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Two Identical Amps-Two Identical Cabs Rig

I have PMd TB member Duke Lejuene, and asked him to advise us regarding the questions raised in this thread.

One of the great things about TB is that there are some very smart, and educated members who are willing to educate us who are not.

Let's see if he can enlighten us with some of his vast knowledge of speakers systems.

Good deal ! You are one of the good guys willing to help as well and I appreciate it :thumbsup:
 
Navel gazing ? Lol, there's a song in there somewhere !

Regarding that vibrato on the Magnatones. Have you ever heard the term wide swing tremolo ?

One of my favorite bands has an album titled Wide Swing Tremolo.

When I Google it all the comes up is that album. I just wonder where Jay Farrar of Son Volt got that term. Perhaps it was just a descriptive term of certain vibrato/tremolo circuits back in the day.

Wide swing tremolo is a term that I haven't heard. Cool though.

Termolo is on and off. It can be mixed in with a dry signal so in that sense can have depth. There are different ways of accomplishing tremolo in an amp design.

Vibrato is a frequency warble. There is swing in that defined by how much the frequency shifts. Many use termolo and vibrato in amps and on instruments interchangeably, but they aren't the same Fender amps have tremolo, Magnatone and others such as some Hammond organs have a true frequency shift.
 
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Wide swing tremolo is a term that I haven't heard. Cool though.

Termolo is on and off. It can be mixed in with a dry signal so in that sense can have depth. There are different ways of accomplishing tremolo in an amp design.

Vibrato is a frequency warble. There is swing in that defined by how much the frequency shifts. Many use termolo and vibrato in amps and on instruments interchangeably, but they aren't the same Fender amps have tremolo, Magnatone and others such as some Hammond organs have a true frequency shift.

I was messing around with my Boss ME20 multi-effects this morning combining tremolo only on the Boss with the overdrive on the MXR CAE and it was wild. I doubt I would ever use it for the stuff I'm planning on playing but it sounded very cool.
 
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Coming to this late, but I have run two simultaneous rigs for different reasons:

1. Clean full range rig + a dirt/FX rig w/ HPF (~ 350) and LPF (between 4.5-6K).

2A and 2B. During my louder Mesa Walkabout quest, I ran two WA combos (each w/ a 4-ohm 1x12), set up two ways to chase two different goals.

2A. This configuration was just to try to get more stage volume by running two combos at similar settings. That rig just stacked the two WA combos and fed each from a Korg DT10 tuner (w/ two outputs). The couple times I tried this, the stacked combos weren't appreciably louder on stage than a single WA, b/c the lower cab was blowing past my ankles. Probably better in this case to run cabs side-by-side on cab stands (which I didn't try).

2B. I've also run two Walkabout combos for a couple gigs in which I've wanted/needed to push combo more than I wanted (trading a cleaner tone for a bit more stage volume). In this case, I still split the signal to the two combos. But I set the bottom combo for my preferred WA tone w/ the bass I was using (gain ~ 11:00, master a hair past noon—the Walkabout DI is post-master). That bottom combo fed FOH from its DI out. The combo on top was the one I pushed a bit more for stage volume, and it ended up a bit hairier than I'd like for the FOH feed. I also shed some lows and gently bumped around 800 Hz in the top combo, to improve intelligibility on stage. Since the bottom combo (feeding FOH) was independent, I could push and eq the top combo a bit harder just to hear it better on stage (not overly loud drummer, but he was using a monitor stack with its own sub).

I haven't played your rig, but it doesn't look like I'd duplicate head and cab for either reason. The kind of "dirty cab" rig I was running doesn't need as much wattage in the second amp/cab. More like a bass rig + guitar rig than two bass rigs. Also, it looks like your Ampeg head already is notable for two DI paths per head—so with one head and the two DIs you can already send FOH a clean and pushed signal.

As for the "more volume" doubled rigs, I'd pretty quickly decided there were easier ways to get the tone I wanted with more stage volume when needed. The one I've stuck with is to use one Walkabout head with one or more efficient multi-driver, high-excursion cabinets.
 
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I was messing around with my Boss ME20 multi-effects this morning combining tremolo only on the Boss with the overdrive on the MXR CAE and it was wild. I doubt I would ever use it for the stuff I'm planning on playing but it sounded very cool.

Never rule anything out. You never know what will inspire you when writing a song. You have to break the rules to take things to the next level.
 
Why do you think that P.A.'s are vertical arrays ?

