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I need matched pairs (quads, etc) of a certain tube, but I don't see matched sets of this type listed. Can you supply this?
I need matched (sextets, octets, etc) of a tube but only pairs/quads are listed. How do I order this?
What does "NOS" mean?
What kind of tubes will sound best in my equipment?
Some vendors sell different "grades" of tubes. Why not you?
What about biasing power tubes?
My tubes glow blue when they're on! Is there something the matter?
The filaments on my small tubes flash brightly when I turn my amp on! Is there something the matter?
I've got a Russian made "Red Bear" guitar amp. Which tubes go in this? What are the right numbers?
Some of the tubes & capacitors on your page are really cheap! What gives? Are these reallynew (or new-old stock)?
Some of the tubes on your list are just described as "USA" or "NOS". What are they exactly?
Where are all the monoplate 2A3's, '45's, mesh plate '50's, UX210's, and etched-base 300B's?
Do you have a waiting list for hard to find tubes?
But, don't you have a lot of stuff that's not listed in your catalog?
What's the deal with Amperex, Sylvania, and Philips? What is "Philips ECG", and why is it different than European Philips or Philips Miniwatt?

Q. I need matched pairs (quads, etc) of a certain tube, but I don't see matched sets of this type listed. Can you supply this?

A.To save on web space and page loading time, we only list matched sets on types where people frequently request matching.
Usually, we can do this even if matched sets are not listed, the cost is $1 extra per tube for single section tubes and $2 extra for dual section tubes (Most preamp tubes like 12AX7 and 6922/6DJ8 are dual section tubes).
If you are using our online order system, just order these tubes as singles and email us letting us know which ones you want matched. The matching charge will be added to the total of your order.

If matching isn't available on the type you request, we will let you know when we retrieve your order from the system.

Q.I need matched (sextets, octets, etc) of a tube but only pairs/quads are listed. How do I order this?

A.This is normally available even if not listed. If you are using our online ordering, you can just order the number of tubes you need as singles or as pairs and send us an email indicating in what arrangement how you want them matched.

Matching is included in prices of tubes where they are listed as matched sets (most power tubes like 6550/KT88,EL34,EL84,6L6 and many preamp tubes like 12AX7 & 6922 are like this).

Q.What does "NOS" mean?

A.New Old Stock. Meaning tubes (or other items) that are unused, but not current production.
A lot of tubes types are no longer being made, but because of the enormous number of tubes that have been manufactured over the years (remember, at one time every family owned several pieces of tube, TV, hifi, maybe even a tube garage door there were lots of other things....test gear, car radios, the list goes on & on), there's still large quantities existing of many (not all, some are getting real hard to find) tubes that are no longer being made.

Q.What kind of tubes will sound best in my equipment?

A.Good question.

The best we can do is pass along our own experience, and feedback that we get from OEM's, other dealers, and customers.Most of the time we can come up with some helpful advice & suggestions, but since there are so many different types and brands of tube equipment on the market, we can't possibly test every combination of tubes, amplifiers, and speakers that might turn up. And we'd rather give some semblence of a factual answer backed up by experience (of ourselves or others), than take the easy way out and just tell you what we think you want to hear. We can tell you that if some particular tube really stinks, we just won't bother selling it, since we have a 6 month warranty on tubes, selling items with an excessive failure rate or poor performance makes no sense, and just costs us a lot of money!

Different tube manufacturers do better a making different types of might find out you'll like one brand of 12AX7, a different brand of EL34, and somebody else's 6DJ8... if that's what works best, why not? Some brands of certain tube types will sound better in some amplifiers than others, this is particulary true of guitar amps, but it's true of some hifi amplifiers as well.

We have two other suggestions that may be helpful.

1. Go to, select "Usenet" and do a "Power Search" on your model of equipment, on both the old and new Usenet databases, in the* and if applicable, and alt.guitar.amps & newsgroups.The Audio Asylum bulletin board has a post search function, this is very useful for hifi gear.

Unless you have a very obscure piece, you should find lots of opinions regarding what tubes are best for your gear, ranging from obviously silly to very informative.

