joek18
23 posts
Apr 16, 2012
1:34 PM
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Hi Gang,
Thought I'd ask those who might know...
For an upcoming sit-in gig, I need to pipe my precious Kalamazoo through my equally precious Blues Junior. (I normally mic the Kal directly through the PA but won't be able to do that for this gig.)
First, can I simply plug the output from the Kal into the input for the Junior? Will that work? Any related issues?
If you have a better idea, please let me know.
As always, thanks in advance for the advice.
Glencoe Joe K
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HawkeyeKane
883 posts
Apr 16, 2012
1:39 PM
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Is the output of the 'Zoo one of Greg's? If so, then yes, you can just patch it together with a guitar cable. No issues at all. I do it all the time with my Peavey Vypyr. If not, you CAN use the second instrument jack and run that into the BJ. It might not have quite the same amount of output that Greg's line-out would have, but you can compensate with the level you set on the BJ.
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Hawkeye Kane
Last Edited by on Apr 16, 2012 1:46 PM
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5F6H
1146 posts
Apr 16, 2012
1:55 PM
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Taking a cord from one of the K'zoo inputs & feeding into the BJ will put the 2 amps in parallel - no signal will be coming out of the K'zoo into the BJ. That doesn't mean that you won't like the sound.
Do not ever plug the "speaker out" of one amp into the input of another, use a dedicated "line out" jack which incorporates a voltage divider to drop the 1st amp's output to a manageable level for the 2nd amp's input. It also isolates the 2nd amp's input from the impedance that the 1st amp's tubes see, avoiding any issues/smoke/fire there.
If you don't know whether you have a "line out", play safe, don't guess.
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www.myspace.com/markburness
Last Edited by on Apr 17, 2012 6:22 AM
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HawkeyeKane
884 posts
Apr 16, 2012
2:11 PM
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@5F6H
Thank you for making that distinction Mark. Obviously I forgot to. :-) On a note related to this, what makes an "emulated" line out different from any other type of line out? I ask because I have a Marshall MG10 that has this type of line out jack, but it also doubles as a "CD in" jack. I can never seem to get it to put anything out, no matter what kind of device I plug it into.
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Hawkeye Kane
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5F6H
1147 posts
Apr 16, 2012
2:33 PM
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I can't see a "line out" on the MG10 specs, there is a headphone out, probably designed for low impedance ear buds expecting to see a few 10's of millivolts at a low ohms?
The "MP3/CD line in" jack appears to be a separate jack socket?
Usually an "emulated" line out would include an inductive component, like a voice coil, or a choke...something to emulate a speaker, rather than simply a resistive load.The line out voltage divider as mentioned in my previous post (used by many tube amp companies) doesn't kill the speaker when the line out is used, but employs "kick back" voltages from the speaker so the "line out" isn't as stiff as with a purely resistive load.
However, inductors & dummy voice coils are relatively expensive and the MG10 "headphone out" kills the speaker signal...might have a cheap alternative like a lightbulb to emulate speaker kick back voltages (sheer guess)?
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www.myspace.com/markburness
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harmonicanick
1545 posts
Apr 16, 2012
2:39 PM
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Just stick a mic in front of the BJ speaker from the pa
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HawkeyeKane
885 posts
Apr 16, 2012
2:53 PM
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@5F6H
Correction....MG10CD
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Hawkeye Kane
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5F6H
1149 posts
Apr 16, 2012
3:11 PM
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"Emulated" in both cases here mean "speaker emulated".
Stick a cable into the "line out", measure the ohms from tip to sleeve on the free end of the cable. Now flick the meter over to "volts AC", have a few hefty puffs on a harp & mic plugged into the input, what does the meter show on the line out?
If the line input from a CD player is intended for use with the "headphone out" from the player, it might want to see a lo-Z TRS jack plug to XLR lead to go to the mixer recorder?
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www.myspace.com/markburness
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MrVerylongusername
2333 posts
Apr 16, 2012
3:18 PM
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@Hawkeye
A quick glance at the specs of your amp show the line out level is -10dBU which is considered the standard for consumer audio equipment.
