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Juicing/Goosing an Amp

Discussion in 'Amps and Cabs [BG]' started by rickbass, Dec 10, 2000.


  1. rickbass

    rickbass Supporting Member

    Toying with the idea of juicing one of my hybrid heads, (tube preamp w/SState power amps), in order to gain more headroom. One thing I know I can do safely is make sure I'm using 14 gauge speaker cable. But do you think any of the following, (which I would have done by a pro), would be worth the trouble/expense? Other headroom ideas ?
    Thanks in advance for any input.

    > In the solidstate rectifier circuit, change the existing diodes to a higher amperage rating, such as the IN5408?






    > Replace the existing 12AX7 with a 12AY7 or a 12AT7?






    > Double the value of the filter capacitor that feeds the screen resistors, (not the preamp)?


     
  2. oo0o00o0oo

    oo0o00o0oo

    Apr 30, 2000
    Chicago
    Changing the preamp tube won't get you any additional volume. This will most likely fry your amp but if you really need volume... Go from your bass to the input of an amp, speaker out to the input of another amp. Amplifying an amplified signal. I've done it before without breaking either amp, but this will fry your amp eventually.
     
  3. > In the solidstate rectifier circuit, change the existing diodes to a higher amperage rating, such as the IN5408?

    This is not limiting your headroom. No change. Not necessary. Kinda like increasing the size of the muscles in your thumbs, it ain't gonna help you bench press more weight.

    > Replace the existing 12AX7 with a 12AY7 or a 12AT7?

    Not that big a deal. Won't change much, and won't give you more power, which is headroom. May change the sound from the preamp to your liking, but I wouldn't do it. Probably won't fry anything to put in a 12AT7 for a 12AX7, but I wouldn't do it without studying the schematic first to make sure.

    > Double the value of the filter capacitor that feeds the screen resistors, (not the preamp)?

    Your SS power amp doesn't have screen resistors, that's only in tube power amps. So not applicable.

    >Go from your bass to the input of an amp, speaker out to the input of another amp. Amplifying an amplified signal.

    Won't get you any more power. The power rating of the last amp will be how much power you get to your speaker. They don't add or multiply or anything. Just plug in to the last amp.

    Short answer to the topic. Buy a new amp. If it was easy to add more power to an amp, the manufacturer would have made it that way to begin with. They squeeze out as much power as possible from the design so they can charge as much money as possible for it.

    You would need a new, bigger power transformer, more output transistors, bigger filter capacitors, a new circuit board to hold all this new stuff, and since there is probably no room in the chassis for all this new stuff, a new chassis.

    Starting to get my drift? Go get a new amp bigger than the one you're talking about dicking with, or buy another one of equal power or so to run along side the first and power another seperate speaker cabinet.

    The 14 Gauge wire is cool to use. You probably won't notice a big change though, unless you were just using a guitar cable to power the speaker, which is a no-no since it is only like 20 Gauge and it's shielded.

    Chris






     
  4. Phat Ham

    Phat Ham

    Feb 13, 2000
    DC
    Buy a new power amp. Run the preamp out of what you have now into the new power amp and you'll get more headroom (assuming of course that your new power amp will be more powerful than what you have now).
     
  5. rickbass

    rickbass Supporting Member

    Thanks!:D I got most of the headroom-increase suggestions from an article by Gerald Weber, pres. of Kendrick Amplifiers. The reason I thought it would be a good idea to trot out in TalkBass was because a postscript to the article mentioned, "The ideas...have not been verified or tested in any manner....".