EQ in front of amp or in effects loop

[talltxguy]

Was browsing the local GC today and saw a used MXR 6-band EQ for $35. Never ran an EQ before but heard good things from the Board; so I picked it up and gave it a try.

I was using a stock DS-1 with no distortion to help chunk things up on rhythm, but I will not be needing that pedal anymore as the EQ does a great job of chunking things up without the thinness of the DS-1.

I tried the EQ with the DS-1 but didn't care for it at all - not before the DS-1 or after it. I did, however, love the EQ in front of the amp! I did try the EQ in the effects loop - just to see if it could get better, but it didn't. I really don't see myself ever using the effects loop and am so glad I can hard bypass it.

Do EQs contain diodes or anything like that? I'm thinking not as the sound is quite a bit better than through the DS-1.

 

[rocknroll9225]

well, the answer really depends (like always) on what your intended purpose for it is. the EQ controls on the vast majority of amps and dist/OD pedals come after the gain stages, so they can shape the already distorted signal, and have a much more noticeable effect on the final sound. if you put the EQ before the gain stages then it doesnt shape the sound as much as it chooses which frequencies get distorted more than others. i personally would use it in the loop to get it after the preamp in the signal path. this is part of the reason i love my mark v so much: the EQ knobs are before the gain stages and the graphic EQ is after, so you can get **** tons of different ways to tailor your sound. nice score on the pedal tho, $35 is a pretty good price, and mxr pedals are great.

Do EQs contain diodes or anything like that? I'm thinking not as the sound is quite a bit better than through the DS-1.

well, the reason the DS-1 sounded like crap is cause the DS-1 is a crappy pedal. i honestly cant see why theyre so popular. if youre on a budget, then sure, but otherwise id stay away.

and im not 100% certain, but im pretty sure an EQ pedal wouldnt have diodes. dont quote me on that tho

 

[94Tremoverb]

EQs are full of transistors, usually in Integrated Circuits - ie dozens of them. I'm not 100% sure whether the MXR 6-band uses ICs, but it probably does - or at the very least it will use half a dozen separate transistors.

The thinness of the DS-1 is not to do with it having diodes, it's the way the rest of the circuit is designed. There are plenty of pedals (and amps) that use diodes and don't sound thin.

The EQ will do different things in front of the amp and in the loop - in front it will push the amp harder in the frequencies you want and increase the distortion, and also can tighten up the sound, if you use it as a mid boost/bass cut. In the loop, it will shape the distortion that the amp is creating and can help to open out the sound if you use it as a mid cut/bass and treble boost. It doesn't work so well the other way round usually (although it will depend on your amp settings) since too much bass in front of the amp will make it flubby.

You can actually do both - the classic set-up is mid boost in front of the amp, mid cut in the loop.

I actually like the DS-1 by the way - if you want that bright, hard crunch tone. It doesn't have a very useful tone range though, basically it does one thing well and if that's not what you want, forget it.

 

[boss4]

I prefer my Boss GE-7 in the FX-Loop. In the front it sounded a bit loose and not so tight.

 

[Chris McKinley]

As rocknroll9225 put it, any EQ is going to have a more noticeable effect in the loop rather than before the amp's preamp. This will be true regardless of brand. It's also possible to use separate EQ's in both places, but if you only have one, putting it in the effects loop (and preferably first before any other effects such as chorus, delay or reverb) will give you the most ability to shape your tone.

Also, using the DS-1 before the preamp was doomed to give you a thin sound because the unit is a distortion box, not an overdrive. Distortion pedals have heavy amounts of compression, and that alone is enough to make a boutique amp sound like a toy. If you're wanting to run something in front of the amp's preamp to drive the preamp tubes into greater saturation, you need to use an OD, not a distortion. You may ideally want to use an OD up front, then an EQ in the loop to really have control of your tone.

 

[zappazapper]

an EQ pedal before the amp is really useful if you like the amount of gain/sustain you're getting, but you lack some "bite" when palm muting... it's similar to an OD pedal in that respect, except you can really hit the frequencies that are going to give you that bite without increasing the gain (which may or may not be what you're trying to do)... just as an example, my pod X3 live has all sorts of amp models that i like the sound of, but they're kinda flubby when palm muting... so i use either a tube screamer model with the gain and volume set flat and just use the tone control to brigten up the attack, or i'll use the "boost + eq" model and use the mid and mid freq controls to zero in on the bite i'm looking for, without increasing the actual gain... you can get some really unique sounds with amps that were not necessarily designed to have palm muting attack like that...

but ya, EQ in the loop is killer... somebody said that in most amps the tone stack is post-gain... i'm no amp tech but just from my own experience, i don't get that impression... tone controls on most amps sound to me like they're pre-gain, or at least somewhere in the middle of two gain points, because they don't really seem to have alot of effect on the tone of the distortion, just more off an effect on the response, just like an EQ pedal into the front panel would... an EQ in the loop only takes a few dB and you start to hear a huge difference, like the way the GEQ works on boogie amps, which is post-gain... and why would a boogie amp have a tone stack and an EQ that are both post gain? seems like more of the same thing to me...

 

[94Tremoverb]

Also, using the DS-1 before the preamp was doomed to give you a thin sound because the unit is a distortion box, not an overdrive. Distortion pedals have heavy amounts of compression, and that alone is enough to make a boutique amp sound like a toy. If you're wanting to run something in front of the amp's preamp to drive the preamp tubes into greater saturation, you need to use an OD, not a distortion. You may ideally want to use an OD up front, then an EQ in the loop to really have control of your tone.

