Effects loop. why?

[Sea Chief]

Hi chaps- just nabbed a marshall dsl 15 head for rainy day fun.. not usually my thing, more a fender man, & the gain channel 2 is silly/ to be mocked.. & modded. Looking at the opinions on it, I keep seeing many folks almost crying out for it not having an 'effects loop'. One mod can add one with some minor fettling I see.

But what is an effects loop? Ive had them on a peavy bandit65 I had, the odd other 'lesser' amps too in my time.. but never understood what their purpose is. I mean if you can put your boxes in a chain after the guitar > into amp, what's the difference, what's the deal with "effects loops" that make folk so adamant this amp is desperately in need of one?

Thanks SC

[Chuck H]

Effects loops can be a very useful tool for players that get their tone in certain ways. Some effects are much better placed after clipping. Reverb should always be a clear echo of the final tone. Effects like tremolo and delay can do odd things because they can have variable amplitude and alter the clipping for only a portion of their operation when used in front of low headroom clipping stages. A lot of phase based effects like chorus can lose much of their character used in front of clipping stages. So, for the player that uses such effects in particular ways an effects loop is good. These would typically be amps that generate most of their clipping in the preamp and then pass the signal through the effects loop. Also, almost any effect will sound different depending on where it's placed in the signal processing chain. Some digital effects for pitch shifting can make a horrendous amount of noises that are greatly amplified by low headroom in high gain preamps and are better placed in the effects loop just for the signal to noise improvement. Another consideration is that many pedal effects alter the impedance or phase of the guitar signal. Some "purists" see this as a detriment and swear they can hear it. These players don't want anything mucking up the guitar to amp interface. Also, for many types of players/users an effects loop can offer "preamp out" and "power amp in" options for connecting to other devices or amplifiers.

Nearly all of these criteria are contingent on preamps used to generate most of any clipping. For a clean amp/tone the advantages of an effects loop are much smaller. So if you get all your clipping from dirt boxes played into the amp set clean then there are fewer advantages to having an effects loop. But there are still some like the in/out options for connections with other gear and keeping the signal chain between the guitar and amp input unfettered.

[R.G.]

Good question. I suspect that it's a result of the problems with ordering effects.

If you distort a signal, t generates a stew of higher frequency stuff based on but not the same as the original signal. We like that sound. If you distort before filters and time based effects (reverb, chorus, flanging, echo, phasing) you get the original distorted signal, but processed by the later effects. If you do the filters and time based stuff before distortion, the distortion then makes sonic hash out of your carefully prepared filtered and delayed signal. Try this with pedals and see how it works.

In today's usage, a guitar amp's preamp does some distortion, and maybe a lot of distortion. There's generally a reverb after it before the power amp. But if you want that amp-preamp distortion to be phased, flanged, chor-iated, or echoed, or otherwise filtered, you have to get at the signal after the preamp distortion. Hence the effects loop.

I think. Could be.

[Sea Chief]

Hi Chuck- thanks for the informative reply, I understand most of it then- but as to pro eg's I'd be at a loss being not much of an effects guy in fact: I think of only one PRO effect I find almost essential, for him & his character/ tone.. & that would be JMarr & a chorus. But via a big 40w fender amp like a vibroverb or twin.. which have no effects loops. So Im at a bit of a loss as to whether I've heard, or would know how to tell, of any recorded gtr > amp using this config. Acdc? no. LZ surely no. Smiths no. Stones no. Bc all use vintage amps, that sound the best, & these had no effects loops afaik. So there never -used- to be them, so I wonder whether they are of any true use then.

It seems i need a pHd to play my 'leccy gtr now then.. all this info & techy stuff, tube sag, compression (another facet i havent a clue about either) finickity bias setting.. drives me fkn mad.. & thats just the amp: then the gtr with tone varying with volume knob inconsistancy/ the xyz of push-pull pots, coil splitting mumbo.. no wonder I just reach for my Taylor 95% of the time!!

