1. Please take 30 seconds to register your free account to remove most ads, post topics, make friends, earn reward points at our store, and more!  

Preamp/power amp questions

Discussion in 'Amps and Cabs [BG]' started by tarp21, Jul 31, 2020 at 7:23 PM.


  1. tarp21

    tarp21

    Friday
    Hey all! First post so please go easy on me lol. I’m gravitating from a small Ampeg 2x10 combo to a GK 4x10 4 ohm 800 watts top and a GK 15 8 ohm 400 watts bottom as I recently got into a fairly loud rock band from my typical country group. I don’t have cash to shell out for a head but I have two Crown XLS power amps at my disposal. A 1500 for the 4x10 at 4 ohms and the 1000 for the 15 at 8 ohms. Can’t use only one power amp I believe because of the split ohm load bringing it to approximately 2.6 ohms and the amp only goes down to a 4 ohm load, hence the two separate amps. Not my main concern they only weigh 11 lbs a piece.

    Pedalboard consists of wireless>keeley compressor>boss ms-60b>Ampeg SCR DI.
    DI to mixer with 1/4” out from it to the front of my combo amp for separate stage control from FOH. Works great! I tried that combo with my 15” cab and the amp farted out on me with the rock group! It’s paired correctly at 4 ohms too. Most are saying I should pair it with another 2x10. This is irrelevant to me because it’s only 450 watts total. I need more with two loud guitar players and a drummer and I’ve tried the in ear thing trust me, not happening!

    Anyway, I rarely step on my pedalboard it just takes up space and is a damn trip hazard lol. I’d like to rackmount my pedalboard sending DI to mixer and the 1/4” out to the power amps. Only caveat is, I lose my separate stage control I had using the combo! And now It’ll be like most bassists that’s just DI from their amps. It’s post control so if I adjust anything on stage it’ll effect FOH too.

    Therefore my question(s) is this:
    Can I send that 1/4” out of the DI pedal to another Ampeg DI pedal input and come out of that unit to the power amps?
    Would I still retain separate stage and FOH control?
    And if this is possible, would I need to come out of the 2nd preamp DI to the power amp via mic cable or use the 1/4” out?
    Would I still have compression in my stage rig from the first connections or would I need a second compressor pedal?

    I’ll enclose some photos of what I have started so far if I can.

    Thanks for any and all help with this guys?
     

    Attached Files:

  2. tarp21

    tarp21

    Friday
    I figure if I set and forget FOH DI, like I did using the combo, I should be able to control my stage sound with the second DI. Basically thinking the second DI is like my combo amp. Am I wrong in my thinking? BUT the other questions remain for sure. Would I need a second compressor or is the original compressed sound still getting to that second DI and amps? I have enough $ for a used Ampeg SCR DI but don’t want to shell it out if it won’t work
     
  3. bucephylus

    bucephylus Supporting Member Commercial User

    Aug 18, 2002
    General Manager TecPadz LLC
    First, you should be able to drive both cabs from the 1500. You don’t need another amp. If that isn’t enough, then the problem is the cabs, not the amp.

    Second, you mainly need a preamp DI, which sends a pre preamp signal to the board, and then use the preamp to feed the power amp. And, the feed to the power amp needs to be at or above the power amp required signal level. Don’t know whether or not the SCR-DI checks those boxes. If not, then a) there are many choices available, which do meet those needs and b) for not a ton of coin, the Mesa Subway preamp/ DI will def get that job done.

    Bottom line: what you are trying to do can def be done for not a lot of money; and you may or may not be able to do it with what you’ve got. I just am not familiar with details of the SCR-DI.

    That said, as a general rule, your 410 will inherently blow away your 115; and the 115 will not add anything inherently to your voicing. That combination is a preconceived notion that generally doesn’t deliver the concept. Suggest you do a bit of searching in this forum for various other synergistic cab combinations.

    Hope that helps.
     
    dbsfgyd1, JRA, jnewmark and 1 other person like this.
  4. 100% what he said.
     
  5. Eddie LeBlanc

    Eddie LeBlanc

    Oct 26, 2014
    Beaumont, Texas
    None
    I have a Crown XLS 1500 great amp.
    Try one cab in one channel and another cab in the second channel. It may be enough for you.

    That's how I used to run mine. The Stereo channels in the Crown will each operate into 2 ohms. But Bridged Mono only 4 ohms.

    Since the Crown has a DSP circuit, I'd try to set up a HPF in it for about 40 hz, that keeps those real low frequency signals out of the cabs, and will tighten up response.

    I think it can be done on each channel.
     
    HolmeBass and Wasnex like this.
  6. tarp21

    tarp21

    Friday
    Yes I should looking at the Crown specs. It is in fact rated at 2 ohms dual. Didn’t realize that.

    I failed to mention I connected the DI to the power amps in the past and everything worked well and was quite loud. My main concern is sending one to the mixer and another one to control the stage sound. I am wanting to know I guess if anyone has ever tried this before. We run our own sound and I don’t want to be messing up FOH by making changes on stage.


    A 15 is all I have. I realize another 4x10 would be ideal. Just trying to get the most out of what I already have. BUT, there are a lot of bassists that use the 4x10/15 combo Thanks for the info, appreciate it!
     
  7. tarp21

    tarp21

    Friday
    I didn’t realize the crown went down to 2 ohms. That would be approximately 650 to 750 watts per channel, varied because of the spilt cab ohms I’m assuming.

    50 hz is as low as the amp will go, you probably didn’t know that lol.
    Thanks!
     