Actually overdrives have more compression than distortions usually! The traditional 'Tube Screamer' overdrive circuit with its diodes in the feedback loop of the gain stage acts as a compressor with the threshold at the point the diodes clip. Distortions are more like a hard limiter - that's why overdrives usually work better into a dirty amp, and distortions usually work better into clean amps.

an EQ pedal before the amp is really useful if you like the amount of gain/sustain you're getting, but you lack some "bite" when palm muting... it's similar to an OD pedal in that respect, except you can really hit the frequencies that are going to give you that bite without increasing the gain (which may or may not be what you're trying to do)...

Exactly, or you can use it to boost gain at just some frequencies, which avoids overloading the preamp with ones you don't want (usually bass) that make to sound too squashed and flubby.

but ya, EQ in the loop is killer... somebody said that in most amps the tone stack is post-gain... i'm no amp tech but just from my own experience, i don't get that impression... tone controls on most amps sound to me like they're pre-gain, or at least somewhere in the middle of two gain points, because they don't really seem to have alot of effect on the tone of the distortion, just more off an effect on the response, just like an EQ pedal into the front panel would... an EQ in the loop only takes a few dB and you start to hear a huge difference, like the way the GEQ works on boogie amps, which is post-gain... and why would a boogie amp have a tone stack and an EQ that are both post gain? seems like more of the same thing to me...

*Boogies* (ie Mark series) have the tone stacks pre-distortion and the GEQ post-distortion, just as your ears tell you! Rectifiers have their tone stack post-distortion - on the dirty channels anyway, it's pre-distortion on the clean channels. Other amps can have it either way, or with the tone stack in the middle. Broadly, anything derived from the Fender Blackface/Boogie lineage has a pre-distortion tone stack and anything from the '59 Bassman/Marshall/Soldano lineage has a post-distortion tone stack. Of course if you push the power stage into distortion as well it's always after the tone stack, so you can get a combination in the same amp.

 

[Blaklynx]

Here I replied on Jemsite. I attached a picture to support my post. Scroll halfway down the page. http://www.jemsite.com/forums/f30/compl ... 070-2.html

Further reading to help with/understand tone issues or uses of EQ etc:
http://forum.grailtone.com/viewtopic.php?f=24&t=49301
http://forum.grailtone.com/viewtopic.php?f=24&t=49265&start=15
http://forum.grailtone.com/viewtopic.php?f=4&t=19660

 

[talltxguy]

Thank you for the great comments.

I recently ordered some KT77's that will be here tomorrow, but until then, I've been running JJ E34L's & JJ 6L6GC's on the EL34 bias mode. The E34L's are on the outer sockets while the 6L6GC's are on the inner sockets.

Strangely enough, while on channels 3 or 4 in either vintage or modern, I get some nasty feedback in 100 watt mode when pushing the master volume while the EQ is activiated in front of the amp. Yet I run the EQ in front of the amp in 50 watt mode and the feedback is not a problem when pushing the master. :? I thought that 100 watts offered more headroom than 50 watts, so I'd think that 100 watts would offer less feedback? And I thought 6L6GC's had more headroom than E34L's? The only thing I can figure is that the 6L6GC's, which are warmer than stock Mesa 6L6GC's, are running pretty hot on EL34 mode and so I'm losing some headroom because of the 6L6GC's running hotter?

 

[boss4]

The Road King can run this two tube models at the same time, the roadster can't. I know people who have use EL34, 6L6 6L6, EL34 in this configuration (like you) but no improvments and you're harming your amp and your tubes! You can run 6L6 with the EL34 bias switch on too, but to do this tricks is better to do a bias modding. Is easier, saffer and give better results.

 

[rocknroll9225]

Thank you for the great comments.

I recently ordered some KT77's that will be here tomorrow, but until then, I've been running JJ E34L's & JJ 6L6GC's on the EL34 bias mode. The E34L's are on the outer sockets while the 6L6GC's are on the inner sockets.

I would not recommend this. I'm surprised you haven't cooked the 6L6's and your output transformer already.

 

[94Tremoverb]

I recently ordered some KT77's that will be here tomorrow, but until then, I've been running JJ E34L's & JJ 6L6GC's on the EL34 bias mode. The E34L's are on the outer sockets while the 6L6GC's are on the inner sockets.

Strangely enough, while on channels 3 or 4 in either vintage or modern, I get some nasty feedback in 100 watt mode when pushing the master volume while the EQ is activiated in front of the amp. Yet I run the EQ in front of the amp in 50 watt mode and the feedback is not a problem when pushing the master. :? I thought that 100 watts offered more headroom than 50 watts, so I'd think that 100 watts would offer less feedback? And I thought 6L6GC's had more headroom than E34L's? The only thing I can figure is that the 6L6GC's, which are warmer than stock Mesa 6L6GC's, are running pretty hot on EL34 mode and so I'm losing some headroom because of the 6L6GC's running hotter?

I think somehow this has got in the wrong thread, but I would guess this is exactly what's happening. With the bias set to EL34, the 6L6s will be running *way* too hot - although whether it's dangerous to them depends on what power mode you're in. Spongy/Tube should be OK, Spongy/Diode might be, Bold/Tube probably not, Bold/Diode definitely not.

You won't fry the transformer, but you could certainly cook the tubes and maybe blow the screen resistors, so it really isn't a good idea unless you can check the tube current and know you're more or less in the safe range.

Try swapping the tubes round so the EL34s remain on in 50W mode and see if it changes.

 

[talltxguy]

I was able to check the bias & discovered the 6L6's were indeed running way too hot; so I won't be doing that again. I have some KT77's coming in today and will see how those work out.