Sometimes people's imprsessions show up on their web pages. Try flipping through some of the web pages on our Links Page, or try a search on

2. Post to one or more applicable newsgroups (usually, alt.guitar.amps ) or bulletin boards, asking for opinions.
There's a number of web-based Bulletin Boards, like Postive Feedback, Audiophilia,Vintage Guitar, Ampage and Vox Showroom you can post on...generally they're a bit more civil than Usenet newsgroups, since the owners moderate (read: censor offensive & off-topic postings) them. Links to these pages can be found on our Links Page.

Be sure and give a brief description of your gear, for example: "I have a PAS-3 preamp, Dyna ST70, and Quad ESL speakers, (if yer a geetah pickuh, eg: I have an Ampeg ReverboRocket..) I'd like some opinions on which EL34's would sound best with that setup"

Try to keep it brief, issuing an excessively long post will cause possibly interested parties that are short on time to skip reading it.

On the other hand, if you post too short of a question, like "What EL34's sound the best", you'll likely get either silly responses, or irrelevant ones, for example, someone might relate about how they sound in Marshall guitar amps, which has little relation to an ST70, or vice-versa, while people that have the same equipment as you and could post a topical, useful answer, might write it off as a clueless newbie question, and never post a response.

Lastly, if someone or a number of folks gives you a useful answer, it's good etiquette to post or email a thank you to the folks who answered...not only is this good manners, next time you've got a question, folks who can answer will be much more likely to do so.

Q.Some vendors sell different "grades" of tubes. Why not you?

A. What you'll find out upon closer inspection, is that the different grades of tubes often

(1) aren't the same thing at all, example, grade "C" might be a Russian tube, grade "B" a Polish one, and grade "A" something NOS, in other words, switching around between brands of tubes will have the same effect as buying different "grades", or,

(2) The difference might just be a different label, and a higher price, ie: a simple attempt at a "power of suggestion" sales technique.

I'd add here that "low noise testing" on small signal tubes is of limited value, for starters, generally, noisy tubes, when tested on top notch tube tester, will turn up having other defects as well, and in most cases, once the obvious duds are sifted out, the remainder will test very close (like within 1 dB) in terms of noise. Basically, paying extra for "hand-selected low noise" gets you a tube that meets spec for the type you are buying! We guarantee you'll get this from us, and we don't charge extra for it!

Testing tubes will not make them less noisy, or change what's inside,it can only cull out the bad ones.
This isn't just us saying this, folks who know a lot more about tubes than we do say so. Quoth J.Alfred Davies in Proceedings of the Institute of Radio Engineers (May, 1949) "Quality cannot be inspected into tubes. Quality must be built in." You can read the whole text of Mr. Davies' article on our Mailbag Page.

Also, most noisy tube problems show up after the tubes have been run for quite a while, or if they've been damaged in transit, all the tube testing anyone can do at the point of sale can do, will not eliminate those problems, which is why we have a warranty, just in case!

We do test our tubes, and warranty them, too, so you are not taking any more risk by buying our tubes, than "graded" ones with fancy gold labels!

Some purveyors of guitar amp tubes sort power tubes into "hotter" and "colder" grades. This has limited value in guitar amplifiers that have adjustable grid bias, as the bias-control adjustment can be used to make the tubes run hotter or colder. However, if you're stuck with an amp without a bias adjustment, you certainly can ask us to pick power tubes that run hotter or extra charge for this.

Q.Now that we're on the subject, what about biasing power tubes?

A.Some amplifiers (both guitar & hifi types...some examples are Fender Champ, Vox AC30, Heath W5, EICO ST40) are "cathode biased". With a few exceptions, these amplifiers have no bias adjustment (some hifi amps like the Heath have a balance adjustment, which really could be omitted if matched sets of tubes are used). In these cases, just get a matched set of tubes, plug in & play, unless you've just got one output tube, in which case don't worry about it at all, since there's nothing else to match it to.

