• Registered: 2007-09-30
  • Posts: 556

Topic: Amp Phasing Question

Hey all - I have a question about overall phasing of an amp.  I have a Mesa Lonestar, a Fuchs ODS50 and a Marshall 1959slp.  I would like to pair the Fuchs and Marshall with the Mesa like Joe, with the Mesa being the amp always on.  So I was researching all this out and I came across this in my Mesa manual. 


NOTE: Engaging the EFFECTS LOOP circuitry adds a substantial amount of circuitry and two tubes and this additional circuit reverses the phase of the entire amp. This is no cause for alarm and if we hadn’t told you of this, you probably would never have known. Sonically there is no difference other than the incredibly subtle difference in the sound the circuit itself adds.  The only time you will ever need to consider this reversal of overall phase is if you ever run the LONE STAR in Stereo with another amp (not another LONE STAR as it would be in phase with its Loop activated). In this case you would probably want to separate the two amplifiers by at least a few feet if not on the other side of the stage.


I would like to keep the amps relatively close, but according to this it says I should keep them a part.  Is there a solution to changing the overall phase of the amp (is doesn't have a polarity switch) and what would happen if I kept them close together.  Is this even an issue or am I totally overthinking this?  As for a switcher I haven't picked one out, but I'm leaning towards the Voodoo Lab amp switcher if that matters. 

Any advice and help would be much appreciated.

Thanks,
Ben

  • From: Pittsburgh
  • Registered: 2008-05-22
  • Posts: 261

Re: Amp Phasing Question

Ben
For your info, I have a Fuchs 50 ODS as well.  After a few weeks of owning, I discovered the Fuchs to be "out of phase"  According to Andy this is an inherent design of the amp.  Like you said most people wouldn't notice.  I didn't UNTIL I made a reversed phase  speaker cable.  To me, the amp opened up more.
Supposedly alot of amps are like this...I never knew Mesa's to be like this though.

How this pictures into pairing them with othe amps...don't know.

Good luck.

DannyG's Website

  • Registered: 2007-09-30
  • Posts: 556

Re: Amp Phasing Question

Yes I heard of the ODS being reversed just recently hadnt gotten a chance to try it out though - I'm really looking forward to trying it.  Also as per my other question each head will have its own cab if that matters.

  • From: Detroit
  • Registered: 2006-06-02
  • Posts: 5,807

Re: Amp Phasing Question

Please post pics. this is interesting....

- Nic from Detroit... posting on JB's Forum since 6-2-2006
Ask me about my handwound Great Lakes Guitar Pickups
Since 2010, Bonamassa fans have taken advantage of my JB friend discount = my cost + shipping. cool
  • From: Oklahoma
  • Registered: 2008-03-28
  • Posts: 263

Re: Amp Phasing Question

I jumpered my loop on my Marshall and it added a lot more bottom end.  I'm going to take it apart later this week and really sus out some tone while I'm on vacation.

Don't play leapfrog with a unicorn
  • Registered: 2006-04-22
  • Posts: 1,168

Re: Amp Phasing Question

Its tough to sometimes to get combos in phase with each other.  The best way I find is to reverse the phase on the speaker by reversing the positive and the negative (if its a 1X12) using a phased speaker cable if it has more that one speaker.  With three amps you will also be using several if ground lifts (if in the UK I dont know what to tell you) If in europe a simple piece of electrical tape over the earth with do. (Be very careful when employing this method especially if you sing).
   Now that you have all the buzzes out and have had a chance to shake off the 120 volt shock you recieved by touching two amps at a time, you are ready to start.   First put the main amp on,  with your favorite alternate. Listen and then switch to you third.  Ask yourself which one has more bass? Thats what your looking for.  The most bass means your in-phase or really damn close.  If the first paring does then reverse the third amp, if the second pairing does reverse the second amp.  If its a tie or very close then its your main amp.  If its your main amp. Stop. Pair the two alternate amps together and look at which way the speakers are moving. ( They should move forward and simultaneously.  Reverse the phase on the main amp and reset it up.  (note: your grounding will change per venue and situation). It should work.  The best way to R and D the rig is in a studio with all three amps mic'd.  Listen through the studio speakers and flip the phase button on all three amps until you get the amps moving air in the same direction..  I hope this helps... This is how we did my rig.  The only trouble we ever had was with the dumble style stuff.  Two Marshalls were never a problem. 
Be careful...Theres a lot of extra electrons floating around looking for a home.. when you do this That home maybe you....!!
Joe Bonamassa

