FX Loop

[yalesmith]

I wonder if PEC sells a 220k pot? I suspect no. Thanks for the info

[Colossal]

I wonder if PEC sells a 220k pot? I suspect no. Thanks for the info

No, but you can take a standard PEC 250k and put a 2M2 resistor across the outer legs for 224k. Same principle as is done with PPIMV implementations to get them closer to the standard 220k grid leak value.

[jjman]

Here's my parallel one. The 18k could be a ~25k pot to adjust the send strength. My voltages are lower so standard voltages might require a lower value there (weaker send) to avoid overdriving effects. It uses an "input" transformer to flip the phase of the overall loop path back to parity. Then the normally-unused triode brings the loop return signal up for mixing with the dry. You could eliminate that tranny and feed the return boosting triode's output into the "other" side of the PI with a few changes to the PI and a return volume control instead of the mixer. See the Trem-equipped 18watt Marshalls for a PI that uses both halves. I wish I knew to try that alternative before I went with the tranny phase-flipper approach.

It's only sacrilege if you do it to a real Trainwreck.

[badtweed]

In my 20+ years of working with these amps this thread (link below) shows in detail the best wet/dry setup I've come up with to date. Sure it is more complicated and requires a little more gear than an effects loop. However to me it's the best way to do this without ANY compromise on the dry tone and/or on the clean to mean range when controlled from the guitar.

Glen

https://tubeamparchive.com/viewtopic.ph ... highlight=

Here is a video of my breadboarded setup that is similar to the approach that Glen has setup for a wet/dry setup. Not much to look at and it was recorded with low fi methods for the video and audio but you can see the components I used. I used random background pics as the video is just static and uninteresting.

http://youtu.be/dkxfJCTM0uE

It is far from optimized and for this setup I used a Boss SE-70 multi effects that I am just getting familiar with. The SE-70 is not my first choice for the effects component and for that matter the speakers and effects amp are likely to be swapped out for better components later.

[milkyBK370]

I have tried both the loop layouts posted here on an 18 watt tmb single input circuit. I certainly wouldn't recommend them, particularly the plexi type interrupt loop, in a build Luke mine. I think those loops are designed for use with an external buffer like the Kleinulator. There's no way anyone would be happy with the tonal loss otherwise.

[El Chiguete]

How about using one of this for a loop?

http://www.ceriatone.com/productSubPage ... -lator.htm
http://www.ceriatone.com/productSubPage ... ulator.htm

[geetarpicker]

Wet Dry Rig
Wet Dry Rig
Wet Dry Rig
Wet Dry Rig
Wet Dry Rig

Seriously you should try it...

GK

[zambo]

Glen, what are the values on the voltage divider. Do you know or have a schematic? kinda working with this idea right now for my gig rig.

[geetarpicker]

Working from memory. 47k in series with the speaker output terminated with a 1k parallel to ground. Then you take the line level signal off the two ends of the 1k if that makes sense. Tweak the 47k up or down to trim the output if needed. This will work if your wet cab is a guitar cab. If you want to use a full range powered monitor for the wet signal you will need more than a voltage divider you would need a speaker emulation circuit. Lately I've been using my Faustine Phantom as it has the line out and speaker emulation. Sadly they are out of production. That said if you use an outboard power amp and a guitar cab for the wet the simple 2 resistor line level circuit will work fine. In my experience I've found a 1x12 works nicely for the wet side, even if your dry cab is a 2x12 or 4x12. I use a QSC K10 as a powered monitor and it sounds very nice for effects and it's even more compact than a 1x12.

[zambo]

Good info! Thanks! I am putting my wet dry rig together today. I am starting with my old peavey as the wetside. Its loud , clean and has a reverb. Probably work ok for now. Again, Thanks!

[zambo]

Just put the 47k 1k divider on my ext speaker jack. Works awesome! Thank you for the help. I used my vox tone lab for fx, which doesnt have a dry kill, but even still it works great. the guitar tone from the other amp isnt horrible either. Its just a peavy transtube but it works. I have to turn the treble down a bunch on the wet amp.