Playing Through Two Amps

Billy Henderson · From: Portland, AR, USA

I want to play through two Nashville 400's with delay pedal but don't know how to connect them. Appreciate your help.

Thanks

Tom Stolaski · From: Huntsville, AL, USA

I play through two Nashville 400's. I run my effects through one and my steel direct into the other. I try to get a nice balance between the two. When I mic my amps I usually just mic the dry amp and use the effects amp for my own enjoyment on stage.

Emmett Roch · From: Texas Hill Country

Back when I played through two N400's, the last effect in my chain was a stereo chorus, and the signal went to each amp from there.

Erv Niehaus · From: Litchfield, MN, USA

Billy,
All you need is a pedal with two outputs. Just run each output to a 400. Or just even a Y splitter would work. Or even an A-B box.
Erv

Jerry Roller · From: Van Buren, Arkansas USA

Billy, you can run from the effects pedal to the input of one of the amps and another cord from the second input of the first amp to the input of the second amp. Works as good as any other way.
Jerry

Eric West · From: Portland, Oregon, USA, R.I.P.

Yup. What Jerry said.

You can also put the delay between the two amps, and either mike both, or the one without effects, or the one with.

Like he said, just run a line from input #2 of the amp coming off your pedal to input #1 of your second amp.

Easy deal.

EJL

David Doggett · Posted 21 Feb 2004 9:29 pm

This may seem like a silly question, but if you go to two amps from the two outlets of the volume pedal, are the two signals weaker than one would be? If not, why? Seems like that would be getting something for nothing.

Eric West · From: Portland, Oregon, USA, R.I.P.

You know, I'd guess they'd have to be decreased by half. Adding parallel lights to a DC OR AC ( like a pickup) circuit will increase the draw on the "generator", or in this case the pickups. In parallel, they will decrease the current equally per device. In series it is more complicated.

They will draw the maximum amount of current available out of the power source, and burn no brighter than either the ampacity of fused conductors, OR the total available power of the power source.

The pickups in this case are the generating source.

Maybe your pickups would get Hot if you added too many amps..

(..burp....)

I think I"m going to try it!

EJL

Jerry Roller · From: Van Buren, Arkansas USA

David, I can't answer that question either but I can tell you it will make no difference to you because it will work fine and you will not know if the power was cut.
If you are cutting the current you are building it back with two amps instead of one so nothing is lost.
Jerry

Eric West · From: Portland, Oregon, USA, R.I.P.

Jerry. He does pose an interesting question.

I can't imagine "feeding" 10 amps and getting the same signal to each of them but then I've never notices a drop between feeding two of them..

Looks like it's time to call Bill at Lawrence again..

I need a bandaid for my brain!...

The pickups are AC generators, aren't they? Amps don't provide voltage to them do they?

Hmm..

EJL

[This message was edited by Eric West on 22 February 2004 at 12:20 AM.]

Jerry Roller · From: Van Buren, Arkansas USA

Eric, I am glad the question was not concerning the use of 10 amps, but with two amps of course there is no problem. On the other hand if you run a faint signal into 10 amps each one amplifying the signal I am not sure you lost a thing. Probably gained. We don't have to know all that stuff to play it anyway.
Jerry

David Doggett · Posted 22 Feb 2004 9:40 am

I think this is a question for Mr. Hilton. If the output drops by half going to two amps, obviously the two amps will double the final output, so you've lost nothing. Except now you are requiring two amps to get the sound of one. What would be the point of that? It doesn't seem to work that way, that's what got me wondering.

Brian Wetzstein · From: Billings, MT, USA

I would also like to know the answer to this. I usually keep my tuner plugged in to the second output of my goodrich pedal. I don't think I have ever played without it plugged in..
brian

Vernon Hester · From: Cayce,SC USA, R.I.P.

I just did some test with your queston about signal into 2 amps or devices.
Set My Pedal with 275K of resistance a little over half on. with one chn into a H-imp mixer 2.7 mv. 2 chs 1.4 mv or apox 3db. So we are looking at some lost signal but the average person cannot tell the difference of 3db. Run a test with some good test equiment. I stroke the "E" string on Bill Lawrence 710 for this test. Using a true RMS digital meter.
Best.
Vern

David Doggett · Posted 23 Feb 2004 10:54 am

So, Vernon, the signal went from 2.7 mV into one amp to 1.4 mV into each of two amps. That does seem to halve the input signal. I'm not sure what the 3db drop means. Are you measuring the dbs from the speaker, or what? One db is the smallest sound increment noticeable by humans. That's how the unit was derived. So 3 db would be noticeable.

Okay, say you run only one amp from the volume pedal, and run the second amp from the second input jack of the first amp. Does that also cut the signal to the two amps in half?

But here's my puzzlement. Cutting each input by half should be exactly restored by having two amps. There would be no overall loss or gain in volume. But that's not what seems to happen. You get much more volume from two amps. What am I missing?

b0b · From: Cloverdale, CA, USA

Moved to Electronics section

[This message was edited by b0b on 23 February 2004 at 11:08 AM.]

Vernon Hester · From: Cayce,SC USA, R.I.P.

