Chinese and Russian tubes

[Steve Conner]

Things are the same if they are the same, if they are different they are not the same.

So what about the 5881WXT and the 6P3SE? Are those different, or the same?

I have a pair of blackplate RCA 6L6GCs and a pair of 5881WXTs. I can do some reamping tests where the only thing that changes is the tubes. (Reamping means that the guitar is recorded into a DAW through a clean guitar preamp, and played back through the amp, the output of which is recorded on another DAW track.) Then I can post the two files and challenge you all to tell which is which.

But I guess you will all argue that the results don't count because I used some oddball home-made amp instead of a real Fender, or the 24-bit digital recording somehow corrupted the mojo, etc.

[MWJB]

There will be variation even amongst tubes of the same brand. I have never seen a tube labelled as 6P3SE, I wouldn't be surprised if it was largely the same as the 5881 WXT, but the 5881WXT looks identical to the 6L6EH...but they sound quite different.

Whoa! I never said that I can tell which tube is which, that is a bizarre claim, I only said that there is often a difference between tube brands. Tubes on their own don't make any sound, you need a circuit, instrument & speakers for that & to be familiar with all aspects whilst conducting A/B comparisons. The same tube (not same brand or designation, I mean the same very tube) will sound different in different applications. I won't argue, if they sound the same then they sound the same, but I'll wager you had to make some changes to operating conditions to replicate plate voltage & current?

Whether I agree with Derek Rocco's test reports or not, he is attempting to put the various tube brands in perspective, in real world tests. Take them with a pinch of salt by all means, but if he was just a profiteer it would serve him better to just stock the brand with the highest mark up & say "they all sound the same, anyone who says different is plainly mad & selling snake oil....by the way do you like my new clothes, they are so fine & light that some people think that they're not there at all".

Example: 6G12A '63 came with NOS Sylvania 6L6s, drop them in 40mA per tube. Replace then for 5881WXT (could be a 6P3SE, I don't like to make assumptions) and now we see 7mA per tube. Biasing the 5881WXT to run at 40mA per tube would be no problem, in order to perform a like for like test. However, rebiasing the Sylvanias to 7mA would have required rewiring the bias circuit as a voltage doubler because there simply wasn't enough negative voltage coming off the diode to get that low. My point being, that even if the difference in sound between the tubes was down to different plate current & voltages alone (which personally I doubt, but let's "assume" that it was) that the work involved to achieve this was disproportional in terms of parts & chargeable labour (besides the owner is unlikely to want anything beyond "in keeping" changes to his prized vintage amp - OK you got me it's Fender ;-) but that's moot, the numbers illustrate the issue). The result is different whichever way you look at it, if it's not the same then it's different, "whys & wherefore's" are secondary.

If tube brand (& even variations within brand) make "no difference" what does make "a difference"? If I subbed my 100K plate resistors for 110K would that make a difference? If 10% difference is "no difference" then 100% difference is ten times nothing & still "no difference", same goes for cathode resistors....so if we follow this thought, then as long as a tube receives voltage on the plate, is biased by a cathode resistor & receives a signal on the grid, then we may as well "assume" that it doesn't matter what any of those values are as they make "no difference".

What is the dividing line between "a difference" & "no difference" as long as the amp makes some sort of noise?

Let's assume I want to watch a John Wayne movie, let's say it is "True Grit" (though "The Shootist", or "The Green Berets" works just as well for this test) - now whether I watch it on a 14" portable black & white TV, a 40" flat panel TV, or straight from cine film in a cinema, I can still recognise the actors, still follow the dialogue & the story line - but is there a difference between the images that I see? Now let's replace John Wayne with Jeff Bridges, same story line ...is there still "no difference" if it's still "True Grit".

Hence things are the same, if they are the same. If they are different, then they are not "the same". Yes, we can put perceived differences down to flaws in human perception, but some are better at perceiving than others....a toddler can spot a flat note in nursery rhyme, Chuck Berry & Johnnie Johnson were apparently happy to record out of tune with each other more than once.

How would you fancy your skills as a single malt blender, compared to someone with experience?

If you can't largely trust your senses (we are all susceptible to some degree), then why bother with any of it?

[überfuzz]

I can do some reamping tests where the only thing that changes is the tubes... ...Then I can post the two files and challenge you all to tell which is which.

This was exactly how I got into the tube swamp. My band couldn't record in our studio because of an other band rehearsing next door. We pluged an amp direct into the comp, then later on we 'reamped' it. It was very interesting, we started to try different speakers, tubes etc. And sure, you can tell different, even if they're ever so small.

[Steve Conner]

What is the dividing line between "a difference" & "no difference" as long as the amp makes some sort of noise?

If you can't largely trust your senses (we are all susceptible to some degree), then why bother with any of it?

3dB. If the 5881s had some distortion harmonic that was 3dB different in amplitude to the real 6L6s, then I'd say that was a difference. (Unless the harmonic itself was small enough to start with that psychoacoustic masking would prevent you from hearing it.)

