What makes and amp "Take pedals well"?

[rosssurf]

I hear many people say that a certain amp "takes pedals well".  Is there some specific design reason that causes's this or is it merely opinion.?

[sean k]

I've been reading up a little bit lately about tube amp design and I noted one description about biasing hot/cold/hot etc whereby the bias voltage would be higher/lower/higher and so promote the signal to hit 0 volts easier on the hotter stages and 0mA on the colder stages... have I got that right? biasing at closer to zero V on the grid means lower voltage but higher current so that'd be hot and a bigger resistor and it would bang into 0V on the cathode with less voltage swing from the grid so opps it around the other way from what I first said, 0V = colder,0A = hotter... So anyways if the first stage is neither hot nor cold and as linear as possible it's going to give your pedals a bigger chance of retaining the personality you want as opposed to something that immediately starts doing it tube amp thing so less stages and higher B+ would promote the tube amp allowing a cleaner signal.

But by the same token your array of pedals might be bosters and distortions and you wan't to hit the first grid as hard as possible and have the tubes do the hot cold thing... so I suppose it's really down to what and how you use your pedals as to what style of amp is going to be seen by you as condusive to getting what you want.

But I'm just guessing as I don't really have enough experience with the consumer side of things.

[petemoore]

  They're different for sure...
 LM386, already distorts, can't really drive a speaker/bass.
 SS little amps, plug in and see...depends on the speaker, the output amps are generally designed to stay with headroom and never distort, this puts the area where distortion can be made in or before the preamp.
 Big solid state amps are like the little ones, only bigger, designed to not distort.
 So far we're basically talking about response related to static loads [no big changes per phase cycle], the resistor or caps or anything that is putting a load on the signal, the value remains constant.
 Little tube amps...with output tubes that get dynamic loading from the speaker[s. Here's where I like it...you get the dynamic loading, each phase cycle gets changes in frequency response and compression etc., that's a whole lot of super-fast adjusting you can get with a loaded output tube, these loading algorythms are influenced by various things, kinetic energies of the moving coil/cone, air pressures etc.
  To get a constantly changing frequency response [and the other complexities associated with 'certain' aspects of guitar sound/tube amp] at such high rates as a small portion of a phase cycle of the source input...is something that has been claimed as possible [if you infer that the term ''sounds like a tube amp''  means works like a tube amp] by 1,000+ various designs which do not include tubes.
 And they do sound like tube amps. At least one or two aspects of one or two sounds, plus anything or everything else which can be done with static loads on AC, or speaker-less dynamic load mixed with ''fancy'' [more complex and higher component count generally than a tube output section] circuitry, but you don't see much of that, Valvetronix is the only sketchy information I know of about dynamic loading [without speaker] + circuits to help use that technology.
 The nature of the tube-beast-roar only really appears when the output nears being ''backed into a corner'', as Mark puts it, they will growl. [tubes loaded by their driven speaker[s, then working with a boosted input].
 Pedal friendly is probably a way of saying 'certain kind of amp' without getting into what I'm probably starting here...tube Vs. SS...the old ''new age'' controversy/competition rages on...

[Boogdish]

It usually just means an amp with a big nice clean sound. 

[Morocotopo]

In my experience:

1) If the amp has a bright switch, or a bright cap in the first stage, it can sound, with dist/od, too brittle
2) if the preamp generates distortion (or the power amp) time domain effects tend to "blur". Distorted chorus, for example.
3) If the pedals generate too much level, it can make the first stage distort in a not nice way.

[markeebee]

I've used the phrase "takes pedals well" fairly often, without ever thinking about what it really means.   

I suppose it's very subjective and unscientific, and it's something to do with clean headroom in the frst preamp stage(s).  Like, it won't mush up your chorus, and it won't overly colour your distorters, but it will overdrive in a jolly way if you stuff a boost up it.

[markeebee]

An AC30, for instance.

[wavley]

My reasoning is big sounding and fairly clean when it comes to delays, reverbs, modulation, loops...

I actually run in parallel, so I have one amp (Oliver PA100XR) that's pretty clean with a great reverb that I run all of those effects to.  Then I have a Traynor EL84 Bassmate that overdrives at a reasonable volume that I run a volume pedal and English muffin, that amp takes a pedal well but in a different way because it drives more as I drive it harder.

