First post here: Hi - MKIV question

[swansong]

I bought a MKIV Long chassis head (no manual) and it has these tubes inside:
a pair of blue E34L's on the outside and a pair of JJ 6L6 on the inside.

Is this supposed to be this way? I'm not exactly digging the sound and want to know why someone might have done this.

 

[Racerboy44]

The tubes are in the correct spots. Doesn't mean they are still good though. Might need a tube change. You need to give us more info on why it doesn't sound good or what you are hearing.

 

[hanson2713]

The amp comes standard with 4 6l6 and in my opinion sounds best that way. The mark 4 does allow the 2 outer tubes to be replaced with el34's. The mark 4 is a complex amp and sounds best in a full band situation, so give it a whirl in a real world scenario.

 

[MesaDCLP]

1) download the manual here http://www.mesaboogie.com/manuals/user_manuals.htm Read and start tweaking. If the tone still sucks...

2) expect all the tubes to be old/useless on any used amp. Change all the tubes just because, when it doesn't sound right...

Best luck with the amp. You are in the right spot for advice and info on it!!!

 

[swansong]

Thanks for the advice. I know I will be posting other questions here but here is one more.
You guys seem to think it could be old tubes. Isn't there a way to check and see if a tube is bad by its color when glowing? Red or orange color, right?

 

[swansong]

The amp comes standard with 4 6l6 and in my opinion sounds best that way. The mark 4 does allow the 2 outer tubes to be replaced with el34's. The mark 4 is a complex amp and sounds best in a full band situation, so give it a whirl in a real world scenario.

I haven't delved into the manual, but why would you want to put the 34's in there? Does it give a radically differnt sound?

 

[JPIndustrie]

Yea it does.

You instantly hear a noticeable upper mid-shift in tone, characteristic of EL34/Marshall amps, a change from the 'heavier' low-mid accentuation of the 6L6/Recitifer/Fender amps.

I LOVE the Mk IV because it lets me run both tubes, which I do. I love the upper-mid shift of the 34's but still retain the low-mid character of the 6L6.

IMO, greatest tube config for killer lead tones. The rhythm tones brighten up very well with the 34's, and make the amp EXTREMELY versatile. I felt the EL34's also made more use of the upper freq sliders on the graphic EQ, making it even much more tweakable.