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  • 8 ohm head + 4 ohm cab?

    do-able?

  • #2
    Not good for a solid state head, tube head would be okay,
    For solid state (which are most heads these days) can should have equal or bigger impedance than the head. 4 Ohm head into an 8 Ohm cab is fine, but not the other way around.
    8 Ohm solid state heads are pretty unusual. 4 Ohm and even 2 Ohm is more common. Make sure you have the spec right.

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    • #3
      It's tube. I've done the opposite with SS before (4 ohm head, 8 ohm cab) and it's worked fine, thanks.

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      • #4
        It's a 2.66666666 (ad nauseum) load.

        There is typically no ohm tap for 2-2/3 ohms on tube amps. Ask your manufacturer which is better - the four or the two - for the life of the tubes.
        <div class="signaturecontainer">Winner of the yearly bassguy-illidian parody thread contest, 2005.<br />
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        • #5
          Originally posted by illidian
          It's a 2.66666666 (ad nauseum) load.

          There is typically no ohm tap for 2-2/3 ohms on tube amps. Ask your manufacturer which is better - the four or the two - for the life of the tubes.


          <div class="signaturecontainer">&quot;Some men see things as they are and say why - I dream things that never were and say why not.&quot; -- George Bernard Shaw</div>

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          • #6
            Originally posted by mxpxfan





            Haha! Now I read the title.






            *sneaks out the back corner*
            <div class="signaturecontainer">Winner of the yearly bassguy-illidian parody thread contest, 2005.<br />
            <font color="Red"><b>Genz-Benz GBE600 and LS-210T for sale. If interested, PM me.</b></font></div>

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            • #7
              Originally posted by brake
              do-able?


              Sure, it's do-able...not for very long, but it's certainly do-able!
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              • #8
                Is there a way to find out what my amp is, for sure? all of the literature i've found on it says it's 8, but for some reason a while back, i KNEW it was 4 (dunno how, but i did) and the repair guy i just got it back from tells me it's 4.



                i've run it with 8 ohm cabs with no problem, so i'm assuming that's what it is.



                i assumed i wouldnt be able to run an 8 into a 4, but the reason i ask, is my guitar player has basically the same amp (yba-1a, mine is a yga-1a..same circuit sans tremolo) and a 5.3ohm cab (the matching cab the head was sold with) and it works fine, i was wondering how that worked when a 4 ohm cab wouldnt?



                does that make any sense? i'm ****************in' tired.

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                • #9
                  For a tube head it's okay to run a lower impedance cab. Shouldn't be a problem. "Tube" here refers to the power amp section not to just a single pre-amp tube somewhere in the low voltage. Tube power amp usually means big and heavy (because of the extra output transformer).
                  If you provide make, model, and year of your head, I may be able to dig up a data sheet.

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                  • #10
                    What the hell are you guys talking about. 8 ohm head??? Since when are heads measured in ohms.
                    <div class="signaturecontainer"><font size="1">WINNER OF THE RIPPIN'ROBIN DISTURBING POST OF THE DAY AWARD! 3/1/05<br />
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                    • #11
                      (loosely quoting L. Ron Hoover, the amp Guru)

                      A tube amp can match a 200% impedance mismatch.

                      But are you sure there's no 4 ohm tap?
                      <div class="signaturecontainer"><b><font color="red">Modulus Mob Member #5</font></b><br />
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                      • #12
                        Originally posted by brake
                        Is there a way to find out what my amp is, for sure? all of the literature i've found on it says it's 8, but for some reason a while back, i KNEW it was 4 (dunno how, but i did) and the repair guy i just got it back from tells me it's 4.



                        i've run it with 8 ohm cabs with no problem, so i'm assuming that's what it is.



                        i assumed i wouldnt be able to run an 8 into a 4, but the reason i ask, is my guitar player has basically the same amp (yba-1a, mine is a yga-1a..same circuit sans tremolo) and a 5.3ohm cab (the matching cab the head was sold with) and it works fine, i was wondering how that worked when a 4 ohm cab wouldnt?



                        does that make any sense? i'm ****************in' tired.


                        I have the yba-1a as well and I use a 4 ohm traynor 4x10 (from the later '70s solid state days) . My tech actually told me about the cab being for sale so I asked the same question about the 8ohm->4 cab and he said its not an issue when dealing with a tube amp. I have an Ampeg B-25B hooked up to that same cab at the moment and it's the same deal.

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                        • #13
                          Originally posted by SA Rios
                          What the hell are you guys talking about. 8 ohm head??? Since when are heads measured in ohms.

                          All solid state amps have a minimum impedance at which the deliver maximum power and below which they will shut down (or blow up). It's listed for any amp out there and usually printed right next to the speaker outputs of the amp. Take a peek at yours.

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                          • #14
                            my personal opinion is always drive your amp. But also keep in mind that its more dangerous to underpower your cab than to over power it. I've had several cab configurations over the years. my advice is if you can handle moving it. Get an 4ohm 610 or 810. Some of the new 412 cabs made by ampeg and aguilar are nice as well. You've got alot more chance of causing speaker damage in a 8 ohm cab than a 4 ohm. I've never had any problems with the 4ohm 610 and 810s (SWR, Peavey, and now Ampeg) I've owed. The biggest factor in my opinion is your amp, watt rating is 99% of the time BS. (IE. my guitar player has had a 200W line 6 head, a 120 watt tube head, and his mesa 50W head is louder than anything he's owned. )

                            If you want to be able to do more things. The cab I have now is actually the ampeg 810E. Its devided. and able to run as one 4ohm load(which is what I do with an SWR 750), or you can actually run it with two different sounds(which I have several friends that are doing this with 2 seperate cabs using ampeg and sansamp pres teamed with a mackie 1400

                            any who as always when it comes to gear, don't half step it, it'll be alot cheaper in the long run if you get save your money and get what you really want. go to your local music store and try things out. If they give you a hard time about it, go to a different store.

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                            • #15
                              Originally posted by boseengineer

                              All solid state amps have a minimum impedance at which the deliver maximum power and below which they will shut down (or blow up). It's listed for any amp out there and usually printed right next to the speaker outputs of the amp. Take a peek at yours.


                              Yea, I know, but he said 8 ohm head. Heads are measured in watts. The term 8 ohm head means nothing. The wattage you get out of the head depends on the impedence of the cab. SS heads can go either 8 or 4 usually, most can't go under 4 but there are some that can see a 2 ohm load. I get 300 watts at 8 and 600 at 4 ohms. The back of my amp says not to go below 4 ohms. I would'nt call my head a 4 ohm head, though. Its a 600 watt head @ 4 ohms
                              <div class="signaturecontainer"><font size="1">WINNER OF THE RIPPIN'ROBIN DISTURBING POST OF THE DAY AWARD! 3/1/05<br />
                              WINNER OF THE FIRST AND PROBABLY ONLY KTREWTHE POST OF THE DAY AWARD 7-21-05!!!<br />
                              Winner of Thumper's 'Most Handsome HCBF Family' Award.<br />
                              Poltergeist award for the most disturbing post of the day. <br />
                              </font><br />
                              -----------------------------------------------------------------<br />
                              <font size="1">Genz-Benz GBE750<br />
                              Genz-Benz NEOX 212T<br />
                              <font color="Red">Eden 210 xlt - for sale</font><br />
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