Just got my Mark I RI...Questions?

[jryan]

Hey all,
Just got my MK I RI today from the big brown truck and I couldnt be happier...well, till I turned it on???

I was expecting paint peeling volume and singing clears out of the channel two input. Thats what I was buying the amp for, not quite what I'm getting out of it though.

Heres what I got so far. Plugged in the guitar, turned it up..and it is loud, but not what I expected for having the master vol. on a 5. Also, and this is the most important. Its breaking up a lot, at all vol. levels..its not nearly as clean an amp as I was hoping for and was told about by others and the original owner.

So, heres my diagnosis, and please give me input. I was told the amp was purchased in 02, I bought it from the original owner. Its in mint condition. I was told it had amazing clean room...not in my opinion at all. The previous owner had EL34 tubes in it..I'm wondering if this root of the problem. I think the 6L6 tubes would solve a lot of the problem. Also, as far as I know..it has the original preamp tubes in it. I'm thinking of switching those as well.

The amp has great tone, but its not a clean amp...theres a lot of nat. break up occuring. I want it to be blistering clean(granted with a little nat. tube breakup)...so do you think the tube swap will help??

I cant imagine anything else being wrong with it, it sure looks to be in perfect cond. even after the shipping. I'm really just hoping a tube swap will get me where I need to be. I've turned it on though and havent seen any preamp tubes glowing more than another, and I've tapped them all...it doesnt seem to be a microphonic issue. I did turn the amp on and it sound like crap...all static, turned it on standby and back on and it went away. The Mesa manual mentioned this kind of problem if there are possibly bad preamp tubes. What do you guys think??

Sorry for the long post and Merry Christmas!

 

[JOEY B.]

The MkI re-issue was never meant to run EL-34's. I think that they would run WAAAAY cold in the power section (early breakup, low volume). The 6L6 will give you the most headroom in the #2 input. Another option is 6V6's, but I think that you can only run them in "tweed" mode. If I were you, I would do a total tube changeout.

 

[jryan]

Thanks.

Got the user manual in hand, previous owner sent along..as well as all the original hang tags and other info, even got a sweet Boogie bumper sticker..LOL.

Your right though, it recommends only using the 6V6 tubes in tweed mode. And I dont think its made to run on EL34s as well, doesnt say anything about that in the manual. I think this is a matter of just having the right tubes in place. Sounds like a total tube change is in order. It definitely sounds like its running cold in vol. and has way early breakup!
Thanks for your input!

 

[jryan]

Anyone else have any input?

 

[Shep]

i think that will fix it dude.. get a nice set of mesa tubes or something with same bais rating and give them a go..

 

[eltrain858]

what kind of guitar/pickups are you using?

 

[jryan]

what kind of guitar/pickups are you using?

Hi,
I'm using a Washburn Semi hollow body w/ SD SH-2 Jazz pup in the neck and JB in the bridge.

thanks again guys

 

[Racerboy44]

Are you saying it's not very loud with the master volume on 5? Maybe there is something else going on with this amp other than the wrong power tubes. That thing should be shattering windows at 5! Make sure all the preamp tubes are good as well. If after changing all the tubes it still sounds weak with no headroom, take it to a tech just to be sure all is well.

 

[ol4t]

5! :shock:
The crew of the space shuttle could hear mine on 5!

 

[Tuna141]

I also think ditching the EL34 power tubes for 6L6's will do the trick.

If not, you can also try some lower gain preamp tubes - try 12At-7 or 12AU-7 in V1 and/or in other positions. This should help clean things up too.

Also keep your volume1 low, and your graphic EQ set low (below md line) or you'll add gain.

Good luck.

 

[jryan]

Thanks all,

I know..on 5 this thing should be making my house shake, but its not. I'm picking up new tubes tonight on my way home from work. I'll probably just pickup a whole new set. I'm hoping the local dealer has them all in stock. I was told I should be looking for white or blue labled 6L6s to provide the most clean headroom, I was unaware that Mesa color coded there tubes. Can anyone tell me where the coloring is..the lettering or is there a color code on the tube or packaging?

The original owner told me that they had only been changed once in the entire time he owned it and he hasnt used the amp much in the last year, its just been idle sitting with the cover on in his studio.

