Bench Amps: A Survey ?

[polaris26]

Hello everybody - I'm just getting around to setting up a small work area to tinker with guitar-related circuits, after a long hiatus.  It got me to thinking about what amp I might want to use in the workshop. 

In the past, I have noticed that certain pedals are very sensitive to what amp you use them with, in terms of how you voice them, particularly distortions where there is a lot of added harmonic content and final tonal shaping before the output.

You might think that if you're only making circuits for personal use, you should just use the same or similar setup to what you intend to use the pedal for.  The problem is that I (like I suspect most gear heads) have a variety of amps, and I want the circuit to be as versatile as possible.  I have also at times toyed with the idea of selling some of my designs, although I have not done so to date. 

That gets me around to the question - what amp or amps do you use when voicing your pedals?  Is there a one-size-fits-most amp for this?  I am thinking something clean but not so Fendery-bright or scooped.  It should also be compact for the sake of bench space, and quiet and reliable to aid in debugging your design.  That leaves out most of my amps, which tend to be largish Fender-style all-tube amps.

I am thinking probably a simple small clean solid-state 1x12 combo (which unfortunately I do not own).  But should it also have any effects built in, in case you want to see how that fuzz you're working on sounds with some reverb or trem after it? 

I would be interested to hear what others are using or have used in the workshop stage when designing or voicing their circuits.  Also, and perhaps more importantly, how well did you find it translated when you finalized and built your pedal and moved it into the end application with other amps?  Did you ever have to go back and mod your design based on how you found it sounded with a different amp?

Regards,
Dave

[GibsonGM]

That's a pretty good question, Dave, but I'm not sure there's a very good answer.  Even a clean power amp from a PA or whatnot would sound different with different speakers!  And the speakers would respond differently with a different amp...this you know. Also, often times the amp is PART of a tone you like with a boost, overdrive, distortion etc...! 

What I personally do when putting an effect together is to run it to a small Marshall solid state practice amp I have.  It's a piece of junk, probably worth $50 when new.   It does have that Marshall scoop, most prominent on the dirty channel.  There is also a nice clean channel, which I run most of my effects on.   I just set the Bass & Treble to mid point.    I will try boosts, distortions...on the clean channel, then see what they sound like on the dirty channel with varying degrees of gain added.  If it sounds decent this way, on to step 2...

If the effect passes this "test", I will mostly then run it into my Hot Rod Deluxe and see what it sounds like thru a tube amp.  Usually, it is much more what I want when going into this amp   Sometimes I'll try things out on my 18W, depending on what effect I'm doing (no distortions on this rig, only boosts...).   

Overall, if I do this and something sounds 'good' on the cheap solid state amp, it only sounds better as I move up in "amp quality", only difference being that I always prefer the response of a tube amp over SS...YMMV...

[karbomusic]

I have a blues Jr. sitting by my bench - I use it for basic testing. However, if it is something I'm putting time into, then I'm going to try it through all my other amps as I work on the design and tweaks. The BJr tests for the basics - does the pedal have some problem and so on - all the other amps are for judging it overall - I mean if it is something I'm putting thought and time into it's eventually going to leave the bench for further testing. In some cases the bread board version ends up at rehearsal.... like the guy here - bottom right...



Not much different than mixing audio, I have a couple sets of monitors in the mix room but eventually it's going to end up in my car and other rooms just to make sure everything translates. Same with pedals.

EDIT: Of the few pedals I sell, I educate the buyer about how the pedal reacts based on which amp it is feeding etc. I share what I ^learned since it's gonna vary and good for them to understand what's going on. If someone has any understanding at all of how their pedal works and reacts, the happier they are as a customer.

[Kevin Mitchell]

For a while I've been using a small solid state Peavy for my bench work. It's clean enough to satisfy and can get dirty enough to bring forward any grit in my circuits.

