My new (sort of) Mesa amp...WOW

[James]

'77 Mark I.

It sounds amazing, so much sustain and crunch...I think I've finally found my tone!

I've already chose the power tubes (EHX 6L6's), but what pre amp tubes do you lot use in your Mark I's?

I have the newest Chinese pre amp tubes from www.thetubestore.com in there at the moment..and a groove tubes 12AT7.

 

[gundog]

I have the 60 watt MK 1 head with the EQ and run RCA 12ax7s and the amp sings. Word of warning, I just replaced my old RCA 6l6's with JJ's and had a hell of a time getting them in the head. Had to pull the chassis to fit the tubes and they barely fit because they were too tall. Thought I was going to break them sliding it back together. (They do sound quite nice but they are not RCA's! It's tough to be a spoiled old guy who last tubed the amp when NOS tubes were just plain old new!) I would go with the best NOS pre amp tubes you can afford. THe amp deserves the best!

 

[James]

Thanks

How much gain do RCA pre amp tubes have? For what I'm using this amp for, they will need to have a good amount of gain. (I play alternative and hard rock, usually)..

Also, I had trouble putting the EHX power tubes in, but I didn't have to take the chassis out at least

Oh, and I switched the chinese pre amp tubes out for some EHX's, and it sounds a lot better..the chinese ones were a little too bright for me.

 

[gundog]

James; not sure about the gain factor of the RCA's. I've only used RCA's and GE's in the amp and have never been at a loss for volume or sustain but I'm basically a clean player. I would guess that if you're into more of a metal sound that the pre amp tubes would not be as critical

 

[James]

I'm not really into the metal type sound, I usually have volume 1 & 2 turned up all the way without the gain boost, and it has the perfect amount of gain as it is...It's the slight harshness that I don't like, I'm trying to make it sound smoother.

 

[James]

uh...one of the power tubes just died and it took the fuse with it.

What's the right type of fuse for it?...all I know is that it says "3A" below the fuse socket. The blown fuse doesn't say anything on the metal parts, so I don't know the exact kind to get. This amp is the 100W version if that helps.

 

[Russ]

I think it is a 250V slo-blo. That is what is in mine. I actually have a 4 amp fuse in mine though.

 

[James]

Yeah, I got a 3A 250V slo-blo from radio shack..it seems to be working just fine.

Also, I switched the pre amp tubes (again) for Sovtek 12AX7WB's along with a Phillips 12AT7WC, and I like it even more now..I still have EHX 6L6's in the power section.

It sounds better at lower volumes, but I think that might be the speakers fault..it's an old series 1 EV 12L, which apparently needs a re-cone.

 

[Russ]

I think that the sovtek wb might be what is taking away from your tone at higher volumes. They aren't really a great sounding tube. They may be ruggedized but they sure don't help in the tone dept. Try out some old (NOS) Sylvania, RCA or GE 12ax7 or even some Amperex or Bugle Boy. I wouldn't necessarily recommend Mullard in a Mesa Mark Series amp. I think that the Japanese Matsushita was supposed to be a Mullard clone but not nearly as expensive. Other good tubes are Raytheon, RFT, Valvo, Mazda, Telefunken, Brimar, Tungsram, etc. Be careful of the reissue tubes or newer production on older tooling. Basically, look for anything made before the mid 70s.

I have some wb's in my Ampeg because that is what came in it and I don't play it much or I would certainly swap them out for something a little nicer. I have a mixed bag in my Marshall 2210 and Mullards in my JMP. I am running RCA, GE, and EH in my Mark IV. I did have some GTs in there but decided to just use my nice old tubes and swap them out if I needed something more modern sounding later.

I noticed that you are running a Phillips 12at7wc. I had a JAN Phillips 12at7 in the reverb of my Mark IV and found that I liked the sound of the EH better even though the JAN Phillips tube was nice. Again I believe that the "w" correlates a ruggedized tube charcteristic. Sovtek used the wa, wb, wc labels as standard ruggedized tube just with varying gain characteristics. I wouldn't be surprised if that wasn't the case with your Phillips tube.

The EVM-12L sounds great even when it needs a recone though if it is really bad it still may be the culprit. Recone kits are getting hard to find. It may be expensive to recone it. The last recone kits I found on E-bay were more expensive than buying an already reconed speaker. I would suggest looking for cabinets that are loaded with EVM-12L and just take the cabinet as a bonus. The last pricing I saw on the EVM was going up and up. The last one I bought was just the speaker for $125 used in new condition with low hours. I bought another one a week later with a cabinet and got it for $120. The cabinet is actually worth more than the speaker but still got it cheap because it would have cost a lot more to ship. I ended up picking it up locally and saved a ton. There are a lot of people getting trid of their older EVM-12L speakers right now in favor of the newer Black Label speaker that is essentially the same thing just rated for more power (300 watts) though I have heard that they are making a 200 watt version also.

