New production 12AX7

[überfuzz]

popoahi - I didn't quite get the thread in you last post... However, if you're concerned by whether a EL34 is a good replacement to a 12AT7 and such you might wanna go with the exact same tube that you found in your amp. Do not try any other.

[Chuck H]

Can you tell me who you get your Chinese 12AX7s from? I've had terrible luck with the batches I've bought - very poor construction, high microphonics and very noisy in general

Huh.?. The Shuguang 12ax7 has been a staple tube for many guitar amp manufacturers at different times for decades. I've always liked the tone of them and had less trouble with microphonics and noise than any of the rusky tubes. I agree with Stan that isolated "opinions" aren't worth much, but this is my experience over some 20+ years of observation. In the last few years I've bought maybe two dozen Shuguang 12ax7's and only one was grossly microphonic, five or six were good candidates for the first stage in high gainers and no noisy ones. Of the various rusky 12ax7's I've bought maybe a dozen. Most were only marginally acceptable for microphonics with two being grossly microphonic. The only non microphonic ones were of the short plate design that are intended to be low in microphonics. But half of those were so noisy as to be completely unusable and are otherwise just not good sounding tubes. Dull with low gain. I try really hard to buy OTHER THAN Chinese only because I'm not a big fan of monopolies. Nothing personal at all. But I make a concession WRT the tubes because I just can't seem to get consistent performance and quality elsewhere. Stan doesn't seem to be a fan of the Shuguang power tubes. Ruby sells primarily Shuguang tubes and offers the best warranty in the resale market. These won't be bulk as far as I know so you pay extra for the Ruby selected tubes. It seems to be working out for many repair techs. Recently for me, of four different sets of el34's only the Ruby selected Shuguang tubes biased up and behaved like el34's. They are also the only ones that didn't fail with 475Vp biased to about 70%. Probably just an isolated coincidence but it's something "I" won't forget. Obviously a large tube amp manufacturer or a tube distributor needs to buy bulk. If this is your game then Stan is the man. Obviously.

[Justin Thomas]

is this true???--EL34 can interchange with a 12AT7,,, KT88 interchange with a 12AX7a,,, and 6550 can interchange with a 7025,,,????????
I havent been able to check to see if the pins or size are the same for all these tube interchangeability.....

got it this info from where I forget, but I had this info written out and just found it so why not just ask???

In one word, NOOOOOOOOOOOOOOOOOOOOOOOOOO!!!

Uberfuzz's advice to stick with the actual tube types is great, and here's why. The EL34, KT88, and 6550 are all 8-pin power tubes. The 6550 & KT88 are roughly equivalent; the EL34 is usually replacement for 6L6s, IF your amp can handle the extra heater current. The 12AX7 and 7025 are 9-pin high-gain twin triode preamp tubes that ARE direct replacements for each other. At one time, there were differences, not so anymore in new production tubes. The 12AT7 is also a 9-pin twin triode preamp tube, but has 30% lower gain. It will "work" in a 12AX7 socket in a pinch, but maybe not as intended. It ideally should have some circuit tweaks.

I wasn't sure if you were aware of any of that, but since no one else mentioned it, I thought I should let you know that info you had is NOT coorrect! Hopefully saving you some trouble in ordering a tube, only to find out that not only is it not exactly right, but won't even fit in the socket! Check some of the online tube vendors, they'll probably have some tube sub charts. Or just ask here! Good luck,

Justin

[popoahi]

popoahi - I didn't quite get the thread in you last post... However, if you're concerned by whether a EL34 is a good replacement to a 12AT7 and such you might wanna go with the exact same tube that you found in your amp. Do not try any other.

I understand..........my line of thought was as long as it doesn't damage my amp I would be curious to see how it would change the sound output???
I might like the new sound using the different tubes???
so you're saying it would damage the circuits in my amp so forget about it???

I forget where I got this info from,,,, I just found where I had written it down in my notebook and thought to ask you all before trying it...
I don't want to risk damaging my amp...

popoahi

[überfuzz]

I understand..........my line of thought was as long as it doesn't damage my amp I would be curious to see how it would change the sound output???
I might like the new sound using the different tubes???
so you're saying it would damage the circuits in my amp so forget about it???

