Charles.Doughty
11 posts
Mar 11, 2013
10:54 AM
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Love my Kalamazoo II from Greg Huemann. It has the line out option and I am wondering if other folks are running an external cab or to a PA for larger gigs. How much can this thing handle and what are my options?
Thanks in advance.
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5F6H
1576 posts
Mar 11, 2013
11:19 AM
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A line level out, derived from a voltage divider at the speaker wires (like Greg's K'zoo line-out & most good amp line-outs) attenuates the speaker voltage to around a half to one volt AC at a hundred ohms or more, by running this to a speaker cab you "turn down" the speaker voltage further, to a tiny, tiny voltage. Not enough to drive a speaker cab alone, it needs to go to an input on a bigger amp, PA, etc.
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Rick Davis
1439 posts
Mar 11, 2013
11:36 AM
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5F6H is correct: A line out is meant to drive the input of another amplifier (such as a PA mixer).
I can only add this to his comment: If the distance is long -- say over 20 feet -- to the device the line out is feeding, you should think about acquiring a DI box, which converts the signal to a low impedance balanced signal that is suitable for long cable runs using XLR cables.
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-Rick Davis
The Blues Harp Amps Blog
The Mile High Blues Society
Tip Jar
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Charles.Doughty
12 posts
Mar 11, 2013
11:44 AM
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Thanks Mark. Is an amp better over a pa or vice versa? I'd like to keep the characteristics of the zoo's "breakup".
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SmokeJS
66 posts
Mar 11, 2013
11:48 AM
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Two questions. 1) Can a KZoo line out therefore be used as if it were a distortion effect box to drive a larger yet cleaner harp amplifier? 2) Working within the suggested 20 foot limitation what kind of cable is most appropriate. Standard guitar type cable?
Last Edited by SmokeJS on Mar 11, 2013 11:49 AM
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5F6H
1577 posts
Mar 11, 2013
11:56 AM
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Hi Charles,
Depends how much volume you need, if it's as much as you can get out of the bigger amp with harp, & that amp makes a good sound for harp, then I'd go with the amp. To fill a big venue, line out to the PA...or if you have roadies, time to experiment & a sound guy line out to the big amp, then mic the big amp through the PA (though this is more amps, leads & stuff to carry so most folks won't bother and will just use one amp or the other - not a "jam" set up).
I got an unholy sound lining out a 5W amp into a Twin...a couple of times...before all the carrying, interconnecting & general faff killed the novelty! ;-)
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5F6H
1578 posts
Mar 11, 2013
12:01 PM
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@SmokeJS - 1) Yes, the second amp doesn't even need to be that clean, if it soiunds good on it's own, it will still sound good with the smaller amp lined out, you can vary how hard either is driven & the little amp will usually impart a little sag to the sound, but the bigger amp (if fixed bias) will still punch it out.
2) Yes, guitar, instrument cord (shielded cable)...in fact line outs are usually low impedance, so cod lentgh is much less critical than that from mic to amp/first device input.
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Greg Heumann
2054 posts
Mar 11, 2013
5:35 PM
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My answer is "try it"!!!
It sounds great through the PA and will sound like a loud Kalamazoo. If you run it to a big amp (I've run mine to my Avenger) and you use that amp to provide the stage volume you want, you will get some of both amps' personalities coming through. In this case you'll want to turn the big amp down so you can run the 'Zoo at its max if you want the most breakup - remember that when you do this you're increasing the overall gain, so you won't be able to get the big amp as loud as when you play it alone before feedback - however it WILL be louder than the Zoo alone. As for putting a pedal inline with the lineout circuit - nothing wrong with trying that- I never have.
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/Greg
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HawkeyeKane
1536 posts
Mar 12, 2013
8:38 AM
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I have a related question on this. Greg, Mark, Rick...you all know by now I've been using my Zoo and my Alamo in sequence as my usual gig rig for a while now. And the only problem I've encountered with that as of yet is the slight humming that comes from the Alamo when the rig is idling.
Now, up until recently, my conclusion to the cause of the hum was because the Zoo is grounded, and the Alamo isn't. But not long ago, I tried running the Zoo's line out through a DI box's ground lift input, and then the 1/4" instrument out jack into the Alamo. That did nothing to eliminate the hum, so I was puzzled once again.
