Tube Question

[adambilz]

Alrighty, I have a Mesa F-100 which I love, and thank goodness it only uses 4 power tubes, but one has blown! Now, I've retubed it before, it's a piece of cake, but I retubed all 4 at once. Now, if I only need to replace one, does that mean that I really need to replace two to keep it matched? Is it the whole 2 outside match and 2 inside match? Do they need to be the exact same kind as the other 2? Thanks for any help guys!

 

[Big Mike]

Alrighty, I have a Mesa F-100 which I love, and thank goodness it only uses 4 power tubes, but one has blown! Now, I've retubed it before, it's a piece of cake, but I retubed all 4 at once. Now, if I only need to replace one, does that mean that I really need to replace two to keep it matched? Is it the whole 2 outside match and 2 inside match? Do they need to be the exact same kind as the other 2? Thanks for any help guys!

Best to change the whole quad with a matching set, unless you use boogie or groove tubes and know what the codes are, then just match 2 and change the outside 2.

Stay with the same type, brand, etc. Also check the fuse at the same time.

 

[hal9000]

Yup, the inside pairs are matched as are the outside. You should at least replace them in pairs, if not the whole quad. BTW, I also have an F-100.

A pic for you:

 

[adambilz]

Best to change the whole quad with a matching set, unless you use boogie or groove tubes and know what the codes are, then just match 2 and change the outside 2.

Stay with the same type, brand, etc. Also check the fuse at the same time.

Yeah, I use Mesa tubes. I know the strength, color, code, I should replace all 4, I'd love to, but boy is it expensive! It's $80 just to do my lil' amp, I'd hate to imagine a triple rectifier or something like that! Thanks!

 

[adambilz]

Yup, the inside pairs are matched as are the outside. You should at least replace them in pairs, if not the whole quad. BTW, I also have an F-100.

A pic for you:

Wow, that is sweet looking! My grill cloth is black, as well as the knobs, you've added a tasty touch (unless that was stock?). Nice pic!

 

[candid_x]

I think the Mesa F-100 uses 6L6 power tubes?

The tubes you choose can make a huge difference in the tone you get. Most stock amps come with Sovteks, under one brand name or another, like "Mesa" or "Groove Tube". Depending on the tone you're looking for, you could probably do better.

I get most of my tubes (I like to experiment) from http://www.dougstubes.com . He tests everything before shipping, and he's a straight shooter.

I'm currently using JJ 6L6's, because of their sweet harmonics, clear bottom and top end. But there's other good ones, depending on the tone you're looking for.

Whichever you choose, having your amp biased properly makes a big difference, opens the amp up. You can also bias the amp hotter or colder, to vary headroom and such.

Or, you can drop in a reasonably matched single tube and play. Most players wouldn't notice the difference anyway.

Bruce

 

[Big Mike]

Can't bias the Mesa without modifications. They're fixed biased, and no bias pots.


I hear Doug's tubes is good, also check Mike at KCANOS tubes. Tell em what mesa rating you have, they can get something in there for you. Should be cheaper than 80 bucks too.

 

[hal9000]

Wow, that is sweet looking! My grill cloth is black, as well as the knobs, you've added a tasty touch (unless that was stock?). Nice pic!

Thanks a lot! I did the conversion myself for about $90. Check out this tutorial I made: F-100 Cosmetic Mod Tutorial

While you're over there, check out this link: Mesa F-Series Lounge.

 

[hal9000]

Can't bias the Mesa without modifications. They're fixed biased, and no bias pots.


I hear Doug's tubes is good, also check Mike at KCANOS tubes. Tell em what mesa rating you have, they can get something in there for you. Should be cheaper than 80 bucks too.

Yup, Mesa amps are all non-adjustable fixed-bias on their Class A/B models. Not to fear, as already stated www.dougstubes.com will sell you a quad matched to Mesa's spec as will www.eurotubes.com.

BTW, if you only wanted to use the inside pair, turn the amp to 60 W, and change the combo speaker plug from 8 Ohms to 4 Ohms.

