Running daul pre-amps to acheive...

Discussion in 'Amps and Cabs [BG]' started by bryan bailey, May 16, 2004.

  1. A clean channel and a distorted channel.

    Okay, here's my plan. I have a QSC RMX850, an Ampeg SVP pro, and an Ampeg BSE410HLF. I had the thought of getting a sansamp RBI pre, and using that one for clean, and the ampeg for distortion.

    Would it be safe to run my SVP at near death gain, and not have it break in any shape, since it has tubes and all? And are there any specific tubes that can handle higher gain, and are cleaner at higher gain?

    I am also planning on buying an Avatar 410, in addition to my current 410. And running one cab clean, one overdrive. But I figured that if the Avatar is good enough I will sell the BSE and just keep that one.

    BTW, all of this will be controlled by an A/B box to switch between channels. And also, I will run both pre's into my compressor too.

    Any tips for better SVP tubes, or any other tips or suggestions?

  2. Hmmm... I thought the RBI was known for it's great tube-like distortion and grind. No?
  3. Frank Martin

    Frank Martin Bitten by the luthiery bug...

    Oct 8, 2001
    Budapest, Hungary, EU
    This is why I got the BSP in the end :p : it has a SS clean channel and a tube dirty overdriven channel. To switch, you only need to push the CH SELECT button or have a footswitch. :cool:

    BTW you stil didnt explain what you called the "sand-in-a-blender" tone... However, whatever it is, I didnt quite hear anything near it. Is that maybe because I rarely used the COMBINE switch? Whatever...
  4. Fuzzbass

    Fuzzbass P5 with overdrive Supporting Member

    I own an SVP-Pro and an RBI. The SVP is a great preamp (and it's OK to run the tubes at "death gain"), but as you've discovered there's no easy way to switch between clean and dirty tones.

    With the RBI, you have a few options.

    First, there is the "Active" switch (w/indicator light) on the front panel (footswitchable). You could set up the RBI for a dirty tone and use the Active switch (or footswitch) to bypass the RBI for clean tone. The downside is, bypassing the RBI circuitry leaves you with no tone-shaping capability (not within the RBI, anyway).

    Second: again, you could set up the RBI for dirty tone, but instead of bypassing it completely you could turn the Blend control down (counterclockwise) to reduce or remove the dirt from your signal. I believe the treble, mid, and bass controls would still be active, but the Drive and Presence controls would not. The downside to this is that you might have to set EQ differently for your favorite clean and dirty tones.

    Third: there is a way to set up two RBI preamps (in your case, one for clean and one for dirty) and use a footswitch to alternate between them. Very convenient, but the downside is the expense of the second RBI and footswitch. But I'm seriously considering getting a second RBI (or one of the new RPM's) and doing just that.

    Then there are fully programmable preamps such as the SansAmp PSA or Bass Pod that can store many different tones (both clean and dirty). And as mutant says, the BSP will switch between clean and dirty.
  5. Benjamin Strange

    Benjamin Strange Commercial User

    Dec 25, 2002
    New Orleans, LA
    Owner / Tech: Strange Guitarworks
    At some point I am going to run two BassTriaxis to achieve the same thing you are talking about. Boogie has suggested getting their Amp Switcher, which is an active switching system allowing you to switch between 4 amps or preamps, or run several at a time, with no phasing problems or signal degradation. If you are running two pre's at once, you should use a good A/B or switcher to run your signal to them, otherwise you could do some serious suckage to your tone.
  6. Wait, so the RBI has a footswich to turn OD on and off?

    Hmm... Maybe I could have two overdrive channels. :D

    RBI be clean/overdrive, the SVP being full on death distortion.
    Like stated above too, I would be using an A/B box to switch back and forth from the pre amps.

    Mmm...this is gonna be sweet [when I can afford it...] :cool:
  7. Fuzzbass

    Fuzzbass P5 with overdrive Supporting Member

    The RBI footswitch bypasses *all* functionality of the RBI: overdrive, EQ, tube emulation.

    The tricky part to using an A/B switch with two different preamps is merging the output signals of those preamps. As I learned here on this forum, it's best to use a little mixer. That's the beauty of using either two SansAmp RBI's or a programmable preamp: your signal isn't split, so no merging is necessary.
  8. mgmadian


    Feb 4, 2002
    Austin, TX
    Hey Benjamin! Sounds pretty interesting... I'm curious, given the MIDI switchability of the Triaxis, what extra capability/functionality are you thinkin' about with 2 Triaxis pres?

    Particulary given the controllable switching capabilities on the Strat 500, I'd think you could already hit a footswitch on Booige foot controller the and immediately alternate between clean and super-distortion (overdriving both preamp tubes and power amp tubes with the Strat at half-power), and anywhere in-between.
  9. Benjamin Strange

    Benjamin Strange Commercial User

    Dec 25, 2002
    New Orleans, LA
    Owner / Tech: Strange Guitarworks
    Not to derail the thread (too much), I've been considering the same thing Kaz is. Running the distortion through my 2x10, and a cleaner tone through the 15, or vis a versa. Or perhaps I could whip up some realtime control and pan distortion, clean, EQs, volume.... ANYTHING to which ever cab(s) I want.

    Now if you will excuse me, I believe I have just soiled myself.
  10. Frank Martin

    Frank Martin Bitten by the luthiery bug...

    Oct 8, 2001
    Budapest, Hungary, EU
    I think Kaz was thinking about using two preamps that feed the same poweramp and the same cabs...

