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Post by vegetablejoe on Apr 21, 2009 8:01:50 GMT -5
... 4, 8, and 16 ohms.
Assuming I have the correct, ohm-matched ext. speaker cabs, can I plug in more than one cab at the same time? Will doing so hurt the amp in the long run?
Thanks for your inputs.
Jaime
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Post by D2o on Apr 21, 2009 8:44:32 GMT -5
... 4, 8, and 16 ohms. Assuming I have the correct, ohm-matched ext. speaker cabs, can I plug in more than one cab at the same time? Will doing so hurt the amp in the long run? Thanks for your inputs. Jaime Hi Jaime, According to the owner's manual, the rating for the external speaker is 4 ohms with the Valve Junior. As for whether you can use multiple speakers, I suppose it depends on whether they will be combined in series or in parallel. What do you have in mind, specifically? I hope that helps. D2o P.S. You can also have a look here and see if it helps to describe ohms for you. |
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Post by newey on Apr 21, 2009 13:32:52 GMT -5
D2o-
I looked at the manual also, and I don't think that answers VeggieJoe's question. The manual doesn't state that it covers the Valve Jr Head, as it only talks about the valve Jr Combo amp. The diagram of the back panel of the Combo shown in the manual has only a single 4Ω output jack. The head, on the other hand, has three separate output jacks, for 4, 8, and 16Ω cabs.
VJ-
The manual doesn't answer this question, but my off the cuff answer is that you probably shouldn't do this. I don't know whether it will hurt your tubes or not but I suspect your output would be drastically cut.
The 3 outputs result from the transformer being tapped at three different places in order to give the different impedance loads, at least as I understand it. But I don't think that gives you the ability to drive multiple cabs without loss of output.
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Post by D2o on Apr 21, 2009 15:27:11 GMT -5
I still haven't been able to locate a manual for the head or cab ... but I came across someone asking just what you are asking in the Epiphone forum.D2o P.S. I am not a member of the Epiphone forum. |
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Post by newey on Apr 21, 2009 18:33:05 GMT -5
I don't know for sure, as I said, but thinking semi-logically here:
1) If plugging multiple cabs into the separate outputs ran a risk of damage to the amp, there would be a warning against doing so on the back of the amp, as well as in the manual. These things are vetted by lawyers, and the lack of such a warning would invite endless warranty claims in any event.
2) It it possible that the amp has been made idiot proof by wiring the ext speaker jacks such that plugging a cable into one disables the other two. Testing, or review of a schematic, would disclose if this is the case.
3) The third possibility is, as I said earlier, that it causes no damage but no one does it for long as it doesn't have much output. If you could do this and have it sound good, they'd be touting it in their marketing as an advantage of their product.
My two cents anyway, in the absence of any actual knowledge . .
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Post by ChrisK on Apr 21, 2009 20:10:54 GMT -5
42. newey, I'll pick on you since you responded the most (nah, it's just easier to cut and paste where there's more words...). My cents, 2. Is this the same as semi-illogically? Yes, it can eventually damage the amp. No, this is too cheap for lawyers to care. No, it came from China, who ya gonna sue? Epiphone? What, ya gonna sue them via unanswered emails? Ha! Not in this $pace-time continuum. Actually I don't know, but it's unlikely. Take it apart and see (please wait at least one hour after swimming - or powering). Well, overloading (under impeding) a tube amp output is much better than unloading the output (as sparks might fly and things might die). Ya, you betcha! I put on my long-range a'searchin' googles and perused the internets. The output transformer has three tap points and the other end of the winding, which is called "0". Pick one jack (please, or sparks might fly). While one could use multiple jacks for multiple speakers, it's complicated to calculate. I can do this, but I won't.  |
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Post by newey on Apr 21, 2009 20:45:19 GMT -5
VeggieJoe- OK, ignore what I said. Don't do it!  It's been a few months since ChrisK had to take me out to the woodshed, so I guess I was due! ;D |
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Post by vegetablejoe on Apr 21, 2009 23:34:28 GMT -5
I very much appreciate all your inputs and humor.  Ok, I won't do it. Thanks for saving my amp from possible disaster. Seeing three output jacks and as many ext cabs lying around everyday, the experiment was almost too tempting to ignore. Good thing I thought to ask you guys first. |
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Post by ChrisK on Apr 22, 2009 12:18:13 GMT -5
Well, experience* and judgment* has taught me that just because something CAN go somewhere, doesn't mean that it SHOULD.
*Judgment comes from experience.
Experience, from poor judgment.
And newey, it wasn't the wordshed, just the most convenient wordpile.
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Post by JohnH on Apr 22, 2009 15:21:04 GMT -5
The diagram makes it clear. I cant see any problem with combining say two 16Ohm cabs , externally with a Y connector, in parallel to make an 8 Ohm load, then plugging that into the 8 Ohm socket. If its sounds good, you could alternatively add another socket to the amp in parallel with the 8 Ohm socket.
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