 

[candid_x]

Woops, didn't know Mesa was fixed bias.

I've done biz with Eurotubes too. Good guy, very helpful, but he's primarily a JJ distributor. Doug's got a better variety, and has been utterly reliable. Had a EL84 go out after just a short time, and he replaced it immediately.

 

[peterd79]

heres one... do all tube amps need to be BIASED when the tubes are changed?

 

[PeteDuBaldo]

heres one... do all tube amps need to be BIASED when the tubes are changed?

You can't set the bias on a Mesa unless it is modified. The same is true of many amps.

My Soldano SLO-100 has a bias adjustment wheel, and I set the bias with a meter when I retube it, or when I hear the bias shift as the tubes age. I like the bias a bit on the hot side - tube life is shorter but they sound more alive to my ears.

Mesa sets the bias cold on their amps to prolong tube life, and reduce the risk of someone putting in hotter tubes and blowing something up.

 

[Big Mike]

heres one... do all tube amps need to be BIASED when the tubes are changed?

No.

My amps are cathode biased. Nothing to bias. It's what is incorrectly reffered to by Matchless and Vox as "class A"

And in most cases, if you replace with the same thing, you don't need to bias.

 

[adambilz]

You can't set the bias on a Mesa unless it is modified. The same is true of many amps.

My Soldano SLO-100 has a bias adjustment wheel, and I set the bias with a meter when I retube it, or when I hear the bias shift as the tubes age. I like the bias a bit on the hot side - tube life is shorter but they sound more alive to my ears.

Mesa sets the bias cold on their amps to prolong tube life, and reduce the risk of someone putting in hotter tubes and blowing something up.

Speaking of which, I gave your store a call today Pete! I was hoping to hear from you, you don't happen to carry any Mesa power tubes do you? I called all the surrounding GC's and they've got none. Definitely wanted to give you a shout!

 

[PeteDuBaldo]

No, I don't have Mesa Tubes here... I've got some matched quads of Sovtek, JJ, and mebbe a few others in stock.

I use Sovtek 6L6 in my SLO, and couldn't be happier. I tried JJ and a couple others, but the Sovtek tubes give me the sound I hear in my head.

 

[roburado]

Speaking of which, I gave your store a call today Pete! I was hoping to hear from you, you don't happen to carry any Mesa power tubes do you? I called all the surrounding GC's and they've got none. Definitely wanted to give you a shout!

You don't want to get them directly from Mesa?

http://mesa.stores.yahoo.net/tuavasdu.html

 

[candid_x]

No, I don't have Mesa Tubes here... I've got some matched quads of Sovtek, JJ, and mebbe a few others in stock.

I use Sovtek 6L6 in my SLO, and couldn't be happier. I tried JJ and a couple others, but the Sovtek tubes give me the sound I hear in my head.

Pete, I'm kinda curious, is your style/sound high gain?

I've found Sovtek 6L6's linear and powerful sounding, lots of punch n crunch. I've found JJ's over all more musical and spongy, perhaps more suited to blues, classic rock, country and such. The GT6L6GE's (GE reissue) have great clarity and are evenly balanced, sorta spendy though.

 

[candid_x]

I think Mesa’s stock 6L6’s are Shuguang Chinese tubes, also may be marketed by Ruby.

 

[wired]

I'm kind of a tube freak & have tried many over the years (Sovtek, JJ, Electro Harmonix).

IMO, nothing beats these:
http://www.tubestore.com/6l6gc.html

Smooth, plenty of bottom end without being muddy, and low microphonics for minimal feedback. Great tubes, try them out.

 

[candid_x]

I'm kind of a tube freak & have tried many over the years (Sovtek, JJ, Electro Harmonix).

IMO, nothing beats these:
http://www.tubestore.com/6l6gc.html

Smooth, plenty of bottom end without being muddy, and low microphonics for minimal feedback. Great tubes, try them out.

Looks like the old Svetlana, now called SED. Usually stock in Marshalls. I tried these a few years ago. Creamy and nice, not my cup of tea though.