Bass Distortion and Stereo Setups 101

OK Kiddies, here's a lesson in bass rig stereo setups to facilitate distortion. I've talked about this concept before, but I am re-hashing the information for 13, and anyone else needing a refresher course.

You all know that I run in stereo, with my bass having two distinct outputs completely isolated from one another. I do this to have as hot a distorted signal as possible without killing the low end. I want to have feedback, screaming harmonics, and endless sustain on my distortion signal, but still have clear thunderous bottom end, and the only way I have found to do this is to run two different signals.

Ever since the 80's, my basses have all had two different pickups wired to their own seperate volume controls and output jacks. My neck pickup runs into a totally clean amp, and my middle pickup runs into my distortion amp. That way, the maximum signal goes to each amp setup. The two paths never cross at any time.

My neck pickup always serves as my clean tone, as this is where you get the lowest, deepest notes. My distortion pickup always sits about where a Precision pickup would sit, as this is where I get the best distortion tones. As a rule, I hate the sound of bridge pickups.

What pickups you use also will affect things. I now run a DiMarzio X2N-7 for my distortion output, since it is the hottest pickup on the market. And for now, I am running a DiMarzio Model J humbucker for my clean tone. I suggest using as hot a pickup for the distortion side as possible. It doesn't have to be a guitar pickup, just hot enought to get the job done.

If you run a typical distortion unit into a standard mono amp setup, you might get really awesome distortion, but it will also kill the bottom end. Now, some players don't mind this. For example, Lemmy from Motorhead plays like this, and one of his trademarks is the fact that his bass runs with screaming distortion, but not a lot of bottom end. For Lemmy, it's all about being as loud as possible.

They do have bass distortion units, but here is my big problem with these. They take the incoming bass signal, and divide the signal along two paths: the clean, and the distorted path. Then the two signals are re-combined at the output. This means that each side is only receiving half of the pickups signal. So what usually ends up happening is that you lose gain and harmonic content in the distorted signal. For me, that's not good.

A really nice stereo setup, and one that I typically use, would be a stereo power amp driven by two preamps. I've used 4x10's and 2x15's for my low end, and 1x15's for my distortion side, and this has worked well for me.

The tricky part about doing this, and usually the deal-killer for most players is that this involves wiring your bass with two pickups, two volumes, and two outputs. Not that this is hard to do, in fact, it's a cake walk. But most players are hesitant to make that kind of commitment, just as many are timid to go with a bass trem. But even this can be overcome by installing a switch to toggle back and forth between having both outputs isolated, and bridged together.

Another downside is this means having two complete rigs running. Two speaker setups, two preamps, and two power amp sources. But I've been doing this for so long now that it doesn't phase me anymore. The results are more than worth it to me.

Then there's the whole "you mean I'll have to run two cords from my bass?" thing. I do, and it's never hurt me, but there are other options. A balanced mic cable with the right plugs and converters with work just fine. I just happen to enjoy the added drama of having two cords coming from my bass.

OK, enough for now. Questions? Comments?

I'm interested in wiring a bass so that it has two outputs, however, when I did this in the past, I missed being able to just be able to plug into one jack and toggle between the pickups with a selector switch. I would like to have a guitar that has stereo outputs, but can be set back to a mono output bass at the flick of a switch. How can that be done?

Whoa thats heavy ... I love it.. yes I will have questions coming soon . but that is a great start

dpst switch on the outputs of each pickup before it hits the vol knob(s) pics would help you obviously ..if you click the switch it will cut your volume slightly on mono mode because your would be combining pups again into whatever 2 amps you were just using the stereo effect for.. (same thing when you have 2 vols and turn them both up )

same thing to have a guitarplayer lay down a clean track, then mix it in with a distorted track and blend them for an even richer sound from the same instrument. Eric does it live that way so for him he needs 2 channels all the time.

EricHaven wrote:

Then there's the whole "you mean I'll have to run two cords from my bass?" thing. I do, and it's never hurt me Questions? Comments?

I guess if you tripped on your cords you'd fall off the stage twice as fast.. :sarcasm:

XLR is too big, midi is a thing of the past...I would have used a stereo 1/4 out of the bass -and on the other end split it off to L/R for both amps.

