Stomping the AMP

Discussion in 'Guitar Gear Talk Forum' started by yazi, Apr 24, 2007.

  1. loyal

    loyal New Member

    A cabinet of 4/8/16 etc impedance ( in ohms ), refers to the net/resultant voice coil impedance of the cabinet. If a 2x12 cabinet is connected as follows 2 8ohm ( voice coil impedance) speakers in series then your cabinet impedance is 16 ohms. if they are arranged in parallel it would be 4 ohms.

    Cabinet impedance should match with that of the head. some Amps are capable of delivering different output powers based on the output impedance to which it is connected. For eg an amp can deliver 40Watts RMS @ 8 ohms load and 60watts RMS @ 4ohms ( provided your transistors/tubes/FETS can handle this increased current and your power supply can source the additional current ) .
    Amplifier specs will mention this.
     
  2. tallkien

    tallkien DIY GURU

    One of those things that makes tube amps so versatile (but also costly), They can handle higher loads without worrying about overheating since that part of the circuit is transformer isolated (and impedence matched). People connect 1/2W amps to 4x12 cabs :)
     
  3. laneymaney

    laneymaney Banned

    tallkien: you really know your stuff...so can u help me. I recently got this Behringer UB802 mixer. But i have no clue on mixing....

    its got
    EQ
    MID
    LO
    FX
    PAN
    LEVEL

    what should i set it at for recording my amp...mostly metal and hard rock
     
  4. tallkien

    tallkien DIY GURU

    Sorry dude, I know nothing about mixing/recording, but r u using a mic or going direct? If you want to go direct, people recommend the Behringer GI100, As for settings, Trust your ears, works best
     
  5. tallkien

    tallkien DIY GURU

    EDIT ....hmmm....
     
  6. tallkien

    tallkien DIY GURU

    Since you have a mixer, there's something I've always wondered about...Try plugging your amps Effects Send direct into the mixer. You may need to patch it back to the amp (Return) if the circuit is open. That should make your amp act like a DI box and take care of Impedence problems, at least I assume so...

    Better yet, mic the amp also and send two signals and mix to taste

    I'm guessing that may be buffered enough for a good DI signal..try it and post back if you feel a little adventurous
     
  7. laneymaney

    laneymaney Banned

    ^Ive plugged pedals directly into the mixer quite a few times. But the extra noise produced by the Death Metal ****s things up
     
  8. Double Click

    Double Click New Member

    @tallkien- Using the effect send will bypass the poweramp and cab of the amp.. It'll be like pluggin an ordinary preamp into the mix without cab sims.. Not always a good sound.

    If u sent the signal back to the amp, then u end up using the mixer as an EQ.

    @laney-- Unless ur using multiple instruments at the same time, the mixer isnt essential... U'll just be using it for eqin. Use it for small adjustments to the tone. If u have to use drastic settings to get a useable tone, that just means the eq settings on ur amp/pedal are F'ed in the 1st place up or u r using a low end Zoom.

    For recording ur amp, The best way would be to get a good mic, and plug inot the pc direct.
    If u must use the mixer, set everything flat 1st, then slowly adjust depending on what u need. Just cause a knob goes to 100 doesnt mean u have to push it that far.

    If u plug a pedal into the mixer diectly, make sure ur using some sort of cab sim.
     
  9. laneymaney

    laneymaney Banned

    Im recording 2 guitars , 1 vox , 1 drums...so i need it badly
     
  10. thehundredthone

    thehundredthone Well-Known Member

    @tallkien: Does it really only cost that much to build a 5-10W all tube amp?
    Put me on your list once my old guitar is sold! Although, 1-2 years from now, how much will it cost me to replace the tubes, bias if required, etc?
     
  11. laneymaney

    laneymaney Banned

    In two years he'll be all famous n shyt and wont remember us
     
  12. tallkien

    tallkien DIY GURU

    he he he, I'm not into fame or money. I could very easily make amps for myself and keep quiet about it. I don't want to hoard them either. Mostly I just love good tone and I'm very sensitive to what I like to (or not) hear. A good sounding guitar makes my hair stand on end, a bad one makes me want to run and hide. I'm making you an amp as a labour of love for good tone

    @hundred: Remember these amps are just that, amps. There's no effects loops, modeling options. The more you play like this you appreciate "Less is More".
    SS amps run on about 6-24 Volts while these run at 200-400 volts so all components are bigger and more expensive, the transformers being the costliest things. The cost of a 50W transformer set is waaay more than a 5W set.

    Amps running Class A will need do be biased everytime you change tubes. Some of the other amps like the 18W run Class AB fixed bias so you won't need to bias them, just get similar tubes and plug them in

    Biasing is like adjusting the tuning of your bike's carb. Class A runs rich, Class AB runs in economy mode ;). Someone like Satch runs his amps so rich he'll need so change his tubes every 8-12 months, An AB Class amp could probably run a set for 4-5 years with no probs before needing new tubes
     
  13. tallkien

    tallkien DIY GURU

    @DC: Yeah that's what I was thinking about, a mic'ed cab mixed with a preamped clean signal colored in software. So you get the best of both worlds, DI and Cab.

    A lot of my fellow amp builders recommend this for pro quality home recording. Never tried it myself but I was wondering if the effects loop of an amp could be used as a DI box. No reason why it shouldn't, and the impedence would be lowered enough to reasonable levels so I was just thinking, will have to try it out ofcourse.

    One of my books has a DI box circuit so I will probably just make one someday. I first need a good mic. The one I bought is crap
     
  14. yazi

    yazi Banned

    Labour of what, Talkien?

    BTW, I want a 5W amp. But I live in Orissa. How can I get it from u?
     
  15. tallkien

    tallkien DIY GURU

    Hey dude, Walking around with aluminum filings dug into your flesh is not funny alright. Making these things is hazzardous, not to mention the "Potential" for a high voltage accident, pun intended

    A 5W what? Head, combo, mod job
    ...and I suppose I'll just have to courier it to you, or EMS

    My suggestion to you would be a 12W P1 Extreme and that Laney extension cab you were planning. I'll give you a grand off for being my first customer :) You won't need to think about any 30W SS with this combo


    Ouch! Those Laney cabs are expensive!. You'll be better off with a cheaper speaker option. I'll be importing some sammi speakers when I come by some cash (depends on how well, if at all) these amp sell. They're quite good for the price
     
  16. yazi

    yazi Banned

    How much will that cost me?

    If its over 10k I can't get it.

    I need a head between 7-9K bucks? Possible?
     
  17. Double Click

    Double Click New Member

    @tallkien - Chk PM
     
  18. laneymaney

    laneymaney Banned

    Nice....tallkeins first customer! Make the body out of wood and metal grills , and make lot of blue LEDs light up when u turn the amp on like a H&K trilogy!
     
  19. yazi

    yazi Banned

    By the Way, If I buy it, I would need 'Talkein 2 Yazi' written on it somehow.
     
  20. yazi

    yazi Banned

    Anyways, my bro is all excited about it.
     

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