Line Out from a Twin

Bobby Lee · Post by **Bobby Lee** » 31 Jul 2003 3:32 pm

The guitarist in my band uses a Fender Twin Reverb. We are on opposite sides of the stage and we want to run a line from his amp to a little Fender Champ on my side so that I can hear him. I'm feeding him a similar signal from the mixer in my rack, which works fine.

There's no line out on his amp - just an external speaker jack. We have a 25' guitar cord. What's the best way to get a signal from his amp?

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<img align=right src="http://b0b.com/Hotb0b.gif" width="96 height="96">Bobby Lee - email: quasar@b0b.com - gigs - CDs, Open Hearts
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Ken Fox · Post by **Ken Fox** » 31 Jul 2003 3:52 pm

Bob, you could use the guitar jack from the Twin's #2 jack of the Vibrato channel (assuming your guitar player is using that channel) to the Champs #1 input jack. You may need to lift the ground at the Champ with a two wire ground lift plug to get rid of hum problems. The Twin's Vibrato channel is out of phase with its own Normal channel. It may well be out of phase with the Champs Normal channel. At that distance it is likely not to be a problem. If it is, just reverse the speaker leads in the Champ.
You can also get an excellent direct box from Berringer that will hook in line with the Twin's speaker jack. If this is a 135 watt Twin, do not use the extension jack to drive a direct box! This would put the direct box in series with the Twin's internal speakers and also change the Twin's output transformer to the 8 ohm tap!!! A normal Silverface at 100 watts or a Blackface at 85 watts does not do this. The speaker jack is just in parallel with the main jack. You could use that external jack to drive the Berringer direct box. Advantage is a signal with the amp's reverb and effects is sent to the Champ with a direct box.
[This message was edited by Ken Fox on 31 July 2003 at 04:54 PM.]

Bobby Lee · Post by **Bobby Lee** » 31 Jul 2003 4:36 pm

Ken, are you talking about the Behringer DI100?

We tried the second input jack idea and got a loud buzz. I'm not sure how I'd "lift the ground" on this sealed 25" cable.

Jim Smith · Post by **Jim Smith** » 31 Jul 2003 4:50 pm

You lift the ground on only one amp's AC line, not the guitar cord. This can be done with a 3-2 prong adapter from a hardware store.

If the amps are that far apart, I believe you will need to be sure they are on the same power circuit.[This message was edited by Jim Smith on 31 July 2003 at 05:51 PM.]

Ken Fox · Post by **Ken Fox** » 31 Jul 2003 5:00 pm

Yes, that is the direct box. Also the ground lift is on the ac cord.[This message was edited by Ken Fox on 31 July 2003 at 06:01 PM.]

Bob Metzger · Post by **Bob Metzger** » 31 Jul 2003 5:07 pm

You could copy the line out circuit used on many Fender amps after about 1976/1977. It's two resistors and a jack you could install this in the Ext. Spkr. jack in the back of the Twin R. It is very easy to do this.

Another idea, if you don't feel like re-wiring the amp, is to use an 'L' pad connected from the stock Ext. Spkr. jack and then connected to the Champ speaker. The L pad provides a volume control to the Champ speaker and as long as it's not turned up too loud, it should be ok. Or for that matter, you could use any extra speaker/cab you've got around. I used this idea alot and it works well.

Another idea is to place a mic in front of the Twin R. and plug the mic into the Champ (use a hi-z mic, w/ standard 1/4" tip/sleeve plug). This also works very well, with lesser fidelity. And most guys have this stuff lying around, not getting used anyway.

If you are using a mixer and have extra inputs, dump the Champ and put the signal from his Twin R. line out into your mixer. You'll have alot more control of it there and will be carrying one less piece of gear.

Bob M.

Gino Iorfida · Post by **Gino Iorfida** » 31 Jul 2003 5:26 pm

If you run from the 2nd input jack, the gain from the guitar will be dropped (it would be like he was plugged into the low gain input). The Pevey EDI box is pretty good, not sure of the power rating etc. Best bet would be if he was using ANY pedals that were buffered (Boss, Digitech, Ibanez -- anything with the LED and silent switching), and simply use a 'y' cable, or if he has a stereo chorus etc, run from the other out there. If he mic's his amp, you could feed some back to your monitor, or do like you do from your amp

Ken Fox · Post by **Ken Fox** » 31 Jul 2003 5:32 pm

The Behringer box will handle the amps power. But beware of using the extension speaker jack on the 135 watt Twin or any Fender amp with an ultralinear output transformer, as these do transformer taps changes and some do series wiring of the internal and external loads.