  • From: Denmark
  • Registered: 2008-04-03
  • Posts: 96

Re: Amp Phasing Question

Joe Bonamassa wrote:

Its tough to sometimes to get combos in phase with each other.  The best way I find is to reverse the phase on the speaker by reversing the positive and the negative (if its a 1X12) using a phased speaker cable if it has more that one speaker.  With three amps you will also be using several if ground lifts (if in the UK I dont know what to tell you) If in europe a simple piece of electrical tape over the earth with do. (Be very careful when employing this method especially if you sing).
   Now that you have all the buzzes out and have had a chance to shake off the 120 volt shock you recieved by touching two amps at a time, you are ready to start.   First put the main amp on,  with your favorite alternate. Listen and then switch to you third.  Ask yourself which one has more bass? Thats what your looking for.  The most bass means your in-phase or really damn close.  If the first paring does then reverse the third amp, if the second pairing does reverse the second amp.  If its a tie or very close then its your main amp.  If its your main amp. Stop. Pair the two alternate amps together and look at which way the speakers are moving. ( They should move forward and simultaneously.  Reverse the phase on the main amp and reset it up.  (note: your grounding will change per venue and situation). It should work.  The best way to R and D the rig is in a studio with all three amps mic'd.  Listen through the studio speakers and flip the phase button on all three amps until you get the amps moving air in the same direction..  I hope this helps... This is how we did my rig.  The only trouble we ever had was with the dumble style stuff.  Two Marshalls were never a problem. 
Be careful...Theres a lot of extra electrons floating around looking for a home.. when you do this That home maybe you....!!
Joe Bonamassa

I really don't know anything about pairing amps, but Im getting a Cat5 in a couple of weeks, and I'd really like to pair it up with my Solton. Do I have to phase anything, when it's two heads?

What did you expect to see out of a Torquay hotel bedroom window? Sydney Opera House perhaps? The Hanging Gardens of Babylon? Herds of wild beasts sweeping majestically over the fields?

Guitargeek's Website

  • Registered: 2007-09-30
  • Posts: 556

Re: Amp Phasing Question

Hey thanks for the reply Joe - sounds like I have my work cut out for me.  I still have a cab to build for the Marshall so hopefully soon I'll have the rig set up.  Oh by the way thanks for the EV speaker recommendations - I have a few more comming for my other cabs.  I will post pics (maybe a video too) as soon as its finished.

Thanks again,
Ben

  • mitch
  • mitch
  • Gold Member
  • Offline
  • From: Swindon, UK
  • Registered: 2006-04-22
  • Posts: 92

Re: Amp Phasing Question

GoT MuLe 31788 wrote:

Hey thanks for the reply Joe - sounds like I have my work cut out for me.  I still have a cab to build for the Marshall so hopefully soon I'll have the rig set up.  Oh by the way thanks for the EV speaker recommendations - I have a few more comming for my other cabs.  I will post pics (maybe a video too) as soon as its finished.

Thanks again,
Ben

Ben-

this might be useful to ya- check out:  http://www.thegigrig.com/acatalog/TheGi … inger.html
This is a really device that'll allow you to run two amps SAFELY and provide a buffer so your guitar sounds as cool as possible- even with long guitar leads.  I'm getting one shortly to help run my Marshall plexi/Ceriatone Dumble Clone dual amp rig & it features an integral phase reversal switch.  Over here in the UK with the voltage running at 240v or so- if you get a shock from bad earth or have an earth 'loop' from running two amps or more you run a high risk of 'danger of death' ;-)   I can't recommend Dan's stuff from GigRig highly enough- I think he's got a US distributor too...

Cheers! Mitch.

This don't look like no express way to me...

10 Reply by DannyG (edited by DannyG 2008-07-05 10:31:07)

  • From: Pittsburgh
  • Registered: 2008-05-22
  • Posts: 261

Re: Amp Phasing Question

Mitch
I checked out that link.  Nice concept but I don't see how you switch between the two amps.  Did I miss something?   All it says is it's a safe way to run two amps simultaneously.

