Need help! My amp sounds like crap...

[jjruiz]

Hi,

This is my problem, I hope someone can help me.

I bought a rect-o-verb combo a month ago, at first it sounded great but last week I notified a loose of punch, volume... since it is a second hand one I thought that probably I would have to change any valve, anyway I took the amp to a technician to make sure of the problem, he checked the valves through a kind of a tester specially designed to measure valves (mighty mite I think), and confirmed that one 12ax7 was bad, he also told me that the two 6l6 valves were not "compensated" (does it make sense to you?), well the thing is that he suggested me to put some used valves he had in his workshop that worked perfectly (also measured with the tester) and then save a good money. We tried but the amp does not sound like the first time... do you think that I have to put new valves or it should sound well if the used valves are measured and have right values with the tester? Also I would like to ask you about other thing I'm concerned about, is it normal that with the master to 5 o'clock (max) There's no changes in overall volume from output control at 9/10 o'clock on? I don't get more volume no matter how I increase the output control, it seems very strange to me... but actually I can't assure it worked different at first since I didn't need more volume. I have checked the amp with different cabins so I can dismiss speaker problems, tomorrow I will take the amp to the technician again, but I hope you can give me some clue of the problem, because the amp sounds awful!! it's not the loose of sound only, it has a very poor crunch as well...

 

[clutch71]

Well sorry to hear the Rect-O-Verb combo is acting up on you. Let me guess, sounded great in the store but when you got it home problems? Happened to me.

Being new to Mesa myself, I'll share my experience in the hopes that it helps you. About week after getting the amp home when cranking it I noticed a "gravely tone" and volume swell. I called a Mesa tech and his first questions were are the tubes Mesa and he asked me to describe the input stage pre amp tube? I looked and they weren't Mesa they were JJ's and the input stage was a JJ; the rest were Groove Tubes. He stated that Mesas uses a SPAX7 (which I guess is a sturdier 12AX7) as the input stage as this stage does the most work.

His first recommendation was to bring the amp in to let them look ($45) at it just in case to see if anything was altered. His other option was to swap out the power tubes and input stage tube (about $65) with Mesa tubes and see if this solves the problem. I went with the latter but replaced everything ($115) and now the amp works as it should new.

I guess my first questions to you are this...are the two power tubes Mesa and is the input stage a SPAX7? Secondly was the person that looked at the amp a Mesa certified technician?

There are veterans and technical folks on this board that probably will be able to give you more technical assitance on the second problem, but that's what I did to solve the problem similar to yours. I'm sold on Mesa's tone and even though I want to step up to bigger and better things (I need a half stack, not sure why, I've just always dreamed of having one!)I don't think I'm going to get rid of the SRC. I figure I can experiment with tubes later.

Sorry so wordy, hope that helps. Best of luck! Don't give up on her just yet!

If you don't have a manual (read mine cover to cover before consulting anyone) I recommend going to Mesa's site and downloading it.

 

[Anonymous]

Post removed.

 

[Russ]

It seems that you had a bandaid put on a problem but the bandaid wasn't clean. I would try a fresh set of tubes and retube the entire amp. Then if you don't see improvement then the amp looked at by someone. Sometimes tubes can test ok but still be bad. Also if you are looking for the same tone as you had before use the same tube types. This means manufacturer and actual model. This should get you back to the tone that it had originally. I would say the SPAX7 is a great tube for V1 but there other choices if so desired. Just make sure that your V1 tube is low noise and microphonics free. This is something that can be selected for. A good 7025 can do the trick in this postition. Just look for something that has been selected for low noise and microphonics. GT is usually pretty good for this as is Mesa's SPAX7. V1 is important because it sets the basic tone for your amp. If you get a noisy tube in here your amp will not cooperate. A microphonic tube will have you squealing so much you will want to kill the amp. I am sure others will say Tung Sol, JJ, EH, or whatever but if you go those routes make sure it is a screened V1 tube. GT screens most manufacturer's tubes. You can tell them apart by letter designation, ie. ecc83s is a JJ of the same name, a 12ax7c is a chinese tube, etc. If you found one bad preamp tube it is likely you needed to replace them all or would have to soon. If you had all the same tube type prior to changing out the bad preamp tube you could try swapping the positions around to get closer to the orignial sound also paying close attention to V1 to have the same type of tube in there that came out of there. With your Master maxed you were seriously loading your power tubes I am sure that this may have been the cause of your power tube issue. Think of tubes as being disposable. They are also consumable. Your tubes will only last so long. The harder you push them the shorter the life you should expect from them. Something to keep in mind is that though you saved a little on the used tubes you actually never got the benefit of new tubes either. Power tubes you replace with should be screened and graded as matching and within Mesa spec. You can get the Mesa tubes or GTs in a hardness of 4-6 or anyone else's matched tubes that fall within Mesa spec. Again, I would completely retube the amp with new tubes and go from there.

 

[Brewski]

1+ on retubing. You'll be able to start with fresh glass and eliminate the tubes as a possible issue.

 

[jjruiz]

Hi All,

Thanks for replying!!

When I bought the amp it came with a mess of tubes, a pair of 6l6 sovtek, three mesa boogie, and two whothehellknows... but sounded well The used tubes we checked for replacement were all Mesa.

Russ, it makes sense to me that the tube problems could be due to extreme output, I took the amp directly to stage the same day I bought it and put it high..., just after that, the next time I played with the amp it seemed to me a little lower but I didn't give it importance, but the following day I played then it could be aprreciated very clear... I think you're all right, I will retube the whole amp and start from here. Then, do you recommend the JJs? I play metal, so what I want is the max gain of the "modern" mode of the amp.

 

[Brewski]

I have JJ's in both my RK1 and F-50. I bought them from Bob at Eurotubes.com. I like them and have no issues with them. They are less money than a full complement of Mesa tubes. If you go that route, ask Bob for a set that will give you early breakup. They should give you the high gain sound that you're looking for.

 

[jjruiz]

I've ordered a JJ full retube kit for single rectifier, both preamp and power tubes, I'll let you know if I fix the problem...

 

[Anonymous]

Post removed.

 

[jjruiz]

Hi All,

I fixed the problem!! I put the new JJs and it rocks again!! I'm willing to check it now with a 4x12, thank you very much to all for your wise advice!

 

[clutch71]

I fixed the problem!! I put the new JJs and it rocks again!! I'm willing to check it now with a 4x12, thank you very much to all for your wise advice!

Let me know how that 4x12 works out. I'm running a 2X12 and thinking about picking up a 4x12.