[Chuck H]

I hear you. The effects loop trend started in the 80's I think. Lots of gear weirdness then. Just a feature that made itself useful to enough players that it stuck around. There are many, many recordings done on amps that have effects loops, though I doubt they were being used since most studios have their own preferences for how to implement effects on tracks. And certainly vintage bands didn't use them. There are a bunch of slightly more contemporary guitarists that do use them for their home recording and live rigs. Since players create their own sound for the most part we get to choose whatever works for us. I use to use an Alesis Quadreverb in an effects loop for live work in a cover band. It helped me to get the right tones for everything easily. I didn't use it much otherwise and I'm pretty much a plug and play guy now. Even to the exclusion of master volume circuits. I like some pedals but I don't use them daily or even have them arranged on a board anymore. My own flagship amp design is a single channel with no master volume and a hot rodded preamp. Not a high gain preamp, but enough to clip some while pushing the whole system into high gain with power tubes clipping. And guess what.?. I included an effects loop in the design. I've never used it outside of testing it for proper operation. Obviously this makes even less sense on an amp like this because the power tubes are intended to be clipped. But people like effects loops and I had an extra triode to use, so there it is. Knowing the players that own these amps I don't think the effects loop has ever been used in any of the half dozen I've built

[olddawg]

I hear you. The effects loop trend started in the 80's I think. Lots of gear weirdness then. Just a feature that made itself useful to enough players that it stuck around. There are many, many recordings done on amps that have effects loops, though I doubt they were being used since most studios have their own preferences for how to implement effects on tracks. And certainly vintage bands didn't use them. There are a bunch of slightly more contemporary guitarists that do use them for their home recording and live rigs. Since players create their own sound for the most part we get to choose whatever works for us. I use to use an Alesis Quadreverb in an effects loop for live work in a cover band. It helped me to get the right tones for everything easily. I didn't use it much otherwise and I'm pretty much a plug and play guy now. Even to the exclusion of master volume circuits. I like some pedals but I don't use them daily or even have them arranged on a board anymore. My own flagship amp design is a single channel with no master volume and a hot rodded preamp. Not a high gain preamp, but enough to clip some while pushing the whole system into high gain with power tubes clipping. And guess what.?. I included an effects loop in the design. I've never used it outside of testing it for proper operation. Obviously this makes even less sense on an amp like this because the power tubes are intended to be clipped. But people like effects loops and I had an extra triode to use, so there it is. Knowing the players that own these amps I don't think the effects loop has ever been used in any of the half dozen I've built

Yep.. and back in the 80s.. a lot of effects stuff you can get in a pedal nowadays was a 19” rack mount. I can remember getting rid of my rickety Roland Space Echo and getting a rack mount Digitech 2sec delay into the effects loop. Anything used in an effects loop really lowers the noise floor too. Some people put additional EQs, exciters, noise suppression etc, in them. Some people even put switchable attenuators. And.. we haven’t even discussed series vs parallel loops yet..

[Chuck H]

Yep. I remember hefting the manual for my Quadreverb and thinking "Jeez! I just wanted some reverb. I'm not applying to the Space Program."

[Sea Chief]

You see, just going back to earlier replies above, I just don't understand what is meant by "Some effects are much better placed after clipping".. clipping? I get that tubes distort.. but why before & after [what] is completely baffling. And for eg "if you distort a signal.." how am I to distort a signal? put some form of distortion on the gtr area-? so er.. a pedal? if I cant make head nor tail of this stuff (another eg "oh its compressed now" eh? what am I listening to? what is 'compressed', is it good or bad? what am I meant to be hearing? again 'sag'.. good/ bad what exactly does it sound like? Ive no idea what it means, what it is or what to hear.. because I haven't had a science lecture to get the information, to know). Its like Ive missed a month's week of lessons from the 2 year 'gtr degree course' I missed or something needed in order to be fully able to play.

Honestly, this is after I'm proficient in playing, have had all manner of amps.. for 38 fkn yrs: many ss & tube amps mainly; built a few- a a scratch built DR (gracing festival stages now Im told) a fine sounding twin reverb totally stripped & rebuilt from a very ropey rip'd amp. I mean its ridiculous it seems to me like you need a science degree to be able to know how to use a flippin gtr into an amp!