    Last edited: Jul 31, 2020 at 10:44 PM
    Eddie LeBlanc likes this.
  8. Eddie LeBlanc

    Eddie LeBlanc

    Oct 26, 2014
    Beaumont, Texas
    None
    Here is from their site:
    upload_2020-7-31_22-59-33.png
     
  9. tarp21

    tarp21

    Friday
    Yeah that’s what I found too
     
    Eddie LeBlanc likes this.
  10. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    1 cabinet per channel, 2 ohms never comes into play.

    Set the amp up for dual mono (NOT bridged mono), one cabinet per channel. Drive the power amp with the 1/4" out of the SCR, use the XLR DI out to the PA.

    Done and done.

    Be careful, the limiting factor of your system will be the 115
     
  11. tarp21

    tarp21

    Friday
    Thanks, you said basically what bucephylus said. I plan to do just that. BUT my questions on a second DI to the power amp hasn’t been answered. And I’ll be getting another 4 ohm 410 when I get some extra $
     
  12. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Why would you need a second DI?
     
  13. tarp21

    tarp21

    Friday
    Before the cabs I used a combo amp and the DI preamp. The DI went to the mixer. I’d set FOH, get an excellent tone and balance with the band and not touch that pedal at all the rest of the night meaning no sound, volume etc ever changed with FOH. Then I’d run a 1/4” out of that same pedal to the front of my combo. Meaning I can control my stage combo independently from FOH. So, I could tweak all night long on stage and never effect FOH. I actually got this idea from someone off this forum a few years back. Works fantastic.

    If one runs out of a bass amp post DI (how most bassists connect) then everything changed on stage effects FOH sound and that is difficult for any sound person to keep up with let alone our band with no sound man to really know what is happening out front. Same concept as a mic’d amp volume change from the stage raises FOH sound. If I use only one DI preamp pedal I’ll be doing what most do by NOT having independent control over both FOH and the stage

    My question is can I run from one preamp DI pedal to another exact one and have independent control of my rig and FOH like I did with the old set up?
     
    Last edited: Aug 1, 2020 at 12:41 AM
  14. tarp21

    tarp21

    Friday
    Apparently not many have done what I’m attempting to do so I guess I’ll have to answer my own questions and borrow a preamp DI and just try it out.

    I’ve seen so many bassists connect to the mixer the old way with one DI out of their amp that having two is actually pretty ingenious for individual, independent control.

    I tweak my amp all night with influx and out flux of people in the venue. Can’t hear well, crank some mids etc. Without the second DI, whatever you do on your amp will come through FOH thus changing it. And what sounds good 40 feet away on a dance floor might sound like complete poopie on stage and vica versa. This is the reason for the second preamp
     
    Last edited: Aug 1, 2020 at 12:51 AM
  15. joshmmorrison

    joshmmorrison Supporting Member

    Jan 17, 2011
    Chicago, IL
    I get what you're saying. You want to give the house their signal and let them do their thing with it but also have freedom to make on stage adjustments, which you lose by giving up your combo amp preamp in favor of just a power amp.

    I think a lot of us run a similar sort of setup - just don't find ourselves needing to make a ton of on stage adjustments. Especially if you have major PA support your on stage changes aren't as impactful. What sort of changes do you find yourself making regularly mid set? Is it something that a simple 10 band eq in between your scr-di 1/4" out and your crown input would suffice? Or are you making drastic changes - if so like what?
     
    tarp21 likes this.
  16. joshmmorrison

    joshmmorrison Supporting Member

    Jan 17, 2011
    Chicago, IL
    another thought and to answer your question. You can absolutely do ms60b > scridi (xlr out to board, 1/4" out to next pedal) > another preamp > power amp.

    It just seems redundant if you're using a PA since they're going to drown out the slight adjustments you make on stage.

    If the kicker is not being able to hear as well, maybe a simple headphone in ear monitor system is what you're after?
     
    tarp21 likes this.
  17. DigitalMan

    DigitalMan Wikipedia often mistakes my opinions for fact Supporting Member

    Nov 30, 2011
    Bay Area, CA
    Simple answer is yes you can cascade two Ampeg SCR DIs. Order doesn’t matter as long as they both are at the end of your pedal chain. Assume you use #1 for stage and #2 for house, then you would start with your Boss into the input of #1. The line out of #1 goes to the power amp. Use the thru out of #1 to the input of #2. Then of the XLR or line out of #2 to the house, depending on which they prefer. That way each DI is independent of one another, and you don’t double up the tone shaping or the gain staging.
     
    40Hz, tarp21 and joshmmorrison like this.
  18. tarp21

    tarp21

    Friday
    So glad you understand! Not any major changes and not all the time. I might adjust volume occasionally with crowd changes or cut or boost mids or change it’s frequency etc. Mostly I use my guitar for sutle changes. But those tweaks on a regular amp DI’d to FOH can have a big impact and not necessarily a good one. Thanks for your input!
     
  19. joshmmorrison

    joshmmorrison Supporting Member

    Jan 17, 2011
    Chicago, IL
    You could also swap out the scrdi for a preamp pedal with a pre/post button - gives you back control of the preap settings and sends the signal to the house for them to shape. (The gk plex for example has this)
     
    tarp21 likes this.
  20. tarp21

    tarp21

    Friday
    This is what I’m thinking too.




    You’re probably right along with others. I just have got so used to the separate controls.

    The issue is sometimes I can’t hear well, yes. And I’ve got expensive custom molded in ears Westones and a great Shure unit and I just don’t care for it. Bass always sounds flabby and farty though them. I’ll take a floor wedge any day of the week. Thanks for the info.
     
    joshmmorrison likes this.

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.