CALIBER 50 + TUBES

[user 7737]

hi everyone,

i'm a newbie 'round here and i want to have your opinion 'bout this :

i've got a caliber 50 + and i had to change the preamp tubes... i read a lot of things on the web (here as well)... and it's very hard to have an idea of what you have to put in your amp...

usually, the caliber is lamped like this :

V1 12AX7
V2 12AX7
V3 12AX7
V4 12AT7
V5 12AX7

the more important for me is to have a good clean at high volume... a retailer recommend me :

2* JJ 12AX7
2* EH 12AY7
1* EH 12AT7

so... what do you think 'bout the 12AY7 choice ?
do i have to put it in V1 ?

thanx

my gear :
tele deluxe '72
turbo rat
tu-2

(i like simple things)

my style :
math-noise-punk

 

[stokes]

The 12AY7 has a lot less gain than the AX7,I like it in V1 of some Fender type amps,but I think it will lower the gain too much in most amps,especially high gain amps like most Mesa's.The 12AT7 is a good choice for the PI position,but I find it way too dull in any other position in almost any amp.If you want something with a little less gain than an AX7,try a 5751 in the V1 position.I would leave the AX7's everywhere except the V1 and PI.In the PI the AT7 or 5751 is a good choice,the AT7 being the better of the two.

 

[user 7737]

hi...

thanx for the answer... and sorry for my english... this is not my native language... i was very surprised by the retailer's advices... really... it hink i'll try anyway and i'll see how it sounds... maybe i'll have a good surprise... maybe my clean sound quality will increase... but i doubt about it...

will this AY in V1 have any influences in the general volume of the amp ? will it sounds less louder ? will my power tube wear out faster ?

even if really like the sound of this amp and i like it very much, i have to say that i'm a bit disapointing of its power... when i play alone, it seem to sound very loud... but when the band play as well, my sound seem to decrease... i tried to adjust the eq but nothing's changed (i mean the sound changed of course but i didn't find the frequences to get out of te "porridge"... if you see what i mean)...

what you guys mean by "headroom" ?

 

[stokes]

A 12AY7 in V1 will decrease your volume.It wont affect the life of your power tubes.If you are saying the amp isnt loud enough now,using anything but AX7's will soften or decrease your volume.Why do you think you need to change your preamp tubes?Preamp tubes last a lot longer than power tubes,by years.I would suggest getting a good set of power tubes first.If you are having volume problems it is more likely that you need new power tubes than new preamp tubes.I am not familiar with the .50+ but Mesa amps are loud and a look at the schematic tells me this amp would be no different than other Mesa amps I am familiar with.Unless you know for sure that you have bad preamp tubes leave them alone and get new power tubes first.But by all means,stay away from AY7's or AT7's and stick with the 12AX7's.If you change the power tubes and you still find that you arent "loud enough" when playing with your band,your problem is more likely with the tone settings.Specifically when you have the volume turned up you should keep your bass control turned down to about 2.When the bass is too high at high volumes your tone will get muddy and you will find your sound getting lost in the mix.

 

[user 7737]

thanx,

i knew the 12AY will decrease my volume... damn...

i think i have to change them because this is a second hand amp (i bought it one month ago) and when i looked at the preamp tube they seem to be be very old, they're all mesa tubes 12AX, except 12AT in V4 (reverb i think)

it's very difficult for me to know if i have a problem with my preamp tubes 'caus i don't have anything i can refer to... so i'll try to change only the V1 (the most important)... i'll try the AY and the new AX, if there is no big difference i'll let the old ones... i have to be honest, i love the tone but once again i got nothing i can compare to !

my power tubes are new, ruby 6L6 (sovtek ? chinese ? i don't know...)

'bout my settings i don't know it by heart, volume (gain) around 2-3, master between 5 and 7, treble around 7... don't remember middle and bass... presence around 6...

i did'nt know about the bass things... i knew that a trebble setting above 7 has a bad influence on the general color...

if i keep the bass around 2, can i boost it on the graphic EQ ?

thanx again for your advices

 

[stokes]

Do you know if the new power tubes are in the proper bias range for that amp?If you just purchased a set of tubes without regard to the bias range and they are too cold it would contribute to the lack of power.As for the bass setting I described,if you have the bass knob set at 2 you can then do whatever you like with the EQ.I would also suggest turning up volume(gain) to 5-7 to give the rest of the preamp a better signal to work with,that alone would give you a big improvement in your overall volume, and shouldnt cause too much distortion.Most Mesa amps can go to 7 before they start breaking up too much.I am willing to bet that just that adjustment will solve your problem.Having that volume set at 2-3 is choking off the signal from your guitar.The rest of the amp downstream has very little to work with.On my MKII I use volume (gain) 7, bass 2,mid 5-6, treble7-8 and master around 3-4 and the clean channel is super loud.It is a 2x6l6 power output just like yours.Like I said if you boost that volume (gain) setting you will have a whole new sound.

