Just got a F-50

I just got a F-50 with a 1x12 open back with a Black Shadow. It sounds pretty good, but a bit bland, is there a secret to setting these up?
Also any recommendations on tubes to try in this amp?

Any thoughts on how to get rid of the muddiness ? Power tubes?
I did put a Tung-Sol ECC803S in V1 and a Sovtek LPS in V4 for the PI, helped a little.

I never had mud from my F50s, they were more midrange-scratchy, which is what I liked about them. If you are trying to get a lot of low-end out of them, then I could see how turning the bass way up could make them muddy. The 1x12 can't produce that much low-end, and you would be cramming it into the preamp just to have it killed off by the cab, and make the preamp signal suffer.

As with many Mesas, try turning the bass down.

I thought the same thing. I turned the bass down to about 9 o'clock still can get bass heavy and muddy real easy. I also am finding that with active pups it sounds really garbled. No clarity at all.
Even the clean channel doesn't clean up very well, I would expect with bright switch on and treble and mids up, it would be pretty clean and chimey, not the case. I tried it through my 4x12 and it sounds the same way. So, not just the 1x12 doing it.

I pulled the power tubes, and look like they are quite old, Tung-Sol 6L6GCs.

I may try changing V2 to something other than a Tung-Sol, this amp has all Tung-Sols in it, not sure that is good, as this is my first Mesa.

That is not normal for a Mesa, and especially so for an F-series.

I always retube my amps when I buy them, all new Mesa tubes, just to see what they sounded like when they left the factory. Costs me 4-5 12AX7 and a couple 6L6, not a huge outlay (free at this point as I already have them laying around as spares).

Only then do I swap tubes if I want to change the tone or feel.

At the least, try a new V1 and power tubes.

That was what I thought. Unfortunately I have a stash of EL34s so I need to get some 6L6s and some more preamps.

I was looking at the schematic, and it shows V2 is the input stage in this amp, so I am wondering if that is wrong, I'll try a better tube in V2 to see.

Oh man I love and miss that amp. I giggled around for about 3-4 months with that puppy. Here's what I did to it. I put 2 NOS GE 5star 5751 in V1 and V2 and a matching pair of SED Wings C's. Thats it! IT SCREAMED!!!

I need to see if I can find more of those GE 5 stars, I had 2 of them before, great tube.
I did order some Mesa 6L6s for now.

Wow! I just took a stroll through ebay for the GE 5751 black plates... Holy sh!t prices went up! When I bought my pair I know it wasn't anymore then say $35.00. And they where NOS. That was only 6-7 years ago. Don't know what your budget is but NOS for those on ebay are roughly $100.00 for the pair. Maybe worth checking out some decent used gray plates for half that. There's also a pair of NOS Siemens 5751 on an active auction going on right now. They made great tubes.

I agree, NOS tubes have been skyrocketing in price recently.
I'm going to see what I can get. I bought a pair about 6 months ago for $45.

I replaced the PI tube and it sounds way better than it did. Cleans are clean, and the gain is more even than it was on channel 2 and contour.

It actually sounds pretty good, I do have some new Mesa power tubes enroute.

Cool! PI position is a tube thats often overlooked because they don't do much if anything for tone unless they go bad. The other thing I remember when I had that amp the previous owner replaced the speaker with celestion creamback. Not positive but I think it was 65watts. Why, IDK. But it had awesome musical feedback control! Do you plan on using the fx loop? If not you can make a cable to turn that into a master volume.

That is interesting to put the Celestion in there, I bet it did sound good though.
Yes, that is so true, didn't dawn on me right away to look at the PI, and there it was, nice crack in the bottom of the tube. Put in another one, and sounded great.

I do plan on using the loop, as the opamp driven reverb is pretty weak, it's nice to see that they went back to tube driven reverb on the newer amps. I have a couple of neutrik plugs on order to do the loop master volume trick.

When I am home I can use the loop with my Quadraverb and use it's input and output controls to act as a master.

I am really liking the clean tones on this amp and going to try running a OD1 into the front to give it a little extra push.