How does send and return really work?

Manfred-Klose

How does send and return work on a full valve amplifier? No one gave ever gave me a straight answer, i'll guitarforum a try. All i want to know is when the signal goes through the send>ambience pedals>return, where in a valve amp does that happen, Before or after the pre amp section? Or does the send and return samples with the input, and then go to the pre amp section? In my case its a "Peavey Delta Blues amp" Is send/Return a standard, or does it differ from manufacturers? I got some schematics, but a bit comfused in the way the signal flows. Here is the schematic> https://s3.eu-central-1.amazonaws.com/attachments.guitartalk/c042f4db68f23406c6cecf84a7ebb0fe-peaveydeltablues.pdf

teleplayer

From what i understand, tube amps have two stages of gain, pre and post.. I know my Vox works like this (or i think, i'm keen to be corrected, Alan ur time to shine). The send is in between these stages.. Guys often like to place effects here.. Ur OD's should be placed before the input of ur amp though.. U wanna drive that section of the amp and time affects eg. Delay should come after.. There are a million threads on effects orders so i'm not gonna go into that all now..

So if u use ur effects loop, u are essentially placing ur effects that u put in that, later in the "fx chain".. If u are using a GT-8 read up on connecting it with the 4 cable method, u can then manipulate EVERY aspect of fx order by placing effects all over, including in the loop or before the input by using the fc chain section of that processor..

Hope that helps?

FenderBender

Hi Manfred,

From what I can make out, the insert loop takes place between the preamp and main amp.
When the plugs are er....inserted, the preamped signal, coupled to the B++ power supply (a rather scary 275V DC that will hurt you and your inserted equipment) is, due to the wiring configuration of the plugs, decoupled via C24 (block C1), conditioned by Q2 (block C2) and again decoupled via C27 to a nice level that your equipment (and you) can tolerate!

Very nifty idea, and essential of Peavey to include C31 (block B1) to decouple the signal from it's power supply (whether this is the PSU in your equipment or, if you do not use the insert plugs, the B++ supply in the amp itself), prior to the main amp. This will ensure that the output of your inserted equipment is not connected to the amp's B++ supply and spoil your equipment (or your life lol)!

Hope this helps.

AlanRatcliffe

It's real simple guys. Basically, the effects loop is between the preamp (with all it's gain and tone controls) and the power amp. So any effects inserted in the loop will be post EQ and preamp overdrive, but pre poweramp.

To get into it a little more:

This also means if you take a signal from the send, you are getting just the preamp. Similarly, if you bring a signal into the return, you are plugging directly into the power amp, bypassing the preamp.

Usually you will notice the amps own speaker doesn't cut out if you plug a jack into the send, but rather when you plug a jack into the return. This lets you plug a cable into the send of one amp and the other end of the cable in to the return of a second amp. The first amp's preamp is then used to drive both amps' power amps and speakers - "slaving" the two together to double the power. The second amps preamp is effectively bypassed, so it doesn't add noise.

Also, if you've got a modelling processor and just want the amp to make it louder without adding too much of it's own tone to the equation, you can just plug its output into the return of your amp and it'll cut the amp's own preamp out.

If you look at the "four cable method" of using a multieffect pedal that teleplayer mentioned, it means that you can have some effects (like wah and overdrive) in front of the amp's preamp and some (like delay and reverb) after the preamp, before the poweramp. It also means that you can bypass the amp's preamp in favour of a modelled amp sound - and switch it in and out on a per patch basis...

Does that all make sense? I'm tired at the mo, so ask if anything is not clear and I'll answer tomorrow.

Manfred-Klose

Thanks for the great anwsers, just what i was looking for.

The reason asked, is because i'm going to use a distortion pedal infront of amp, and ambient effects in the fx loop.

I used to put everything infront amp, but would like to experiment to get better sounds in the signal chain.

Where would one put a chorus and octave pedal, in the fx loop, or infront?

THis is the basic step i would follow to get the most of a signal chain.
I found this on the boss website a while back.
This is all in the situation where the pedals is pre.

Guitar>>>>Wah>>Compression>>Distortion>>EQ>>Modulation>>Ambience>>>>>Amp

would this order be correct?

teleplayer

I use all of my effects infront of my amp, purely because i'm lazy and i enjoy having one cable go from my board to my amp.. Also easier for gigging, I can set my rig up really easily and troubleshooting is easy, less places for my signal to die if to suddenly chooses to once i've rigged (funny things happen when they shouldn't)

As for your order, play around, but that little diagram looks correct, some guys will move wah after the Distortion though, depending on what u want - remember that it's all up to u, if ur sound involves wanting to distort or overdrive ur modulated sound, then move it, play, that's how u'll learn what does what..

I'd put the Chorus in the loop for sure if u splitting things up, the octave u'll have to play with though.. Try it all over and see.. Not such a mission to do if u in the mood to change ur rig around anyway..

Let me know what works best for u, i'd be interested to hear ur conclusion.. I love learning about effects

FenderBender

Guitar>>>>Wah>>Compression>>Distortion>>EQ>>Modulation>>Ambience>>>>>Amp

If this comes off a Boss website, it should be more or less correct. Remember that using inserts effectively seperates an integrated amp into it's individual parts (preamp and power amp in your case) and that the "Amp" in the chain represents only the power amp inside the Peavey enclosure. In the bigger picture, everything prior to the power amp can be regarding as a preamp. Experimentation in electronic signal processing is usually the best way of getting sounds very different from the norm so check out the specs of the equipment to see if each of the pedals are electrically better suited to the guitar's output and the Peavey's preamp input or Peavey's preamp output and amp's input and then experiment. The pedals will colour whatever you put into them and placement in the preamp chain can drastically change your "amp ready" sound.