 

[user 7737]

well... i don't about the bias adjustement... i'll check that...

i'll try your settings... but above 3 volume, my sound break at 5 master... i'll try again tomorow...

this is weird... in the settings advices i found in the user's manual, there's one with volume at 3

http://www.mesaboogie.com/manuals/50%20Caliber%20Plus.pdf

 

[stokes]

Of course those settings as well as the ones I gave you are just starting points.Everybody hears things differently.The settings you see on the chart with the volume at 3 are going to be very quiet,probably unusable in a rock band.Where did you get the new power tubes?If you are unable to check and reset the bias,you should only use power tubes that are graded or matched to your amp.These tubes are probably a little harder to find and more expensive outside the USA.If you just purchase a set of power tubes that arent graded for use in that particular amp,it is very unlikely that they will be properly biased.If too cold your tone will suffer drastically and could contribute to the lack of volume.If too hot it could be dangerous,as the tubes could fry and possibly burn out other components in the amp.If they are dangerously hot,you will know by looking at the tubes and seeing the plates,or the large gray structure in the tube glowing red or orange.This should not be confused with the small orange glow from the heaters,which is normal and can be seen with the power on and the amp in standby.If you switch the amp from standby to play and see more glowing then you may have a problem.

 

[user 7737]

thanx a lot ! i will check that tomorow... it's geat to talk to someone who seem to know what he's talking about...

i'll keep you posted, but i got a little more clue now ! thanx for that...

 

[stokes]

No problem.Glad to be of help.

 

[user 7737]

is this image ok with the term we usually use when we talk about tubes ?

it will help me to discribe the tubes...

i don't really know about the power tubes ! the saler told me they were new... that's it !... :?

i can't wait checking all that stuff

i can play on my amp only 4 or 5 hours by week.. 'caus it stay in te rehearsal room and i live at 150 km from it... so...

 

[stokes]

That tube diagram is fine.The only thing is that inside most tubes you cant see all those components,the plate usually covers them all,so all you see is the very end of the heater at the top and bottom of the plate.But the plate is the important part,that is the component you want to watch while you play,to make sure it isnt glowing.Mesa has all thier amps biased the same,in other words all .50 Calibers have a certain bias voltage,all MKII's have a certain bias volts,etc.They then grade thier tubes so when you order tubes from them they give you tubes that will fall into a safe bias range.You can also get tubes from some suppliers who check the tubes and grade them to fit in Mesa amps.GT also grades thier tubes and a rating of 4-7 is safe to use in most Mesa amps.If the tubes you have are too cold they could sound weak,best case or have a very ugly crossover distortion,worst case.If too hot they will break up very easilly,best case or overheat and die,worst case.Never put power tubes in without being sure they are properly biased.I dont like the Mesa system,I check and adjust the bias in all my amps,but even if a customer wants to use the Mesa tubes,I still check the bias to be sure it is okay.A simple bias check can head off many potential problems.

 

[user 7737]

ok...

you were right, i think my main volume problem came from my setting... i tried with a higher gain (5) master (4), i was at 110db... with each tube i tried : old mesa 12ax, JJ 12ax... with the EH12ay i was at 107-108 db... but the sound was absolutely awfull... so i changed V1 and V5 with JJ 12ax7, V4 EH 12AT7 and i let the old mesa tubes in V2 and V3 for now... i'll change them next w-e... i still don't know what kind of tube i'll put in V2 and V3... what do you think ? what do you suggest (you already told me that the 5751 could be a good choice) ?

there are some big changes in my sound, the general sound is less "mellow", more clear (more headroom as you say i think), more "attack" (i don't know how to say it in english... in french we say "attaque"), the sound is more "hard-hitting"...

my big mistake was to try to have a little disto on lead mode... it's impossible... so i changed the way i use my turbo rat... i think something is missing in my lead mode... i think it's because of the old mesa tubes in V2 and V3, those are the disto position ! isn't ?

'bout my 6L6 i think there's no problem at all... there's only the heaters become orange...

well ! i'm quite happy ! i'm curious to hear the difference on lead mode when i'll change the V2 and V3

 

[stokes]

I see no reason to use a distortion pedal with a Mesa amp,there is already a lot of distortion available in the lead mode.Just krank up that lead drive.Adding a pedal can thin out your sound some and contribute to it getting lost in the mix with a band.I dont have a schematic for that amp so I cant say for sure what V2 An V3 do.I would guess V2 is for your rythm channel,V1 gets added to the chain when in lead mode.I would leave 12AX7's in V2 & 3.Also leave the AT7 for your reverb,a 12AX7 can cause noise problems with the reverb.

 

[user 7737]

the mesa disto is fine, i really like it... but with gain at 5 it is really too "hard"... i only use big disto on 2 or 3 songs... most of the time i use clean and light disto, crunch as we said... i can have this "dirty clean" with my rat by one stomp, if you see what i mean...

for V2 and V3, i know i have to put some 12ax7... but what kind ? EH, JJ, Svetlana, Sovtek (12ax7lps), GT, EI... i mean what kind will fit with the JJ ?

i saw some configuration with sovtek (lps) in V1 and JJ in V2...

 

[stokes]

Cant really commrnt on the EH,JJ or Sovtek except to say I dont like any of them.I have a fairly large supply of various NOS tubes-I never use current production.There are many here on this board who do like the current production tubes,maybe someone else with more experience with them will jump in here,or you could try starting another thread specifically about that point.

 

[user 7737]

thanx anyway ! you were very helpfull...

but i have one question how can you say that you don't like any of the modern product if you never used them ? :wink:

 

[stokes]

Didnt say I never USED them,I said I never use them.I have tried them,I also have customers who insist on using them.I dont like them.I'm not knocking them,if they work for you thats great.Tone is a very subjective thing,what sounds good to me wont necessarilly work for someone else.

 

[user 7737]

the NOS have such a different tone ? or is it only a question of reliability ?

 

[user 7737]

ok and what about the power tubes ? i'm still looking for a good clean at high volume...