Learn Me About Tubes

[soulman]

So, what do I need to know about the 6V6?

Not whole lot more than it's the main power tube that amp was designed around. In a single ended Class A amp they produce about 5w of power output. A pair of them in a AB push/pull amp like my Egnater Tweaker will produce 15w of output power. They've been around for a very long time and are one of the most popular tubes used in US voiced amps like many that Fender produces

Here's a good basic primer on tubes in general; https://www.thetubestore.com/vacuum-tube-basics

These reviews may help you to understand 6v6 tubes; https://www.thetubestore.com/6v6-tube-review

Overall the Tube Store site is a good place to pick up general knowledge about vacuum tubes.

 

[Jim C]

So, what do I need to know about the 6V6?

6V6 - Wikipedia

en.wikipedia.org

 

[knuckledust3r]

6V6 - Wikipedia

en.wikipedia.org

Ok, I've got one EHX 6v6 saved on Reverb and one Raytheon 6v6 saved on eBay, so we'll see where hte spirits lead me. I've got an open auction on the 'Bay so if I win those, I'll buy the 6v6 from there...if not, I'll buy everything from Reverb.

 

[Jim C]

I've heard good things about JJ tubes as well as this seller in case the others don't work out.

JJ 6V6S Power Vacuum Tube

This is the newly released 6V6 with a robust tone & overhead - this may be one of the best sounding new production 6V6 available. Withstand high voltages!

tubedepot.com

 

[soulman]

Ok, I've got one EHX 6v6 saved on Reverb and one Raytheon 6v6 saved on eBay, so we'll see where hte spirits lead me. I've got an open auction on the 'Bay so if I win those, I'll buy the 6v6 from there...if not, I'll buy everything from Reverb.

For modern production Tung-Sols are one of the best and JJ if an amp runs a hot adjustable bias. Some amps are biased so hot they literally "cook" other 6v6s over time. So JJ made an especially stout one that's almost rated as a 6L6.

My Tweaker is cathode biased so it can run any octal tube. It came with 6v6s and I also tried a pair of EL34s to get it really close to a Marshall tonality. But then the Fender and Vox voicing suffered so I finally settled on NOS US made Tung-Sol 5881s. They're rugged military grade tubes that fit the amps bias almost perfectly and sound great.

 

[knuckledust3r]

For modern production Tung-Sols are one of the best and JJ if an amp runs a hot adjustable bias. Some amps are biased so hot they literally "cook" other 6v6s over time. So JJ made an especially stout one that's almost rated as a 6L6.

My Tweaker is cathode biased so it can run any octal tube. It came with 6v6s and I also tried a pair of EL34s to get it really close to a Marshall tonality. But then the Fender and Vox voicing suffered so I finally settled on NOS US made Tung-Sol 5881s. They're rugged military grade tubes that fit the amps bias almost perfectly and sound great.

Sounds like you're a pretty big fan of JJ tubes then? I mentioned Raytheon because...well, it's a long story and I just thought it was funny seeing their name as a tube manufacturer. I mentioned ElectroHarmonix because that's a name that I recognize as being pretty good around the rest of the guitar worled.

 

[Jim C]

I don't think any of the reissues are as good as any of the older tube stock that tests well.
For a 1 power tube amp, a 60' Telefunken is not going to make that much difference.
The JJ's are what every major manufacturer uses and according to Mesa, it's all about availability, quality control, and warranty issues.

 

[soulman]

Sounds like you're a pretty big fan of JJ tubes then? I mentioned Raytheon because...well, it's a long story and I just thought it was funny seeing their name as a tube manufacturer. I mentioned ElectroHarmonix because that's a name that I recognize as being pretty good around the rest of the guitar worled.

More a fan of Tung-Sols. I've used JJs before too but they've always seemed a little to hard ass and too quick to break up for my style of playing. Tung-Sols just seem more creamy and evenly balanced and compress less when driven hard. But overall JJs are extremely popular with the masses especially their 12x7 and those 6v6s are perfect for amps that run a high plate voltage.