I forget where I got this info from,,,, I just found where I had written it down in my notebook and thought to ask you all before trying it...
I don't want to risk damaging my amp...

popoahi

Well it is kind of out off topic. If you're really curious you should start a thread and ask about it. (If you don't know what you're doing the proper, but maybe boring, answer is don't thinker until you know what you're doing. There are quite interesting swaps you could do. Curious now...) :-)

[popoahi]

aloha,

so it seems you don't like the JJ 6L6 tube so are you a importer of tubes?
can I buy tubes from you 6l6 and 12ax7, at7, 7025?
what are your prices and where do you live so I can estimate shipping?

aloha, popoahi

[überfuzz]

aloha,

so it seems you don't like the JJ 6L6 tube so are you a importer of tubes?
can I buy tubes from you 6l6 and 12ax7, at7, 7025?
what are your prices and where do you live so I can estimate shipping?

aloha, popoahi

No I don't ship tubes, but you'll find vendors on ebay that offer free shipping, world wide. The tubes I got hold their own in a band setting. Not sure what dudes with golden ears might say about these tubes though. I use new production winged =C= 6L6 tubes in the power section and these pre-amp tubes I just mentioned.

[überfuzz]

Verdict: The cheep Chinese tubes I bought on ebay isn't that consistent. When they're in their lifespan they sound fairly good, definitely good enough for live situations. I'd say that, rough estimate, 1 of 4 tubes are not suitable for the studio.

[popoahi]

TWBF tubes

Verdict: The cheep Chinese tubes I bought on ebay isn't that consistent. When they're in their lifespan they sound fairly good, definitely good enough for live situations. I'd say that, rough estimate, 1 of 4 tubes are not suitable for the studio.

so whats the brand name of these tubes???

know how many brands of 6L6 tubes readily available for purchase ,,, and if I just wanted to buy just 1 or 2 sets of them???
I've seen JJ's I think they were called (just named with 2 letters), groove tubes, and a couple of other brands here in honolulu,,,now my mind has gone blank..? wouldn't you know it... I have macintosh 6L6 in my amp now and they make the Fender sound that I like.. I can't tell by looking as to who actually made the tubes for macintosh?
I'll post again when my brain starts working...

what I need is a easy to understand manual on biasing tubes mainly my 6L6's... my amp guy (he was in a rush) said I would need to put put a meter,,,
(what kind of meter?) on the number 3 pin to get the figures to start the process... I don't know which way to count to get to the no#3
pin??? asked how would I get a fat alligator clip on the #3 pin and still have enough length in the pin to have it connected to the electrical current,,as he quickly ran out the door???so no answer???
so I need a book on how to do it.... does fender sell a book on doing these kinds of things???

and I don't like buying electronics like tubes from Ebay,,, but it seems a lot of guy's do buy tubes off Ebay...I like to buy from a store so I can go to them if I get a bad tube...

almost midnite..
thanx and aloha, popoahi

[überfuzz]

popoahi - Dude, it's time you get your hands dirty. Just buy a set of 12AX7s from your local vendor. The difference in tone among tubes is very detailed, not many people can tell the difference.

[Audiotexan]

There's a ton of questions so I'll try to tackle them one at a time. Also, it's strongly evident that you're just "starting out" in the world of tubes... so I'll try to keep things limited.

But bear in mind on the topic in general, *you're dealing with an almost 'dead format' when dealing with tubes*. Meaning we've come a LONG way in technology, and tubes are almost exclusively the domain of musical instrument amps etc -a limited niche market on the grand scale of products (and to a even more limited extent: tube stereo/amplification -a VERY niche and HIGH dollar market) these days.

So with that said, the current choices in tube manufacturers are extremely limited (again, compared to days of old). There are primarily only two sources of *mass produced* tubes: Russia or China. There are sub-markets within both of these, each having varying levels of quality. And there's even some "smaller" manufacturers outside of Russia/China. But those are the only two major sources currently (that I can recall offhand).