Few guitar amps (Ampeg SVT is the main exception) have outboard bias adjustments. This means if you don't know how to do it yourself, you shouldhave an amp tech do it for you. This may sound like an extra unnecessary expense, but if this is an amp you use regularly, having a good amp tech check out your amp every once in a while (like, about how often your power tubes wear out) is an excellent idea, he may spot other things he can fix before they cause problems, which could save you more money &grief than you're spending. Think of it like changing oil on your car...sure, it's a pain, but it beats a blown motor!

Changing the small preamp/driver tubes (like 12AX7, 12AT7, 6DJ8,etc) in your amp or preamp does not require making bias adjustments,only changing the power tubes (ones that drive the 6L6, EL34, 6550, KT88). There's one major exception, the Ampeg SVT, which has a couple of tubes (a pair of either 12AU7 or 12BH7), which do require a rebias if you change them.

Many tube hifi amps have outboard bias adjustments, and in some cases, even meters. Generally the manufacturers' documentation will tell you how to set the bias on these amplifiers.

If you've got more questions on tube biasing and tube amp maintainence, please see our Tube Amp Links Page, which not only links to a lot of pages with information on this (including other Frequently Asked Questions pages), but many pages devoted to certain brands of amplifiers (like Fisher, Scott, EICO, Fender, Ampeg and so forth) that give more detailed information of specific amplifiers than we have space to cover here.

Q. My tubes glow blue when they're on! Is there something the matter?

Usually not. Many large power tubes exhibit some blue glow on the glass, caused by electrons from the cathode flying past the plate (the the large metal structure, aka  anode) and hitting residual phosphorous atoms in the glass (how much depends on how much phosphorous there is). All tubes have a small amount of blue glow in the center caused by loose nonreactive gas ions (the fact is that there's no 100% perfect vacuum, so all do this to some extent) such as argon & helium that won't react with the silver stuff ("getter") that's sprayed inside the tube envelope.
Some tubes, such as 0C3 and '83 are GAS tubes, NOT vacuum tubes, and if they don't glow some pretty color (which color depends on the gas used), there's something the matter.

Internal shorts or over-voltages in an amplifier can cause tubes to arc over internally, if you see bright blue glow in a tube after such an occurrence, it's dead.

For more information on blue glow, please follow this link.

If the blue glow in your amplifier looks like this, you'd better buy a lead suit!

Q. The filaments on my small tubes flash brightly when I turn my amp on! Is there something the matter?

This usually has something to do with the filament construction, small tubes made by certain companies (particularly Mullard, East German & Yugoslavian tubes) commonly exhibit this behavior. So long as the amplifier operates properly otherwise, this is normal.

Q.I've got a Russian made "Red Bear" guitar amp. Which tubes go in this? What are the right numbers?

A.There's a lot of confusion on this, mainly we suspect due to people mis-transliterating the Russian letters on the tubes.People confuse the Russian letter "pi" for an "n", etc.
The Russian name for the large tubes is " 6П3С ". This is just the Russian name for a Sovtek 5881. Other 6L6 types should work as well.
The number for the small tubes is "6Н2П -ЕВ ". The only US tube that could interchange (but normally won't since pin 9 is usually grounded on the socket) is a 6AX7. We have the real Russian item for only $6.95. It is possible to rewire the filament connections to accept 12AX7/ECC83 tubes. See:
We don't know a lot about these amplifiers except for the tubes, some folks have reported being able to shake loose some info from the former importer (Gibson ), others report having no luck asking them.

Q.Some of the tubes & capacitors on your page are really cheap! What gives? Are these really new (or new-old stock)?

A.Unless stated otherwise, yes. The cheap price on the tubes is just a function of our cost (meaning we didn't pay much for it), and supply & demand.. basically, it means there's not much call for them, and we've got loads of them and we didn't pay much for them.
There's a lot of these that homebrewers can put to good use, as many are similar, but pinout different, to more expensive, more widely used tubes.

The capacitors in our Bargain Bin are either items that we have discontinued, or overstock from manufacturers or other distributors. They're all unused (not pulled from equipment), with full (not cut for board insertion) leads, either mylar or polypropylene, no old leaky stuff. These are guaranteed to be as reliable as the other capacitors we sell.