Older Raytheon tubes are good if they test out well and EHX actually owns it's own tube factory in Russia where they also make the Sovtek tubes. Some of it is a matter of taste KD. Around 7-8 years ago or so I had a 5w single ended amp. A Bugera v5. It was great for experimenting with different preamp and power tubes enough so that I could hear some of the subtle differences between them.

But as far as new production goes there a lot of preamp and power tubes to choose from still. You might find this interesting too. It's gives the tonal characteristics of quite a few 12ax7 tubes and rates their gain and noise levels. Higher gain means it will push the power tubes harder for fast break up and noise level is self-explanatory. The lower the better.

https://www.tubesandmore.com/tech-articles/12ax7-comparison-current-made-tubes

 

[soulman]

I don't think any of the reissues are as good as any of the older tube stock that tests well.
For a 1 power tube amp, a 60' Telefunken is not going to make that much difference.
The JJ's are what every major manufacturer uses and according to Mesa, it's all about availability, quality control, and warranty issues.

Ed Zachary. They are not always what a player wants to hear but they are some of the easiest for amp builder to obtain with consistency so they use them and often design with them in mind.

Agree with you on older US made tubes but they're getting very scarce and pricey and as a buyer you do have to be aware of sellers pushing bad tubes with little life left in them. I'm running a 60s RCA Blackplate 5751 in V1 and US made twin Tung-Sol 5881s as power tubes. The amp sounds so much better than it did stock. Even though I got a pretty good deal on those tubes two Blackplates and four 5881s cost me 2/3 as much as the amp head itself did. But I have a back up for all of them now too.

 

[knuckledust3r]

Found a couple of well-reputed sellers on eBay and bought a matched set of 12ax7's (one for each amp - I didn't necessarily need matching, but it was nice to buy a pair....tehehehe, a pair) and a 6v6 that's still in the original box.

 

[Jim C]

What brand tubes?
For all you that swear that a particular brand of tube or vintage is important for all tube amps, I say your full of shit.
Years ago I did a reasonably organized test with 12AX pre-amp tubes in a Mesa Walkabout and an SWR SM400.
The tubes were the following: new Electro Harmonic, Mesa, JJ, Nos Raytheon, Nos Mullard.
Old used tubes that tested well were Telefunken, Amperex from Holland, and an RCA
All tubes tested to specs.

The WA used a pre-amp tube and a driver tube. I probably spent 8 full hours over a few weeks with a notebook and friends stopping by, with me playing the same few riffs over and over. In the end, the Telefunken sounded better as the pre amp tube and the Amperex was the best as the driver tube. The differences were really small but noticeable although I'm not certain it would stand a blind listening test. I am certain that no one including Jesus would hear the difference in a busy rock band mix.

With the SWR? Zilch, nadda, no difference at all. Maybe the Mullard was a little better.
Also tried a few of these in a black face Deluxe Reverb although not all that scientific. The Mullard and Telefunken sounded better than whatever was in V1.

I've had better results in high end studio gear and hi-fi equipment but again, nothing mind blowing.
I started to swap tube in the tube Dynaco tube pre-amps I have but quickly realized that the Dynaco branded tubes were Telefunkens!

Playing solo is where I think the difference occurs.
I think the older European and US tubes (assuming the meet specs) are the most robust and sound slightly better.
YMMV

@NSYMCE and @4strings - In your design and testing over the years, do you find the above to be true?

 

[4strings]

100%. In my all tube preamps the Telefunken was the only tube that stood out.

Except a few really shitty cheap tubes that sounded bad.

 

[knuckledust3r]

What brand tubes?
For all you that swear that a particular brand of tube or vintage is important for all tube amps, I say your full of shit.
Years ago I did a reasonably organized test with 12AX pre-amp tubes in a Mesa Walkabout and an SWR SM400.
The tubes were the following: new Electro Harmonic, Mesa, JJ, Nos Raytheon, Nos Mullard.
Old used tubes that tested well were Telefunken, Amperex from Holland, and an RCA
All tubes tested to specs.

