Son of Boogie

[straycat]

Saw one of these heads for sale locally for $579 whats the story on these?
The combos sell for $300 to$500 so I think the head is over priced I may be wrong tho'.
Its a 6V6 head as far as what I could find out.

[Cygnus X1]

Yup, that doesn't compute.
Head should be less expensive.

[straycat]

I got for less than advertised so a decent deal. It has some issues Cyg Volume drop on 1/2 and full power and on full power the tubes look to me to glowing too much I mean the power tubes get red freakin' hot. Voltage issue maybe bad tubes too. Had Mesa 6L6's BTW. I'd love to keep it because it sounded so good for 30 min before it started dropping volume. Any ideas Cyg?

[Cygnus X1]

Red plating?
Tubes are old, bias may be off.
Just the basics, you know them...get new tubes.
From Mesa's recommendations of course.
They setup according to an expected match and don't encourage biasing to get the tubes where they should be.

[straycat]

Tapped all the tubes and no arcing or funny sounds shut it down let it cool down.
Took all the tubes out and checked for burned sockets looks good no damage there.
Tapped the power tubes and two had a springy type sound two sounded solid.
Put them back in and no volume drop and no massive red plating like before just a small strip in the center of the 2 center power tubes.
Marked on the chassis 12 AX7 for V1 and 2, 12AT7 for the V3.(has a 12AX7 in V3 right now)
There is one small tube in the same area as the power tubes and curious what that tube is for (rectifier maybe IDK) no marking on it.
Sounds killer I will say that so I'm happy with it.
Has a cascading gain section from what I read, pretty damn good sounding amp no need for an od pedal so far.LOL
Off to get new tubes tomorrow.

Thanks Cyg I appreciate the help.

[straycat]

Found the date written on the chassis 6/83 couldn't really tell what it said until I flipped it over.
The tech would mark tube type for each socket on the pre-amp and his initials of final inspection in black marker.High tech for sure.LOL

[Cygnus X1]

Heh...old tube for certain.
Preamp tubes may still be just fine.
Get the power and phase inverter swapped.

[straycat]

No marking for the phase inverter tube so not sure what to use in that.Nothing on the tube itself.
I'll call them and find out.

[straycat]

Called Mesa and they suggested STR 440's so thats what I put in it.12AX7 for Pi tube.
Sounds great and running fine now.

[straycat]

Been wondering how long it takes for tubes to settle in.
The old tubes had problem but sounded fantastic.The new tubes are fine and figure they need to break in some.
Did an OD pedal comparison today and used a VFE Alpha dog,Washburn Scott Ian PMD,Fulltone OCD and BBE AM 64.
VFE pedal it did not care for at all the best setting was on the mosfet chip and vintage.Still not what i would call good.
Next was the OCD better and lots more bottom end but not all that great.
Up next was the Scott Ian PMD sounded killer more separation and thicker,smoother OD,kick in the boost switch and still more clarity and nice drive not woofy or muddy.
Last was the BBE AM 64 my $25 dollar pawn shop pedal.
Sounded fantastic nice buttery OD and lots of grit but a lot of mid range punch too, nice and clear rolling the guitar volume down.
I'm hoping the new Mesa tubes will get a bit more musical in time.
I'm up for suggestions on tubes too if these don't settle in.It's had a total of 10 hours running time maybe 5 hours has been playing so I think that is plenty of time to settle in.It sounds good but not like it did with the old ass tubes.

[Cygnus X1]

That's a Mesa number for 6L6GC's.
Mesa likes their "no-bias" design, sorry but I (and most other amp techs) don't like it.
It's not self-adjusting, it's just a cold fixed bias.
So it may warm up with some more hours on it.
Double check your speaker impedance settings...just to make sure.

Or keep throwing different STR440's at it.



The real answer is to either get it to a qualified good Mesa shop, or another tech that is willing to put a bias adjustment pot in it.

[DonP]

Exactly what Cyg said. The old tubes were matched to the built in bias. Hopefully it might get better, or you can just go back to the old tubes.

I really dig this Randall Lynchbox I picked up with individual bias points and adjustments for each tube. I could get "funky" and throw a (solid!) 6V6, 6L6, EL34 and a 6550 in it. I'd love to see the output in a scope if I did that.

[straycat]

It had 420's and 425's in it when I got it and the Mesa support guy said those were used in a simul class amp and not what they used in them when they were made.
I have no idea what they used in 83.
I'm going to take the old ones in and test them and see if they are still good.
Having had them red plate I'm not sure they are any good to be honest.
Odd how just taking them out and putting them back in stopped the red plating and volume drop issue.

[jgcable]

440 is the newest version of the 420

[straycat]

Thanks JG.
The 440 is touted as being the shit on the gear page.I got the green set so its a middle of the road tube as far as break up I can live with that may try a red set later on.
Put the old PI tube back in and much better than the 12AX7 short plate.The original tube was a long silver plate 12 AX whatever, no marking on it. PI tubes make a huge difference I found out.
Read up and have a pretty good handle on it now and getting some nice tone.
Learned the bass and mids run off the treble so its an active system.Quite sensitive too.
Vol 1&2 control the gain so you have two stages and a wide range of gain options.
Input 1 is higher gain, input 2 is more like a Fender Bassman.
The presence is very useable and controls more than any other tube amps I have.
The limit control is the key to getting some great tone.
I can see why people that just dime'd them out thought they sucked.That is not how this amp operates.
I had one setting that had got online that nailed a Marshall 2203 tone in spades.
Man this is a monster amp!