Q. Some of the tubes on your list are just described as "USA" or "NOS". What are they exactly?

A.These are tubes that don't have a lot of demand, and either we've got small quantities of several brands in stock, or there's not many available, so what we've got on hand changes with whatever we can turn up.
To save web page space and time updating it, we've grouped all tubes of that variety under one heading. If you want to know exactly what we've got, please drop us an email or call.

Q. Where are all the monoplate 2A3's, '45's, mesh plate '50's, UX210's, and etched-base 300B's?

A. Mostly in the hands of private collectors, and I suspect Hong Kong and Tokyo dealers. I'd love to have the stuff, I'd have charge such ridiculous prices that people would be accusing us of being a ripoff. Since there's very little available stock of these items (read: wouldn't add much revenue overall), I've elected to pass on dealing in such items unless I can sell them at some semblance of a reasonable price. As it is, there are plenty of nice sounding tube amplifiers that can be made with tubes that are readily available.
These items often turn up for sale on online auctions & Usenet newsgroups.

Q. Do you have a waiting list for hard to find tubes?

A. No. There's a lot of problems with that idea. First, we'd be getting 50 or 100 phone calls a month from people wanting to know if the tube they are looking for has shown up yet. Not only does that eat up a lot of time, (both yours and ours, it'd almost certainly be a better use of your time to search on your own) on many of the more arcane items, one just never knows if and when anything will ever turn up.

Thus we'd answer about 1200 phone calls a year for maybe 5 or 10 sales. In most cases you will do better searching for these items yourself, anyway, just trying to keep a good stock of the more common NOS tubes really doesn't leave much time for us to go searching all over for the rarer items like the monoplate 2A3's and mesh-plate '50s!

Secondly, most of the really rare items are, as stated previously, in the hands of collectors, or dealers operating in markets where really rare tubes command higher prices than in the USA. Those folks cannot be expected to sell their goods for less than market price, thus even when we turn up stuff like mesh-plate '50's, there's no profit for us, and we have to pay for the rent and the beer somehow.

Q.But, don't you have a lot of stuff that's not listed in your catalog?

A.Yes. If an item has very limited demand, or if we don't have sufficient stock to fill lots of orders, it won't be listed. Some items we keep a small stock around just for the convenience of our customers, for example, say, if you called to buy a set of tubes for a Jadis Defy-7, and wanted to retube you Dad's 1950 Zenith clock radio, we'll probably have the tubes for that too.

We keep stock on tubes for certain items people frequently retube that use odd, but not particularly rare tubes, for example Leslie speakers, the aforementioned clock radios, jukeboxes, Ampeg guitar amps, Altec compressors,etc. In some cases, we won't list tubes because we don't want speculators cleaning out our stock, thus inconveniencing regular customers when they just need a tube or two.

Q.What's my amp (preamp, tuner, etc.) worth?

A.As a matter of policy, for your protection & ours, we do not "guesstimate" what other people should be selling their gear for. (Think about it...all we can do is "guesstimate", anyway, and if we guesstimate too high or too low, and you take our advice, you probably ain't gonna be to happy with us!) Prices on old electronic gear vary quite a bit, based on supply, demand, condition, parts availability, publicity the item has recieved on the internet or in the press, and the financial resources of the people doing the buying.
Please try using the "Search" function of Deja News, Remarq or Ebayto get an idea of the general asking prices of the gear you wish to buy or sell.

What's the deal with Amperex, Sylvania, and Philips? What is "Philips ECG", and why is it different than European Philips or Philips Miniwatt?

Man, the answer makes trying to sort out the facts of the Mexican Revolution seem easy.

Here's the history on this. Royal Philips, NV, is a Dutch based company (royal, because they've got a charter from the Dutch monarchy), began as a lightbulb manufacturerin 1891 and later expanded their range to many types of electronic components (tubes in the 1920's), and electrical & electronic consumer products. Being shrewd and profit minded as the Dutch are prone to be, and bearing in mind many of the tricky legalities involved in exports in pre-Common Market Europe, Philips began acquiring tube manufacturers in other countries, and licensing designs to other tube manufacturers in localities where they could not buy into the market (such as Japan). They also licensed tube designs from US tube manufacturers such as Western Electric (yes, they made some WE numbers such as 310A).
Some of the brands owned by Philips were Mullard, Valvo, Mazda, Adzam, Miniwatt and Dario.