Though I'm giving it up soon. Within the next couple months I'll have a submini tube amp and probably a home brew solid state on the side for my bench work/midnight noodles.

[anotherjim]

Small solid state combo here + the aux input of an old shelf hi-fi for non-guitar stuff.
I don't think there is a perfect answer. After a while - trial & error, you get an instinct for how it might work with other amps and adjust accordingly. I'm still working on developing this instinct.

[bcalla]

I bought a Footnote by SKB on clearance at Parts Express (they still have them here for $29).  It has 9v jacks to power the pedal you're testing.  It even has a cable tester.

Then I installed it in a wine case that a local liquor store was going to throw away.



(not sure why my picture isn't coming up)

[ElectricDruid]

I think you should use something clean and uncoloured - a hi-fi amp. Guitar amps are great for playing guitar through, but they're not so good for hearing what's really going on in an audio circuit. You're not *playing*, you're *testing* and *developing*. Once those jobs are done, by all means give it a blast on a guitar amp. But by then you should have a good idea what the frequency response is like, and how it responses to a range of signals and so forth. It's not a question of hearing the pedal at its very best, but rather hearing it at its very worst and making sure that's fine too. In a similar way, you used to see a cheap crappy transistor radio speaker in a recording studio, so that the engineer can get an idea how the record sounds on a cheap radio. You want to hear all the detail so you can fix it, not hear the tonal response of your favourite amp.

I got caught out like this recently after trying a flanger pedal design through an old valve amp. It sounded amazing. "That's great!", I thought, "I'll have to record some sound clips!". So I plugged the output from the pedal into the computer. Of course, it sounded *terrible*. The great sound I'd heard was largely the amp, not my pedal. I don't want that to be the case. Instead, I'd like people to plug my pedal into their amp and think that the pedal makes their amp sound good!!

The idea that different pedals react differently to different amps indicates to me only that the pedals and/or amps weren't well designed or suffer from limitations of their time. This is true for several famous circuits, but there's no way we should be designing stuff now that falls into the same traps. A good modern pedal shouldn't suck tone, and should have a low enough output impedance and good enough drive that it can cope with low impedance inputs and unreasonable cable capacitance. I work towards this ideal!

Tom

[GibsonGM]

Well, Tom - this is all true...we should seek to have our impedances in line, and have done the math to be sure there's no tone-sucking or other 'first day on the job' crud happening - that is just good engineering....but bud...who plays thru a hi-fi amp in the real world?

Another trap you can fall into is having something sound freaking AMAZING thru a VERY clean amp...like a PA, or a 100W bass amp set on "1"...your pedal is pushing the device into mild OD while doing its own thing, and the results hypnotize you. The amp is not adding coloration...

Then, you bring the same effect to a real guitar amp (Fender, Marshall, Mesa...) and it's overloading it, or just sounds flat.  Because the guitar amp's frequency response, and speakers, are tailored to guitar.   I do like the idea of "try it with a CLEAN AMP", esp. for flange/phase/trem/delay/OD, but a GUITAR amp.   You are right that amps ARE designed with 'limitations', which is where their particular tone comes from...they are what we play thru, so IMO our effects should be sorta tailored to THEM, not to a theoretically clean amp...a distortion will sound one way thru a super clean power amp, but can be wholly different thru a gigging rig.

Is there a "right way" to test stuff like this?  Don't think so, as long as the long road leads from the test bench to real application with real guitar amps  

[karbomusic]

So I plugged the output from the pedal into the computer. Of course, it sounded *terrible

That should sound terrible, it isn't the pedal's fault, it's not an amp simulator and we need something to provide the 'amp' unless the pedal is to be used for something other than going into a guitar/bass amp. For example a distortion would be a very bad idea to judge in a full range environment like direct into a computer; it's missing half the circuit - the amp/cab.

Amps can usually be broken down into handful of categories for this purpose; we only need to test across those categories instead of worrying about every amp ever made type concerns. I don't totally disagree but somewhat do if the pedal is designed to go into an amp.