Side by side gives you midrange beaming issues. Separated loses you 3db from loss of coupling, and - unless placed properly, you will actually lose low end due to wave cancellation.
Line Array PA system performance approves a lot from side by side stacking the low end cabs

I have got no idea what about a "wave cancelation" has got anything to do with dynamic transients and spectrum of audio program material
 
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.... Also, it looks like your Ampeg head already is notable for two DI paths per head—so with one head and the two DIs you can already send FOH a clean and pushed signal...


Thanks for sharing your thoughts and experience with trying those configurations.

The the text of your post I quoted has my interest, but I'm not sure how to achieve sending a clean signal from one DI and a pushed one from the other.

There is no effects loop on the amp if it matters.
 
The PF50T has a gain control on the preamp, and a master volume control on the output section. The DIs on the F50T are tapped off the signal at the secondary of the output transformer, and also at the preamp out. The preamp DI can be selected to be pre, or post eq.

I don't think that this will provide the capability to have an overdriven signal on one, and a clean signal on the other.

From the PF 50T manual:

16. POST-EQ/PRE-EQ: The signal at
the preamp out can be set to either Pre-EQ or Post-EQ with this switch. With the switch in the IN position,
the signal at the preamp out is Pre-EQ. This is a direct output not affected

by any EQ or boost settings. With the switch in the OUT position, the signal is Post-EQ and is controlled and modified by the tone controls.

17. PREAMP OUT: This signal may be used to feed an external power amplifier, mixing console, interface or house PA system.

The lift/gnd switch [18] is available to reduce any noise that may occur.

18. LIFT / GND: When this switch is engaged, it connects the ground connection to help reduce residual hum and buzz sometimes picked up in the signal cables.

19. TRANSFORMER BAL OUT: This signal may be used to feed an external power amplifier, mixing console, interface or house PA system.
 
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Never rule anything out to. You never know what will inspire you when writing a song. You have to break the rules to take things to the next level.
True. It did sound awful sweet and I'm sure it could sound better if I took more time messing with EQ or even a different tremolo pedal. I didn't touch the EQ on my head and I had the EQ on the Boss set flat.

I usually just the top cabinet of my stacked 12s here at home but I did hook up both briefly after I heard how good it sounded. With both cabs it even felt good !
 
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The PF50T has a gain control on the preamp, and a master volume control on the output section. The DIs on the F50T are tapped off the signal at the secondary of the output transformer, and also at the preamp. The preamp DI can be selected to be pre, or post eq. I don't think that this will provide the capability to have an overdriven signal on one, and a clean signal on the other.

From the PF 50T manual:

16. POST-EQ/PRE-EQ: The signal at
the preamp out can be set to either Pre-EQ or Post-EQ with this switch. With the switch in the IN position,
the signal at the preamp out is Pre-EQ. This is a direct output not affected

by any EQ or boost settings. With the switch in the OUT position, the signal is Post-EQ and is controlled and modified by the tone controls.

17. PREAMP OUT: This signal may be used to feed an external power amplifier, mixing console, interface or house PA system.

The lift/gnd switch [18] is available to reduce any noise that may occur.

18. LIFT / GND: When this switch is engaged, it connects the ground connection to help reduce residual hum and buzz sometimes picked up in the signal cables.

19. TRANSFORMER BAL OUT: This signal may be used to feed an external power amplifier, mixing console, interface or house PA system.

Yeah I didn't think it would work that way either. I've got the manual right here and was actually looking at it after he posted the idea.

Perhaps he thought the amp has an effects loop and the post preamp signal would be clean and then go from the effects out into a boost or overdrive pedal, then back into the effects return ?
 
One last question.

You offered "If you were to stack your cabs and use both heads you would see approx. +6db"

That would be approx. +6db whether or not the cabs were 112 or 212 ? Or would doubling the speaker surface area also add 3db for a total of 9db ? Talking identical cabs with two heads as you described.

That's the question I would like to hear the answer to.
 
One of our very famous bass players here in Germany placed one 115 at the left side on stage and the second 115 at the other side of the stage. If I remeber correctly his main aim was just to improve the stereo chorus effect on stage.

Back around 1980 or so the bass player in a blues band had two Music Man cabs on each side of the stage. Pretty sure they were 115 cabs and he was just using a single Music Man head. Fairly small bar.

No effects or anything but it was the best sounding bass tone I ever heard in a small venue.
 
Back around 1980 or so the bass player in a blues band had two Music Man cabs on each side of the stage. Pretty sure they were 115 cabs and he was just using a single Music Man head. Fairly small bar.

No effects or anything but it was the best sounding bass tone I ever heard in a small venue.
Acoustic is little more complex than surely ask for pure phase of the signal or the way how two differnt sources add in room invironment.
Some folks try to explain everything with phase, other folks do the thing what sounds best.
While most of the phase policy folks can't even distinguish phase from delay.
 
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