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RPM or RBI With Poweramp

Discussion in 'Amps and Cabs [BG]' started by Growly Lytes, May 6, 2010.


  1. Growly Lytes

    Growly Lytes

    Dec 4, 2009
    Downunder Oz
    Bass player
    Is there any bassists here that use the Tech21 RPM or RBI to run their Poweramp ?
    The question is about sensitivity, what do you set the amp Sensitivity at ? The RPM puts out 1.0v. The amp i use has 3 settings 0.7v, 1.0v, 1.4v so what would give the best results using this actaul Preamp or a Preamp with 1.0v sensitivity?
    The RPM & RBI both are @ 1.0v they put out the same volts.
    Please Help :help:
     
  2. Fuzzbass

    Fuzzbass P5 with overdrive Gold Supporting Member

    My guess would be 1.0, but I don't know. Here's a bump for your question.
     
  3. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    What's the maximum output of the RPM and RBI?
     
  4. Fuzzbass

    Fuzzbass P5 with overdrive Gold Supporting Member

    Does this answer your question, Bob? I'm pretty sure the RPM is the same.

    Model Number: RBI
    Input Impedance-Input 1: 1M
    Input Impedance-Input 2: 1M
    Output Impedance-1/4”: 1K Ohm min
    Output Impedance-XLR: 600 Ohm min
    Input Level-Input 1: 1V RMS max
    Input Level-Input 2: 1V RMS or 10V max, with -20dB pad engaged
    Output Level-XLR: Switchable to -20dB or 0dB range
    Maximum Output Level: +10dB or better
    Effects Loop Send: 1K Ohm min, -20dB
    Effects Loop Return: 100K Ohm min, -20dB
    Low Frequency Response: 10Hz or better*
    High Frequency Response: Harmonic content, 20kHz or better*
    Maximum Power Consumption: 5 Watts
    AC Input Power (factory set): 100V, 117V, 220V, 230V, 240V
    Cycles: 50/60 Hz
    NOTE: Each unit is constructed for specific
    voltages. AC power cannot be switched.
    Enclosure: Aluminum and steel, fully shielded
    Dimensions: 19.0”w x 1.75”h x 5.25”d / Overall depth: 6.25”
    Weight: 5 lbs.
     
  5. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    It says the maximum output level is +10 dB or better, which would actually make sense if they also indicated what the reference level was. ;)

    Here are two likely meanings:
    If they actually mean +10 dBu, then that would translate to "2.45 V or greater"
    If they actually mean +10 dBV, then that would translate to "3.16 V or greater"

    Either way, it's higher than any of the amp's input sensitivity settings, so you can choose any of them. There's a 3 dB gain difference in each step from 0.7V to 1V to 1.4V.
     
  6. Boostedrex

    Boostedrex

    Feb 24, 2009
    Shreveport, LA
    Bob, if it's higher than the amp input settings does that mean that you could drive the input stage on the power amp into clipping? Or am I misunderstanding your post? Thank you in advance.

    Zach
     
  7. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    It means it could be capable of driving the output stage into clipping. That's what an amp's "input sensitivity" voltage spec means.

    I doubt that it would drive the input stage into clipping, but I have no idea what power amp you have or at what input voltage it would clip.
     
  8. Growly Lytes

    Growly Lytes

    Dec 4, 2009
    Downunder Oz
    Bass player
    O.k thanks guys but im still left asking the same question,
    What should the amp be set to for the RPM to really give it a push ? I know theres heaps of factors but the main would be with the Sansamp should it match the amp or is it better to have the amp at a lower sensitivity ? Every cab is going to put its 2 cents worth so a rough guess is good enough.
    Should i set my amp on the lower setting of .7v because the RPM is 1.0v ?
    If i set it at 1.4v would the RPM be working harder ? If so that would mean its better to have it set to 0.7v so the Preamp doesnt have to be pushed so much?
    What about when its set to 1.0v matching the RPM is this good ?
    Im lost cause i cant find any info & if i do its not helping much.
     
  9. Implosion

    Implosion

    Oct 19, 2007
    Finland
    Try all options? You won't damage anything.
     
  10. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    http://www.talkbass.com/forum/showpost.php?p=9088649&postcount=5

    You're agonizing over something that doesn't matter. Choose one and adjust the knobs; that's what they're there for. Don't worry about non-issues like the preamp being "pushed" or matching a number in one place with a number somewhere else.
     
  11. Fuzzbass

    Fuzzbass P5 with overdrive Gold Supporting Member

    What Bob said. Pick a setting and run with it. They're all good.
     
  12. Boostedrex

    Boostedrex

    Feb 24, 2009
    Shreveport, LA
    Perfect. Thank you for the info Bob. I figured that I was off/over thinking the whole thing.

    Cheers,

    Zach
     
  13. Mo'Phat

    Mo'Phat Supporting Member

    Oct 1, 2003
    San Diego, CA, USA
    For what it's worth...I ran an RBI through QSC and Carvin amps to great success for a long time.

    I never once thought about what you're obsessing about.
     
  14. Growly Lytes

    Growly Lytes

    Dec 4, 2009
    Downunder Oz
    Bass player
    Thanks
    i guess il just go with whatever works.
    G.L
     
  15. alangoldstein

    alangoldstein

    Jul 23, 2007
    Charleston, SC
    Endorsments: Aguilar, Hartke, DR strings, Analysis Plus "Oval" Cables
    rpm i hear is better
     
  16. alangoldstein

    alangoldstein

    Jul 23, 2007
    Charleston, SC
    Endorsments: Aguilar, Hartke, DR strings, Analysis Plus "Oval" Cables
    buy both return one. or just get the all new vt bass deluxe pedal. it smokes!!! has a di too where as the vt bass didnt.
     
  17. johnk_10

    johnk_10 vintage bass nut Supporting Member Commercial User

    Feb 16, 2008
    Thousand Oaks, CA
    John K Custom Basses
    i used my RPM with a crown xti2000 that has a 1.4V input sensitivity and the RPM had way more than enough output to drive it. i had to turn the rpm's output level down to about 50% or less so i wouldn't overdrive the xti's front end. so yes, any input sensitivity setting will work with an RPM.
     
  18. Growly Lytes

    Growly Lytes

    Dec 4, 2009
    Downunder Oz
    Bass player
    Thanks dude thats all i was really after....an insight to what other bassists set their amps sensitivity with the RPM or RBI.
    Thank you all,
    Keep Rockin
     
  19. Fuzzbass

    Fuzzbass P5 with overdrive Gold Supporting Member

    Well, it's like saying "what's better, a P-bass or a J-bass?" I own both the RBI and RPM, and like 'em both so much that I use them together. If I had to pick just one I'd go with the RBI, but some prefer the RPM.
     
  20. rpsands

    rpsands

    Jul 6, 2007
    Phoenix, AZ
    The RBI needs too much gain to drive the less sensitive power amps in my experience (e.g. yamaha p2500s type). Just my two pence though. I don't like the gain sound on that pre much so I am pretty sensitive to it.
     

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