Jeff A. Smith · Post by **Jeff A. Smith** » 31 Jul 2003 7:49 pm

I'm not really an electronics guy, and maybe plugging a Champ into the ext. speaker jack would be different. However, back when I had a Twin and used to blow speakers out of it, I tried using a Bassman cabinent as an ext. speaker.

The main speakers weren't then driven enough to get a good sound.

I forget if there is a variable ohmage control on a Twin, which needs to be adjusted if the speaker load changes.[This message was edited by Jeff A. Smith on 31 July 2003 at 08:54 PM.]

Keith Murrow · Post by **Keith Murrow** » 31 Jul 2003 8:04 pm

..[This message was edited by Keith Murrow on 26 October 2004 at 04:26 PM.]

Terry Downs · Post by **Terry Downs** » 31 Jul 2003 9:16 pm

b0b,

Sounds like you have a grounding problem where any direct connection would require you both to plug into the same power source ground.

I've never liked any line out because it don't sound like the speaker. But...you might get lucky.

The new Fender tube amps have an additional output transformer secondary that feeds an XLR differentially. That is cute, but you still can't compensate for the speaker characteristics.

I would change the band rules and get your guys close together.

Good luck b0b.

Your friend, Terry[This message was edited by Terry Downs on 31 July 2003 at 10:21 PM.]

Ken Fox · Post by **Ken Fox** » 1 Aug 2003 6:24 am

Changing the rules and setting new precedents could result in having to sit next to the accordian player! Careful now!!!

Bobby Lee · Post by **Bobby Lee** » 1 Aug 2003 8:47 am

We like the visual and sonic impact of having the leads on opposite sides of the stage. We also like having a separate lead monitor system, so that we're not messing with the singers' mix (that includes the acoustic guitars, and it's tricky enough already).

We've run these Champs with mics (and hi-Z transformers) and we really like them. A direct line would be easier to set up and tear down. We have it working in one direction (steel to guitar side) just fine, using the aux out of the Rolls mixer in my rack. Very simple.

Thanks, everyone, for your ideas.

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<img align=right src="http://b0b.com/Hotb0b.gif" width="96 height="96">Bobby Lee - email: quasar@b0b.com - gigs - CDs, Open Hearts
Sierra Session 12 (E9), Williams 400X (Emaj9, D6), Sierra Olympic 12 (C6add9),
Sierra Laptop 8 (D13), Fender Stringmaster (E13, A6),
Roland Handsonic, Line 6 Variax

Grant Johnson · Post by **Grant Johnson** » 1 Aug 2003 8:48 am

Bob, What about splitting the signal before it reaches the twin?? In a three piece, I used my super on my side of the stage and split the signal from my stereo delay over to a princeton on the far side of the stage so our bassist could hear better. It seemed to work well.

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www.bigsmokey.com

Bobby Lee · Post by **Bobby Lee** » 1 Aug 2003 11:01 am

We're trying to avoid affecting the main guitar sound, Grant. Signal splitting tends to change the gain structure.

Bob Metzger wrote:

You could copy the line out circuit used on many Fender amps after about 1976/1977. It's two resistors and a jack you could install this in the Ext. Spkr. jack in the back of the Twin R. It is very easy to do this.

Can you post that schematic or email it to me, Bob?

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<img align=right src="http://b0b.com/Hotb0b.gif" width="96 height="96">Bobby Lee - email: quasar@b0b.com - gigs - CDs, Open Hearts
Sierra Session 12 (E9), Williams 400X (Emaj9, D6), Sierra Olympic 12 (C6add9),
Sierra Laptop 8 (D13), Fender Stringmaster (E13, A6),
Roland Handsonic, Line 6 Variax

Bob Storti · Post by **Bob Storti** » 1 Aug 2003 11:31 am

Bobby -

I ran into the same issue several year ago. We had an extra Shure SM-57 laying around, so we set it up in front of the guitar player's amp speaker, ran the Lo-Z mike cable to my side of the stage, and used an in-line Lo-Z to Hi-Z transformer into a Peavey Backstage amp, tilted up at me with the help of a couple of beer cans (empty of course!). It was simple and sounded great - just a thought.

Bob

ajm · Post by **ajm** » 1 Aug 2003 11:54 am

Someone else eluded to this: whatever you do, DO NOT plug the speaker output of the Twin into the Champ (or any other amplifier/mixer) input. You will severely hurt something.

Micing the Twin and feeding it to the Champ would be the easiest and least dangerous to your equipment. I don't see how you could hurt anything here. The cleanest and quietest gear wise may be to use a DI box, but you need to have it connected properly or you may blow up the Twin or Champ. It's not complicated, but you need to know what you're doing.