Most pro audio is designed for a line level of +4dBV which is a higher level signal. Some middle ground "pro-sumer" gear lets you switch.
It could be the gear you are plugging the amp into is expecting the higher level +4dbV signal.
What have you tried to plug it into?
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HawkeyeKane
886 posts
Apr 16, 2012
4:30 PM
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Other amplifiers mainly. PA's sometimes.
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Hawkeye Kane
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MrVerylongusername
2334 posts
Apr 16, 2012
4:50 PM
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Yeah - different operating levels. That's your problem. At -10dBU it's designed to connect to hifi, consumer recorders etc... it'll be very quiet into pro gear like a desk or an amp.
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joek18
24 posts
Apr 16, 2012
9:40 PM
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So no? I shouldn't plug the Kal into the Junior? The Kal is vintage, of course, and though I've had most of my mics redone by the SuperHeumann, I haven't had him work on this Kal. So no line out.
I won't plug one into the other... right? I'll probably just play straight through the Junior and heat it up.
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5F6H
1150 posts
Apr 17, 2012
1:01 AM
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@ Hawkeye - did you try connecting to the PA using a balanced 1/4" TRS (stereo jack plug) to XLR/TRS (if the PA has a lo-Z TRS input jack)?
Joek18 - If you have no line out, then you cannot connect the output of the Kal to anything but the correct ohmage speaker/cab. There are devices, such as "speaker load boxes/emulators/attenuators" that also have line outs, that you can plug the amp into, in place of the speaker (TAD Silencer/FANTA, Palmer PGA1)...these are typically much more expensive than fitting a line out (2 resistors, a jack socket, few inches of wire) to your amp.
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www.myspace.com/markburness
Last Edited by on Apr 17, 2012 1:05 AM
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SuperBee
225 posts
Apr 17, 2012
5:59 AM
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But surely you could still use a passive split on your line in and use both amps.
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HawkeyeKane
888 posts
Apr 17, 2012
7:19 AM
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@joek18
You still have the option of stacking the 'Zoo on top of the BJ and running the 'Zoo's #2 instrument jack into the BJ's input. Like Mark said, you won't be conducting the 'Zoo's output signal into the BJ, but instead you'll parallel the same signal from your mic into both the 'Zoo and the BJ at the same time. You can adjust the levels on the amps themseleves and find a good mix between the two. And if your 'Zoo is a Deuce, you have the tremolo to use with or without the BJ's reverb.
@5F6H
No, I always ran 1/4" mono from the ELO jack to a hi-Z input on the PA. Same thing when I plugged into another amplifier. Are you telling me that the CD/ELO jack is stereo?!
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Hawkeye Kane
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cliffy
8 posts
Apr 17, 2012
7:25 AM
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Somewhere, many years ago, I found a diagram online for a "Slave Box" that used alligator clips to clip onto the speaker terminals of the smaller amp, then there was some circuitry inside, to a 1/4" jack where you could use a guitar cable from the slave box to the input of the larger amp. It works great... I used to use it with a Super Champ into a Bassman RI. I'll see if I can find the diagram anywhere.
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HawkeyeKane
889 posts
Apr 17, 2012
7:40 AM
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Going along with what cliffy has said, another option is the line out I put together for my Vypyr. Take a small speaker cable and cannibalize it into two pieces with the 1/4" plugs intact, connect the split ends to some fast-on plugs, put fast-on plugs on the 'Zoo's speaker leads, connect the leads to one of your cables and run that into the amplifier jack of some kind of DI (I used a Peavey EDI box), run the other cable from the DI's speaker jack to the 'Zoo's speaker terminals, and you can use the XLR Jack on the DI to run into a PA or another amp. A long way around, I know. But it does work.
@joek18
Joe, I know you're trying to find a solution to this on short notice. But FWIW, the line out circuit that Greg and Gary co-developed for this is truly bulletproof. You really oughta look into getting it added to your amp one way or another. If you have the funds to get it to Greg, he really will turn your 'Zoo into a bitchin' sonofagun and make her safer and more durable to use.
