# Passive Effect Loop- Two Rock



## pstratman (Jan 26, 2012)

My Two Rock has a passive effects loop- and I have read I will need to buffer the loop with something- I have my eye on a Fuchs buffered tube effects loop pedal- anyway- when I put my delay in the loop everything sounds really good still. Am I missing something? Would it sound even better with the buffered pedal? I contacted Two Rock and they said, "If the loop sounds good, I wouldn’t worry about it. You don’t always need a buffer.
Hope this helps!"

Can anyone else share their knowledge?


Phil


----------



## pstratman (Jan 26, 2012)

My Eventide Timefactor on the line setting sounds great in the loop...


----------



## Boogieman (Apr 6, 2009)

I am quoting Andrea "Stinkfoot" Moller from another forum (forgot which one) on this subject a few years ago:

---------
Before buying anything, I'd want to rule out the loop circuit (inside the amp) itself as the culprit. Most fx loop sends already are low impedance, so cable length usually isn't a problem. It's far more common to get sound changes when a series loop is inserted in the amp's signal path (especially when the signal level is dropped to fit stompboxes, and then re-amplified back up to line level before the power amp stage).

To test this, run the fx send -> pedalboard cable from send to return (just the cable), and see what effect that cable length has. For comparison, turn the fx loop off (or remove the cable). Then compare with a short patch cable from send to return, to determine what effect (if any) _that_ cable length has.


If you hear a tone change (for the worse) with the loop on, regardless of cable length, the loop itself is the problem, and a buffer probably won't make any difference.
If you get treble loss with the longer cable, a buffer could help with that. But it'd have to be located at the amp - as close to the "send" jack as possible - and not on the pedalboard.
If you don't hear any change at all when comparing the two cable lengths, the loop is already sufficiently buffered. Any tone loss when the loop is inserted is either due to #1 above, or the pedals themselves.
Effect loop buffer/matching units can help the tone - the Vox unit mentioned was really good, for instance. But if the loop circuitry already in the amp is costing you tone, even when the send/return levels are set to their optimum settings, the buffer/matching unit will not get rid of that loss.

/Andreas
------------

The Vox unit that he was referring to was the Vox V941 Valve Effects Loop Buffer (discontinued).


----------



## jb welder (Sep 14, 2010)

If everything sounds good, it probably is. If you need a buffer, I think you will know right away something is wrong. Most likely sounding weak and thin with the particular effect that needs buffering.
If it sounds good with your delay already, I don't think a buffer will make it sound even better. But you may run into other effects later that need buffering in your loop.
Perhaps @mhammer would further comment on the buffering issue.


----------



## mhammer (Nov 30, 2007)

My own sense is that much depends on what one is buffering _*for*_. If the buffering is to send a preamp signal directly to a mixing board, or to line-level rack equipment, then it will anticipate a much lower input impedance in the board than what would be provided in a pedal. The board is expecting a 600-ohm mic, where the pedal likely has an input impedance of at least several hundred kilohms, because it is designed in anticipation of receiving a guitar directly.

I would concur with the posts here by others that your next steps should be dictated by your ears.


----------



## pstratman (Jan 26, 2012)

I tried 2 different delays in the loop with very different results.... the Eventide Time factor has a setting on the back to switch it from amp to line- when I switched it to line I get much more of a signal and I realize I was experiencing signal loss the other way. It sounds pretty good a few more tests are in order based on the previous messages. I will let you know.


----------