    However, the SVP-BSP has two preamp outs: one is the CLEAN/MIX: if you run only one poweramp from it, then plug it into this, but if you are using two poweramps, then you can plug into the CLEAN/MIX and the OVERDRIVE: the clean channel with one rig and the overdrive channel with another :cool: :D

    Of course you should also think about the cost of two rigs, and the size and weight of two rigs with all its problems (transport, unpacking, setup, ...) :eek: :rolleyes:
  11. BruceWane


    Oct 31, 2002
    Houston, TX
    What works really well is keeping your clean amp and cab running while adding a distorted amp and cab when you want that crunch. I used to do it with a Morley ABY switch. The "crunch" rig doesn't need to be very big. A 2x10 and 100 watts will do fine; since your clean rig is still running, you can cut the lows in the crunch rig and crank it up LOUD.

    I used to use a guitar Rockman into a Sunn Concert Bass with a 1x15. Worked great.
  12. Well, here's how it would be setup.

    bass---A/B box QSC---cab

    There are two inputs on the power amp, and two outputs. And most cabs have two inputs on the back, so I think it would work.
  13. MascisMan


    Nov 21, 2003
    Dallas, Tx
    I personally would rather use a BBE BMax for clean and the SVP for dirty
  14. Frank Martin

    Frank Martin Bitten by the luthiery bug...

    Oct 8, 2001
    Budapest, Hungary, EU
    Based upon the clips at basstasters, i will add +1
  15. Acepiloto


    Aug 25, 2000
    I had thought of this for a while. I have an SVP-Pro, and thought about buying another one, then running one clean, and the other dirty run through the effects loop. Then when I want to turn off the distortion, use the mute function. Only thing is, is that (at least with mine) the mute on the SVP isn't completley muted, just attentuated a lot, so the volume is very low. So some distorted bleed could come through when the distorted pre is muted, but in a band situtation, probably not noticeable.

    I never put the money into the idea, and then I started using my Bass Pod in the other side of my poweramp, to get a two rig sound.
  16. quallabone


    Aug 2, 2003
    Don't plug 2 poweramps into one cabinet. It tends to make things explode. If I were in your position (and hated distortion pedals) I would run the SVP as my clean channel and the RBI as distortion it would look like this if it were me.
  17. 4Mal

    4Mal Supporting Member

    Jun 2, 2002
    Columbia River Gorge
    Quallabone is dead on. Do not do that or stuff will smoke!

    Me? I'd dump the Ampeg pre and get a pre that will do it all for you. Bass Pod Pro, ART NightBass etc ...

    One real good item to remember - what you sound like on stage isn't usually what you sound like out in the room. In a live rig - simpler is better ... save your obsessing for your studio time where you actually have control of your sound. In the meantime ? close might be good enough 'specially if it doesn't break, smoke, bust your back or bank account, etc ...

    I let my rig get a little too over the top in the early 80's. One night I ended up playing through a Di with no real monitoring on stage after a critcial piece melted and me with no spare ... not fun, probably didn't sound like it either. After that - simpler is better ... spares are good too!
  18. coyoteboy

    coyoteboy easy there, Ned Supporting Member

    Mar 29, 2000
    Sactomato, CA
    I've been toying with the dual pre- thing for a little while with my DB-680 and SWR IOD. The 680 has an input through which goes to the IOD, then the IOD out goes to the FX return of the 680 giving me a blendable and switchable dirt channel while never loosing the Aggie's niceness. I'ts too bad I'm not really in the sort of band right now to make use of such fun, and I haven't used it in a gig. Could be fun with arco on an EUB!
  19. jobu3

    jobu3 Artist formerly known as Big Joe

    Feb 17, 2002
    Mountain Top, PA
    I thought that the BSP's dirty channel was SS and not tube. :meh:
  20. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    mutantbassist...not to ruin your day...the overdrive in the BSP is entirely solid state...Billy Sheehan had said in iterviews that he prefers solid state distortion for bass. When I saw his rig during the latest G3 tour, he was using his Pearce BC-1 preamp which is solid state.

    The block diagram for the preamp in the manual show a tube gain stage before the signal is split off to clean and mean channels...

    Kaz, speaking of the Pearce's perfect for what you want to do...two channels, voiced differently one more distortion oriented, footswitchable, etc. Unfortunately they haven't been made since the early '90s. Some even have the Billy Sheehan mod which gives (to quote an article I read) lead guitar like gain and distortion. My BC-1 doesn't have the Billy mod, but it still distorts quite a bit.

    The channels are blendable but there are effects loops galore so that you can separate the signals at will.

    I used to run the clean channel to an Acme B2 and the combined output to an EVM 15. That way if I was just using the clean channel, both cabinets would be clean. Then, when I took a solo, I could kick in the distortion channel for harmonic enrichment and a volume boost (since both channels have output volume controls). Since the distortion was only going through the 15, there was no raspiness through the tweeter of the Acme.

    Since the distorted signal will already be compressed, I would probably save the compressor for the clean channel only. Besides, compressing distortion will bring up the unwanted noise along with the good noise.

    Instead of an A/B switch, I might be inclined to try to incorporate a pair of volume pedals in the preamp's effects loops or a similar patch point so that you can blend the signal. The only problem with that is that distortion through tweeters sounds terrible (and probably isn't very good for them do to the enhanced harmonic content).

    We could always help you rewire your 4x10 so that 2x10s and the tweeter will always play clean and the other two 10s can play clean or dirty.... :D :hyper:

    Have fun!!!!