# Effects loop question...



## rwe333 (Feb 18, 2006)

Apologies in advance if this in a bone-headed question...

I have the option of having the factory add an fx loop to a new amp (Matchess).
I understand that the addition of the loop could rob some signal from the amp...
Is this the case? Best to for-go the option? Or is it negligible as the amp already has reverb and tremolo?
Only things I'd consider putting in the loop would be delay and perhaps a looper now and again...
Thanks for any advice... My main concern is having the amp sound as good as it can...


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## Guest (Oct 30, 2008)

rwe333 said:


> Apologies in advance if this in a bone-headed question...
> 
> I have the option of having the factory add an fx loop to a new amp (Matchess).


drrrooooooolllll....opps sorry...I got distracted...



> I understand that the addition of the loop could rob some signal from the amp...
> Is this the case? Best to for-go the option? Or is it negligible as the amp already has reverb and tremolo?
> Only things I'd consider putting in the loop would be delay and perhaps a looper now and again...
> Thanks for any advice... My main concern is having the amp sound as good as it can...


Right: so I'll prefix this with my knowledge of amp circuit topology is limited. Someone else will chime in. I just like to type...and give opinions...like this: a loop adds another stage of buffering to the circuit. Your signal needs to be strong enough to send down a possibly long wire to your effects in the loop and a buffer/driver setup is used to condition it for the journey. Similar to what is done to the signal for sending your signal to the reverb pan. How that changes the overall sound of the amp I think it is going to be pretty specific to the amp topology and the type of loop (parallel or serial) and the buffer/driver design. If I'm hazarding a guess at negative effects I think it might reduce some of the responsiveness -- you don't have as straight a signal path now between the output of the preamp and the input of the power amp, even if the loop is bypassed (I'm not certain but I don't think the buffer is bypassed when the loop is not in use...high probability I'm wrong here though).

Personally I can't give up the loop. I tried. But I can't have my delay and loopers running in front of the amp. I've even started running my wah in the loop. Heck, I can't even function with a single channel amp. It's a mental thing. Just like I need a delay on the floor in front of me or I feel naked playing. Even if it's off. I need to know it's there...my silly brain...

So what's my point? As always: if it feels good do it.

This has always been a hard thing for me to get my head around: ordering stuff from manufacturers. Like Tom Anderson guitars for example. Man, I wouldn't know where to start with the options. How do I know if I like SS frets or not? Or if a compound neck radius would be the bees knees? It's option overload for my brain. If you think you need a loop I say get a loop. That's the best sounding amp for you because effects-in-the-loop are what you need. The sum of all the parts will be different with and without a loop. But if you don't need the loop I'd say omit it -- why clutter up your head space with unnecessary options?


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## mhammer (Nov 30, 2007)

Hi Wayne,

Whether the loop does something negative, positive, or neutral is a function of the type of loop itself. Certainly, there are loop types where if you don't insert anything into the jacks it's as if there were never any loop at all. The signal sent to any outboard devices via the loop may be awful, but you get 100% of your amp back when you don't use the loop.

What type of loop is desirable will depend on what you want to stick in there. If it's guitar pedals, that have a tendency to clip when pushed (e.g., a FET-based phaser), then you'll need a means to tame the outgoing signal, and bring the return signal back up. If you use the loop to drive rack stuff expecting a line-level signal, you may be quite content with just an unbuffered loop.

If you are considering using the Matchless as a sort of slave amp, by feeding its power stage with the preamp output of another amp, then all you may need is some attenuation on the loop return.

Again, a "best" FX-loop will depend on what you have planned.


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## rwe333 (Feb 18, 2006)

iaresee said:


> drrrooooooolllll....opps sorry...I got distracted...
> 
> 
> Right: so I'll prefix this with my knowledge of amp circuit topology is limited. Someone else will chime in. I just like to type...and give opinions...like this: a loop adds another stage of buffering to the circuit. Your signal needs to be strong enough to send down a possibly long wire to your effects in the loop and a buffer/driver setup is used to condition it for the journey. Similar to what is done to the signal for sending your signal to the reverb pan. How that changes the overall sound of the amp I think it is going to be pretty specific to the amp topology and the type of loop (parallel or serial) and the buffer/driver design. If I'm hazarding a guess at negative effects I think it might reduce some of the responsiveness -- you don't have as straight a signal path now between the output of the preamp and the input of the power amp, even if the loop is bypassed (I'm not certain but I don't think the buffer is bypassed when the loop is not in use...high probability I'm wrong here though).
> ...


 Awesome - thanks Ian.


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## rwe333 (Feb 18, 2006)

mhammer said:


> Hi Wayne,
> 
> Whether the loop does something negative, positive, or neutral is a function of the type of loop itself. Certainly, there are loop types where if you don't insert anything into the jacks it's as if there were never any loop at all. The signal sent to any outboard devices via the loop may be awful, but you get 100% of your amp back when you don't use the loop.
> 
> ...


Thanks a ton for this mate!


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## Guest (Oct 30, 2008)

iaresee said:


> (I'm not certain but I don't think the buffer is bypassed when the loop is not in use...high probability I'm wrong here though).





mhammer said:


> Certainly, there are loop types where if you don't insert anything into the jacks it's as if there were never any loop at all. The signal sent to any outboard devices via the loop may be awful, but you get 100% of your amp back when you don't use the loop.


I will say: at least I'm right about when I'm probably wrong! :smile:


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## Guest (Nov 24, 2008)

So what'd you end up ordering?


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## RHGraham (Nov 13, 2008)

Matchless loops are un-buffered and are just switching jacks between the pre and the PI... nothing fancy, and after playing a couple of matchless amps fairly regularly, I can say they didn't effect the amp when not used, and worked ok for me with a funky alesis microverb and a funkier old lexicon digital delay.
In any case, if the loop hasn't got jacks in the sockets, it's fully bypassed.