What I do know, & just as well as anyone here, is when a good gtr/amp tone is evident to me. Its the 1st thing I listen for, naturally now, as soon as I hear any 'leccy gtr in whatever situation, live, or recorded cd or vinyl of course to get the best eg's (& a linn sondek to get the best eg of all IMO so you see my ears are very finely tuned flappy flank instruments both).. but sag? wtf is that? I turn my 5f1 up (to 12 & around the 10 mark which seems the sweet spot) & down, the gtr too, picking hard & soft- so" in all available configs.. but have I heard any "sag"? nothing at all my earflaps hear, or my fingers feel, could I use the word "sag" to describe. Nothing (& apparantly a 5F1 might be the clearest eg of any tube amp for this bewildering facet I read about so often- its like the higs boson to me, tho I'm at 2 years ago when it was said to exist.. but not proven yet).

[olddawg]

Simply put.. a lot of effects on the input sound like crap if distorted by the front end of an amp. REVERB especially, but also most modulation effects. As said before.. if you are a clean player you will never notice except for an increase in the noise floor. If you distort the preamp it’s like putting a reverb pedal in front of a fuzz box in your chain. Most people prefer to put modulation (reverb, chorus, delay, tremelo) last in the chain. The FX loop let’s you put it even after the preamp.

[Chuck H]

Stop troubling about sag You've been doing it right by just adjusting your amps to the sweet spot. Usually sag is not so overtly evident as to be able to show someone. It's a subtle softening and gain reduction on the attack and sometimes a little bit of up swell on sustained notes, like someone is adjusting the amps gain up as the note tries to decay. But, again, it's subtle. I'll just say you might notice if one day your "sweet spot" sounded too strident and snappy. That would be a lack of any sag and I'll bet you wouldn't be happy about it. Your 5f1 probably exhibits the "clearest" tone because it's class A. FWIW that means that when played clean there is absolutely no sag. Getting on with it...

If you use a preamp that smashes all the input signal into a square waveform and your phase/time based effects are going in then they're going to get frappe'd into one harmonic sauce. But!!! If you run the square wave from your preamp into the phase/time based effects you get the intended doubling of those effects on the square wave form. Trust me, it sounds different.

And yes, you could use a dirt box for your distortion if you wanted to. In a pedal chain it would typically be the first one for the same reasons discussed regarding effects loops.

Without the need to understand anything (and there's really no NEED to understand unless you want to design amps or effects) just plug a chorus pedal in front of a dirt box and set the dirt box for hard distortion. Then move the chorus to after the dirt box. The difference you hear is all you need to understand about it. And, FWIW, if you like the sound of the chorus in front of the distortion pedal you wouldn't be the first and it's perfectly OK. No rules here.

[nosaj]

nosaj

[Chuck H]

I always liked this one for these situations.

[Sea Chief]

..and ohms. Argh! Drives me mad there are 4, 8, or 16 ohm "different loads" to consider. Why? what does it mean? Ok I can choose the right one fine, bc I'm told to (or rather if not something drastic will happen apparantly). But as to -why-.. I ask WHY I should have to delve into the world of physics (which I always hated same with maths.. I'm artistic-based & languages FFS, not a technician, as musicians just tend to be) in order to just play a fkn gtr. GRUMP!

[Sea Chief]

..the only fkn sag I see around the fkn place.. is my wife's fkn TEETS!! JesusH fkn christ. where's my taylor Im done with this sh*t.

am I allowed to say that?

[nosaj]

..the only fkn sag I see around the fkn place.. is my wife's fkn TEETS!! JesusH fkn christ. where's my taylor Im done with this sh*t.

am I allowed to say that?

Why aren't you allowed to drink bleach, gasoline or any other liquid?
Did you have to try them to know why or cause someone told you. Same theory or difference doesn't take a genius to picture an amplifier with the transformer pictured as a triangle and using the 2,4,8,16,or even 32 to balance the load like a seesaw.

Why should you have to delve into it? Because you came to the one group of people who are techs and you ask our help for free.
you don't want to have to understand it? Don't come here and go to your local tech and pay whatever price he tells you just because you DONT want to know how this works.

You either Learn or you pay the choice is yours
nosaj