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Tech21 RBI vs. RPM

Discussion in 'Amps and Cabs [BG]' started by kcdbass, Sep 22, 2004.

  1. kcdbass


    Feb 27, 2002
    New Jersey
    Former Sales/Web, Sadowsky Guitars
    i did a search, but didn't seem to find what i was looking for ... which is ... a very simple overview summary comparing the RBI and the newer RPM ...

    i glanced at the tech 21 site, but seeing as i only had three hours of sleep last night ... i could not compute the differences between the two ...

    i was hoping somebody here could just compare and contrast these two units in a quick 30-words or less nutshell ... thanks.
  2. sk8rboymc


    Mar 28, 2003
    I have the RBI, Got all the sounds I wanted in the store, finally got one. Very unimpressed when I played with a group.

    There's always a possibility of user error in there, but I can't get the sound I want out of the thing.
  3. cetera


    Apr 29, 2004
    Surrey, England
    Endorsing Artist: Spector Basses & Cort Basses
    Both are great pieces of gear! :) :bassist:

    Simply put:-
    The RBI is a dedicated bass preamp which can produce everything from a crisp slap tone to a majorly overdriven tube emulation.
    The RPM is an acoustic preamp which doubles up superbly for string/electric bass. It doesn't realise the same levels of overdrive but it features a Parametric Mid EQ rather than a set Mid on the RBI (affected by the bass & treble controls).

    Here is the reply I received from the extremely helpful LLoyd at Tech 21:

    "The RPM's Mid Shift control replaces the RBI's Presence knob. Additionally, the signal path flows a little differently: After the input, the Drive comes first with either unit. Then, the RPM's Mid and Mid Shift come prior to the Blend knob (which governs the oveall mix of those three knobs). On the RBI, the Presence comes next, and the Blend knob governs just those two controls ... the Mid comes later (in the EQ section).

    Either one is capable of being used for bass OR acoustic guitar, but the RPM's Mid Shift might make it a bit more usuable with acoustic guitar or string bass."

    Hope this helps! Both are superb, and are even better when combined (as in the Landmark series of Amp Heads)! :hyper:
  4. Fuzzbass

    Fuzzbass P5 with overdrive Gold Supporting Member

    You're encountering the mid-scoop inherent to the RBI/SABDDI tube emulation. Here's a couple things you can do to minimize that effect:
    1) Reduce Blend below 50%
    2) Reduce both treble and bass below 50%

    On my SABDDI, I often have all knobs set to around 10 or 11 o'clock.
  5. ster


    Oct 18, 2003
    New Jersey
    I have both and I use the RPM most the time because of the fantastic parametric mid control. The RPM is way more mid friendly overall and it "warms" up the tone as well. Also the overall sound is darker and the highs are sharper (and not as full in the higher harmonics) than the RBI. The Drive is more compressed too.
    I switch to the RBI (by footswitch) when I want a killer slap sound, a mean overdriven or grinding sound or other special sounds. The RBI can go to extremes that the RPM doesn't go to especially in the upper harmonics(the Presence control).

    Sorry if I went past 30 words!

    Truncated version:
    Rpm = darker,mid friendly
    RBI = Brighter,meaner,mid scooper

  6. Lyle Caldwell

    Lyle Caldwell

    Sep 7, 2004

    How exactly does toggling between the RBI and the RPM work with one power amp?

    I have an RBI on the way, and I'm intereste in the RPM, but how are they connected to each other and to the power amp?

    Tech21 has no actual info on this on their website.

  7. ster


    Oct 18, 2003
    New Jersey
    Just say you have the RPM on top of the RBI in your rack.
    The footswitch OUT of the RPM connects to the footswitch IN of the RBI.(You would connect the actual footswitch to the footswitch IN on the RPM) Then the Sansamp or unaffected output of the RPM connects to the line or instrument level in on the back of the RBI. Next, the RBI connects to the amp from the Sansamp or unaffected output.
    Then Rock on! :bassist:
  8. Lyle Caldwell

    Lyle Caldwell

    Sep 7, 2004
    Ah... thanks.
  9. kcdbass


    Feb 27, 2002
    New Jersey
    Former Sales/Web, Sadowsky Guitars
    thanks for the clarifications.

    i guess the RBI = bass driver pedal and RPM = acoustic di.
  10. mgmadian


    Feb 4, 2002
    Austin, TX
    Just learned about the possibility of chaining/linking together two Tech21 preamps, so I'm a little behind the curve here, but...

    - I assume you plug the bass into the input on the RPM (on top), right?
    - Each preamp can use it's own effects loop at all times, right?
    - You can then hit a footswitch and either the RPM or the RBI will send signal to the power amp?
    - Any idea if you could possibly have BOTH preamps sending signal to the power amp at the same time? That could yield an interesting result... :D
  11. mgmadian


    Feb 4, 2002
    Austin, TX
    Update: spoke to Lloyd at Tech21 this morning, so all questions answered... one thing to note about using the 2 pres linked together: you won't be able to run a single XLR out to a mixing board in a live situation. Apparently, the first pre's signal make it only slightly into the second pre's XLR-out... Tech21 is aware of this and is beginning to look into how to remedy this.

    Lloyd also mentioned that you may encounter a problem if you run 2 separate XLR-outs (one from each pre), as the first preamp's signal still does mix in slightly with the 2nd pre. But this may not be a big deal since the difference in levels would be so high... anyone have experience in trying this?

    BTW, Lloyd at Tech21 is a friendly, talkative guy who was very helpful...
  12. Mcrelly


    Jun 16, 2003
    Minnesota, USA
    I have an RBI and an RPM. it took me a few months to realize that for me I prefere the RBI. although I do like the mid-sweep control on the RPM.

    My opinion:

    RBI: brighter (than RPM), cleaner, as flexible

    RPM: Darker (may not be good on cheaper basses), more easily over driven into a "brit" sound, flexible, but cannot brighten up to RBI clarity

    I'm considering selling my RPM and getting a second RBI for my second rig.
  13. CamMcIntyre


    Jun 6, 2000
    Sorta a derailment, but Mcrelly-if you decide you do want to sell the RPM-let me know via PM or AIM. I've got an RBI, BBE BMax T, and have 1 open rack slot that makes me tempted to get an RPM to use as a DB pre as i dig the RBI & BMax for Electric Bass.

    Original Post stuff......I don't have an RPM, but have read about it on here. Overall impression that i get is that it's like a cousin to the RBI-same to a certain extent, but still different. [how's that for vagueness?] I've got the RBI and can say it nails a wide variety of tones for me. I do want to try out an RPM in my setting to see how it fits with the rest of the pres that i currently have.

    That's all