugging into the Front "input" (See attached picture "Carvin Head Front View"). Everything sounded horrible. I then noticed there is a "Effects Send" and "Effects Return" on the back of the head (See attached picture "Carvin Head Back View".

Would things sound a lot better if I used those inputs instead of the front input?

If so, what do I connect to what? I also included a picture (See attached picture "Boss Power Supply") of the Boss power supply which has a bunch of inputs; AMP, SEND, RETURN.

Any help you can give me to connect everything the correct way would be appreciated

Carvin Head Back View

  • 1
    Can you clarify what your question is regarding the Boss power supply/switch pedal? That pedal does not change the sound by itself, it allows you to turn on and off a whole set of other pedals at once. Jan 24, 2017 at 15:10
  • 1
    Which channel have you selected on the Carvin?
    – Laurence
    Jan 24, 2017 at 15:12
  • Sorry, I was wondering what to connect to what. Im sure I start at the"Send" port on the back of the amplifier head. Then, Im unsure where to plug the "Send" cable into on the Boss pedal; Send, Return, or AMP? Then my second question would be, going back to the amp head "Return" port, where do i plug the "Return cable into on the boss pedal; Send, Return, or AMP? I hope I have asked this the correct way and I have not caused more confusion! Thanks for your help so far! I use the Boss power supply to power about 6 or 7 other Boss effect pedals in my effects chain.
    – Joe
    Jan 24, 2017 at 15:43
  • At first I chose the clean channel (#3). I have tried all 3 channels and everything sounds horrible. Thats when I got the idea to look into using the "Send" and "Return" on the back of the head and see if that makes a difference
    – Joe
    Jan 24, 2017 at 15:55

2 Answers 2


The effects loop provides a way for you to insert effects into the signal path after the pre-amp, but before the power amp. The signal level here is higher, roughly line-level, than the signal coming straight from the guitar. This (usually) provides higher signal-to-noise.

Most players like to keep drive/fuzz pedals in front of the pre-amp (it is their interaction with the pre-amp that is desired) but other effects, especially modulation effects like chorus, phasers, delays etc., into the effects loop.

So a typical signal chain would be

guitar -> drive/fuzz -> front input 
              -> preamp  -> efx send -> modulation effects -> efx return  ->
                     -> power amp -> speaker

But as with all things pedals, you need to experiment in order to find what sounds good to you.


Pros tend to use both send/return and before pre-amp. Some effects are better going gtr>pedal>amp input (pre), whereas others are better linking between the pre and the main amp, where the signal has already been coloured by the pre-amp.

So, to do a really good job, you need to create the wiring so that some of your pedals have the guitar plugged directly into them, then into the amp., and others by a wire that comes from send into 'in', and their 'out' goes into the return.

Generally modulations sound better beyween send/return, whereas overdrive/dist. go better at the very front. Having said that, you need to try each combination - a lot of choices there - but also bear in mind, if you don't already, that the order of pedals will make a big difference, too. Do you want the chorus to be delayed, or the delay to be chorused, for example?

Once you have a good idea on where they go, it's probably worth making up a sort of wiring loom that goes from the pedalboard (you do have one, I hope!) to the amp, using 4 cables instead of the 2.I also ran the DC power from a socket which had the wallwart in it, in the back of the amp., that wire being an extra in the loom.

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