MK IV clean channel overdrives and rthm II peaks... help!

[DaveyJack]

I recently got my new MK IV long chassis head and the amp is just sweet!

I've managed to get the perfect lead sound from it but i've experienced
troubles to keep my clean channel "clean". It begins to overdrive at gain
2. Is it normal?

I don't know if the pickup on my guitar have something to do with it
(EMG-HZ).

For, the rthm II, the sound peaks when I hit high notes, but neither of my
treble or presence are really set high, so this results in peaking notes that
does not really cut through the band. Is it normal? Or do I have a
tweaking problem ( I must have)?

If anyone could help me with that, I would definitely be happy!

THX

 

[jezzbro]

Hi,

If you got spare preamptubes at hand, try and replace them.
One by one. (so replace one beginning at V1 and try your amp, if it doesn't get better, swap V2, try, V3, etc. )

 

[Platypus]

I recently got my new MK IV long chassis head and the amp is just sweet!

I've managed to get the perfect lead sound from it but i've experienced
troubles to keep my clean channel "clean". It begins to overdrive at gain
2. Is it normal?

I don't know if the pickup on my guitar have something to do with it
(EMG-HZ).

For, the rthm II, the sound peaks when I hit high notes, but neither of my
treble or presence are really set high, so this results in peaking notes that
does not really cut through the band. Is it normal? Or do I have a
tweaking problem ( I must have)?

If anyone could help me with that, I would definitely be happy!

THX

Hello, first off welcome to the board.

Secondly, EMG's are not good pickups for clean tone at all but they should still be getting clean, especially with the gain on 2.

Please post your full settings here for your R1 and R2 channels

Furthermore, when you say peaking.. do you mean clipping? Where are your mids at?

It sounds like you *might* have some sort of preamp issue going on but it totally depends on how you have everything dialed.

 

[DaveyJack]

But the amp is brand new, is it possible that the amp could suffer bad tubes already?

And the Lead channel seems somewhat perfect to me, so I didn't feel it possible to be bad tubes.

 

[DaveyJack]

I don't remember my exact settings, but these are close:

RthmI gain: 2
RmI treble: 5
RMI-II mid: 4
RMI-II bass:2
RMI pres:6
RMI master:9
Overall Output:9
tweed power
class A

 

[Platypus]

But the amp is brand new, is it possible that the amp could suffer bad tubes already?

And the Lead channel seems somewhat perfect to me, so I didn't feel it possible to be bad tubes.

Different preamp tubes are responsible for different channels.. and just because the amp is brand new doesn't mean tubes can't be bad

Do you get similar noise when using the FX loop? I'd check V2 for starters.. but go ahead and post your settings first.

 

[DaveyJack]

Actually, the "strange" sound seem to be even worst when FX Loop engaged. Does that mean anything?

 

[Platypus]

I don't remember my exact settings, but these are close:

RthmI gain: 2
RmI treble: 5
RMI-II mid: 4
RMI-II bass:2
RMI pres:6
RMI master:9
Overall Output:9
tweed power
class A

Wow.. you're cranking that puppy.. I wouldn't put the R1 master up that high personally but that's just me. Furthermore you're in tweed power in class A so you're limiting your power down a LOT.. down to near 15W I believe.. try using the full power so you have more headroom, you're basically pushing the amp to its limit in the tweed mode with a volume setting that high.

 

[Platypus]

Actually, the "strange" sound seem to be even worst when FX Loop engaged. Does that mean anything?

Yeah, I would check out V2 preamp tube first.. it's responsible for the R1 and R2 channels as well as the FX return function.

 

[DaveyJack]

By the way, is normal that I have the Lead master at 2 and find it to sound as lead as loud as Rthm I and II that are set to 9-10?

 

[Platypus]

By the way, is normal that I have the Lead master at 2 and find it to sound as lead as loud as Rthm I and II that are set to 9-10?

There is way more gain on tap in the lead mode.. I have mine on 3 and my R1 at 7 or so... that's normal

Also, you have your gain set low on R1 and R2 so you're losing volume there.. try bumping your gain up and lowering the volume for a more even tone.

I would try full power w/ simul class.. you'll have tons of clean headroom then!

 

[DaveyJack]

OK, but can you get a decent tight chunky Lead channel, even when Simul-class and full power engaged?
I'm speaking of big growling tight distortion. I've been told you can only achieve that sound with tweed power and class A. Is it true?

 

[Platypus]

OK, but can you get a decent tight chunky Lead channel, even when Simul-class and full power engaged?
I'm speaking of big growling tight distortion. I've been told you can only achieve that sound with tweed power and class A. Is it true?

No, if anything you'll get more of that sound at the volume you're playing at. 9 on the master output must be excruciating loud

The difference is, you'll get more growling tight distortion at lower volumes in tweed/class A.

Experiment with this: Simul Class and Tweed mode
Lower your channel volumes to 7 or so for R1 and R2.. keep it on 3 for lead
Raise the gain/drive on R1/R2.. experiment there

 

[Platypus]

I think most if not all of your problems will be solved if you replace that preamp tube.. you probably have a bad triode in V2.. easy to replace. You should be getting zero noise in the FX loop and way more headroom on R1 and R2.

 

[DaveyJack]

OK, thx, I think my problem is only a tweaking problem, I've spent plenty of tikme to tweak the Lead channel, but I think I left Rtm I and II a bit.

Thanks for the help!

 

[DaveyJack]

I'll try that, I think that V2 is identified in the user's manual? Am I wrong?

 

[Platypus]

Well... play around with it.

Preamp tubes are 5 bucks and easy to replace in about 5 minutes. You should definitely not be getting the noise you're getting in the FX loop and R1/R2.

 

[DaveyJack]

thx, i'll try it

 

[Shep]

hi, you are getting breakup[ off the power tube's.. try turning the master to 2 to 3 and the channel master's to rhy1-4.5 rhy2-3 lead-3 but can go higher.. then turn the gain on your rhy1 to 7.5 thats what i do.. it sounds super.

 

[DaveyJack]

OK, then again, my problem is a tweaking one. Thanks for the help.
I think that I just tried to get the best Lead channel out of the amp but by this, I compromised a lot of the rhyI and rhyII.

As you say, I'll try to lower the master on the amp but I'll engaged the full power, I think this may be helping. My band plays really loud ( tiny drummer... big double-kick Tama!) and I got to push the amp to its limit in triode/tweed/class A to get a decent volume. The Lead Channel is still really low. I got plenty of juice on this one ( master around 2-3), but both RhyI and RhyII's master are around 9-10. This, combined with a 8-9 Output Level gives real **** on both channels.

I'm convinced it is why I experienced unwanted overdrive on RhyI and both peakness and flubiness on RhyII.

I think we have it there! I hope I'll manage to fix that in a few hours. The only time I'll have to play the amp is Friday, and I've got a show to do in the night!

So thanks!