New guy needs some advice

[Agraebner]

I just purchased a very nice condition 50 caliber MESA. I replaced the pre amp tubes with Mullard reissue tubes and it already had new JJ power tubes. I love the clean and I love the lead channel but to get the sounds I am after I have to adjust the volume and turn the guitar down a lot too. What is the best way to balance the two channels better on this. I do not use the massive amount of gain this has on tap but I am learning new styles so I do not want to just go with low gain tubes. I heard there is a mod to install a pot to control the imbalance. A added pot would seem to be the ideal solution for my needs. Does anyone here know how to install the mod????? I have been doing basic repairs on all sorts of electronics I just need to know what to mod if anyone can help. Which tube is V1 viewed from the rear of the amp??? ( I have received conflicting info here) Thanks in advance for your help. I am very happy to have stumbled across this amp it truly sound amazing and has gone against a lot of hating that I have heard for the brand for years from people around me. Even having heard a few MESA newer, larger, flashier models in a local shop kinda put me off Mesa for my COUNTRY past that is slowly progressing towards classic rock. (Eagles, Clapton, CCR ...) I am really impressed with every detail of this amp accept the channel balance issue.

 

[jpdennis]

Welcome to the board. Before I get ahead of the question, what type of power tubes do you have? Are they 2 6L6 tubes or 4 EL84 tubes? The answer will let me know if I can help.

Thanks

Dennis

 

[Agraebner]

I have a 50 caliber NOT the + version. Mine uses 4 EL84 power tubes.

 

[RR]

Since your's not a "+", [ I think ] the mod you are inquiring about adds another volume [?] control. But I'm not sure.

Now why don't you want to use lower gain preamp tubes?

I have a Studio .22+ which I think is a Caliber .50 little brother. I can't recall the tube configuration but I change the V1 and V2 tubes from the 12AX7_s to 12AY [?] and a 5751. Yes, a low gain 12AY preamp tube!

This give me a better volume control balance switching between channels. This also gives me a better control of tweaking the gain to your liking. Pretty much covers the classic rock stuff you like. [ that was my era when I started to play guitar ] :wink:

You will lose some of the preamp hi-gain shred, metal tones but also you won't have the hiss that goes with it either.

If you do need hi-gain, shred tone I'm go with another amp that is dedicated to that stuff.

I'm planning to get a Mini-Recto for all the hi-gain shred / metal stuff and have my Studio .22+ for everything else.

My suggestion doesn't require any mod and keep your amp original.

Hope others chime in about that mod your are inquiring about.

 

[jpdennis]

Well then we have a similar beast. I will give you a complete run down on what I have done and found. Most the threads I found here are about the Plus version with the 6L6s so I may be a little wordy having found someone with the same EL84 power tube amp. :lol:

But first, V1 is the preamp tube closest to the input jack, period. I will find the link to the mod you are asking about and post it in a few minutes.

In addition, here are the things I have done;

1) Mesa tech complete service
2) Installed a mercury magnetics OT & mercury magnetics fender black face reverb tranny
3) Tubes used
...........V1 - Mesa SpAX7
...........V2 - Tung-Sol 12AX7
...........V3 - Mesa 12AX7
...........V4 - Mesa 12AX7
...........V5 - TAD 12AX7-S
4) power tubes are Mesa EL84 green rating
5) cooling fan for tubes
6) new reverb tank

I play contemporary C&W, AC/DC. Worship, Eagles, SRV, R&B, etc. I was using the Line 6 M13 for OD enhancement until the #2 & #3 items. I found for home practice this thing can get a little loud. However, on stage I no longer use any OD. This thing cuts through the mix whether produced via PA w/ e906 Sennheiser or on it's own against a Dr. Z Stangray, 50 Watt Marshall, VOX AC30, or Fender Duo Sonic. It has great definition which I attribute to the mercury transformers since I used it without them for some time and they are amazing in my amp.