Agreed on all counts. I also think that an XLR is too big, and a MIDI plug is just plain silly. But a stereo plug wired to a mic cable (remember that a mic cable is actually three shielded channels of sound, and that you can make the grounds all common) would do the job nicely.

As far as how to wire up a combiner switch, let's pick apart what's going on. For this example, I am not going to include any tone controls to simplify things, but adding one wouldn't be hard to do.

Mike/Amimbari does describe a way that will work, but I can make it even simpler than this.

Let's take for example a Jazz bass. You have two pickups, each wired to their own volumes, running to the output jack. The positive side of both volume pots are wired in parallel going to the jack. So, to replicate this function in a bass wired like mine, you would take your stereo isolated circuits, and add a SPST (single pole/single throw) switch wired between the positive tabs of the volume pots. With the switch open, the bass would function in stereo. With the switch closed, the bass goes back to mono.

I'm working on a schematic to better illustrate the concept, and I'll post it here soon.

OK....don't laugh, as my computer art skills are really poor.



Look at each group of pickups/volumes/jacks as separate circuits. Add the SPST switch between the positive sides of the pots, and you make the bass mono again. You can then use either jack.

See?

Ah okay. That makes sense. Thanks!

Would this work? http://www.radioshack.com/product/index.jsp?productId=2062503

I had an idea--since I don't want extra switches on top and I want to minimize the number of push/pull pots on the bass, if I do this, I'll mount the SPST switch in between the output jacks on the jackplate (Carvin stereo jackplate)...it'd be out of the way, guarded by the cables, and I'd only have to drill a hole in the jackplate, not on the guitar...

That would work perfectly, Martin. And I think your idea of putting it in the plate would work just fine.

i have the bi-amp / bridged system integrated into my model of amphead ( carvin bx1200 ) including the separate send and return effects loop for each channel. my processor also has the stereo left and right splitting capabilities.

after extensive fiddeling with this technology (and still not using it), i gotta agree with eric about the purity of the levels of running 2 completely separate channels, from pickup to speaker / pickup to speaker. i've fiddeled with two separate tracks while recording; one with oodles of effects and another with clean low end channel, with the result of ... "omg, thats what i want it to sound like!" i chose to not use it (for the recording) because with using the mono channel and signal splitting ... i just cant sound that way live ... and i just feel like thats cheating (the listener). the mono channel splitting just ends up loosing something ... one way or the other. in the biamp mode with the separate channel effects loop, the distortion bleeds into the clean, the clean into the distorted or just overall cutting the signal by a 1/3. ugg.

i continue to battle this with the gear that i have; striving for that perfect effect / clean tone. of course ... i am always aquiring new gear. this has been my mission with the 2X15 cab (and frustrated me into just building my own) ... to further separate the two and get that clean channel low end. perhaps the gear i have can do this and i just havent sent the signal to the correct speaker setup. the bother to produce this tecnology leads me to believe that there is someway that its supposed to work ... or that i assumed that this is the way its supposed to work and i'm a sucker for shelling up the bucks for it.

if not ... i'de have the gear to do it then. its just the matter of wiring up a bass and taking the leap. after watching some videos of sheehan with his yamaha and having more of an understanding of stereo these days ... it looks like this is where i'm eventually gonna end up.

EricHaven wrote:

OK....don't laugh, as my computer art skills are really poor.



Look at each group of pickups/volumes/jacks as separate circuits. Add the SPST switch between the positive sides of the pots, and you make the bass mono again. You can then use either jack.

See?

i just read this topic and WOW!! i was inspired!!
so, our friend madmike was trying to build a bass based on my specs, the link below had all the story
https://basstremfanatics.forumotion.net/t832-some-question-about-kahler
so my question is, can this stereo wiring works on active preamps?
it will going like having factory wired active preamps added with SPST switch, can it be done?

Awfully quiet at the time. Is summer keeping you guys from your trem exploring efforts?

So my question:

Would there be any difference when two seperate channels are powered between running them through a poweramp in stereo and bridged mono?