The WA used a pre-amp tube and a driver tube. I probably spent 8 full hours over a few weeks with a notebook and friends stopping by, with me playing the same few riffs over and over. In the end, the Telefunken sounded better as the pre amp tube and the Amperex was the best as the driver tube. The differences were really small but noticeable although I'm not certain it would stand a blind listening test. I am certain that no one including Jesus would hear the difference in a busy rock band mix.

With the SWR? Zilch, nadda, no difference at all. Maybe the Mullard was a little better.
Also tried a few of these in a black face Deluxe Reverb although not all that scientific. The Mullard and Telefunken sounded better than whatever was in V1.

I've had better results in high end studio gear and hi-fi equipment but again, nothing mind blowing.
I started to swap tube in the tube Dynaco tube pre-amps I have but quickly realized that the Dynaco branded tubes were Telefunkens!

Playing solo is where I think the difference occurs.
I think the older European and US tubes (assuming the meet specs) are the most robust and sound slightly better.
YMMV

@NSYMCE and @4strings - In your design and testing over the years, do you find the above to be true?

Raytheon. The eBay sellers had impeccable feedback. The 6v6, as mentioned, is actually NOS and the 12ax7's test as NOS.

 

[4strings]

100%. In my all tube preamps the Telefunken was the only tube that stood out.

Except a few really shitty cheap tubes that sounded bad.

There was one other tube that stood out as exceptionally good sounding- RCA clear top 12an7, where n=x or n=u. I think they were from the 60s. I still have one that I use to this day in my pre, a clear top 12au7 paired with a 12ax7 from Telefunken.

 

[soulman]

The WA used a pre-amp tube and a driver tube. I probably spent 8 full hours over a few weeks with a notebook and friends stopping by, with me playing the same few riffs over and over. In the end, the Telefunken sounded better as the pre amp tube and the Amperex was the best as the driver tube. The differences were really small but noticeable although I'm not certain it would stand a blind listening test. I am certain that no one including Jesus would hear the difference in a busy rock band mix.

I getcha but you weren't doing a blind listening test nor using them in a busy rock band mix when you evaluated those tubes and neither was I when I spend time evaluating the ones I did. Yeah, in many cases the differences were subtle and in others not so subtle somewhat depending on both amp and tubes. I could hear differences that were enough to make me settle on what I use now. Others may have different tastes and want something else.

IME what's in V1 and the V3 phase inverter in my Egnater make a difference. Overall I've found I prefer the Tung-Sol to others I've tried and I made my decisions by listening to what I heard and felt when I was playing. But I've also found some NOS stuff I liked and even if they don't sound all that much different they should hold up better than much of the new production. It someone believes there's no difference that's fine. I do and that's fine too.

 

[NSYMCE]

What brand tubes?
For all you that swear that a particular brand of tube or vintage is important for all tube amps, I say your full of shit.
Years ago I did a reasonably organized test with 12AX pre-amp tubes in a Mesa Walkabout and an SWR SM400.
The tubes were the following: new Electro Harmonic, Mesa, JJ, Nos Raytheon, Nos Mullard.
Old used tubes that tested well were Telefunken, Amperex from Holland, and an RCA
All tubes tested to specs.

The WA used a pre-amp tube and a driver tube. I probably spent 8 full hours over a few weeks with a notebook and friends stopping by, with me playing the same few riffs over and over. In the end, the Telefunken sounded better as the pre amp tube and the Amperex was the best as the driver tube. The differences were really small but noticeable although I'm not certain it would stand a blind listening test. I am certain that no one including Jesus would hear the difference in a busy rock band mix.

With the SWR? Zilch, nadda, no difference at all. Maybe the Mullard was a little better.
Also tried a few of these in a black face Deluxe Reverb although not all that scientific. The Mullard and Telefunken sounded better than whatever was in V1.

I've had better results in high end studio gear and hi-fi equipment but again, nothing mind blowing.
I started to swap tube in the tube Dynaco tube pre-amps I have but quickly realized that the Dynaco branded tubes were Telefunkens!