Another speaker to look at is the JBL. It may be a little pricier than the EV but it sounds a tad better at times. The model I was looking at was the E-120 but there are others in the same 120 series like the D and K versions that would sound great too. The E-120 is discontinued and sounds great so if you find one of those jump on it. They will have the chrome dust covers if original JBL cones. They sell recone kits too though so that is always reassuring. There was a guy at a service center selling NOS/NP JBLs that were made from the NOS parts on the shelf. The speakers were exactly as you would have bought them prior to the speaker being discontinued. They were selling for about $200/speaker. Considering the price of the new Black Label EVM it was pretty comparable still.

There are a couple small companies making clones of the EVM and the JBL discontinued speakers. They use all the same stuff and are slightly cheaper than you would find NOS for. Apparently the JBL clone is an incredible speaker. I will have to look the name of that company up and let you know what it is. I was just looking at them a couple months ago as alternatives to the EVM sound without having to shell otu quite so much money on a JBL.

 

[kdove]

I am using groovetubes - Chinese 6L6 power tubes - no different from originals in my opinion.

Tried many groove tube preamp tubes - hands down winner ECC883 groove tubes in V1 & V2 slots.

 

[James]

wow, thanks Russ

I think it might be time to replace the filter caps, as it makes the sound of paper being crumbled when I stop playing...or is something else causing that?

I still have the WB's in there, and they're pretty good...not great, though.

kdove, I used to have the GT Chinese 6L6's in my IIB..I loved how they sounded...are these the same as the Ruby 6L6GCMSTR's?

 

[Tuna141]

Faulty tubes can cause the "crackling sound" you described. I'd try swapping them out first...

 

[kdove]

kdove, I used to have the GT Chinese 6L6's in my IIB..I loved how they sounded...are these the same as the Ruby 6L6GCMSTR's?

This is what I used ... picked of at Guitar Center. They sounded OK to me.

http://www.groovetubes.com/product.cfm?Product_ID=1678

 

[James]

Faulty tubes can cause the "crackling sound" you described. I'd try swapping them out first...

actually, when I got the amp it had different tubes, which were JJ's (not good!) and GT's..still did it before I changed the tubes. Also, I used this tubes in another amp without a problem.

kdove, I used to have the GT Chinese 6L6's in my IIB..I loved how they sounded...are these the same as the Ruby 6L6GCMSTR's?

This is what I used ... picked of at Guitar Center. They sounded OK to me.

http://www.groovetubes.com/product.cfm?Product_ID=1678

yep, those are the ones I had

 

[James]

sorry to bring this up again, but I think I might have to go to a tech with this amp...

Well, the 'crackling' stopped when I replaced the cheap sovteks, and the amp was fine up until two days ago. I went to turn it on, and after I took it off standby, it made an unusual 'pop'. After playing for about five minutes, it made these really LOUD crackling and popping sounds...I switched it off right after that, and turned it on again today. Not nearly as bad, but it's still there.

Doesn't look like anything bad happened, I really hope it's a bad tube...the only thing I did different was plug into input '2'.

I highly doubt that would cause it to do this...

Well, I have a new set of tubes on the way, so I'll see what happens...if that doesn't work, I would suspect the filter caps...how fast do these go bad?

Weird thing is, the amp was dead quiet since I got it a few months ago....

 

[Russ]

Filter caps are kind of a funny thing really. They can honestly go whenever they want to. Some people never change them and they last forever. Others change them every couple years. It is a good idea to change them before they go bad though it is hard to tell exactly when that is because there is no real warning other than a slow degradation in tone if you are lucky enough so that they even give you that. There are some wives tales that you must play your amp often for them to last longer or that playing your amp wears them out. There is some truth to both of those though for the most part it is just kind of a question of time more than anything else before they go bad. Just as a battery has no real life expectancy except an observed amount of energy that is expected to be discharged from it before failure, your caps have a simliar job. Though the energy passing through them is not something that is a fixed ending supply their life really depends upon their craftsmanship and your luck. There are some old Marshalls and Fenders out there running on their original caps from the 60's. Then again there are some that are not. There are more modern amps that get recapped than not. I am a believer in the thought that electronic parts like everything else in this world are getting overproduced and that the quality control is going down. Granted there have been worlds of technological advances since the invention of the cap but the basic idea of its function and construction are the same. The only differences really being just the care given to their production and the quality of the materials used. Like everything else in this profit driven world the cheaper the better for the manufacturer. This doesn't exactly do too much for the consumer except drain their wallets because inflation doesn't help the fact that the manufacturer has cut production costs. The manufacturer still sells for a profit. So let's turn this tangent back toward the issue here. I would say if you find that your amp is beginning to have strange noises that are not explained by things such as your cables, guitar, tubes, speakers, or environmental issues, then it is probably a good time to have your amp checked out. Popping could come from caps as well as many other small electronic components that could fail such as resistors, diodes, transformers, etc. The problem could be component failure or simple arcing. Needless to say, a tech should be able to thoroughly check out your amp and return you to a clean bill of health. Just be sure to go to a reputable tech.