[Blitz Krieg]

[chuckd666]

Late 80s Peavey Rage 108 which I got from some dude for $20. #tonezone

[samhay]

I'm with Tom/ElectricDruid, I like to listen through a clean full-range (Hi Fi) system, often with headphones. As I predominantly play through a clean amp anyway, this isn't much of a compromise.

Some caveats:
I know what many of the classic dirt/fuzz circuits sound like through this system vs. through a guitar amp. As such, I can usually make a pretty good guess about what a new circuit will sound like in front of a guitar amp. I made some un-usable circuits in the learning phase, before I had this experience.
This is not a good approach if you are designing or testing the next SHO or Rangemaster - well, anything that is designed to overdrive an e.g. valve amp. You can test that it makes things louder, but that's about it.
Also, testing with headphones can be a little dangerous if you get the level wrong, so it is good to put some form of limiting in place to preserve your hearing.

Finally, I do have a small valve amp I use for noodling and testing. It's a somewhat-modified one of these:

[Mark Hammer]

I bought a Footnote by SKB on clearance at Parts Express (they still have them here for $29).  It has 9v jacks to power the pedal you're testing.  It even has a cable tester.

Then I installed it in a wine case that a local liquor store was going to throw away.



(not sure why my picture isn't coming up)

That is a crazy good deal, although shipping outside the US might bump it out of that category.  My own bench amp has a 6-1/2" Marsland with 2W of battery power.  A well-designed/constructed cab will provide more than enough low end and oomph to provide valid bench-testing.

[bloxstompboxes]

I use the only amp I have, a Peavey Express 112. I don't gig or anything. My playing is just for personal enjoyment.

[LightSoundGeometry]

My stuff goes through two types of amps - a solid state crate g20 ..crate is very underrated and a solid product. then through an all tube amp using a vox night train.

I like the versatility of a head as you can place it anywhere you wish and then run a line out to a cab placed anywhere as well

[newfish]

Any clean SS (battery powered!) amp will do.

I pick from one of the following...

Pignose 7-100
Marshall MS-2
Danelectro Honeytone

Noisy Cricket

Once I'm satisfied that everything works as it should, it gets boxed up and pushed through a Peavey Valve combo - which the neighbours really enjoy!

[deadastronaut]

try the ''punch 1 watt amp''... i have it on breadboard at the moment..(trying stuff with it)

pretty cool...and is acceptably loud through a 6-12'' speaker...in fact the 12'' speaker is really nice.

accepts pedals nicely too

very simple, very cheap..


tda7052 or tda7052a

[ElectricDruid]

So I plugged the output from the pedal into the computer. Of course, it sounded *terrible*

That should sound terrible, it isn't the pedal's fault, it's not an amp simulator and we need something to provide the 'amp' unless the pedal is to be used for something other than going into a guitar/bass amp. For example a distortion would be a very bad idea to judge in a full range environment like direct into a computer; it's missing half the circuit - the amp/cab.

Maybe I'm unusual, but I don't play guitar, so often pedals I've built are used for synths, or ahead of a mixing desk or for somehow else mucking about with signals. So I'm definitely *not* thinking that the amp is part of the circuit. It isn't. Yeah, if you're building the perfect guitar tone, then the amp is a part of that sound - and clearly running the pedal "raw" into a computer (or hi-fi amp) gives you a completely different sound. But it gives you the "sound of the pedal" in some sense, rather than "the pedal plus the amp". That's useful for debugging, if not for playing, and a bench amp is for debugging, at least for me.

[deadastronaut]

distortions into a pc are nasty...shrill and tinny usually, thats why we use 'cab sims'

put them into an amp/ even a little amp...and it becomes a very different animal..

just my 2p.

[karbomusic]

So I'm definitely *not* thinking that the amp is part of the circuit. It isn't.

If it isn't for guitar, I would agree.