Ofcourse I know that in bridged mono the both channels would sound through one cab, and in stereo through two L/R. Would this make much of a difference? I am particularly interested in the fact that in stereo I would lose the use of one channel when I play mono (and so only use half the power), and in bridged mono I would have all sound through one cab, does this affect the sound in a negative (or positive, or whatever) way?

It usually flows and ebbs here, Jim. Just depends on what folks are doing.

Since I only run my power amp in stereo, I cannot comment on the difference.

The only thing I can say is that since I run my distortion signal alongside the clean signal with the intent of filling in the gaps, I try to mix the two separate volumes so that the result is something akin to a rhythm guitar along with the bass signal, but not having one overpower the other.

There are times in songs where the distortion comes down, and even completely out. At those times, the entire band is usually quieter, so turning down the distortion signal doesn't so much represent a loss in power per se since everything else is at a lower level.

Are you considering, or already, running your bass with stereo outs like I do? Or do you mean splitting the mono signal?

Well, as you might be aware of as I mentioned it before here on the forum, I am going to build my own bass (have evrything except for the wood which I hope to go out and buy soon).

This Bass will be evrything I've ever dreamed of:

Kahler (hybrid for price reasons) 6 string bass tremolo (chrome) with John brown midi saddles,
6 string Emg p pickup in middle position
6 string Emg tw pickup in neck position
6 string Emg j pickup in bridge position
(these pickups wired through a 5 position stratf switch but then with the tw pickup wired as the middle pickup)
Sperzel locking tuners chrome
Midi capability (trough graphtech hexaphonic preamp)
Piezo sound (trough graphtech acoustiphonic preamp)
Necktrough quartersawn maple neck
Hidden pickups (under zebrano veneer)
Ebony lined fretless fingerboard with epoxy coating
Swamp ash body core
Zebrano top and back and headstock cap
Chrome hardware and knobs
Carbon neck reinforcement
Two way trussrod,

I'm sure I forgot something, but it paints the picture. It's not everybodies cup of tee, but I like this stuff, and I think it will turn out to be a great bass.

Now on the stereo, As you can read the bass essentially will get three outputs, midi, pickups, piezo. The midi goes trough 13 pin to a axon ax100, which goes to a laptop, and then through the aux in of one of my preamps. The piezo goes to the same preamp to the normal input. Then the pickups go to the other preamp (I still have to buy one, I'm working on it), this preamp will have a overdrive or distortion from my boss me50b in the paralel effects chain for a mildly overdriven tube growl.

Still following?

I was wondering what to do with this? Should I send it to bridged mono, sending evrything to one cab, possibly making the sound a bit blurry when I use all stuff at the same time? Or should I use stereo out and use two cabs, losing half my wattage and thuss some volume when I'm not using either the piezo/midi channel or the electric pickups channel?

Ideas/oppinions?

if it was me......... I would take a single output from each pickup going into your amp like this:

neckpickup/bridge pickup left/right into a stereo preamp like my Behringer Vamp. use your amp on stereo correct not as many watts, and you do have to use 2cabs for true stereo.

(since my bass only has one output, it still goes into my preamp on the mono channel, then is split from there into l/r into my rack mixer then the amp )

basically if I use my stereo chorus in the preamp, it sweeps gloriously from cab to cab, but the INPUT is still mono.

if I HAD a true stereo output from my bass, it would not make any difference as one channel would still go to the left side of the preamp, and one into the right side, and the out of the preamp is still l/r into the mixer which is also set to l/r so my amp is still true stereo.

BUT, I dont have a stereo bass so I use the 16channel rack mixer with the pan controls swung all the way l and r to make it reproduce the same scenario.
so channel1 is L and channel 2 is R and I can adjust the balance on the rackmixer and not worry about the vol knobs on the amp.
( channel 3 is pre effects so I can also blend the DRY signal into both cabs or one or the other )

as soon as you go bridged on the amp, it loses the stereo ability as you can only use one input on the amp BUT with a rack mixer( any mixer ) you can still blend in any amount of dry/distortion/effects you want coming out of 1 cab or multiple cabs daisychaned.

oh wow all that explanation and I should have simplified it.... pretend your a sound engineer with a 24channel board.

you want 3 outputs from your bass? good, use 3 channels on the mixer
adjust the levels accordingly to blend in any amount of whatever you want or pan l/r to your tastes.
If your recording your laptop will be on the l/r output of the mixer so your recordings will be in stereo.