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Hawkeye Kane
Last Edited by on Apr 17, 2012 8:07 AM
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5F6H
1151 posts
Apr 17, 2012
7:53 AM
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@Hawkeye "Are you telling me that the CD/ELO jack is stereo?!"
If it is designed to carry a MP3/CD out/headphone signal (L&R), then typically it should be. Hence you might have better luck running the line out via a stereo 1/4" jack (TRS) cord, or "stereo jack to XLR" to feed a PA?
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www.myspace.com/markburness
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Greg Heumann
1575 posts
Apr 17, 2012
8:25 AM
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If you don't have the line out - then the best way to do this is to use an A/B/Y box in "Y" mode, or a "Y cable" to split the mic signal straight to the two amps. There are other ways but this is simple, cheap and effective. This will cut the input impedance in half so if you use a crystal mic, you will probably lose some tone/output level. For dynamic elements this is generally not an issue.
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/Greg
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5F6H
1152 posts
Apr 17, 2012
8:42 AM
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A "universal" line out, to feed an amp's input, or unbalanced 1/4" instrument jack, could easily be made using Cliffy's method (if I remember right Don De Stefano publicised such an idea on Harp-l many moons ago), without a DI. Just 2x alligator clips, 2x resistors, stranded wire (22 awg upwards), a jack socket & a small enclosure (need not be conductive material as the jack socket itself ties everything together).
One alligator clip goes to one end of a 2.2K 1/2W (or better on the W - This ohms value stays the same in ALL scenarios) resistor. The other end of this resistor goes to the hot/tip terminal of a 1/4" jack socket (non switching type). This alligator clip gets clipped to speaker "+".
The other Alligator clip goes to the ground/sleeve terminal of the 1/4" jack socket. This alligator clip gets clipped to speaker "-".
The hot/tip & ground/sleeve terminals of the jack socket are bridged by a 180ohm load resistor (1/2W will do).
The jack socket could be mounted in an amp's back panel, or a small enclosure. You could even mount the parts into a fat 1/4" jack plug (Neutrik do a fat 1/4" speaker jack plug), but securing the alligator clip end of the 2.2K resistor, to stop it waggling around & breaking would take some thought...you DO NOT want the speaker wires to short!!!
This gives a 13:1 drop ratio which will work as a ball park "universal" line-out from 5W@8/16ohms up to 50W@2/4/8ohms, or 80W-100W@2 or 4ohms.
For say, 5W@4ohms swap the 180 for a 470ohm load resistor. If I was making a line out box for "5W amps" I'd use 330ohms load, as this works with 4, 8 & 16ohm speakers.
For 40-50W @ 16ohms & 80-100W at 8/16ohms use a 75-90ohm load resistor, instead of 180, to bridge the jack socket/line out. If I was making a line out box for 40-50W@16ohms & "100W amps" (4/8/16ohms cabs) I'd use a 75ohm load resistor.
Line-outs depend on a certain speaker voltage range, rather than "amp power", so what works for 20W@16ohms works just the same for 40W@8ohms & 80W@4ohms as all make max power with 18volts AC at the speaker.
As an amp's power doubles or halves the voltage at the same speaker ohmage (e.g. if 20/40/80W all use an 8ohm cab) only goes down by 0.7 or up by 1.4...and you don't have to be "rocket science" precise. Half a volt to 1.5Volts at the line out work.
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www.myspace.com/markburness
Last Edited by on Apr 17, 2012 10:11 AM
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MrVerylongusername
2335 posts
Apr 17, 2012
11:54 AM
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@Hawkeye and 5F6H
The socket is dual Line Out and CD in.
The switch from input to output will be dependent on the presence of the ring connection. So if you plug a 1/4"TRS ("stereo jack") in, it will treat it as a stereo input. Without the ring connection ("mono jack") it will be a line out. line outs at -10dBV are usually unbalanced.
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bloozefish
18 posts
Apr 17, 2012
12:27 PM
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So what am I doing when I "slave" my Harpgear 1 with a Kalamazoo clone. I plug the mic cable into the low- gain input 2 on the HG, then run a cable from the HG input 1 into an input of the 'Zoo.