I have a friend that was running a soul preacher and reverb into a dimed Champ, the soul preacher sounded great, the reverb sounded like crap.

[caress]

it's pretty subjective... i love it when i hit my rv-5 set to full and the amp can't quite handle it and breaks up a bit.   

[wavley]

it's pretty subjective... i love it when i hit my rv-5 set to full and the amp can't quite handle it and breaks up a bit.   

This very true, I guess I shouldn't have said it sounded like crap, because it did sound neat, but not with the guitar part he was playing.

[sean k]

Well I suppose, and I'm just thinking out loud here. something close to being able to cover all your basses might be a two channel amp with separate inputs, one clean and one mean, and you split you signal between modulation and boost/distortion channels, then mix, one or the other or a combination might be nice. Then you send the fx out to delay style things and mix again on the input, then have a kinda switchable output and a master volume so you could have either a big headroom clean set of output tubes using a fixed bias but be able to switch to cathode bias to lower the voltage between the plate and the grid... to dirty things up somewhat.

[liquids]

I hear many people say that a certain amp "takes pedals well".  Is there some specific design reason that causes's this or is it merely opinion.?

I think more so, amps were 'discovered' or 'decided' that they take pedals well, well before it was a design consideration.

The mentioned points were good - caps across gain controls (in general) often make it hard to 'eq out' the unwanted frequencies that dominate in that scenario when running a 'dirt' or 'fuzz' pedal into said amp.  Not everyone has or wants a schematic of their amp to know the difference, hence some amps get sworn off as 'unfriendly' for something as simple as one capacitor! 

In the case of using external delays and reverb signal processors, sending such a signal into an amp that is even on the edge of distortion with dynamics, often makes the amp 'less pedal friendly' to most ears.  But similarly, to others, pedal friendliness is a dirty amp that can be slammed with boosts or distortion pedals (think hendrix) for more gain and sound natural, and that makes it pedal friendly...   In many circles, certain blackface fender amps were considered the pinnacle of pedal friendliness.  In other circles, they are touted as 'too clean' 'too hi-fi' and 'too bright' for pedals and only good clean.  YMMV.

Most of the blackface fender amps have the same preamp, but subtle differences.   Champs don't take pedals that poorly when you isolate the variables, but their tiny speaker, lower plate voltages, and low wattage make them not fantastic to run pedals into unless you work around these factors...as I do.  =D   Princetons - maybe - some love them, some hate them, more so used by guys who want something blackface they can crank it up more comfortably.  Deluxes, maybe not so much, since they break up at fair volumes, and do often have that hardwired bright cap on the vibrato channel.  I think they are fine pedal platforms if you know how to work them...  More so the Pros and the Supers, in my opion, I'd say are generally considered the most ideal blackface amps for pedals.  Plenty of other variants  though - some favor Twins in this regard, bandmasters, etc.  They're all similar in many ways, while preference and user bias has a lot to do with liking one over the other as much as anything else.

In general what makes these amps good is their tenancy to not break up until a fair amount of volume is reached, their having a seemingly huge bass (though like all things, this strength is also a bit of a liability), and tone controls that, well, actually seem to work to shape the tone.   The bigger ones have quite a bit of headroom, and you can hit them with a pretty hot signal before they start to break up to the ear.

That said, many amps followed the blackface topology.  Most of mesas amps seemed to spring from fender blackface amps, both for clean and high gain.  Most have mods and tweaks though that some find an improvement on that sound (possibly more pedal friendly even) and others worse. Riveras, Traynor and others are, at their core, blackface fenders under the hood to some degree...

There seems to be a small growing trend for developing amp specifically to sound (or market as) great when clean but also be an ideal platform for pedals, some based on the blackface amps, some not.  One amp that comes to mind, that RG can speak for, is  the Visual Sound Workhorse amps - I think some of their add copy was that they were single channel clean amps that sounded good and would work great with pedals, though correct me if I'm wrong..likewise, those may not be like a blackface at all (never seen a schematic).   

Most of the dumble-type amps out there are touted as taking pedals very well in the clean channel.   They are known for having a rich, somewhat blackface-like clean sound with plenty ofEQ options, and potentially less midrange dip than the blackface amps which are known to be mid scooped anyhow, making these potentially even 'sweeter' sounding with dirt pedals.