But reading Rick's point about XLR and how it's better shielded against noise and interference, I've got another possible cause in mind. Since the line out on the Zoo is on the underside of the chassis, and whatever instrument cable that gets plugged into it is subjected to the nearby current running through the transformers and tubes, might that also cause some kind of hum?
I mean, to my knowledge, the only times the Zoo's line out has created any kind of buzz in the past was if there was a ground mismatch, or if the line was running past some other interfering device like another amp or a neon light.
Would it make sense to try running an impedance transformer with an XLR cable from the line out so it's better balanced and shielded from interference, and then another impedance tranny on the input of the Alamo?
Please advise me on this, because I'm on the fence as to whether I'm on to something here, or I'm just overthinking the problem.
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Hawkeye Kane
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Greg Heumann
2055 posts
Mar 12, 2013
9:23 AM
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It is unlikely the location of the line out jack is the problem. It is mounted to the chassis sheet metal, all of which is a "ground plane" - that's why I do it there. If you remoted it with wires and mounted it on something insulated (like the back panel, which I have seen done) it would more likely to be the culprit. The problem is more likely that the Alamo is ungrounded. Ground lift is not a great solution. Every single wire touching that amp is a potential antenna for 60Hz EMI. The fact that the grounds of the 2 amps are no longer connected when you use the ground lift doesn't change that (although it was a reasonable thing to try!) If both ARE grounded at the same potential then they all cooperate as an EMI shield.
At least, that's my understanding. I hope Mark will correct me if I'm wrong.
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/Greg
Last Edited by Greg Heumann on Mar 12, 2013 9:24 AM
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Rick Davis
1448 posts
Mar 12, 2013
9:36 AM
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Tim, does the Alamo hum when played by itself, not connected to the Kalamazoo?
Do you mean the Alamo does not have a grounded 3-prong power plug? Man, I'd get that done before doing anything else. It could solve the problem and save you from getting zapped.
The issue with the XLR cable and DI box for the line out is really kind of academic. It is only for ridiculous long cable runs (like when using a snake) or for plugging into things that require a balanced XLR connection. I use line out a lot and I always use a regular 15-foot guitar cable into the my Mackie powered mixer. I get no noise at all.
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-Rick Davis
The Blues Harp Amps Blog
The Mile High Blues Society
Tip Jar
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HawkeyeKane
1539 posts
Mar 12, 2013
9:45 AM
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@Rick
No, the Alamo doesn't hum on its own. Just with the Zoo lined into it.
And no, the Alamo has it's original two-prong power cord. I've been meaning to get that remedied, just haven't had the time. One little issue with that detail is that the amp has a two-prong convenience outlet on the back of the chassis enclosure. Now...ideally, I'd like to also replace that with a modern three-prong outlet so I have more options of what I could run from it, namely the Zoo itself. I just haven't figured out how to go about this yet either. Any ideas?
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Hawkeye Kane
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JTThirty
209 posts
Mar 13, 2013
7:10 AM
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Got a question for those of you who have used a line out with the Kalamazoo. I built a line out in a box following directions from this site: http://www.rru.com/~meo/Guitar/Amps/Kalamazoo/Mods/ezlo.html Alligator clips are used to clip it on to the speaker terminals. When I've experimented with it, I set the Kalamazoo's volume for the optimal tone and plugged into a larger amp. The Kalamazoo's tone comes through the larger amp great, but the volume coming from the Kalamazoo itself drops out dramatically. Is that a normal scenario?
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Ricky B
http://www.bushdogblues.blogspot.com
RIVER BOTTOM BLUES--crime novel for blues fans available at Amazon/B&N and my blog
THE DEVIL'S BLUES--ditto
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Greg Heumann
2060 posts
Mar 13, 2013
9:09 AM
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No that is not a normal scenario. I'm willing to bet you swapped the 2 resistors in the circuit.
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/Greg
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JTThirty
210 posts
Mar 13, 2013
9:46 AM
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Ricky B
http://www.bushdogblues.blogspot.com
RIVER BOTTOM BLUES--crime novel for blues fans available at Amazon/B&N and my blog
THE DEVIL'S BLUES--ditto
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JTThirty
211 posts
Mar 13, 2013
9:49 AM
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This is my third try to respond thanks to Greg. Thanks Greg. I'll not bet against you on that.
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Ricky B
http://www.bushdogblues.blogspot.com
RIVER BOTTOM BLUES--crime novel for blues fans available at Amazon/B&N and my blog
THE DEVIL'S BLUES--ditto
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