This is interesting.  I's love to go to a multiamp setup.  Our road crew would hate me smile

Once this is done.  I need to figure out effects.  Right now I have a small effect rack with a Rocktron multieffect unit for the verbs. delays, roto and what not. an effect switcher, and a power conditioner.

Also in the rack are a few choice pedals which frankly since I got the Fuchs I rarely use.

Pedal board consists of a Rocktron midi controller which enables me to have anything on or off with one button.  A Crybaby and Xotic AC Boost which I use in case I have a clean sound I want to add a little dirt to.  The contoller changes channels in the amp, switches patches and any combination of pedals all at once.  Great.  No tap dancing around on stage.

The Rocktron goes into the amps effect loop.  The Guitar goes into the Boss tuner-->Crybaby--->AC Boost---> front of amp.

How would I do this with mulitple amps?  I understand the front of the amp stuff but what about the effect loop stuff? 

Outside of running a mixer like EJ and Carlton I don't know how I would do this?  Any suggestions?

DannyG's Website

  • mitch
  • mitch
  • Gold Member
  • Offline
  • From: Swindon, UK
  • Registered: 2006-04-22
  • Posts: 92

Re: Amp Phasing Question

DannyG wrote:

Mitch
I checked out that link.  Nice concept but I don't see how you switch between the two amps.  Did I miss something?   All it says is it's a safe way to run two amps simultaneously.

This is interesting.  I's love to go to a multiamp setup.  Our road crew would hate me smile

Once this is done.  I need to figure out effects.  Right now I have a small effect rack with a Rocktron multieffect unit for the verbs. delays, roto and what not. an effect switcher, and a power conditioner.

Also in the rack are a few choice pedals which frankly since I got the Fuchs I rarely use.

Pedal board consists of a Rocktron midi controller which enables me to have anything on or off with one button.  A Crybaby and Xotic AC Boost which I use in case I have a clean sound I want to add a little dirt to.  The contoller changes channels in the amp, switches patches and any combination of pedals all at once.  Great.  No tap dancing around on stage.

The Rocktron goes into the amps effect loop.  The Guitar goes into the Boss tuner-->Crybaby--->AC Boost---> front of amp.

How would I do this with mulitple amps?  I understand the front of the amp stuff but what about the effect loop stuff? 

Outside of running a mixer like EJ and Carlton I don't know how I would do this?  Any suggestions?

Danny-

the buffer just keeps you safe & sorts out your tone & any phase issues using two amps... The way I do it is to have both amps on at once- using the Dumble clone effex loop to drive a simple TC chorus & stereo EH Memory Man set-up - using the stereo outs from the EH MM to return to the Dumble clone & the effex return or input of another amp- usually a Marshall Plexi or or a smaller amp depending on the size of the venue.  I find mixing the tones from two amps gives you a bigger spread of frequencies & quite simply much more 'beef' in my tone- not necessarily louder.  Like Joe, I use a Stereo Cab to run two amps at once.  You could run your Rocktron in a similar fashion if it has a stereo out- running the other output simply into another amp/speaker.  Then you'd keep all those cool tones from the Fuchs pre-amp & just spread them out more in stereo - I think Robben Ford does it this way using a twin reverb with his Dumble...

If you wanted to switch between 2 or more amps there are many options available ranging from the very simple passive system used by EJ- (he uses a mixer for sure- but that's really for monitoring purposes & to add delay/echo from the amp mics rather than to the amp inputs- like Larry Carlton) I think recently he's dispensed with this set-up too and gone back to his old echoplex's & home made switches...!

Tonebone & Frantone (I think thats the one Joe uses) make a good A/B/Y switcher or if you wanted something more complex & needed to switch between amps- or if you really need something more complex then look again at the GigRig site pedal switcher- which'll just about do anything you'll ever need- send Dan an email if you need advice & say Mitch from the UK sent ya... he's a cool guy & is obsessed with getting a great tone with complex set-ups... and is more than happy to advise...

Hope this helps & good luck...!  Mitch.

This don't look like no express way to me...
  • From: Pittsburgh
  • Registered: 2008-05-22
  • Posts: 261

Re: Amp Phasing Question

Thanks Mitch.  Great input and advice.  I wil strat experimenting as soon as I get some time off.

Thanks again

DG

DannyG's Website