Help with tube tweaks for Mark V

[RustInPeace]

Hello all! Long time viewer, first time caller, im looking for some advice on tweaking the tones on my mk V. I bought my mk V head used last September for $1200 with no tubes, so I ordered a standard replacement set from eurotubes and outfitted it with JJ's. I've had good success with them in the past with my previous amps, so I figured the mk would be ok with this set. Now after several months of fiddling, replacing my 1x12 cab speaker (c90) with a ghs veteran 30, im STILL not quite happy with this amp. Im not ready to give up on it yet because ive heard too many fantastic sounding clips from other players but still ask "why doesnt mine sound like that?". Its time for me to swap some tubes.

Now the biggest problem I have with this amp is ch2 mkI mode. It is so unbelievably bassy and muddy and dark its unusable. I dial the bass to 0 on the pre slider eq AND the slider eq and its still muddy as hell. Its like theres a blanket on top of the amp. I want to like it so badly every time i hear a clip of someone else using it and sounding fantastic, but i keep comming back to it and discovering the same problem. Is there one of the tubes i can replace that can rid this problem? Id like to use this channel and mode without having to use an extreme eq shape that i cant use on ch 1 or 3.

The other problem I have is that ch 3 doesnt seem to have as much gain as ive heard others achieve with it. Isnt extreme mode supposed to have more gain and low end than mkII or mk IV mode? To me it sounds like it voices it similar to mkII but with more honky low mids that wont dial out, where as mkIV mode clearly has a tighter bottom end than either and feels fuller.

Ive read around the forums that JJs can be pretty dark and might not be the best for a mark, which might explain ch2 problems, but still doesnt seem right for ch 3 feeling honky. I also need to crank channel 1 to keep volume levels par with the other 2, which might be because the tubes arent high gain enough possibly?

Suggestions?

 

[Mister Joshua]

Eh a tough one. Well to chime in i bought a Mk IV with JJ's and replaced them with Tung Sols. The difference was definitely noticeable but i don't recall the JJ's being overly muddy or so quiet in the first place. In fact they are on par with the Mesa stock tubes. I would have to inquire as to why the head came sans tubes and why it was so cheap?

Peace,
Joshua

 

[RustInPeace]

The different speaker really helped to begin with though, the c90 was way to trebly and harsh sounding. I was hoping it would help with ch2 tho Ive seen a few weird things happen with the amp...when I go to switch it off from on to standby there is an intermittent flash that comes from the back..one of the power tubes? Nothing ever seems to work improperly though...

 

[screamingdaisy]

Hello all! Long time viewer, first time caller, im looking for some advice on tweaking the tones on my mk V. I bought my mk V head used last September for $1200 with no tubes, so I ordered a standard replacement set from eurotubes and outfitted it with JJ's. I've had good success with them in the past with my previous amps, so I figured the mk would be ok with this set. Now after several months of fiddling, replacing my 1x12 cab speaker (c90) with a ghs veteran 30, im STILL not quite happy with this amp. Im not ready to give up on it yet because ive heard too many fantastic sounding clips from other players but still ask "why doesnt mine sound like that?". Its time for me to swap some tubes.

The stock preamp tubes are JJ ECC83s. The stock power tubes are Chinese 6L6s. I don't like using a JJ in the V1 position as I find it dulls and does the "blanket on the amp" effect with most of the amps I've owned over the years. The current setup that's worked well for me with various Mesa amps is installing a Tung-Sol in the V1 to brighten up and stiffen the attack a bit, then leaving there rest of the preamp as JJ/Mesa.

Now the biggest problem I have with this amp is ch2 mkI mode. It is so unbelievably bassy and muddy and dark its unusable. I dial the bass to 0 on the pre slider eq AND the slider eq and its still muddy as hell.

Go crazy with the treble and presence. On older Marks it wasn't uncommon to run either of them at 7 or above, which would roughly equal 2:00 to 2:30 on the Mark V's knobs. Don't be afraid of reducing the mid knob... somewhere around 9:00 is neutral... above that creates more of a boosted mid response. Also, consider putting the channel in 45w mode... it'll thin the sound out a bit and bring it more on par with channel 3.

Its like theres a blanket on top of the amp. I want to like it so badly every time i hear a clip of someone else using it and sounding fantastic, but i keep comming back to it and discovering the same problem. Is there one of the tubes i can replace that can rid this problem? Id like to use this channel and mode without having to use an extreme eq shape that i cant use on ch 1 or 3.

Have you considered reserving the graphic EQ for channel 2 and using the preset for channel 3?

The other problem I have is that ch 3 doesnt seem to have as much gain as ive heard others achieve with it.

Turn up the treble. The treble knob on a Mark is a secondary gain control.

Isnt extreme mode supposed to have more gain and low end than mkII or mk IV mode? To me it sounds like it voices it similar to mkII but with more honky low mids that wont dial out, where as mkIV mode clearly has a tighter bottom end than either and feels fuller.

Extreme mode is the same gain as Mark IV mode, it just bypasses the negative feedback loop in the power section. It's a similar to going from Vintage to Modern high gain on a Recto... more bottom end, more of a scooped sound... same amount of gain.

Ive read around the forums that JJs can be pretty dark and might not be the best for a mark, which might explain ch2 problems, but still doesnt seem right for ch 3 feeling honky.

Channel 3 is honky. It's a characteristic of a Mark amplifier and why most people tend to run the graphic EQ in a big old V shape with the bass boosted and the 750 slider fairly low. The mid heavy sound tends to sound kind of crappy in the bedroom, but it sounds awesome on stage when the drums and bass are filling in everything around it.

I also need to crank channel 1 to keep volume levels par with the other 2, which might be because the tubes arent high gain enough possibly?

You probably have the channel master on channels 2 and 3 way too high, which will tend to emphasize the bass and mud up the sound. Try bringing the channel masters down to between 9:00 and 9:30 and use the master output to raise the volume back up to the level you're accustomed to. If you did have the channel masters up too high you may find this new setting sounds really bright and harsh, so you may need to adjust your EQ settings to compensate.

 

[Tuna141]

Try swapping preamp tubes with brands other than JJ. I had a simialr problem as you describe (dark sounding ch2, volumes of ch2 & ch3 did not match, etc) and this cured my woes. I'm presently using mostly NOS 12ax7 tubes with a 5751 in V7 (PI tube).