Likewise, on the other side of the pedal friendly amps are the DR Z amps, which are designed for break up to some degree, though many of which have input tube stages designs that are said to 'take pedals well.'  These Dr Z amps come in many different topologies and power amps.

Last I looked, a few guys (Fuchs is the first that comes to mind) are building on the concept of the tube bass amp as another platform for pedal friendly guitar amps - namely Ampeg SVTs.  I've yet to try one but would like to.  It does seem like a great idea on paper, and a great basis for a sound that is big, warm, clean, and tube.

In the end, there is a market for guys who want a good, no-compromise clean sound that they can run a huge pedal board into to get all those sounds we tinker with.   That is my proffered setup, but the amp is an important factor in the final sound.  All that said, you'll find some guys saying their Roland or Crate solid state amps are the best pedal platforms, and who can argue? Whatever works for you and your ears.   Hope that answers your questions with more info than you ever wanted.   

[T1bbles]

When it comes to 'taking pedals well' my usual test is to play a big muff into it at full volume. Amps with bugger all headroom cant take it and it sounds like you're pushing ear plugs in every time you hit a note with any force, amps with loads of headroom can take it, and you get a very clear, dynamic, and harmonically rich sound that's verypleasing to listen to.

The more headroom you have, the better your amp will take pedals.

Also, in my experience, using you're amp's drive channel as your go-to driven sound is a bad idea when you also use a pedalboard as drive channels in general will have less headroom than your clean channel and like to pick and choose which pedals they'll push up front, and which one's they'll try to bury. As well as this, the changes in impedence which the amp sees when you switch from your direct guitar line to a pedal (true bypassing) can change your distortion characterisitics to a greater or lesser extent depending on what you've got going on, but this can result in some 1:1 pedals like phasers/choruses etc, also changing your distortion characteristics, this can be for better or worse, but it's just not something you want to happen.

That's just in my experience though, I'm sure some of you have amps with beautiful drive channels, I however, have only ever gotten use out of clean channels.

That's what little knowledge I've gathered, hope you can get something useful out of it.

[petemoore]

The more headroom you have, the better your amp will take pedals.
  I tried 'em through the Mackie sa1530z, touted as high SPL super low distortion amp/speaker. The boost stayed mostly clean, the phases nice, the distorters...not so good to highly irritating.
   For purely louder and ''still as clean'' when using a booster, big-clean-huge-amp highly recommended, [up to the point where the tone doesn't change or room for more speakers is at a premium] bigger is better..
   For enhancement of output tube distortion via booster, er, it's the other way round, smaller amp'll distort at lower volume when pushed, really works great, I use it.
   Me and my amp don't have too much headroom, I'm almost 6'2'', my biggest amp I use for guitar is 18w right now.
  The Mackie is 1340watts, 3-way speaker, way too clean/dry for my general guitar to sound.

[Ben N]

My model of "takes pedals well" is a 50 watt silverface Bassman. So, I guess that boils down to: an amp that is basically clean but can be pushed to a nice natural power-tube overdrive; no preamp overdrive.

[wavley]

My model of "takes pedals well" is a 50 watt silverface Bassman. So, I guess that boils down to: an amp that is basically clean but can be pushed to a nice natural power-tube overdrive; no preamp overdrive.

I quite agree with this.  Dick Dale runs his reverb in front of a showman amps and it sounds great, a little power tube crunch can do nice things, I'm not fond of preamp drive personally.  None of my amps have master volumes.

[Paul Marossy]

IMO, an amp that is "touch sensitive". If an amp is sensitive to all the nuances of your playing and breaks up nicely all on its own, pedals will generally augment the sound. I have several tube amps, but the one I consistently play is the one that is the most touch sensitive. It also is 15 watts, breaks up very nicely without an OD pedal and has a 20 watt alnico speaker in it. I get a lot of comments about that amp. Don't usually get comments when I play any of the other ones. And this vintage amp only cost me $75

I agree that power tube distortion sounds mucho better than it being created in the preamp section.

[petemoore]

  Open back, the kind with the nice pedal compartment.

[liquids]

  Open back, the kind with the nice pedal compartment.

   Good one.

[FlyingZ]

If I may suggest when it comes to stomp box distortions the amp must not have a nice tube distortion channel.