Here are my last produced stage settings [this was a big stage so the Vol & Master may be a little hot for more of a club setting when it is mic'd so you could roll the V back to about 3 & the Master to about 3.75 AND the presence just has to be adjusted every time since it really determines how I cut as well as how sharp my overall sound is];

Vol = 3.5, Mast = just above 4, Treb = just under 6, Bass = 7, Mid = 6.5, Rev = 6.5, Pres = 6.25

Still not sure about imbedding pictures or I would put some in. Mine has the amber/red light and no EQ and component board is stamped 1985. I do use the FX loop with my pedal board. I use the Mesa footswitch to switch between clean and crunch. I also use my guitars' volume knobs a lot for less or more bite based upon chording or soloing. These settings work with my 2008 Les paul Traditional, 1970 hotrodded Les paul Gold Top, hotrodded 1983 Stratocaster (SSH DiMarzio P/Us), and my 1981 Fender "The Strat". I do turn down the Master just slightly for the hotrodded guitars.

When the amp isn't being mic'd I just run up the Vol & Mast about the same a little at a time until the stage mix is fairly balanced. And so far I have no hum/hiss/noise issues.

While I have read about the extra lead level mod in this forum I have yet to feel I need that. Also, Mike Bendinelli at Mesa suggested using the Red rated power tubes in Class A amps like this due to heat and power tube life, though that was without having a fan. I have yet to try that as well and this thing has been going strong for about 2 years now.

Thought I would give you a COMPLETE run down. This way you might be able to try at least the settings without all the other stuff and let me know what you hear.

Dennis

 

[jpdennis]

O.K. - I am not an amp tech. But here are what i found.

Seems that premier guitar speaks tech ;

http://www.premierguitar.com/Magazine/Issue/2008/May/Boogie_Tricks_A_Fuse_Fix.aspx

From our own board;

http://forum.grailtone.com/viewtopic.php?f=28&t=42474

And something with pictures from a plus but down further from a none + with Mesa factory mods

http://acapella.harmony-central.com/showthread.php?2223437-boogie-.22-lead-drive-mod-PICS

Dennis

 

[jpdennis]

O.K.

I found this htread and if you read everything from start to finish, with your technical skills, you will probably get a lot more out of this then I did. However, it seems fairly thorough in several ways to do a "mod" to the 22 which is supposed to be very close to the 50

Hope this helps

http://forum.grailtone.com/viewtopic.php?f=3&t=30067

Dennis

 

[Agraebner]

This was just what I was hoping for, GREAT advice and info....I installed the volume pot for the lead channel. I re-soldered anything suspect. I cleaned a bunch of stuff. I have one more must do before I start using it for real, I want to install a cooling fan. jpdennis what kind of fan did you install and where did you tie in for power??? I am thrilled with the clean sound. I have a little tube swapping to find my sound on the lead channel but now I have perfect control of the balance between channels. When I can get the time and a few different tubes I plan on swapping a few around in v1 and v3 to find just what I am after. I believe that a 5751 will likely be in the equation. I also want to get a decent 12at7 to try in PI and V1 spots as well. Right now I get about the amount of over drive I want out of the lead with my pot set at half. The only thing im not keen on is that the sound is thinner than I want at lower volumes. Turned up it fills out great. With my pot turned all the way up I get the same sound I had before, I am very happy with that cause the amp can still be itself with the twist of a knob. As far as I can tell the amp is very healthy and looks great inside. I get no noises from it at all and the caps look as if they were replaced so its been fairly well taken care of.

 

[jpdennis]

The fan is here;

http://www.newark.com/multicomp/mc19677/axial-fan-119mm-115vac-130ma/dp/70K8560

the cable for it is this one;

http://www.newark.com/jsp/search/productdetail.jsp?SKU=56P2995

and I used this cover - finger guard;

http://www.newark.com/jsp/search/productdetail.jsp?SKU=56P2945

I put an in-line rotary click switch like you find on older lamps then plug it into my Monster power conditioner. This way I can plug it in and turn it on before I power up the amp itself since I don't like arching nor do I like to hear the click :shock: of the fan switch once the amp is running. I placed the fan at about a 40 degree angle or so just opposite side of the reverb tank and under the power tranny. This way the air circulates across the tubes as much as possible while still cooling the board as a secondary measure since keeping the tubes cool is paramount to what this amp needs. I don't see how pushing the hot air up into the board before it cools makes sense if it can be helped [I did this to my Mark III as well]. Mike at Mesa said to definitely use the Red color Mesa EL84 power tubes since they will stay coolest. I have green in right now since I keep the fan running for about 10 minutes even after I turn off the amp. I do have a set of Red and a set of Yellow I will use once the green are spent just to hear if there is any dramatic difference to tone and breakup.