Is this simply acting like a Y-splitter, sending the mic signal separately to the two amps? 'Cuz whatever it is, I like the sound of the two amps combined.
The HG has a line-out, but I think it is to feed into a separate 4 ohm speaker, and not into an amp input.......correct?
James
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HawkeyeKane
891 posts
Apr 17, 2012
12:41 PM
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@bloozefish
I'm not familiar with the HG1, but if it's set up the same way as the HG2, then that's a line-out, usable with PA's and other amplifiers. Anyone feel free to correct me on that. Like I said, I don't know the HG1, and it could be that Brian built her with an external speaker jack instead of a line-out.
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Hawkeye Kane
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5F6H
1153 posts
Apr 17, 2012
1:00 PM
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Bloozefish, you are putting the 2 amps in parallel (like a Y splitter), probably sounds great, but there is no "lining out/slaving" going on (feel free to carry on though).
When you have cables plugged into both the #1 & #2 inputs on the HG1 both now see the high gain load, because the low gain voltage divider is switched out...or, at least, it would be if you didn't plug the 2nd cord into a K'zoo....as this pulls the whole input circuit down to it's lower load...as with parallelling amps, if it sounds good, keep doing it.
Line-out on a Harpgear amp is for plugging into the input of an amp/PA/mixer/recorder....you won't get much from plugging the line-out into a speaker cab.
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www.myspace.com/markburness
Last Edited by on Apr 17, 2012 1:05 PM
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5F6H
1154 posts
Apr 17, 2012
1:00 PM
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Oooo-er, double post!?
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www.myspace.com/markburness
Last Edited by on Apr 17, 2012 1:01 PM
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Greg Heumann
1578 posts
Apr 17, 2012
5:39 PM
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@bloozefish: When you use an amp's second input to connect to another amp's input - it is definitely NOT a line-out, and may or may not be a Y-cable. On the amps I've seen with multiple inputs, doing it this way puts resistors inside the amp in parallel, lowering the input impedance more than just using a simple Y-cable. There's no harm in trying it - but unless you try it both ways you won't know if there's a difference. I'm telling you there just might be, which is why I recommended a Y cable over this "daisy chaining" approach.
(A line out is a separate circuit, either tapped into the amp's pre-amp stage or speaker circuit - and doesn't have any effect on input impedance. )
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/Greg
Last Edited by on Apr 17, 2012 5:40 PM
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CapnKen
40 posts
Apr 18, 2012
5:15 AM
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I saw Mr. Microphone at the Tulsa Harp Summit take a short cable and patch two inputs together and played out of the third input. I don't know exactly what that does but the sound was great. I don't know if DJ is a member here, but maybe he can chime in and explain what happens when you do that.
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LINK
"Blues with a vigor and determination hitherto unknown to the people of this area." Mudflap Nichols
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5F6H
1155 posts
Apr 18, 2012
5:38 AM
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@ CapnKen,
If this was with just one amp, it's called "bridging channels", it's a very old trick that can be employed with any 2 channel amp that has both channels "in phase" with each other, like a tweed Deluxe/Pro/Bandmaster/Bassman/Twin, blonde tolex Vibrolux/Tremolux & 2 channel BF/SF Fender amps without reverb (Bandmaster/Tremolux/Concert) - reverb on BF/F amps & the trem on Brown Concerts, Pros & Bandmasters puts one channel out of phase with the other, meaning the mic signal strength appears to drop, compared to using 1 channel only...you can still do it if you want, but the result is different).
There are several examples above explaing how this method can be used to split signal between 2 amps, but as Greg says a Y splitter is slightly more transparent as there is no series resistance between the amps inputs. A "Y splitter" can be picked up at Radio Shack or similar for a couple of $, a stereo splitter works fine for our purposes. This can also be used to bridge channels if your amp only has one input per channel.
Boss DD2/3 delays also have a "direct out" allowing you to run a dry (no delay) signal to a second amp.
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www.myspace.com/markburness
Last Edited by on Apr 18, 2012 5:43 AM
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