Tube Amp Forum: The Ultimate Tone
fx loops - Printable Version

+- Tube Amp Forum: The Ultimate Tone (
+-- Forum: Tube Amp Community (Hi-fi too!) (
+--- Forum: Preamp Mods & Design (
+--- Thread: fx loops (/thread-189.html)

fx loops - Adam - 08-19-2020

no one seems to have posted about this so I thought id ask a few questions!

Firstly if I add a ‘Best all-tube loop’ (BATL) in TUT (fig 7-16) if I want to bypass it do I do it a) Completely with relays or b) can i just mute send/return portion?
Secondly, If I have two preamps with their own loops, each channel can have their own send but share a recovery ( like the example in TUT 4 fig. 6-45)

Where would the two signals mix? I’m guessing at the “0” virtual earth point in the BATL? I can mute each loop when each channel is switched in/out?


RE: fx loops - K O'Connor - 08-19-2020

Hi Adam

The usual acronym is BFX, like the kit we sell for this loop.

There is no need to fully bypass the loop; rather, simply disable the send and make sure the dry mix path is enabled for the bypass regardless of whether you typically use it in series mode. Our Q-MNR kit switches the loop properly as described, using relays for the audio control.

Since you have TUT, you can read that the return mixer is exactly that - a mixer. This opens up the possibility of "sideways expansion" where multiple channels or loops can be configured in parallel, all sharing a common return mixer. This saves some tube sections and hopefully will not result in an unused section.

Have fun

RE: fx loops - Adam - 08-21-2020

thanks! I see there's a kit (Q-Mini) especially for switching preamps and loops so I will invest in that.