Valves

[Dubs]

I have a few ‘noobish’ type questions about valves, but I’m sure others are wondering similar things:


What is it about valves that make them sound different? - from a manufacturing perspective that is. I’m probably talking more specifically about pre amp valves such as the 12AX7/ECC83s rather than power valves, but I’d be interested to hear how this relates to power valves as well.

Why does one 12AX7 sound different to another?
Also, what do the numbers mean after them – such as “12AX7 WA” or “12AX7A” or “12AX7M” or “12AX7-R” etc…

Why are some £7 when others of the same spec (by “spec” I mean model number – 12AX7 etc) are edging on for 30 quid each?

Do the more expensive valves sound fundamentally ‘better’ or is it just that they’ve been manufactured to a higher standard so their life span and reliability is improved…or what? – Obviously the quality of the sound is subjective though, but in general do more expensive valves sound ‘better’? And going on from this, is there a case that people might believe that a more expensive valve sounds nicer when in fact it’s pretty damn similar to a cheap one? - Could you clearly hear the difference between a cheap valve and an expensive valve in an amp with a tiny bit of pre amp valve drive? Could you do the Pepsi Challenge on that sh*t?


That might be it for now…my main questions are to do with the differences in sound from different manufacturers. I’ve probably made myself look like a right amateur when it comes to valves, but if you don’t know then you don’t know, innit.

Thanks

[Dubs]

Does no one know? Or does the question have a really obvious answer? Or…have I posted this in the wrong section?

[jmesa]

All I know is I just spent £200 on the f**kin things !

[Dubs]

[quote name='jmesa' post='262785' date='Aug 14 2008, 10:35 PM']All I know is I just spent £200 on the f**kin things ![/quote]

yeah re-valving can be properly expensive for valve amps, i know that much.

Does anyone have [i]any[/i] insight into the reasons why valves sound different?...or any of the other questions?

[SS73]

Here's just a few random points on Valves.
Companys that made valves would have had different spec's, quality control, components made to higher standards and better machines, etc etc, so many differences were inc in each make, ie, thicker or thinner glass, welded internals or crimped internals, this all was reflected in the price, you get what you pay for.
Not sure about the numbers, but diff Companys have their killer valve model, GEC KT88 for example was the best KT88. Or Mullard's ECC83 they all set the standard.

Try some old english valves in your pre amp, if they are replacing chinese ones you will hear a difference.

I have just paid £200 for 8 General Electric 6550 power valves, but this make is the only one to go in an SVT.

Hope this helps, Sean.


[quote name='benwhiteuk' post='263240' date='Aug 15 2008, 04:56 PM'] yeah re-valving can be properly expensive for valve amps, i know that much.

Does anyone have [i]any[/i] insight into the reasons why valves sound different?...or any of the other questions?[/quote]

[Zerofret]

An interesting and controversial topic! Getting down to the nitty gritty though - Some of the differences are real and some are just not there and people are willing to jump on the bandwagon of this 'old is best' thing. If you can buy new old stock Mullard EL34, ECC83 and GZ34s or GEC KT88, Sylvania 6550 etc etc then that's fine but to pay the silly premium people want for old valves is plain barmy. In the 60s and 70s I dealt with more valves than I can remember and occassionally even a good brand would fail prematurely or be faulty from new; matching was virtually unheard of as most amp designs where made with valve availability in mind. I regularly run amps with all manner of the latest Russian or Chinese valves and they sound great. In the early 1990s some really bad valves came over from China and ever since then there has been a distrust in Chinese valves. We have to get over it as there are some great valves being made in China. One of the most overlooked problems is the spec of new valves being different to the originals - this doesn't make them bad but it is a real problem when trying to make like for like comparisons. A lot of the new makers rationalise their production, so the internal build of a valve could be quite a bit different to the originals and the specification will be different. An ECC83 (12AX7) can have a lesser or greater gain characteristic or even linearity than an original type. This can change the sound but the difference is not necessarilly an inferior sound, just different and can be subjectively better or worse. In the case of a guitar amp, where Hi-Fi is definitely not a consideration, this is rarely a problem. Output valves in a cathode biased amp are less of a problem from a compatibility point of view and using different manufacturers valves will generally produce similar results but you do have to watch the nomenclature - A 6L6 will not always be a suitable replacement where a 6L6GC has been specified for instance - Over the years some manufacturers have taken a valve type and upped its specification which means an original type would now be unsuitable. In a grid biased design, the bias setting is critical and needs adjustment every time output valves are changed - if not the valves can have shorter lives, have a harsher sound, or the opposite depending on their characteristic.