Some other things to consider are that your contacts in your switches may be getting a little dirty and will pop when you go to energize. Also if your amp was remedied by new tubes before, it is very possible that you are just due for new tubes. Wait until after you try the new tubes to take it in to the tech because if you resolve your problem then you may end up saving yourself some $. Also if you are not the orginal owner, which it appears as so, you may consider having your amp checked out anyway. This will at least give you piece of mind that you are at least starting off running in proper form. I have bought a couple amps used and after having had experiences with friends and whatnot with used amps I have found that even if you think you know the history of the amp it should be checked out just so you know exactly where you stand with it. Afterall I am sure that the amp was not as cheap as some throwaway keyring flashlight. You obviously spent the money to get it. Spend the money to ensure it stays running right. This means take it in for service whether you think it needs it or not. Sometimes things have a way of creeping up on you. Then you do something really bad like burn up your board because some little made in Taiwan POS melted down on you or worse you end up frying a tranny. These amps are not rocket science to figure out nor are they neurosurgery to work on. You might if so inclined and dextrous enough work on it yourself once you learn a bit more about it. I would not suggest just sticking your hands in there too hastily though because there are voltages there that will drop you deader than sh!t. Educate yourself thoroughly before removing the chassis. Also have the necessary tools at hand to work on the circuitry before starting. Preparing yourself for electronics and repair is invaluable/ priceless.

 

[James]

Thanks

Well, I had all the caps tested today, and they're all fine....!

I did turn on the amp again, and it still sounds great, but the annoying crackle happens like every five seconds. (I had it on for only a few minutes)

if the tech here can't figure out what's going on, should I call Mesa?

 

[stokes]

James,an amp that age likely needs a basic service,you should clean and retension the tube sockets,that is a likely cause of intermittent crackling and the like.Clean the pots,too.With filter caps that age there is no way to "test" them and definatively say they are okay.Manufacturers such as Sprague tell the retailers they supply that they have an unused shelf life of ten years.It is true there are people who leave them in for 20 or more years and have no problem,but if you ever have to clean up a chassis that had a cap explode and spew its guts you wont ever wait even the ten yrs.I change mine after about 8 years on all my own amps and I always notice an improvement in tone,particularly the bass response.And dont use the cheap Taiwan or Jap crap.Sprague and F&T are good choices.Russ,it is not a wives tale about not playing an amp causing the caps to deteriorate.If the amp is let sit without being fired up from time to time for years the electrolyte in the cap dries out and the first time they get hit with full voltage they will likely fail.That is why you form them even when you install new ones,and in an old amp it is advisable to bring the voltage up slow with a variac to re-form the caps before hitting it with full voltage.James,again I would suggest a good cleaning before looking for other sources of noise,it just might be all you need.You could spend a fortune in tubes when all it needed was a good cleaning.As for the caps,there are a lot of different opinions on when to change them,but if your caps are original,you cant go wrong if you replace them before they fail,and you will notice an improvement in the amps response.

 

[Russ]

Stokes-

I guess I assumed that we all form new caps and re-form when taking an amp out of deep storage. Sorry if I seemed to assume that we all knew that. Really though, what idiot takes an old dusty amp out of the closet after 20 years plugs it in and cranks it? Personally if I don't play an amp for more than a year I get it serviced before I play it at all. Also, if I buy an amp I get it serviced before I begin to really play it whether it needs it or not. It is just added security. Being that I don't have the time typically to do it myself I let others do that work for me. Being a contractor takes up a lot of my time. I would rather be playing a different amp while one is getting serviced than have the down time or have it fail on me for any reason.

 

[Russ]

^ The amp purchase assumes used. I haven't bought a new amp in a long time. There is just too much depreciation for such nonsense.