Just got into Tubes is it worth the money for Mullards?

[Cleveland Metal]

Day late and a dollar short...

[Cygnus X1]

+1 on judging an amps tone (tubes, or whatever) with anything plugged in for effects.

I just finished a Matchless Spitfire build...talk about sensitive to everything!
I ended up with a very expensive vintage Telefunken 12AX7A in V1 and an Amperex 7025 for the pi. It just sounded honky with the many other 12AX7's I have.
But who wants to pay over a 100 bux for a preamp tube?
This is one amp that really shows the differences...temperamental.

OTOH, I have said before, and will say it again...Chinese AX7's sometimes give the best tone in high gain amps.

[AK47]

Tha AIC tone is sweet... Like Man In the Box era?

I've never quite nailed it myself. Very organic and chunky I think. Not a main tone I'd want all the time, but I'd love to have it available.

I know you're a fan, probably know more about that than I do. Heard he used a Haffler preamp a bit?

I know for sure Jerry used a Bogner fish preamp on Facelift and on the Dirt Album he used a early 2 channel rectifier. He may have used other stuff but that was pretty much the cliffs notes of the overall tone behind the two albums.

This is one of my dilemmas I have a rackmount rectifier coming in with non stock tubes I am not sure which ones. That is why I am thinking about going back to stock Mesa tubes to get that tone.

[Cleveland Metal]

Heard of him using a Fish, wasn't sure if that was a story or what... Seems I'd seen ads with him and a Haffler.

Of course "I" can never get a MESA to sound like that Haha...

MESA tubes from that era to the current era are going to be different actual brands. They just source from whatever works for them at the time. Not sure what to tell ya. I think if it was mine, I'd contact eurotubes or Tubestore and see what they have to say.

As you know, MESA are fixed bias and generally run pretty cold from the factory. there is a lot that can be eeked out of them with tube crafting.

http://eurotubes.com/euro-n.htm Mentions a lot about them if you haven't been there yet.

[Cygnus X1]

Good info, John.
I saw an option to run a GZ34 rectifier with 6V6...Deluxe Reverb!
Completely different designs, though.

About running the power tubes cold-normal.
People tend to think they are getting power tube distorion out of high gain amps, but the truth is you want the power stage clean and punchy to accentuate all that preamp distortion. I have adjustable bias built into the Marshall inspired SEL-2.
If I set the gains to low, just barely breaking up, then I can bias the power stage hot, and it sounds like a vintage Fender, Vox, Gibson amp with the brown sound.
But turn the gains up with that setting, and it sounds like mud!

The power stage will change how the distortion appears because it is working on whatever hits it. The winged C that John likes is a higher fidelity tube...that is why it tightens up the amp. They aren't even close to clipping at all.

AK...I suggest trying different preamp tubes more than anything. You never know what you will come up with. Get a spare set of power tubes, and see what kind off difference you get. I predict not much. If you have the 5U4 rectifier, don't touch it if it's working....it should last literally forever. Subbing a GZ34 is a crapshoot, and getting a good GZ34 will cost some major money. The only thing it would do in that amp is bring it closer to a diode rectifier sound.

[nhspike]

Seems like the cats who are into HiFi tube amps (for listening to music, not making it) tend to go with the JJ tubes quite a bit.

That tells me they must be very clean, with very little break-up (not my cup of tea for a tube guitar amp).

Maybe JJ's in the power section would work for some?

Also: I've always had good luck with Mesa tubes in my Mesa amps... but that's just me!

[Cygnus X1]

From what I have seen around the tube amp sites (both Hi Fi and guitar amp) is that JJ makes some great tubes, as well as some duds overall. Like many tube companies.

I understand the process is specific to each general type of tube, so while EH may make a good preamp, stay away from their power tubes. Ruby has a bad rep overall! JJ makes some good power tubes, especially the 6V6.

[Cleveland Metal]

I totally agree w/Cygnus's posts there.

Yeah, I like my power tubes to be hi-fi and stable (not distorting), and use preamps to get my tone. Probably why I lean toward KT88 and 6L6 as opposed to EL34. And why I use a VHT2150. It doesn't distort and just reproduces my preamp with a lil KT88 flavor...

However, running tubes so cold (MESA,5150s) really takes a lot of tone out of them. Cold, they are very reliable (hence OEM bias settings that are cold to make reliabilty standards), However, I don't want them so hot they are distorting oddly. Just hot enough to where they are responsive. Makes a huge difference to my ears.

5150 amps (which get most of their distortion from the preamp), just explode with tone (compared to stock) when bias modded and the bias set up nicely.

What I find with the JJ's (power and preamp tubes), is that they sound bland and somewhat weak to me. Had a few JJ 6L6's flame on me many years ago... But hey, stuff happens. I still think their longetivity is above the norm.. Generally, I feel they are extremely reliable and pretty much sound the same all the time. So, there's something to be said there.

I went to JJ 12ax7's for just that, as I was always running a combo of NOS stuff and when one died, my tone changed (aaaagh) Sadly, I'm not at all happy with my tone with them tho, so the search continues.

[Cygnus X1]

Fugget.

Tone comes from the fingers.
I say this due to the fact I have now had the opportunity to built some very fine designs, and it is stuff like pick attack, grip on the fingerboard, and other things we can't always quantify that makes tone.
These finer points become clear when my hacking sounds great through a compressed setup, but bad through the hand built amps. I can't figure out if I need to get rid of the amps that show my weakness, or bone up and get over it!

[Joelski]

The problem with JJ's is they are overbuilt, and will never break-up like almost any other tube that is built to original spec. That's why they're stiff and bland compared to most other brands out there.

[Cleveland Metal]

I'll go with that for the most part...

Rare something is actually overbuilt...

And, the best things always seem the best on the brink of destruction...

[DonP]

However, running tubes so cold (MESA,5150s) really takes a lot of tone out of them. Cold, they are very reliable (hence OEM bias settings that are cold to make reliabilty standards), However, I don't want them so hot they are distorting oddly. Just hot enough to where they are responsive. Makes a huge difference to my ears.

Biasing tubes cold actually introduces cutover distortion. A push-pull amp works by having one tube (or set of tubes) push the signal positive, and one set pulls the signal negative.

Bias is set so that you have a smooth sine curve. If set too cold, you'll have flat - positive - flat - negative. The flat spots are cutover distortion.

Setting bias "correct" cleans this up and lets the sine curve flow smoothly.

Setting Bias hot allows the tubes to overlap on the pushing and pulling. You might get a cleaner signal because there is less chance of a flat spot, but most likely you'll just overheat your tubes without any real benefit.

[Cleveland Metal]

I guess what I mean is that colder usually equals distortion (when YOU make the amp distort) that is not musically as pleasing. More odd harmonics? Compared to more even harmonics when biased appropriately.

I've just found the cold biased amps seem to "fight" me and feel cold/stiff, and a nicely biased amp just seems to feel alive... or nice and bouncy. If that makes any sense.

If you bias them hot, yeah you're very hard on the tubes

[Cygnus X1]

I was thinking of what I have doing with the single-ended amps.
Not so much PP configuration.
D'oh!
Thank you for filling in the hole, Don!

[DonP]

Yep, crossover distortion is nasty odd-order harmonic stuff.

The funny thing is, is that with the negative feedback loop on most amps, it "cleans up" the distortion. Without the negative feedback loop a cold biased amp would sound real bad.

Single ended is where it's at for even order harmonics. You want one side of the sine wave pulled harder than the other, which is easier with a single ended design.

Preamp tubes are single ended, BTW.