Same reason you watch the John Wayne movie: because fantasy is enjoyable.

[MWJB]

That's not really an answer Steve.

The 5881 are REAL, they fit in the socket, they light up, they make a sound, drop them from the top story of a multi story car park & they'll smash...just like a 6L6.

[Steve Conner]

The John Wayne movie is real too, in the same sense. All of the actors and props actually existed, and you can hold the reel of film in your hands. What's unreal is the rich world of imagery and fantasy inside it. I argue that much of the subjective experience of the sound of tubes is unreal in the same way.

Of course, if you took me to the top of that car park, I would rather drop the Sovtek 5881s than the 6L6s. In the Sylvania example that you gave, tubes that bias up so differently are going to change the effective gain of the power amp. Even if they had exactly the same distortion harmonics (which they won't) then the change in gain would alter the sound of the amp by changing the amount of NFB, hence affecting the speaker's frequency response. The power output of the amp might change too.

I believe the reality of tone is in interactions like these. If you say that a given tube has such and such a tone, that's the fantasy. It's an oversimplification, like how John Wayne can make everything OK by just shooting all the bad guys.

[MWJB]

"I believe the reality of tone is in interactions like these" .Fair enough, I don't disagree. But if a trend in plate current, say like 90% of tubes from brand A run a colder current/higher plate voltage than 90% of brand B....or even 100% of the tubes you have tried (OK limited sample, but typical for your average musician) you can see how perceived attributes from brand to brand might be identified . The "reality" of why becomes less significant.

I have a foot in both camps to some degree, I see a lot of the "same" models of amp & Frequently have "control" & "test" models. If a difference in sound between 2 models is perceived then I'll measure whatever I can to try and determine why...sometimes, when you have measured every volt & milliamp and eliminated as many measurable differences as you can detect, a sonic difference is still detectable in an instant A/B test, if an identifiable characteristic follows tubes of a certain brand, whilst the v's & mA's remain constant, what would anyone conclude?

Alternatively, I all too often hear guys who have spent money on this or that brand of tube & quote a review that they have read on line, installed the tubes & obviously been determined to like them & hear what they are told to hear ,to justify the expense/achieve an illusory degree of comfort.

I recall one guy reading an on-line review to me, on the differences between 2 brands of the "same" amp. He was telling me how true the review was and how it helped him determine the differences between the amps...great, but he actualy owned both versions, had adequate supply of same brand tubes to tube up both amps & the know how to bias both amps identically (save for a plate voltage discrepancy of 5vdc that remained between the 2), enough speakers to equip both amps with the same array - I asked him what the hell did he need a review for, if he couldn't hear a discernable difference between the 2, then there wasn't one. Reality was, when you equipped one amp with preffered speakers &/or tubes, it was the best sounding amp in a direct A/B, the desirable qualities followed the parts, not the amp. The only discernable difference between the 2 amps was the sweep on the volume pots as one had a slower taper (he percieved this as the amp being "underpowered"), otherwise they were as much "the same" as any similar amps I have ever heard...nevertheless he still talks about them as if they have differing characters & MO's, whilst I'm largely at a loss to identify a perceivable difference (or to spend any more time going over minutae to "prove/disprove" otherwise).

If you can measure a difference & hear a diffrence great, some can measure but not hear, some can hear but not measure (let's not leave out the can't hear, can't measure) & at the end of the day, music is appreciated by human senses, yes, you bring a lot to the table with you, but I am reluctant to take as gospel anyone who is firmly entrenched in one camp, or the other (physics v goldenears).

[Pedro Vecino]

Sorry, Steve, but 3db? In what strand of the skein exactly?
How many decibels and where they are located comparing a rosewood with a maple fingerboard in a Telecaster?
The difference between tubes subjected to a dynamic process is not a simple matter of amplitude or frequency linearity. In a guitar amp it´s a matter of timbre (infinitely more complex).
Excuse my poor English.
Regards

[Steve Conner]

Sure, but "timbre" is just a bunch of harmonics each with its own amplitude. These are easily measurable by a FFT.

Timbre - Wikipedia, the free encyclopedia (oddly enough, the first thing you see on this page is a FFT spectrogram)

I argue that any perceivable change in timbre would correspond to a measurable change in a harmonic shown on a FFT. You should be able to look at a FFT of distortion harmonics produced by a tube power amp, and if two sets of tubes give the same result, they will have the same timbre and will sound the same.

Really you should use a sine wave input that ramps up with time over the full expected range of inputs, and plot a spectrogram that shows how the harmonics evolve with increasing drive. The two sets of tubes might have timbres that only differ at some level of drive, so if you only test at some other level, you might miss the difference.

But it turns out easier to just plug a guitar into it and rock out.

[Rhodesplyr]

I generally don't trust tube reviews at all anymore, other than warnings about reliability problems. (JJ can make excellent tubes, but they have sent out some substandard batches over the years.) A particular tube can deliver a certain character in a certain circuit, but that doesn't mean you'll get the same results in a completely different circuit topology. There are times when a specific tube brand gives you a system synergy that you're looking for.