Playing solo is where I think the difference occurs.
I think the older European and US tubes (assuming the meet specs) are the most robust and sound slightly better.
YMMV

@NSYMCE and @4strings - In your design and testing over the years, do you find the above to be true?

Our friend Andy feels that gear that responds drastically to tube rolling is not ncessarily all that well engineered, and I think I mostly agree with that.

 

[soulman]

Our friend Andy feels that gear that responds drastically to tube rolling is not ncessarily all that well engineered, and I think I mostly agree with that.

I would agree as well but we can probably also agree that there is shit ton of poorly designed and engineered gear out there both for sale and being played. I'm far more on the side of hearing minor nuanced differences than a wow is that ever different kinda deal. IME it's far more about the circuit and overall design of an amp that makes it sound the way it does. Different tubes may "season" it a bit differently but they're not the main dish themselves if that makes sense.

For example; the first time I ran the NOS '60s RCA Blackplate 5751 in V1 of my Egnater I could immediately hear more depth or softer 3D quality in what I was hearing. Would that make any difference at all in a full volime band gig? No, but I won't deny that it was there. That alone didn't make or break the basic voicing of the amp but to my ears it sounded much better for my needs. Another player may not have liked it at all and wanted more hard edged gain or grit.

The one area where I did find tubes made a difference though was in it's Brit setting which emulate a Marshall using EL34s did make a noticeable difference vs the stock 6v6s. But then the opposite tended to be true when using the US and AC voicings which responded better to the 6v6s and much better to the 5881s I eventually wound up using. The amp can use any of those tubes and others too but certain voicings sounded much better with a specific tube type.

 

[NSYMCE]

I would agree as well but we can probably also agree that there is shit ton of poorly designed and engineered gear out there both for sale and being played.

Of course, arguably every FSO ever made for starters, and the vast majority of Gibsons, Rics, etc etc. And of course there's nothing wrong with that at all and we should probably all just play whatever feels good to us and go practice more.

Power tubes are a whole other thing and IMO unless you change the output transfomer whan you swap types you're basically re-engineering the amp, not tube rolling. Same for swapping 12AU7, 12AT7, etc for 12AX7, from my perspective. If you want lower gain in an amp designed for 12AX7 you don't need a 5751 (which I often dig a lot BTW), you need a larger cathode resistor value. A ten cent part or a 25 dollar one, you choose. I won't judge...oh, wait.

 

[soulman]

Of course, arguably every FSO ever made for starters, and the vast majority of Gibsons, Rics, etc etc. And of course there's nothing wrong with that at all and we should probably all just play whatever feels good to us and go practice more.

Power tubes are a whole other thing and IMO unless you change the output transfomer whan you swap types you're basically re-engineering the amp, not tube rolling. Same for swapping 12AU7, 12AT7, etc for 12AX7, from my perspective. If you want lower gain in an amp designed for 12AX7 you don't need a 5751, you need a larger cathode resistor value. A ten cent part or a 25 dollar one, you choose. I won't judge...oh, wait.

Unlike you I'm not qualified to change the cathode resistor itself. That's your game Charley. I have to opt for the tube change. But another question might be if in doing so would that in any way alter is usefulness as a cathode biased amp?

Unfortunately most of the players in this world are also not qualified to re-engineer their amps other than via tube swaps and/or speaker swaps. While the Tweakers output transformer doesn't change the internal design of the circuits for each voicing does and while no one will ever accuse them of being a dead nuts copy of the true voicings it allows it emulates them well enough to satisfy the user.

That said if you want an 18w Marshall buy one or a 22w Fender Blackface Deluxe, or a VOX AC15 because it will never satisfy any true aficionado of those amps. That wasn't it purpose any more than a pedal can get you what a cranked amp can really sound like. Unless it's the "real deal" all else is a compromise of one sort or another.

 

[soulman]

As long as we're doing a deeper dive into amp topology I thought this might be interesting to at least some. Uncle Doug is giving a primer on how Fender and Marshall tone stacks differ from each other primarily through the values of their components even when the basic design of both are quite similar. To me this is far more where voicing resides.