Amperex was originally a small industrial tube manufacturer in Long Island, NY. After WW2, Philips acquired this company (which continued to make certain tube types in the USA, including the ubiquitous 6922), and began using them to distribute European made Philips products (including but not limited to tubes, there were also Amperex semiconductors, resistors & whatnot) in the USA.The products sold could've been from the Netherlands (made by Philips themselves), or any of their subsidiary companies, across Europe or elsewhere. So strictly speaking, there's very few tubes that were actually made by Amperex, and these tubes would've been sold in Europe under their home brand names. So what you've got in a 1960's Amperex tube would've really been a Philips Miniwatt if it was marked "Made in Holland", a Valvo if it was made in Germany, and so forth...usually. Philips, like other tube manufacturers, was not adverse to buying in tubes from other tube manufacturers to fill out their distributor product line, so simply being labelled Amperex doesn't mean it was made by Philips or a Philips company.

Sylvania was yet another lightbulb manufacturer that got into the tube (and later, radio) business. In the 1930's they merged with the Hygrade company and adopted Hygrade's logo. Some military tubes made by Sylvania are marked "Hygrade Sylvania Corp.". In 1959, Sylvania merged with AT&T/Bell Telephone's much smaller but feisty rival, General Telephone Corp, to create General Telephone and Electronics (GTE), I would guess because General Telephone was jealous of the big profits AT&T's Western Electric subsidiary was making in manufacturing & licensing electronic components. So, GTE made telephones [Automatic Electric], electronic components [Sylvania] and ran a telephone system [General Telephone], just like AT&T, sort of, albeit on a much smaller scale. Consider that in the 1960's, AT&T was the world's largest and most profitable company, so aping AT&T made plenty of sense at the time.

In the 1970's GTE reorganized Sylvania into several "groups", the Lighting Group, the Consumer Electronics Group, and the Electronic Components Group. Thus , Sylvania tubes began carrying the "Sylvania ECG" logo, ECG meaning Electronic Components Group. Sylvania was a large supplier of all types of replacement electronic components to electronic distributors at the time, including both tubes and transistors.Its successor, Philips ECG, still is.

About 1980, some weird transactions took place. Philips got tired of making tubes in Europe, and its Amperex subsidiary wasn't doing too well, so they sold off their English & Dutch tube making assets and the rights to the Mullard & Amperex brand names to Richardson Electronics of La Fox, IL, and withdrew the license to use the Mullard brand name from International Electronic Components of Long Island, NY.But at almost the same time, in a shrewd move that greatly strengthened their position in electronic components and consumer electronics in the USA, they bought the Electronic Components and Consumer Electronics divisions of Sylvania from GTE, which included the Sylvania tube plant. This plant continued to make the same tubes, but under the new Philips ECG brandname, which doesn't have anything to do with European Philips Miniwatt, or Amperex tubes.Production was discontinued ca. 1987, but Philips continued (and as far as we know still does) to market tubes under the Philips ECG brand name, by outsourcing tubes from current production manufacturers, when stocks of US made tubes were exhausted.

The Amperex & Mullard brand names (as well as TungSol) as noted above are trademarks owned by Richardson Electronics, Ltd, which continues to market tubes under the Amperex brand name. The larger & more expensive industrial Amperex tubes are indeed made by Richardson, but the smaller tubes (like what you'd use in a usual hifi or guitar amp) are not, they're either US military surplus (usually, Philips ECG) or current production sources such as Svetlana or Tesla-JJ. New Sensor Corp is marketing new reproductions of Mullard & TungSol tubes, we don't know whether they own the names or merely licensing their use from Richardson.

GTE retained ownership of the Sylvania Lighting Group, which it sold to Osram GMBH in 1993. Sylvania Osram is now a division of Siemens.

A brief history of Philips can be found on this page, and a history of Sylvania can be found on this page.