Converting a Parallel Effects Loop to Series?

[strtdv]

Can it be done?

 

Ideally with a mix knob that lets me go from 100% wet to 100% dry

[WRGKMC]

Not sure your terminology is correct. Effects loops are normally series and you idea needs more explanation. Parallel effects usually sound terrible and need either multiple amps or buffered ins and outs, or a mixer used to adjust the individual levels. The pot thing is incorperated in many guitar amps. My marshall has it and also a button that places the effects pre or post preamp. Otherwise effects are usually chained in series in the proper order.

[Dthraco]

Possible, but depends on the amp for the dial you are talking about.

 

Most amps that have a paralell loop already have a mix knob.

[WRGKMC]

I dont see where a paralel loop can be used on an amp. The effects loop usually disengauges the preamp from the power amp and inserts the effects in series between the two so you have preamp>effects>power amp.

 

To have it in parallel you would need to have a mono send and stereo return and the stereo return is monoed using buffers. I suppose the stereo return can have a balance knob to balance between the two effects but the sound quality will suck. if you bypass one of the effects, you'd be pumping full clean signal through and it would mix with the remaining effect cutting its effectiveness in half.

 

To prevent that from happening the effects would need to be wired to disconnect it from the loop vs bypassing it. But with both effects off no signal will pass.

 

Series is the best way to go unless its a stereo rack unit. there again most rack units alloe mono ins and outs so the whole issue is moot.

[Dthraco]

WRGKMC -

 

I am talking about guitar amplifiers. Lots of them have paralell effects loops. They work just fine. Degredation in the tone, some, but again it depends on the amplifier.

[WRGKMC]

I'm talking in terms of electronics not what someone labels an amp. The term Parallel effects loop is a missuse of the term by both the manufacturer and the users. It doesnt matter weather the amp is labeled a serial or parallel loop both place the effects between the preamp and power amp weather it has a blend knob or not.

 

The misused term Parallel effects loop comes about by installing a bypass pot that adjusts the level of bypass the same way a bypass knob on an effects unit adjusts between dry or wet.

 

It basically connects the ins and outs to make a straight connection the same way as a bypass switch works. Its done with buffers so the effects arent damaged and the effects ins and outs arent shorted, but audio wise thats what happens.

 

Its definately not considered parallel unless you consuder a light bulb thats shorted to be in parallel with the wire shorting it. I dont because you dont have a dual signal flowing, you have one or the other. I consider that bypassed. You could make a case that a knob adjusted 50% up has a signal passing half through an effect and half through the pot but most who understand that still consider it bypassed or blended, definately not parallel.

 

A mixer with 2 channels and an effect on both channels, then blending those two effects with volume sliders is true parallel. If one effect is bypassed and the volumes are set equally, you will have half one effect and half straight signal.

 

If an amp has a stereo effect send (A true stereo parallel send) and two blend knobs or a pan between the two it can be considerd parallel loop because signal remains passing through both channels.

[Dthraco]

Didn't need the explanation, and not interested in pointing out the flaws in your theory.

 

But hopefully some of this helps the thread originator.

[strtdv]

Er right..

 

Whatever the terminology, my current effects loop is a 50:50 mix with no control to either turn it off or to vary the mix from 100% to 0%. Any way I can change this?

[Dthraco]

You can. But you need to know how to solder and read schematics. Or, you could hire a tech to do it. Your call.

 

If the amp is under warranty, you might re-evaluate if it's worth it or not.

[tedmich]

I have just made a PCB layout which duplicates the fully by passable, input & output variable, discrete transistor effects loop of the PV JSX. Haven't etched and tested yet but soon...Just supply +/-17VDC and tap into the pre.

 

Oh STRTDV, is it a Laney or Orange? lots of schems for them, tell us the model and you'll get better guidance!

[troolucas]

you offer guidance thank you so much , I have a trouble with mine marshall valve state 8240.

It has a parallel stereo loop effect and I definitely need to turn that into a series one. How can I modify it? Which resistor should I bypass?

I have replace some condensers and transistors because the manual says that with the knob fully to wet, it becomes series.

Thank you for all your help, I don