I've seen JJ's I think they were called (just named with 2 letters), groove tubes, and a couple of other brands here in honolulu

Groove Tubes and Ruby Tubes are just rebranders/relabelers for the most part. They don't make their own tubes. They are just resellers. They take a manufacturer's (Russian/Chinese) tubes and put them through their tests, or set forth the requirements (performance specs) that they want in the batch being ordered, and then have their names "inked/stamped" on the tube.

I have macintosh 6L6 in my amp now and they make the Fender sound that I like.. I can't tell by looking as to who actually made the tubes for macintosh?

You could learn a bit more on sites like this one: TubeSound » Blog Archive » Who really manufactured your Tube? or even just perusing valve (tube) retailers who try to provide general descriptions of the sound of a given tube such as Watford Valves :: Valves - 6L6 especially those who specialize in vintage or NOS tubes. You can also gain examples of who might have manufactured your tube on those types of sites by comparing the pictures to what you have in hand.

However, once you start learning to identify tubes by their phsyical construction, you're going to find examples (typically exceptions) that break the 'rule' in the above link. Relabelling was as common back in the heyday of tubes (1950s-60s) as it is currently. However there were a TON of manufacturers then. Not so now.

An example of why this was done (in most cases):
Given that there were *MANY* companies manufacturing tubes at the height of tube use (Amperex, Brimar, CBS, Ei, Hitachi, Hytron, GE, Genalex, Ken-Rad, Matsushita, Mullard, Philips, Raytheon, RCA, RFT, Sylvania, Telefunken, Tesla, Tung-Sol, Tungsram, Western Electric just to name some of the top brands)...and even though the base specifications were set at a "standard", there were often variations in the process due to materials/machinery used/available, etc.

So if a designer intended/required the use of a tube with a given set of parameters, once they had sourced a tube that was acceptable, they would order a batch from a given manufacturer, and then have those tubes stamped with their own brand IE: "McIntosh".
[Also, please note the difference as was kindly pointed out earlier: it's "McIntosh" (a stereo company) -not MacIntosh (the computer company IE: Apple) The reason I emphasize this, is because it DOES make a difference in your search results!]

Though, even within the same brand, you might find different STR's (Special Tube Request or Special Tube Requirement depending on whom you talk to.)

EG: Mesa STR-415 (6L6, Sylvania)
Mesa STR-416 (6L6, ECG-Philips)
Mesa STR-420 (6L6, Chinese - Shuguang factory)
Mesa STR-425 (6L6, Sovtek - Reflector factory)
Mesa STR-454 (6L6, =C= - St.Petersburg factory)

what I need is a easy to understand manual on biasing tubes mainly my 6L6's... my amp guy (he was in a rush) said I would need to put put a meter,,,(what kind of meter?) on the number 3 pin to get the figures to start the process... I don't know which way to count to get to the no#3 pin??? asked how would I get a fat alligator clip on the #3 pin and still have enough length in the pin to have it connected to the electrical current,,as he quickly ran out the door???so no answer???

What I'd *strongly* recommend you do, is continue to further your understanding of tubes, and MORE importantly SAFETY precautions, before even considering grabbing a meter and going poking around, much less opening your chassis! You don't have to even have your chassis open to DIE.

*NOTE: THIS IS A WARNING, NOT A SUGGESTION, DO *NOT* DO THIS: if you got over-anxious to learn, without the proper knowledge, and pulled a tube far enough out, then grabbed a multi-meter and started probing around, potentially, you COULD STILL BE INJURED/KILLED if that meter lead slips and you touch the wrong pins/chassis/etc together*

Now, with that said, there are tube biasing kits that are well-suited to the beginning repair-tech/self maintaining types out there. (Regardless of whether you're wanting to simply further your own knowledge/education, or just 'thrifty') I get a feeling of genuine curiosity from you, and I think that's wonderful! But what we're trying to let you know is, make sure you know the risks involved *before* attempting things that definitely involve your safety/health!

so I need a book on how to do it.... does fender sell a book on doing these kinds of things???

Any purchased biasing device will include instructions on how to use it providing that you purchase it from the manufacturer, and not second-hand from a previous owner. If you go the latter route, make sure they're including the original instructions for using the device in the sale!