Thanks again guys..your input is very appreciated..I'm really enjoying getting to know my way around this forum.

 

[jryan]

Update:

Hi all, well...I'm very happy to report that I picked up 4 new 6L6 tubes tonight along with new preamp tubes...I figured I'd just replace them all while I was at it. The results were more than substantial. THe MK I RI is now so loud I can barely turn it up past a 2 in the house And clean tone that just melts! I couldnt be happier with the results!

Now a couple other questions since I'm learning my around this amp..my first Boogie too!

One..I think I've got a dirty input on channel 1 as there is some static and what not when I jiggle the input. But, I dont really use it, as I prefer channel 2 and its crystal clear..so should I just not worry about it right now?

2nd..I've noticed the Treble adjustment doesnt take effect quite as early as the Bass and Mid. The Bass and Mid really become noticable around 2 on the dial when adjusting from zero. the Treble takes considerably longer and never quite has the power that the Mid and bass do? So, is this a matter of where they are in the chain or just the nature of the treble adjustment? BTW, the Bass and Mid both have a great effect on the treble...so if I turn the treble up a bit and then adjust the bass and mids..I get a good sound. but if I just try to adjust the treble with everything else off..not so good unlike the bass and mids. Am I being ridiculous??? As long as I turn up the bass and mids..the treble begins to come through nicely, although I have to turn it up quite a bit more than the others.

Thanks again for all the input and feedback. The amp sounds outstanding!

 

[JOEY B.]

From page two of the users manual:

"TREBLE: This control varies the amount of treble frequency in the preamp. The first in the series of tone controls, it is the most
powerful of the three because its setting determines the amount of signal fed to the BASS and MIDDLE Controls. High settings of the
TREBLE Control will greatly diminish the effectiveness of the BASS and MIDDLE, causing them to have very little effect on the sound.
Low settings of the TREBLE Control will increase the strength of the BASS and
MIDDLE, making those the dominant tone controls. In addition, when using
overdrive sounds in either channel, the TREBLE Control tends to behave like a
subtle gain control. At high settings it increases gain as well as adding top end.
If you find this gain effect TREBLE: Continued desirable, but don’t wish to
increase the top end, simply compensate by reducing the PRESENCE Control
located on the Rear Panel of the chassis. This will reduce brightness without
sacrificing gain. Dial with care! Subtle tweaking of this control tends to produce
the best results."





Also check out the Ayan Smooth-n-Slim filter. It was made for the MkI's post gain tone stack. It helps the bass and mid controls become more usable.

 

[Tuna141]

I think I've got a dirty input on channel 1 as there is some static and what not when I jiggle the input.

Since the previous owner didn't use the amp for a while and possibly nver even used that input at all, the jack may have oxidized.

Here's all you have to do to clean it: With the amp off, dip a Q-tip in rubbing alcohol (isopropyl alcohol) and then work it around in the jack - just be careful that the Q-tip is not too saturated and make sure that the cotton doesn't fall off in the amp - if the cotton starts breaking apart remove it. After usingcleaning the jack with alcohol Q-tip, next plug your guitar cable in and out of the jack several times. Let the amp sit for a few minutes so that the alcohol evaporates. Then power it up and see if it still crackles. You should be all set.

While you're at it, you should probably clean all of your jacks like this. It's one of the first things I do when I buy a used amp.

 

[jryan]

I think I've got a dirty input on channel 1 as there is some static and what not when I jiggle the input.

Since the previous owner didn't use the amp for a while and possibly nver even used that input at all, the jack may have oxidized.

Here's all you have to do to clean it: With the amp off, dip a Q-tip in rubbing alcohol and then work it around in the jack - just be careful that the Q-tip is not too saturated and make sure that the cotton doesn't fall off in the amp - if the cotton starts breaking apart remove it. After usingcleaning the jack with alcohol Q-tip, next plug your guitar cable in and out of the jack several times. Let the amp sit for a few minutes so that the alcohol evaporates. Then power it up and see if it still crackles. You should be all set.


While you're at it, you should probably clean all of your jacks like this. It's one of the first things I do when I buy a used amp.

Thanks..this is great advice and I'll give the amp this treatment tonight