If you are going to try something different with the preamp tubes in V1 I would suggest a 12AY7 since percentage is not just the only value to consider when thinking about preamp tubes and tone/gain. For the PI I would be more inclined to stay with the 12AX7 in a TAD maybe. But there are others who may have better insight into the value of using an AT in the PI of this amp.

And yes, the cleans are very sparkley and shimmery for me and I didn't do the mod. Plus the gain just kills if and when I need it. It is an amazing amp. :mrgreen:

Dennis

 

[jpdennis]

... The only thing im not keen on is that the sound is thinner than I want at lower volumes ...

Thanks for that info. I read somewhere that there was suggestions back in the early 1980's about changing out resistors in case of FX or reverb problems but that tone would be sacrificed based upon value. I don't really understand the techie side, however, my heartbreaker has a diagram about splitting the preamp tubes for the various circuits. With the tone stages in the Mesa amps I was wondering if there is some mysterious mod no one has come up with yet when a volume mod is done on these boards to compensate other than having to turn it back up.

Anyway, just a thought.

Dennis

 

[Agraebner]

I am currently unemployed so money is a little short.... any small gigs around here dried up so I have been downsizing my gear some for home use and jams. Till about 3 months ago I had all Larger amps: Fender model 94 twin(100 watt 2 12), Peavey classic 50 (410 version), AC30 (with greenbacks), Peavey Windsor Head and 412 cab, Bassman 100 head through the same cab. I have a couple more little guys I will get as I get the opportunity and money comes along. I want an Ampeg Reverberocket (with 1 12" and the EL34 power section) and I want a classic 30 or delta blues with a 15. Either way there will be a cab made with a speaker from the other version so I can get both sounds when I want them. If I get the DB I will have Tremolo too....
I will wire the fan in so its on when the amp power is turned on. It worked on my Peavey Classic 50 (original equipment)well enough for me. I did a similar mod to my ac 30 (also hot running) since it was a pcb amp with a nearly closed back. I have to do a little planning on where the fan will go and how. I may mount it somehow to get fresh air and duct it or make something to direct it...... The first thought I had when I woke up this morning was I should have used a stacked pot and installed it in the first position on the amp. ( outer ring clean gain, center lead gain) I am not an engineer. I just figure things out as I go. I prefer to do a known good mod rather than my own concoction if one exists. I am pretty sure once I get the money to get an assortment of tubes for testing and trading around Ill get the thinning at lower gain sorted. I get the feeling that a little softer gain tube in there will let me turn my gain up a little more and be fuller sounding. I figured out that I goofed its actually a set of new pull tubes from and ac15 that I have in the pre amp stages now. I forgot that I put the ac15s tubes in the mullard boxes...... there is no printing on them so i didnt give it a thought. I have to get more mullard tubes for this thing. I currently have a Fender blues junior (first of the Mexican made ones), an ac15c1, a Marshall class 5 and MY 50 Caliber. All these amps have Mullards in them. They brought the amps to LIFE!!! Every time I hear one of them I cant believe the full rich sounds and responsiveness of these amps now. I tried JJ and of course all the tubes the amps came with including Chinese tubes in the ac Sovtek in the classic 50 and groove tubes in the fender. I have been selling off all those tubes since I didnt like them in anything so far compared to the Mullards. I wanted to use Mullards in the power section but till I get a fan and maybe a bias mod too I will stick to the JJ EL84 as they seem to be pretty tough tubes.