David, I did the test at different levels.
1 ch 214 mv---2 ch 116 mv. as you know the componet path has a plus or minus 10% load factor. (resistors,ETC)
Audio levels are like water they add. If you set one amp at 10 watts out and then another the same way you have a room full of audio.
I measured the output of the footpedal for the voltage levels, the output of the mixer for the DB's.** Here is some info Logarithmic scale measuring the intensity of sound (the sound pressure level); a 10 decibel (dB) increase represents in a doubling of sound level.

Since the decibel scale is logarithmic, there is not a linear relationship between levels. For example, on a linear scale, 4 is twice is big as 2 and 8 is twice as big as 4 and 4 times as big as 2. When measuring decibels, 20 is twice the sound level of 10 decibels but 30 is twice as loud as 20. That makes 40 decibels twice the sound level of 30 decibels and four times the sound level of 20 decibels (on a linear scale, 40 is two times 20). In an audio system, to produce three decibels more sound output, the amplification power must be doubled.

One decibel is the smallest perceptible change in sound level that the human ear can detect. Some examples of sound pressure levels are: whisper – 20 dB, normal speech – 70 dB, passing subway train – 100 dB, large jet plane – 120 dB. The threshold of pain is around 120 dB.

C Dixon · From: Duluth, GA USA

The signal coming off a PU is in micro-volts! A micro-volt is one millionth of a volt. This is WHY we need to amplify it with PRE Amps either separately or built in to the amp!

The current flowing thru the PU is not a consideration in most amplifiers; since its input is based on voltage swings rather than current swings. This is particularly true in tube amps.

DB stands for Decibel and is based on a Logarithm of voltage OR power ratios (input versus output) using a base of 10. In sound power ratios, every 3 DB increase, doubles the sound level, every 3DB decrease halves the sound level. If one is talking voltage swings ONLY, then change 3 to 6. IE, every 6DB increase......etc, etc.

Unfortunately, human ears do not repond in like manner to this equation. For it takes 10 times an increase; or 10 times a decrease for the human ear to sense a sound level has doubled; or halved respectively. AND this is ONLY in young "normal" ears and ONLY at 1Khz. At other ages and/or frequencies it may take MUCH more for us to sense (perceive) a change in level.

Thus, why most players can connect one or two amps to the output of the volume pedal and not notice the difference from a sound level perception point of view.

As to using two amps with a Delay unit, you might consiser how Boss recommends it be done:

1. Connect the output of your guitar to the input of the delay unit.

2. Connect the direct output of the delay unit to one amp.

3. Connect the delay output of the delay unit to the other amp.

This matches impedances better than using the two outputs from your volume control.

carl

Ray Jenkins · From: Gold Canyon Az. U.S.A.

What about differences using a Hilton pedal.I can't tell the differerce using 2 amps coming out of my volume pedal(Carl,I have 65 year old ears

ray

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Steeling is still legal in Arizona

Vernon Hester · From: Cayce,SC USA, R.I.P.

Carl,
Thats why we have the Flecther-Munson audio curves in a lot of equipment. (Human ear curve). This could get deep
So I will close.
Vern

Dwayne Martineau · From: Edmonton, Alberta, Canada

My music shop buddy and I were talking about playing thru two amps and he mentioned that you have to lift the ground on one of them.

Anyone know anything about that?

(Don't take my word for it where electrocution is concerned!)

Pete Burak · From: Portland, OR USA

The Ground-Lift on one amp eliminates buzzing.

Larry Bell · From: Englewood, Florida

re: the ground loop
Best/SAFEST remedy I've found is an isolation transformer. The Hum Eliminator by EBTech works great. You don't increase your risk of shock, but you eliminate the hum.

re: fx
If you use stereo effects, use their left and right outputs, one to each amp. If you use effects that don't have stereo out's, I would do as my old buddy Tom suggests. Most modern effects (especially the rack stuff) is stereo these days.

re: other topics
Unless you're playing a very large stage, your amps will probably be close enough together such that stereo separation is not attainable. Don't expect stereo. At best, you may hear SOME stereo effect onstage, but don't expect the audience mix to reflect that stereo image. If you mic both amps and pan hard l and r through the PA you can get the proper stereo image, but nobody will really notice.

So my answer to Billy's question is I'd only run delay to one amp if the delay is mono, with the second output from the volume pedal to the other amp (dry). If the delay has two outputs, I'd use them (for reasons others have mentioned).

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Larry Bell - email: larry@larrybell.org - gigs - Home Page
2003 Fessenden S/D-12 8x8, 1969 Emmons S-12 6x6, 1971 Dobro, Standel and Peavey Amps

C Dixon · From: Duluth, GA USA

I received an email this morning advising me of an error in my original post. And indeed I was in gross error above. I should have said millivolts instead of microvolts. A millivolt is 1000th of a volt.

I have reread the post, and to the best of my knowledge, the rest is correct. Thanks for the email. 'preciate it

I apologize for the blunder,

carl

Erv Niehaus · From: Litchfield, MN, USA

As far as effects go, I think the only one that you can get a good stereo effect from is "chorus".
Erv

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