I'm not endorsing any of these, but just providing links to give examples of what I'm referring to above:
Bias Tester - AMP-HEAD Bias Tester Probe for Vacuum Tube Guitar Amplifier
Antique Electronics -
Bias and Matching Meter, Alessandro | Antique Electronic Supply
Bias King | Antique Electronic Supply

Compu-Bias™ Computerized Tube / Valve Bias Meter

BiasPlug - Tool for Biasing Tube Amplifiers

and I don't like buying electronics like tubes from Ebay,,, but it seems a lot of guy's do buy tubes off Ebay...I like to buy from a store so I can go to them if I get a bad tube...

Unless you're content with current production tubes (again, primarily Russian/Chinese), going to a 'store' to buy a tube is a thing of the past. Sad but true. That's why so many of us rely on secondary sources such as electronic swap meets (think ham/antique radio, etc), or surplus electronics shops (selling used gear/tubes), or eBay.

If all you're concerned with is being able to return a defective tube, then all you have to do is find a local music dealer who sells tubes, and verify their return policy on tubes!

Just realize that those tubes (regardless of brand) are probably coming from one of the two current sources, and will not give you the longevity or performance of an old RCA/Sylvania type that you seem to regard fondly (and with good reason) in your McIntosh labeled tube!
The old saying "They don't make them like they used to" is ENTIRELY appropriate where tubes are concerned.

Regards,
Audiotexan



PS: if I had to use current manufacture ("off-the-shelf") tubes, I'd prefer:

for output tubes (EL34, 6L6, etc)
---------------------------------
=C= (which is referred to as Winged C, or more aptly known as the original Svetlana tube factory in St Petersburg, Russia)
or EH (Electro-Harmonix) tubes.

for preamp tubes (12ax7, 12at7, etc)
------------------------------------
Shuguang (chinese tubes) first choice by far
EH

[überfuzz]

Audiotexan, popoahi - I've actually come to like new production of preamp tubes more and more over the years. That is in guitar amps. The reason for this is that new tubes seem to add that little extra roughness to the tone. Take a set of tubes from the golden age, the frequency response is flatter, the breakup is smoother over the frequency range etc... If you ask me, I'm not looking for tidiness when I strike a chord on my amp. A set of Chinese preamp tubes in my Twin Reverb makes it much more 'dangerous'. The only real drawback is the lifespan which is a far cry from old European tubes.

[überfuzz]

double post...

[Audiotexan]

Audiotexan, popoahi - I've actually come to like new production of preamp tubes more and more over the years. That is in guitar amps. The reason for this is that new tubes seem to add that little extra roughness to the tone. Take a set of tubes from the golden age, the frequency response is flatter, the breakup is smoother over the frequency range etc... If you ask me, I'm not looking for tidiness when I strike a chord on my amp. A set of Chinese preamp tubes in my Twin Reverb makes it much more 'dangerous'. The only real drawback is the lifespan which is a far cry from old European tubes.

There's the key though!

Newer tubes (generally) do a more than acceptable job within newer amps, simply because in most cases, they were designed to accomodate them.

You're not going to play metallica through an old 67 vibrolux, just like that same amp isn't going to like (read as: have a preference for) new tubes.

Totally different style/sound goals.

Now, as to "Take a set of tubes from the golden age, the frequency response is flatter, the breakup is smoother over the frequency range etc..." there was still quite a bit of variance back then (if not more so, because of more manufacturers) in the frequency response/breakup points than what there is now.

IF tolerances/QC was tighter nowadays, you wouldn't have nearly the wide range of "freq. response" that we due, thanks largely in part due to manufacturing inconsistencies. Never mind the lifespan (or lack thereof) of vintage tubes as you mentioned. Though don't make the mistake of just limiting that long-life to just European tubes! There's still plenty of old RCA/Westinghouse/Sylvania/etc still kicking...as well as Japanese, Canadian, etc.

Regards,
A.T.

[überfuzz]

Though don't make the mistake of just limiting that long-life to just European tubes!

I apologize for my Eurocentric post.