IMO the distortion pedal should sit, traditionally, on the guitar's output. The ambience, if this is what the octave pedal is used for, should come right before power amplification, although if I were you, I'd summon the Ratmeister for experienced advice on that, as some pedals have a huge dynamic range and can reach very high volume levels depending on how they are set up ?

Manfred-Klose

Do have all the pedals i want yet, still battle testing at music shops to find the ones i'm looking for.

I'm just planning my rig before i buy the expensive pedals.
This is what i already have:

Sans amp tech 21 GT2
Boss DS-1
Boss SD-1
Mxr 6 band EQ(Blue model)
Boss tu-2
Boss NS-2(Noise suppressor)

Still looking for :
Wah
Chorus
Delay
Octave pedal

The reason having all of this is, that it is handy in the studio when recording, and you're looking for the right tone.

AlanRatcliffe

Manfred Klose wrote The reason asked, is because i'm going to use a distortion pedal infront of amp, and ambient effects in the fx loop.

That's usually the way to go, with one important caveat: the effects pedals should be able to handle the level of the signal or the effects loop should have a level control. The thing is, the level in an effects loop is naturally very high (it's after the preamp, remember) - usually line level (+4dB), while stompboxes are mostly designed for instrument level (-20dB). There's a huge difference in levels and it's very possible to damage a stompbox if it's inserted in a line level loop.

Where would one put a chorus and octave pedal, in the fx loop, or infront?

It's modulation, so chorus can go either way. It's one of those "preference" things. Octaves are a special case. They need a solid, clean signal to work at their best, so after compression and before overdrive is best.

Guitar>>>>Wah>>Compression>>Distortion>>EQ>>Modulation>>Ambience>>>>>Amp

That's more-or-less it, but a few points:

- EQ/tone effects can go anywhere in a chain. I used to like using EQ before AND after distortion, to "tune" the distortion.
- Wahs are EQ/tone effects too (and I like a wah after distortion for a more radical effect), but some wahs have problems with anything other than a guitar feeding them and can boost the signal level quite a bit, so the generally accepted way to do it is after guitar and before compression.
- Modulation can also go before distortion for a more subtle effect.
- Think of the amp's preamp as a distortion effect (of sorts), and everything is illuminated (as to what works best in a loop and what works best in front).
- Digital pitch-based effects (pitch shifters, harmonizers) usually come later(post overdrive, pre time-based), but I've gotten good results by using the stereo outputs to split the signal, giving each voice it's own EQ and distortion and mixing them together again - makes for a more convincing illusion of more than one guitarist.

Also see: http://ratcliffe.co.za/articles/effectchain.shtml

Manfred-Klose

SAy i am going to boss route(CH-1,DD-6,OC-3) would that match the level coming out of the send loop?

(+4db)???

I like your diagram, very handy.

teleplayer

I know my amp (Vox ac30) has a level switch for the fx loop, so i can lower it down to -10bB (could be -20dB don't have my amp nxt to me, i'm at work) or have it at +4dB... See if u have that, rack stuff should handle +4 perfectly (depending on what stuff u have of course) but i wouldn't bang that through my pedals

AlanRatcliffe

SAy i am going to boss route(CH-1,DD-6,OC-3) would that match the level coming out of the send loop?

No! I know for a fact that Bothner's workshop sees a lot of Boss pedals (particularly the DDs and the RVs) with fried input circuitry because guys have tried using them in loops on amps and mixers.

I can't remember the exact figures (I've always had problems remembering all the ins and outs of decibels), but the difference between -20dB and +4dB is huge - remember, every 3dB is double the power.

I know my amp (Vox ac30) has a level switch for the fx loop, so i can lower it down to -10bB (could be -20dB don't have my amp nxt to me, i'm at work) or have it at +4dB...

Yeah, which is a nice feature. It might be -10dB (which is the hi-fi reference level), most pedals have the headroom to handle that.

Manfred-Klose

So if i dont have rackmount units, i dont even have to bother putting pedals in the signal chain, I dont want to fry my pedals!!!!

Scary, i'll go look in the catoloque of my amp, and check out the specs of the send/return loop.

Manfred-Klose

I just checked out the specs.

From the send its -6dbV at 0.5 volt RMS, and the same for return.

AlanRatcliffe

Odd figure! You'd have to check the pedals specs or contact the manufacturer to find out if it can handle those levels.

Manfred-Klose

Will do so.

The reason why the amp is odd, is because it is made in mississippi(the home of the blues), where they probably never bothered use the send and return anyway, they just played the blues all day long.........

Manfred-Klose

just joking, but it wouldbe a cool storie to tell.

FenderBender

You forgot to mention the Jack Daniels' part in all this!
You're welcome to send a link for, or scan and send me the spec section of each pedal's manual and I'll take a look so long.

Manfred-Klose

I going to do some reasearch on this subject.

The pedals i am planning to put in the FX loop is Boss CH-1, Boss DD-6.

FenderBender

Great, give me a while to settle the family and other delinquent acquaintances and I'll do some checking up.