Topic: Polarity problem with paired amps
I am having a problem with the polarity of the amps when switching channels on my JVM 410H.
It gets out of phase when I change from crunch to OD. Anybody with similar problems too? Solutions?
- Stratovari
- Titanium
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Re: Polarity problem with paired amps
Hi Klaus,
do you have some more informations?
What is the second amp that you have paired with the Marshall.
Its strange that the phase changed during an internal channel switch...
Is the JVM go out of phase or the other amp?
What pedals are you using and how is the layout?
Alex
...it's a musical journey
www.u2-experience.de
www.u2-experience.de
Re: Polarity problem with paired amps
I talked to Burkhardt Lehle (Lehle switches). He told me that the polarity of a tube amp changes depending what gain stage is used. The polarity also can change even by adjusting the tone pots. So it is an unpredictable process. No way to change it, I guess.
Good thing that the new Lehle Dual has a polarity switch to manage part of this problem. At least I can turn it arround now. I set the "out of phase" sound now to the crunch channel because it sounds stronger anyway and get a fuller "in phase" sound when using the OD channel.
I pair the JVM with a Petersburg P-100 (JCM 800 clone).
- Stratovari
- Titanium
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Re: Polarity problem with paired amps
Hi Klaus,
I see. Interesting, never heard about this... Was es nicht alles gibt...;)
I always believed different amps can be out of pfase if they get paired.
Yes Lehle stuff is great. I use the p-split to connect my amps (currently a Budda superdrive
and a bluesbreaker) and it works great.
Alex
...it's a musical journey
www.u2-experience.de
www.u2-experience.de
Re: Polarity problem with paired amps
If your getting a polarity issue when switching channels then your clean channel is also out of phase.. You just dont realize it.. use a phase speaker cable.. (switching the ground and the positive).. try that , that will work.. I think..
Joe B
Re: Polarity problem with paired amps
I was going to say it but Joe beat me to it. If the lead channel is out of phase then the clean channel is also. There aren't as many harmonic overtones in the clean channel as the lead so it wouldn't be as noticable. Like Joe said it's an easy fix. Switch the wires on the connectors to ONE side of the speaker cable. That's all I did with my Fuchs and it works great.
Some guys like that out of phase sound though. Amny amps are made that way.
7 2008-12-18 20:13:58 (edited by LesKlaus 2008-12-18 20:24:28)
Re: Polarity problem with paired amps
Maybe it's a misunderstanding. Here is my basic setup:
Marshall JVM > 2 x 1x12 HK (effects in the loop - wet and dry signal)
Petersburg > 2x12 HK (no effects - TS-9 in front)
both paired with Lehle Dual
Now I set the JVM to CRUNCH channel. When engaging the Petersburg I hear an increase of volume AND an increase of punch and bass (don't know how to describe - it's not just louder, it's fatter).
The Lehle Dual (new one) has a polarity switch which I now set to OFF. Then the sound gets thinner. It looses the fullness. That I assume is the out of phase sound.
JVM CRUNCH > Polarity switch OFF= thin sound
JVM CRUNCH > Polarity switch ON = fat sound
Now the phenomenon:
JVM OD > Polarity switch OFF= fat sound (not the thin sound as expected)
JVM OD > Polarity switch ON = thin sound
That means, if I change from CRUNCH to OD the polarity behaves the other way around.
I rather like the "thin sound". It's not really thin but it's more articulated and clearer than the fat sound which tends to be a bit muddy.
I don't see a way to have the thinner sound for both JVM settings. Am I thinking in the wrong direction? The cable you adviced will do the same like the polarity switch on the Lehle I guess?
P.S.
Joe - have a nice stay in Tokio! I wish I could play gigs like you do. I read the thread about the blues award. The band I am in is nominated. But I am still sitting in germany having only a few gigs. If we get this award, let's trade :-)
Rock the house - your are the best!!