I don't know if they offer buffered loops now. Personally, if they are implemented in parallel, I think they have exceedingly little negative effect on the original signal.

DC-30's make me warm n fuzzy...

Randal


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## silentbob17 (Jan 10, 2011)

This is an old thread, but I found it searching for info on this very subject. And there are few details that apply to my concerns.

I recently got a Traynor YCV40 and have been sorting out my pedals. It has an EFX loop. I use the channel-select footswitch, I have 2 true-bypass distortions between my guitar and the amp, and I have one mediocre-quality digital multi-effects unit. My impression is that this digital unit should be in the EFX loop so that it doesn't mess with the signal in series with the guitar.

I did some testing and found the following: There is no change in sound when connecting to the "send" jack. All sound cuts out when connecting to the "return" jack. When the digital unit is fully connected ("send" to input and output to "return"), there is a noticeable change in sound when disconnecting and reconnecting to the "return" jack (this is with the unit set to it's bypass mode).

This leads me to conclude that (within the amp itself) the loop is unused unless there is a physical plug in the "return" jack. And when the loop is fully connected and functioning, it appears to be in series, since the output can be completely overwritten by a unit in this loop. For example, if I set the digital unit's rocker-pedal to control volume and rocking it all the way back (even when it is in it's bypass mode) I can cut out all sound entirely.

So my concern is this: am I running through this crappy, non-true-bypass unit all the time that it is connected to the "return" jack? I only use it in one song at the moment so I've simply been keeping it unplugged the rest of the time, since it dampens the volume and makes me worry about tone.

I think I'm going to call Traynor and inquire further about this. I can't see what the point of a loop is if it's in series like this... how is it different from just putting everything between your guitar and the amp? My initial impression was that it was like a parallel path that is there specifically for things you don't want in series with your guitar.... From what I read in the YCV40 manual, the "return" goes right to the power-amp, so I guess that means the loop is after the pre-amp stage... but I still feel like it's directly interfering with the final signal in an undesirable way.


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## Guest (Aug 13, 2011)

silentbob17 said:


> This leads me to conclude that (within the amp itself) the loop is unused unless there is a physical plug in the "return" jack. And when the loop is fully connected and functioning, it appears to be in series, since the output can be completely overwritten by a unit in this loop. For example, if I set the digital unit's rocker-pedal to control volume and rocking it all the way back (even when it is in it's bypass mode) I can cut out all sound entirely.


Yes, this is true of any loop that doesn't include a blend pot -- it's series. A parallel loop requires a blend pot to mix the preamp and the loop return signals together.



> So my concern is this: am I running through this crappy, non-true-bypass unit all the time that it is connected to the "return" jack?


Yup.



> I think I'm going to call Traynor and inquire further about this. I can't see what the point of a loop is if it's in series like this... how is it different from just putting everything between your guitar and the amp?


It's different because the loop appears after your preamp and before your power amp. So after your signal has been distorted by the preamp. That's different than in front of the preamp.

Buy or build a little true-bypass box for your effects unit and use that to remove it from the loop when you're not using it. Some thing like is all you need: True Bypass Switching Systems, Guitar Effects, A/B Pedals, Pedal Boards, Stompboxes, Guitar Buffers, DIY Kits!!!


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## silentbob17 (Jan 10, 2011)

BLAST!

hmmm, that's a good suggestion about the true-bypass box... I actually had thought about just making a switch that cuts the circuit on the "return" patch cable... but I'm not sure if the amp has like a latch inside the "return" jack that activates the loop, in which case the only way to achieve what I'm talking about is to physically remove the plug... so I'm back to the bypass box. I'll have to do a quick test on this.


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## Guest (Aug 14, 2011)

I'd bet good money the return jack is of the latching variety.


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## silentbob17 (Jan 10, 2011)

Turns out that it is latching. Basically the "send" is pre-amp-out and the "return" is in-to-power-amp, and if there is a male plug in that "return", the latch changes the circuit so that the power-amp only receives the signal that enters the "return".

So, I managed to get around my issue of crappy digital-bypass by fabricating a true-bypass box from scratch .

The "send" from the amp is the black cable, plugged into the "input" of the box.
The "send" from the box is the white cable, plugged into the "input" of the effects unit.
The "return" to the box is the grey cable, plugged into the "output" of the effects unit.
The "return" to the amp is the brownish cable, plugged into the "output" of the box.

So the result is that when the box is dis-engaged, it simply jumpers the black and brownish cables together. This effectively sends the pre-amp signal (sent from the amp's "send") right back to the power-amp (into the "return" of the amp), in a true-bypass manner. And when the box is engaged, it effectively adds the effects unit into the amp's effects loop. I simply have the effects unit powered on and pre-set to the desired effects at all times. I used it for the first time in a gig and it works perfectly .









Full Resolution Image

Hope this helps anyone who may be wondering about a similar issue.


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## bcmatt (Aug 25, 2007)

Great! Glad that works well for you. 
It always feels nice to build a solution yourself to make your rig appropriate for your needs. In this case it was merely a true-bypass looper with only a single loop. I made on in a pedal too, and added a momentary DPDT footswitch which allows me to also have the option of having the loop engaged while my foot holds down the second switch. I used this for a while for Fuzz and Whammy pedal together, to get that high pitched jack White synthy squeaky sound for short bursts of a few seconds... quite handy. It also solved the issue of tone-drain from the Whammy since it is not TB. 
Here's a blog entry with pics and links I did for that project:
Guitar Amp Talk: True Bypass Looper Pedal for Whammy


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