For example, I've read that JJ ECC803-S types are way too microphonic for guitar combo amps. I have a couple of clients who are using them in combo amps because they liked the way they work *in their amps,* and, thus far, knock on wood, no problems with microphonics after months of constant use.

And, sometimes, there's a more radical difference between an old stock 9- or 7-pin tube before and after cleaning the pins than there is between two different tubes.

David

[km6xz]

This is an interesting thread, and it starts to reveal some assumptions about testing and auditioning methods that add more ambiguity than removes. The self tester being the player is the least revealing since the player is in the system feedback loop. When he claims a particular tube brand has a particular tone or unmeasurable quality he is revealing his huckster-ism or ignorance of the process of hearing, or how electronics work. If he left as simply...."I liked the tone I was getting from my rig that just happened to have XYZ tubes in it" I would be content to accept his opinion as not trying to con anyone. But when he said, "XYZ" tubes have a shimmering high end" he is lying or deluded. Either one is not commendable in a person.
It would make the same sense to say this brand of oil paint red has great ripe apple. There are just too many interdependent relationships between any active device such as tubes and its operating environment. Give the gain bandwidth of those tubes are all at least 60Mhz, the chance that a tube alone would have an emphasized mid bump is beyond stupefying.
Considering that most of those tubes with the fancy prices and names came from the same plant, same production date and were just as NOT a EL34 as ever, him hearing so much subjective difference between what started life as being identical items from an assembly line, it further confirms my calling the article total BS.
How many EL34 tube plants are their right now? 4? Yet there are 100 or more brands of EL34's. Even more brands of 5881/6L6 many of which are and have always been 6п3с-е Russian tubes that were never intended to be a 6L6. They were intended to be a general purpose low RF and power tube for TVs, radios and industrial applications that were entirely domestic. Russia was isolated enough for most of its 20th century that it evolved its own alternative universe of technology with its own ICs, tubes, capacitor types, batteries, materials etc. After WWII the Soviet Union and the US were the only self contained countries that made everything they needed in materials, chemicals, electronics, pharmaceuticals etc. There are lots of interesting tubes the tubists from the west have not discovered yet, many with unfamiliar sockets. When guys like Mike Mathews discovered that there were a million of these funny cheap tubes called 6п3с and 6п3с-е that could be put in a socket intended for a 6v6 or 6L6GC respectively, a whole industry developed but not without a bunch of needed misinformation and smoke/mirrors. The tubes were going for 10-15 cents a piece at the time. Now they go for $3 for the 6п3с but go for $20 when a bit of ink is silkscreened onto them. Same happened in China which had its own domestic designs but being so eager to do business, the few companies doing vacuum tubes started modifying them to be more in line with what the wholesale buyers wanted.
The funny thing here is that tubes are very hard to find and when they are found in music stores they are expensive. For example the importer for many brands of MI gear here also buys some New Sensor brands but very little stock. There are no pairs of EL34's for sale in stores in a city with 7,000,000 people and 100,000 musicians. I did a survey last week, called dozens of stores and visited another dozen and found 1 pair of 6L6GC ;labeled Groove Tube for 3100 Rubles, about $110, in a store that had 40 or more different tube guitar amps on the floor...Mesa, Peavey, Fender, Marshall, Ampeg etc. That was the only pair of tubes found. Another 8store had 2 12AX7's and a EL84 but for prices that shocked me so much I forgot what they were. I started the survey initially because I was hunting for a pair of JJ EL34s to replace in a guy's brand new Yerasov Detonator 4 EL34 guitar amp. It just came from the factory with a broken IEC jack and two back outputs.
I even tried Svetlana, the real one, which makes quality tubes, ,mostly high power RF tubes. They did not have any at the factory, besides their wholesale cost or one was more than double the price of any other type. I called New Sensor who would not ship tubes to me because they had dealers in Russia. The idiot on the phone did not know that none of their dealers stocked tubes. I had contacted them all. Ruby tubes, did respond positively but I had known them since Tom started.
So in self defense I got quotes for 100 lots from Russia, for "6L6", "EL84" and China for 100 each for 6550, 12ax7, 6V6, El34 and a smaller quantity of 12AT7s and now just have to come up with a brand name. My GF is Valentina so thinking of her name, or the nick name for Valentina which is Valya as in Valya Valves. I have a tube curve tracer and will design boxes now and automate the plotting of each tube to create a personalized spec sheet and curves in each box. Two days ago, on a Russian language music forum I posted that I would have tubes for about half price and have gotten dozens of emails wanting to order them.
My "6L6GC" is a 6п3с-е and a Chinese version I've been testing. Both look good but different in parameters as expected.
So I am accepting suggestions for the name of the brand;>) I will be different, and promise not to turn every 14 year old into another Hendrix, but they will get a reliable workable tube with a good warranty at 1/2 the price....and be available. These generator power, not tone, tone comes from imagination and playing technique. Both are needed but don't come from the same thing, certainly not tubes.