effects send/return mixer

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jfv

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Hello,

Definitely a newbie question here.

I've been using a hardware mixer send/return effects loop in and out of one stereo side of an RC3 loop pedal (and running the out of a pedal board through the other side of the RC3 into an amp). I make bass and voice loops from the mixer, and guitar and keys loops from the pedal board (merged those signals with a mini mixer at the beginning of the pedal board, the idea being to use my pedal board and amp with both instruments).

The setup was perfect using a Peavey powered mixer (powered mixer because we're also doing rehearsals in the same room, it's not a desktop setup). I just upgraded to a small passive mixer (and active speakers) with effects send and return and tried to pull the same trick. It's not working because it's too noisy. If I crank the effects return volume on the mixer the hiss is really not tolerable to work with. I wonder what's the difference between the two loop circuits and if there is a solution. I'm guessing the strength of the effects send signal is weaker on this new mixer, but I would have thought an effects send signal would be of similar loudness if not standard.

The new mixer is Yamaha MG82CX. It has a single balanced send jack and two unbalanced return jacks. I'm not sure I understand why the send is balanced and the return unbalanced. I'm thinking maybe it's for sending a stereo signal from the single jack. What I'm trying to do is mono out of send, through the one side of the RC3, and mono back into "L (mono)" return jack.

Would using a balanced cable out of the mixer send jack and into only one side of the RC3 loop pedal somehow cut the noise? Also, I'm wondering if stereo jack cables are the same as balanced jacks. In any case I'd like to understand where the noise comes from and if there is a way to eliminate it. Thanks for any help.
 
You're not going to be able to use a balanced cable to go from mixer to RC3 - I assume it doesn't have a balanced input. Balanced cable = +, -, gnd. SImialrly, stereo jacks are not balanced, they are +, - (or if a 3 wire 'stereo' cable, L, R and 'common').

I suspect the source of the noise is the Yammie mixer's FX Send output does not match the impedance of the RC3 input. You'd have to check all the specs to see that. If its not the case, then the problem is the Yammie send signal itself (noisy circuit).
 
I'd say test and compare your set ups -with how you had them set in the other rig, and maybe try for example maxing out the channel fx send -presumably max to the loop box, and the return lower etc.
 
checked specs

Thank you very much for your reply. I'm dense with respect to these concepts, need to study. Here is the information which probably confirms what you're saying:

YAMAHA EFFECTS SEND AND RETURN JACKS SPECS:
SEND
Output impedance:150 Ω
Appropriate impedance: 10 kΩ Lines
Nominal level: +4 dBu (1.23 V)
Max before clipping: +20 dBu (7.75 V)
Connector specifications: Phone jack (impedance balanced [Tip = HOT, Ring = COLD, Sleeve = GND])
RETURN (L, R)
Input impedance: 10 kΩ
Appropriate impedance: 600 Ω Lines
Sensitivity: – 8 dBu (308 mV)
Nominal level: +4 dBu (1.23 V)
Max before clipping: +24 dBu (12.3 V)
Connector specification: Phone jack (unbalanced)

RC-3 LOOPER INPUT AND OUTPUT:
Nominal Input Level: -20 dBu
Input Impedance: 1 M ohm
Nominal Output Level: -20 dBu
Output Impedance: 1 k ohm
Recommended Load Impedance: 10 k ohms or greater

Given the above is there anything I could do or just give up connecting the loop pedal to the mixer? I wonder if adjusting the various volumes relatively to each other would make a difference, and I wonder if it would be possible to connect one side of the mixer's normal output (balance is dead center on all channels for now) to the pedal and the other directly to a speaker. Loop would come out only on one speaker but it's not a big deal
 
Sometimes there is am master volume on the effects send buss. if that is turned way down and the effects return turned way up to compensate, you can run into noise issues.
 
Thanks for all the help. I've now experimented with all the volumes in the path and indeed it seems that an effects send volume pot would help, but there is none on this mixer. The central problem seems to be low volume going into the pedal. The effects send volume appears to be controlled by the particular channel's, gain, effect (still active when turning off mixer's own effects) and main volume. For some reason it works fine on the vocals channel, with an acceptable amount of noise, and not on the channel I use for bass (eventually we're gonna get a proper bass amp but the sound is pretty rich and versatile through this mixer and powered speakers). I'm guessing the volume from the vocal microphone cable is higher than the volume from the bass cable. I see that higher range mixers in that series have auxiliary effects send and return volume as well as an auxiliary effect pots on each channel. Guessing that would solve my problem. If you guys can confirm or correct these general impressions that'll be all the info I need and we can put this thread to rest. Thanks again. JF
 
If you aren't getting enough signal out of the effects send, you probably don't have the gain on that channel set properly. Hit the solo button and turn the gain on that channel up so that the meter reads an average of zero, with peaks going higher. Then, if that makes that channel too loud in the mix, turn down the fader.

Using the effect as an insert might work better in this case.
 
Hi, man
I just stumbled on your question and wondered if you found a solution to lower the noise level? I have the same looper and guess what - intend to user the same Yamaha mixer with its send/return options to loop phrases. So this problem really interested me!
Thank you in advance!
 
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