If your in bridge mode it dont matter you can still blend in whatever you want then out to your amp+cabs.

Animbari, your last post clarified your previous post very well.
The main thing it pointed out to me was: If I decide to use my power amp in stereo, I need a rack mixer, otherwise my left or right channel would go dead when I don't use the pickup or midi/piezo.

Now that raises the next question:
Why should I use my power amp in stereo, or why do you?
And:
What's the difference soundwise with stereo and bridged mono if I would leave my pan control in a rack mixer flat?

you dont have to use your power amp in stereo if your only using 1 cab, your goal is to blend in the 3 bass channels so your peizo/neck/bridge give you the total tone you want to hear.

do I use my amp in stereo? YES. Why? mainly because my cabs only hold 200watts rms and tossing 1500 into them is a risk factor and the crown only puts out 300@8ohms.
Have I used it in bridge? YES, many times when the PA is doing all the work.


"What's the difference soundwise with stereo and bridged mono if I would leave my pan control in a rack mixer flat?"
no difference.

remember your goal is to blend in the amount of tone from each of the pickups exactly like a soundguy mixing vocals to come out of the same stacks he has setup..etc.
you never hear one vocal on left only, and another on the right, usually a slight offset from dead center, but still mono and blended thru the same cabs.

and you dont "need" a rack mixer, but they are cheap as hell so buy one for around 100 bucks or less
you could use a small stand alone unit like I also have in my gigbag IF god-forbid everything else blows up I can still go bass to mixer for the preamp/tone, then out to the PA.

here's the small stand alone mixer i keep in the bag:

http://www.ebay.com/itm/Behringer-Eurorack-UB802-6-Channel-Mic-Line-Mixer-lightly-used-/320942102884?pt=LH_DefaultDomain_0&hash=item4ab9a3d964

and it has 2xlr or 4 1/4" inputs, plenty for your bass and 4 outputs 2 main 2 sub, so you could drive 2 stereo amps with it if you wanted.

The tinkering with the volume of my three independent channels can be done on my preamp.
I have a master level for my piezo/midi channel, in which I can independently change the level from the midi with a aux volume control.
I have a master level for my pickup channel.

I could always ad a volume pedal for each channel on the ground if I would want that, right?

And when my bass is finished for each output there will also be a volume pot on the bass. Lookt like plenty of options IMHO.

I do understand the stereo, so I won't blow my speakers idea, I think when I get my speakers this won't be a problem.

Looks to me like that for what I would want to do a bridged mono makes life easier then a stereo setup because I just wouldn't use the options.

Still.... I might buy a mixer to use it to equal out the volumes of other equipment I will put on the aux in like Cd player or such.

ya that's pretty much it.

the mixer just gives you the "easy" ability to do it on the board and not fiddle with vol knobs on the bass, like Eric said sometimes he wants heavy distortion sometimes not.


plus if you have a midi trigger into your laptop for weird sounds, that also can be outputted from your laptop back into the mixer and then into the amp with the other signals.

Quote :

plus if you have a midi trigger into your laptop for weird sounds, that also can be outputted from your laptop back into the mixer and then into the amp with the other signals.

That is exactly what I'm going to do! But I was going to use "normal" sounding stuf VST instruments from Kontakt I guess.

see, even I can be helpful.

AND even though guitarplayers love the sweeping chorus/phaser junk more than bassplayers, it is cool to have 2 cabs on either side of the stage and listen to the subtle l/r panning effect as I have done in the past.
AND if your PA guy isn't an ***, they would let you take TWO outputs to their board so the audience could hear the l/r sweeping effect as well

I bought this and it has TWELVE outputs 2 main and 8 subs...imagine if I had a REAL studio because right now it is sitting in the box as it won't fit on the table where my 16channel mixer is currently---just way too big but the price was right so unless it gets sold on CL, I'll have it for a while..lol

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