Interesting problem at the dance tonight.

Keith Hilton · From: 248 Laurel Road Ozark, Missouri 65721

I played a big dance with a 6 piece band tonight.
It was a big place so I took two amps, a Session 400 with a neo speaker,and a stock Nashville 112. The only effect I planned on using was a DD3 delay unit.
At first I ran two separate cords from the guitar pedal to the amps. The DD3 was hooked to the Session 400, and there was just a straight cord to the Nashville 112. The sound was terrible, and the DD3 acted up. I then tried running one cord from the pedal to the DD3,and sent the delay of the DD3 to the Session 400. Then used the mono out of the DD3 to the Nashville 112. Again the sound was terrible, and the DD3 acted up. The Nashville 112 was eating the Session 400 alive in volume. Finally I totally disconnected the Nashville 112 and just ran the Session 400 with the DD3. Everything became crystal clear and the sound was wonderful. I have used one DD3 with two amps before and the sound was great. I can't figure out why the tone quality was not good when hooked to the DD3 and two amps tonight. Also why the DD3 acted up. Does anyone have any ideas? It was not a low battery as the DD3 was hooked to a 9 volt power supply.

Craig Baker · From: Eatonton, Georgia, USA - R.I.P.

What kind of volume pedal were you using?

Seriously Keith, it sounds like the amps might have been fighting each other in an out-of-phase condition. This may have been due to the placement of the amps in relation to each other.

Craig
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Len Amaral · From: Rehoboth,MA 02769

What Craig said! Also, maybe a ground loop?

I think the DD-3 has the echo going to one amp and the other output to another amp is dry or ping pong the signal. I tried this once and didn't care for it.

Doug Palmer · From: Greensboro, North Carolina, USA

Are the speakers in phase?
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Keith Hilton · From: 248 Laurel Road Ozark, Missouri 65721

Doug, that is an excellent question. That might be the answer. If being out of phase is the answer it had a huge effect on the output of the DD3. The more I think about it, the more it makes sense. I have tried this same thing with other amps and got a good sound. Maybe those speakers were in phase.
Craig, as to the volume pedal I was using, it was "BRAND X".
Len, no ground loop because there was no hum, just a bad tone quality.

Jamie Mitchell · From: Nashville, TN

could be phase. no bass?
out of phase also gives a weird sensation of the sound being in each ear but not in the middle of your head. that sound right to you?

j

Craig Baker · From: Eatonton, Georgia, USA - R.I.P.

Keith,
Try a Hilton pedal. I hear there excellent !

Craig
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DG Whitley · Posted 14 Feb 2016 3:08 pm

...lol...good one Craig...

Keith Hilton · From: 248 Laurel Road Ozark, Missouri 65721

Jamie, that is what it sounded like. The amps are really old, and it makes me wonder if one of the speakers has not been hooked up correctly. But individually both amps sound great. Also,since the amps are really old I wonder if anything had been changed interally. I also wonder if the out of phase problem would still be there if one amp was made a slave of the other amp. This really brings up a lot of questions about mixing amps. I learned the hard way not to mix a solid state amp with a tube amp. The tube amp had a higher ground potential so there was a lot of hum. Two amps being out of phase brings up a "lot" of questions in my mind.

Lane Gray · From: Topeka, KS

Remember some speaker coils are wound in the other direction. So amps in phase could have speakers out of phase. Easiest solution would be to reverse the phase in a speaker.
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Craig Baker · From: Eatonton, Georgia, USA - R.I.P.

It is easy enough to phase speaker cabinets properly, but when you feed the signal through two different amplifiers, especially two different models of amplifiers you introduce a variety of unknown phase shifts and delays. With the circuit delays involved, the phase shift is not necessarily 180 degrees, it might be 90 degrees, or 135 degrees, or any number in between.

Each time the signal passes through a stage of amplification the phase reverses. When you play through one self contained guitar amplifier phase is of no consequence, but when you run a signal through two different amplifiers in the same room, the results are unpredictable. . . anybody's guess.