I'll stop before I really get going!!

Steve

[Dubs]

Thanks Steve. Very interesting and informative stuff; It seems crazy that the spec of certain valves has changed over the years which is effectively making them incompatible with some amps, but I guess that improvements in manufacturing technology and a better understanding of the physics of the valves has probably lead to it?

So there is definitely a case for the more expensive and vintage valves to sound noticeably different to cheaper newer valves, but they’re not fundamentally ‘better’ or ‘worse’, just subjectively different?

Are there valves that you think sound cheap and nasty, or ones that you just don’t like or wouldn’t use? – again, I’m talking more specifically about the ECC83/12AX7 pre valves.

[Musky]

[quote name='benwhiteuk' post='263868' date='Aug 17 2008, 11:05 AM']Are there valves that you think sound cheap and nasty, or ones that you just don’t like or wouldn’t use? – again, I’m talking more specifically about the ECC83/12AX7 pre valves.[/quote]

[url="http://basschat.co.uk/index.php?showtopic=42"]This thread[/url] used to be a sticky and is very useful for pre-amp valves.

Brycie and Oxblood were a wealth of information on all things valve, but sadly they're not about anymore.

Though DHA is still about

[Zerofret]

Probably the most common ECC83 out there is by JJ Tesla - these are made in the Slovak Republic and the old Tesla factory has been making valves for a long time. Good value at around £8 and work well and are very reliable in my experience. they even got a 'Great Gear' award from Better Guitar. Look at the review here:
[url="http://www.betterguitar.com/equipment/other_gear/eurotubes/jjel84.html"]http://www.betterguitar.com/equipment/othe...bes/jjel84.html[/url]

Cheers
Steve


[quote name='benwhiteuk' post='263868' date='Aug 17 2008, 11:05 AM']Thanks Steve. Very interesting and informative stuff; It seems crazy that the spec of certain valves has changed over the years which is effectively making them incompatible with some amps, but I guess that improvements in manufacturing technology and a better understanding of the physics of the valves has probably lead to it?

So there is definitely a case for the more expensive and vintage valves to sound noticeably different to cheaper newer valves, but they’re not fundamentally ‘better’ or ‘worse’, just subjectively different?

Are there valves that you think sound cheap and nasty, or ones that you just don’t like or wouldn’t use? – again, I’m talking more specifically about the ECC83/12AX7 pre valves.[/quote]

[ped]

What Zerofret doesn't know about valves isn't worth knowing!

[escholl]

[quote name='Zerofret' post='264218' date='Aug 17 2008, 10:13 PM']Probably the most common ECC83 out there is by JJ Tesla - these are made in the Slovak Republic and the old Tesla factory has been making valves for a long time. Good value at around £8 and work well and are very reliable in my experience. they even got a 'Great Gear' award from Better Guitar. Look at the review here:
[url="http://www.betterguitar.com/equipment/other_gear/eurotubes/jjel84.html"]http://www.betterguitar.com/equipment/othe...bes/jjel84.html[/url]

Cheers
Steve[/quote]


+1 -- i've got some of these in a compressor, good value.

[jensenmann]

To expand what Steve said a little bit:
If one person tests a Brand XYZ in a certain circuit it might sound superior to Brand ZYX. In another circuit it might be exactly the opposite.
If you take one batch of these XYZ tubes and put them into the same circuit each tube will sound different. Even the best brand tubes will have a bunch of sh*tty tubes amongst them, even worse, some are crapping out very early. That´s how it has been since the beginning and it will never change. This has to do with the manufacturing process and quality control. There are one thing to consider when putting a tube in a circuit: checking if it´s microphonic (spell?). But that´s it. Turn your amp on and snip with a finger (not touching anything except the glass of the tube - otherwise you might regret it or your family might regret it) against the tube. If you hear a ringing sound it´s bad. You will always hear something but the better the tube the shorter the sound is. Do it with a few tubes and you will get an idea of what good and bad is.

Since I´m building tubegear I did quite a lot of listening tests: brands, types, series, old/new, whatever. But what I do is proaudio studiogear where quality is highly required. For this application I found a way (my way) how to deal with it. In a bass- or guitaramp where distortion is wanted I personally give a flying f*** on the tubes. Put them in and turn it up. If it sounds right it is right. If you have to complain about the sound swap tubes or better use a different amp because the circuit itself adds way more to the sound than one particular tube.
If you think this particular tube is essentially important to your basssound then you´d better not play in a band where other musicians disturb your perfect sound perception. But that´s just my humble opinion. YMMV