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Is It Possible?......

Discussion in 'Amps and Cabs [BG]' started by heath_the_great, May 4, 2004.


  1. Just a really wierd thought ive got, is it possible to either upgrade the power amp in a head or change it so it acts just as a preamp.....obviously i dont have the technical skills to do it, but just is it possible? oh, im talking about my peavey mark 3 Btw...
    [​IMG]
     
  2. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    I looked at the on-line manual and it doesn't indicate where in the signal chain the effects loop is. If it's post EQ, I suppose you could run a cable from the send jack to the input of an external power amp.

    If not...one would have to make some internal changes to your amp. It's certainly possible, but I don't know how much it would cost and whether it would really be worth it or not.

    What do you want from your amp that it's not giving you right now?
     
  3. Frank Martin

    Frank Martin Bitten by the luthiery bug...

    Oct 8, 2001
    Budapest, Hungary, EU
    Thats the same I've come up with lately :cool: - namely, the cheapest solution to getting a pre + power setup here might be that i will just get a power amp and use my GK's "effects send" to go to the power amp.
    Not many pres seen here, especially not used and all is expensive... :( :bawl:
     
  4. About another 250 - 300w, its only a 150w head, but it does have a line patch on the front, Send and Receive, 1volt rms nominal....

    so in other words i could use a seperate power amp and run a line from the send into that?, i heard somewhere that if you run a setup like that you could damge the head by not using it to run a cab from its normal speaker outputs?
     
  5. Frank Martin

    Frank Martin Bitten by the luthiery bug...

    Oct 8, 2001
    Budapest, Hungary, EU
    For eaxample, the GK manual says that you can run the head without plugging a cab in. Why would that damage it, anyway?
     
  6. ive got no idea really, its just what ive been told, plus the gk might be ably to do it, but ive got a peavey
     
  7. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    Solid state amps won't be damaged by not having a speaker load attached. On the other hand, amps with power tubes and an output transformer should never be operated without a load connected.

    Heath...you're not going to really notice a large volume boost when going from 150 watts to 300 watts. Theoretically, you'd need 1500 watts to be twice as loud, while 300 watts would only be noticable, not significant...

    You would gain some headroom though, so if you're clipping the poweramp on the Peavey, the move might be a good one.
     
  8. well my main bass (kubicki) has an extremely high output level distorting and clipping the amp real easily and thats at halfway on both pre and post gain, so i just need more headroom, so would it be better to use say a 500w power amp or somehow get it upgraded to 500w
     
  9. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    Funny...my Fender Stu Hamm Urge I with Kubicki preamp behaves the same way...

    I trust that you're using the low gain input on your Peavey.
     
  10. of course, im not that stupid :p , and i keep the volume on my bass at about 75%, i was checking out the swr workingmans 4004 and it said to plug all basses into the high gain except for a few basses like the kubicki into the low gain, which is a bit wierd
     
  11. Humm...., so using the line from the head to a poweramp is possible without damaging the poweramp or the head? This would be a good way to start building a rig, until you have enough money for a good pre-amp.
     
  12. I've added a power amp to my signal chain comming from a head and I like the results. IMO it is a good way to start upgrading a rig.
     
  13. So, if running the line out on the head to the poweramp is possible, couldn't you also use the speaker outs on head at the same time to a different cabinet for even more power, rather than having the head just be a preamp?
     
  14. the whole point of adding a power amp is because my head isnt giving me enough power, so why would i use the speaker outputs on the head instead of the power amp?
     
  15. Frank Martin

    Frank Martin Bitten by the luthiery bug...

    Oct 8, 2001
    Budapest, Hungary, EU
    Hmmm this is an interesting question...
    It depends on the head. If the signal goes from the preamp part to fx loop and back to power amp, then maybe if you dont put back a line you will have nothing to go to the power amp - but if you have a bass that runs an fx chain parallel and mixes the tones of the clean and fx, then it should work... at least that is what I think... I dont know, this is just some thoughts I've come up with...
    But if you have an XLR out and the power amp has an XLR in, then both should be working at the same time (do power amps have an XLR in anyway, or am I just making things up? :confused: :D )
     
  16. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Chicago
    You should be able to simply take a signal from the effects send to drive the power amp and still be able to use the internal power amp if you wanted to. It's usually the effects return jack that disconnects preamp from power amp.

    Easy thing to figure out though...plug a cable into the effects send and see if your amp continues to function normally.
     
  17. Indeed it does work. I tried playing my bass through the regular input with a speaker cabinet attached to the heads regular speakers out, also with a cable plugged into the line out. It didn't mute the speaker, so in theory this will work if there aren't any electrical issues.

    Ohms, impedence, and all the other stuff blows my mind, so I'm not sure what the specifics of that stuff would be with that kind of setup, but it is an interesting experiment. If this is so, you could probably do the same thing with mutliple heads, though at the point you might as well just get a bunch of power amps and a mixer or something, so no practical use there, though I imagine it would work for having multiple range speakers without worrying about ohm load, wouldn't it?