Regards,
Craig Baker 706-485-8792

cmbakerelectronics@gmail.com

C.M. Baker Electronics
P.O. Box 3965
Eatonton, GA 31024
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Keith Hilton · From: 248 Laurel Road Ozark, Missouri 65721

Lane, yes, but which speaker would you want to change? Yes,coils could be reversed. I was mixing a new Eminence Neo speaker in the old Session 400 with a real old stock speaker in a Peavey Nashville 112. Craig, what you said is really good. Being around music and electronics is a constant learning experience. Before I try hooking up two amps again, this expience has made me much wiser.

Lane Gray · From: Topeka, KS

Since they're in two different amps, it doesn't matter which one you switch.
Also, given the slow (relatively speaking) speed of sound, spacing will play hell with sound phase, especially as frequency climbs.
Lower notes out of phase will be out of phase, as the A of the C6th 10th string with Boowah pedal has a wavelength of over 6 meters, while the E9th third string with B pedal is only 78 centimeters (2.5 feet).
To get 180Â° out, electrically in phase A1 (the low one) will be ten feet or so apart (and multiples thereof), but at 15 inches apart (and multiples thereof). Higher up the neck, it gets even wackier.
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2 pedal steels, a lapStrat, and an 8-string Dobro (and 3 ukes)
More amps than guitars, and not many effects

Jamie Mitchell · From: Nashville, TN

Keith Hilton · From: 248 Laurel Road Ozark, Missouri 65721

Jamie, I doubt that the DD3 reverses phase, otherwise the delay would be fighting the original signal. Here is "food" for thought. What "if" different amplifiers in a band, or even the PA, were out of phase? Maybe that is why on rare occassions things sound wonderful. Maybe all amps and the PA were in phase. It is really a interesting concept.

Jamie Mitchell · From: Nashville, TN

i also doubt it flips phase, but if it did, it would be flipping both wet and dry, so there would be no fighting between echo and original signal.

as far as PA phase goes, it is not only possible, but somewhat common for the PA to be out of phase with the stage. it feels weird...

quick story time.
at one point, I got interested in trying to get a handle on the PA/stage phase thing. you know that feeling where the stage is feeling and sounding great and then they start bringing in the house and everything just goes to hell? all the sudden you're fighting yourself. that's what the out of phase PA/stage feels like. messy.
anyways, a few years back, we were at a gig, at sound-check, had the stage feeling nice. FOH guy brings up the house on my guitar and it just feels (and sounds) off. i ask the dude to flip the phase, instant fix, which is not that remarkable, but it was so noticeable the whole band turned and went "wow". it's big.

so that's a go to thing for me to check if I'm getting weird vibes from the PA. good FOH, to me, is I can't even tell its on.

j

Jamie Mitchell · From: Nashville, TN

ok, one more phase-related story!

I used to play with the same bass player a lot. hundreds of gigs. for a long time, he would always drag around two cabinets anytime we went out to play. said he needed them. so, when time we're packing up for a gig, maybe a different lineup, or a smaller vehicle or something, but anyways we didn't have room for both cabinets. he's bummed, because again, he needs both of them to get the lows. that finally struck me as odd, so we listened to them one at a time.

first cab, fine. second cab, fine.
together, wimpy. you could tell in one note, after plugging the 2nd one in.
he missed it for so long, maybe by hooking them up at the same time, but whatever the reason, we had been hauling around a second (heavy) bass cab for a long time, and all it was doing was crippling the bass tone... Rolling Eyes

i got a kick outta that.

i was also the phase good-Samaritan for a steeler at country fest in Nebraska or something this summer. sat down at this guys rig, it's beautiful. Sarno stuff, stereo, nice...
play a bit, sounds weird, look at the amp and the bass is all the way up.

so, you guessed it, quick speaker lead flip and all was right in the world. so yeah, i keep my ears open for it.

j

Ian Rae · From: Redditch, England

I use a pair of identical amps, which gives a good stereo image to the reverb and avoids any mismatch problems.
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