I want ZERO overdriven power tubes... SUGGESTION?

[WellYourMomLikesMe]

I have pedals for that and want the cleanest power tube out there. I'd like to try a few things before I go spending hundreds of dollars shipping my head across america for mods. I have a stock Heartbreaker head(fixed bias). Stock Mesa 6L6 power, JJ 5AR4 rectifier, EHX 12AX7 pre-amp. I'd like to stay with the 6L6's.
~Thanks

 

[212Mavguy]

Unless you are playing like REALLY loud you won't have much if any power tube distortion anyway...Amps like your HB are designed to put the distortion in the preamp.

 

[talltxguy]

White Mesa tubes are the coolest. The Groove Tubes equivalent would be 6's.

 

[yeti]

get a bias mod for it for like 40 bux. then just use 6550's in it.

 

[Jackie]

Unless you are playing like REALLY loud you won't have much if any power tube distortion anyway...Amps like your HB are designed to put the distortion in the preamp.

Yep.

My Marshall JVM doesn't start clipping until it's DIMED. Completely. And it's biased a bit more than your standard amp plus it has EL34s which have a little less headroom than 6L6s.
Like 212Mavguy said, in an amp design like the HB, you'd have to really crank it to get the power tubes to clip.

yeti's suggestion of 6550s is also a good one. 5881s might also cut it, if you want to get really crazy you could use KT88s or KT77s (KT77s are like a "mix" of 6L6 and EL34).

 

[212Mavguy]

Installing a bias mod will set that amp free...

 

[Jackie]

Installing a bias mod will set that amp free...

I think it's hilarious how Randall Smith advertises fixed bias operation and how he says bias adjustments are "useless" and how you insult the company by asking for adjustable bias... while everyone and their granma installs a bias mod on their boogie :lol:
To my ears, it's DEFINITELY worth screwing around with, jacking up the bias on my Marshall JVM made my amp sound at least 50% better.

So I agree that a bias adjustment can have a positive impact on your amp's overall tone quality.

 

[94Tremoverb]

If you want to stick with strictly 6L6s, NOS Philips/Sylvania 7581As have the highest headroom (and the most bottom end, if that matters). They're also among the most expensive but will last nearly forever. Second choice would be the nearly identical late-production Philips/Sylvania 6L6GCs - they may actually be the same tube (I'm not certain - they look identical) but the 7581As were simply selected more rigorously. But given that it's a 100W amp you'll be going some to get power-tube distortion with more or less any 6L6s, as already said.

6550s would also be a possibility and might not even need a bias adjustment - they don't in late-Silverface (70 and 135W) Fenders, these amps are likewise biased fairly cool for 6L6s and the 6550s just run a little hotter, but still well within their rating range. The extra filament current for the 6550s won't be an issue if the amp will take EL34s.

Also be sure to select solid-state rectifier, which will give you more voltage and headroom with any set.

 

[b0nkersx]

while everyone and their granma installs a bias mod on their boogie

I wouldn't be so sure about that. A lot of people who read forums like this may do bias mods, but a lot of those people ALSO tend to be hardcore tweakers.. I would wager a decent majority of Mesa users never really worry about the bias, or would rather have their warranty.

 

[WellYourMomLikesMe]

I'm a "tweaker", I guess. Mods are an opinion if all goes well with work(side jobs). I've been talking to Monsta-Tone on here about the mods. I currently have the white 6L6s(the originals, I believe. Atleast 10yo), EHX 12AX7's, and JJ 5AR4.

 

[RussB]

Consider running a 12AT7 phase inverter

 

[RussB]

while everyone and their granma installs a bias mod on their boogie

I wouldn't be so sure about that. A lot of people who read forums like this may do bias mods, but a lot of those people ALSO tend to be hardcore tweakers.. I would wager a decent majority of Mesa users never really worry about the bias, or would rather have their warranty.

The majority of players are very happy with simply replacing the power tubes when they're worn, and not worry about paying a tech to install/bias the amp.

The power tubes are biased "cold" from the factory, which gives you a lot of headroom. Turn up the current flow (by reducing the bias voltage) and you get more output tube distortion

 

[dodger916]

White Mesa tubes are the coolest. The Groove Tubes equivalent would be 6's.

The OPPOSITE is correct. Whites and Blues are the hottest; Red/Yellow run coolest (most headroom). Board members have measured the idle current draw of the various colors. See JOEY B's post at the end of Page 1: http://forum.grailtone.com/viewtopic.php?f=16&t=16487.

The same issue was raised two years ago. The GT ratings apply to adjustable bias amps when biased properly. The opposite is true in Mesa fixed-bias amps, so a 4 has more headroom than a 6. Here's the thread where I learned the facts from some very knowledgeable Board members (see JOEY B's post at the end of Page 1): http://forum.grailtone.com/viewtopic.php?f=33&t=39067.

 

[Jackie]

Turn up the current flow (by reducing the bias voltage) and you get more output tube distortion

Not really. Maybe earlier power tube distortion, but unless you run your master at 9 or 10 there is very little (I don't dare say no) output tube distortion because most modern amps have a lot of negative feedback in their poweramp section, which keeps the poweramp clean and the sound tight at high preamp gain levels.
I did notice a more lively tone and a slight increase in gain when I jacked the bias up on my Marshall, the clean was a teeny bit darker too. But I had to dime it to get any powertube distortion at all (we're talking low gain channel, full tilt)

 

[talltxguy]

Thanks for the clarification, Dodger. And sorry for the misinformation. Mike B from Mesa even told me if I wanted to run 6L6s in my 295's EL34 spots to put the coolest tubes Mesa offers, which is RED!

I stand by Dodger's correction. And yes, my bias tests reflect the same thing.

Sorry for the confusion!

 

[fluff191]

I wouldn't be so sure about that. A lot of people who read forums like this may do bias mods, but a lot of those people ALSO tend to be hardcore tweakers.. I would wager a decent majority of Mesa users never really worry about the bias, or would rather have their warranty.

I went bonkers (no pun intended) with mods with my FJA Recto and am glad I drove down that proverbial road to check out the scenery, but man it's so nice just being able to pop some new power tubes in and just play. But I don't think I could appreciate 'stock' as much as I do without first spending massive amounts of time and money going the opposite direction. Just food for though.

 

[RussB]

Consider running a 12AT7 phase inverter

This is worth repeating, because the PI tube is part of the power stage. A 12AT7 or 5751 tube can keep the power section from distorting

 

[yeti]

a sovtek LPS is a great PI tube.

so is the mullard cv4024

 

[RussB]

a sovtek LPS is a great PI tube.

so is the mullard cv4024

The LPS will distort the power section, and the CV4024 will not :wink: