Simple Effects loop

[rjgtr]

Here's a real simple effects loop for a 18 watt...

First, you'll need to mix both channels together to one side of the PI. Disconnect the second channel from the PI and take the un connected PI side to to ground with a .01uf or .1uf cap. Add a 220k resistor to each channel output on one side and connect them together on the other. From this point take a .022 cap and connect to the Send jack tip. On the return jack tip add a 47k resistor and attach a .01uf cap from the other end of the resistor to the PI input. You'll want to jump from the shorting connection of the Return Jack to the Tip of the send jack.

If the send is too hot take a 220k and put it between the send cap and the send tip. From the send tip add a 1 Meg to ground. If the signal is too hot adjust the 1 Meg down to 470k or even 100k. Of course you replace the 1 Meg with a send pot and add a return pot on the Return side, but then it's getting less simple!

I've found this loop has a minimal change in sound from the normal connection. OF course this loop is designed more for a rack effect, where you have control of input and output. I use a TC Electronics G-Major.

Richard

[kmenard]

would something like this work with the pod pro?

I want to be able to use the effects, but not the amp models.

[massygt6]

great post man, can you provide a schematic? it would be great!

[rjgtr]

Since the effects loop is a passive type the device used would need to be able to compensate input and output levels, but it could work. The only issue with an effects loop in a standard 18 watt is that a lot of the distortion is gained from the power section, so some effects would be blurred. But it should work.

[jersey_aaron]

I have a simpler method. I use two 18 watts. One has a simple line out (two resistors on a speaker out jack) that I feed into a delay unit, which outputs to the input of the second amp. This method also adds real stereo spacial delay. There is also no "dual amp" buzz problem, since the speaker out on my sending amp isn't grounded to the chassis.

[rjgtr]

Here's a schamatic of the loop. It doesn't show the channel mix resistors.


Jersey - That's a great way to do it. But why not go all the way like the big boys and add a third amp for a try wet-dry-wet stereo rig!

[kmenard]

After last night playing with my effects, I realized this is probably something I need to do.

Do you still have 2 channels though?

Any chance of a layout view?

Thanks Rigtr

[rjgtr]

I built this into a modified 18 watt circuit that uses a single input channel switching arrangement.

To use it with a normal 18, you'll need to mix the two channels to one side of the phase inverter and put a .01 cap to ground from the other side of the phase inverter. This is how most amps do it anyway. If you look at a Fender Deluxe, you'll see two 220k (I believe) resistors that are used to mix the channels. The other option is to just build two effects loops, one for each channel.

I don't have a layout of this, but it is pretty simple. I usually just build it across the jacks and fly the input and output caps from the main board. Also, don't be afraid to experiment with the input resistor values. Some amps need them higher or lower to balance the input signal. Plus, since this isn't active, you may have to boost levels on you effects device, especially on the return side.

[kmenard]

Sorry to be thick headed...but would this bring me down to 1 channel then?

[JonFrum]

Sorry to be thick headed...but would this bring me down to 1 channel then?

from the first post:



" First, you'll need to mix both channels together to one side of the PI"

[rjgtr]

kmenard,

No, you would still have two channels. That is why you want to use the mix resistors to mix both channels to one side of the PI. The effects loop is inserted between the mix resistors and the PI input.

Richard

[johnnybegoode]

Hi

I have some questions:
1) What is PI?
2) What is passive and active effect loop?
3) Do you have the schematics?
4) I want to add the effect loop to my AD30VT, can this work?

Thanks!