Look for a H&K Red Box, the peavey DI, or a palmer PDI-09. There are others as well but these are some of the more popular ones. If you go to the web sites for H&K or Palmer you can download the manuals and they show how to connect things.

Many speaker attenuators like the THD Hot plate also have DI outs.

I have a Palmer that I use with a load box to record a cranked amp silently.

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Artie McEwan

Tom Mortensen · Post by **Tom Mortensen** » 1 Aug 2003 12:21 pm

Bob, I think this is all you need.
http://www.brookmays.com/prod_disp.asp?itemnum=EDI

Same idea as what Ken Fox posted.
Not sure if this is active or passive DI.

Speaker Out to Direct Box >
Direct Box to speaker >
Line from Direct Box to Champ[This message was edited by Tom Mortensen on 01 August 2003 at 01:22 PM.][This message was edited by Tom Mortensen on 01 August 2003 at 01:30 PM.]

Bob Metzger · Post by **Bob Metzger** » 1 Aug 2003 12:26 pm

b0b,

I have sent it!

P.S. I'd like to reinforce what has been said by ajm about connecting two amps together. You cannot safely send an output of one amp ("To Speakers") to an input of another amp. Something will be damaged, besides your brain.

However, you can safely use an 'L' Pad to connect the output of one amp to the SPEAKER of another amp with the benefit of being able to control the overall volume of that speaker. This is very similar to a 'power soak' but with a different intended result. A good L Pad will keep the load constant, regardless of the volume point chosen. Please use proper speaker cables and not guitar cords for doing this.

B.[This message was edited by Bob Metzger on 01 August 2003 at 01:41 PM.]

Bobby Lee · Post by **Bobby Lee** » 2 Aug 2003 9:23 am

The Fender Champs are great for this because they give each of us control over the tone of the monitor. Also, they have no effect on the other guy's tone, like an external speaker would.

Of course, I know better than to connect speaker output directly to guitar amp input.

The Champs don't have a ground switch or ground lift option. We're going to try using a 3-prong adapter. Those things make me nervous, though.

We know that a microphone works, but it requires a high-Z adapter and we don't really have a spare mic lying around. We'd rather go with a direct line if we can.

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<img align=right src="http://b0b.com/Hotb0b.gif" width="96 height="96">Bobby Lee - email: quasar@b0b.com - gigs - CDs, Open Hearts
Sierra Session 12 (E9), Williams 400X (Emaj9, D6), Sierra Olympic 12 (C6add9),
Sierra Laptop 8 (D13), Fender Stringmaster (E13, A6),
Roland Handsonic, Line 6 Variax

Jim Smith · Post by **Jim Smith** » 2 Aug 2003 9:39 am

The 3-prong adapter will be perfectly safe in this situation. The amp will get its ground from the other amp through the guitar cord, which is what is causing the ground loop in the first place.

Ken Fox · Post by **Ken Fox** » 2 Aug 2003 10:02 am

If you want, take a voltmeter and test from the chassis of the Champ to a known good ground after installing the ground lift adaptor plug. You should a few volts at most to ground from the Champ.

JB Arnold · Post by **JB Arnold** » 2 Aug 2003 6:44 pm

Dang, you wouldn't think this would be that complicated-but it kinda is.

Wouldn't a direct box work? Take the powered signal from the twin down to line level, then you can send it anywhere?

JB

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Michael Brebes · Post by **Michael Brebes** » 4 Aug 2003 6:35 am

This will work the same as many of the "Line Outs" available on some Fender Amps. This can either be done inside the amp, inside a connector, or in an external box:

1. Using the External Speaker, tie a 2K ohm resistor to the hot lead.

2. You will use a second resistor, or a pot, to set up the level of signal you need. Tie the second resistor (start out with 100 ohm) or a pot (500 ohm) and tie that from the other end of the 2K resistor to Ground.

3. The signal to the other amp will be the new Hot (where the 2K resistor and the small resistor/pot connect) and Ground. Adjust the small resistor/pot value for the desired attenuated signal level.

Either inside the amp chassis or external box are the best choices, IMO. Hope that helps.

John Bechtel · Post by **John Bechtel** » 4 Aug 2003 9:01 pm

The Peavey EDI is intended to connect the speaker of one Amplifier to a mixer-board of a P.A.! I don't see any reason why that “P.A.” mixer could not be replaced by your small 'Monitor-Amp! When you run the XLR cord from the EDI, just use the available Lo-Z to Hi-Z Adaptor on the other end of the Balanced Lo-Z patch-cord. (reg. mic. cord) and plug the 1/4" plug into your monitor amp. Input! What's the difference between P.A. Amp. and Musical Instrument Amp.? And, What Do I Know?

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