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> Difference between 6DJ8 / 6922 / 7308
- The 6922 is designed to handle higher power than the 6DJ8, and for longer life. Otherwise, they're the same. A 6922 will work in a 6DJ8 circuit. The converse is not always true, as a circuit that pushes a 6922 hard may overload a 6DJ8. Usually they are interchangeable.
- In order of longevity and toughness of the tubes the order goes like this: 6DJ8 - 6922 - 7308. I think it is something like 2500 hour longevity for the 6dj8; 5000 for the 6922 and about 10000 for the 7308.
Other than that they are the same exact design and pinout. The higher the longevity the more the tube can handle voltage wise, so replacing a circuit specifically designed for a 7308 tube with a 6dj8 will DRAMATICALLY reduce your tube life. You might only get a few hundred hours out of your 6dj8 in this case for example.
- these were the best sounding tubes of the entire 6dj8/6922/7308 family. I bought two pairs of early 60's tubes, the ones with the dull grey all around the middle section, and thought that they were absolutely incredible sounding tubes. A little dry sounding, but very detailed and nice. I had mine cryo treated and that gave them a little longer life and a slightly different sound. (In a good way different.)
- If you go to Audio Asylum to the FAQ section and look under Joe's Tube Lore, http://www.audioasylum.com/scripts/d...oes-tubes.html you will find a good bit of information regarding these as well as other small signal tubes. Also Vacuum Tube Valley http://www.vacuumtube.com/ publishes a magazine and under back issues you can order Issue 7 from Spring/Summer 1977. The lead article is "The 6DJ8 and other Frame Grid Tubes" which also gives you a good overview of what was made and the differences between the different tube types. ServinginEcuador summed it up well though in terms of the evolution. The latter tubes (7308) were made to be more durable than the earlier versions.
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> 6DJ8 / ECC88 / 6922/ 7308 Tube List
- 6DJ8 / ECC88 is the "standard grade" of this family. They normally have steel pins.
- 6922 / E88CC is a "premium grade" version of the 6DJ8. Most have gold plated pins, but many Sylvania manufactured 6922's have steel pins (a few Sylvania's are gold pin).
- 7308 / E188CC is "generally the highest quality tube" in the 6DJ8/ECC88 family. Most have gold pins. Sylvania's are steel pin. They are designed with low microphonics and low noise. Sections are usually pretty closely matched.
- 7DJ8 / PCC88 These are "7 volt filaments" which were designed to be used in series string circuits. However, they work well in standard 6DJ8 circuits and can generally be used as direct substitutes. You can some some money using these.
- CCa This is a "special version of the 6922 / E88CC" which is usually only found as Siemens or Telefunken. These are very rare tubes and usually not in stock. But as for everything else, call or email to make sure.
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> 6DJ8 / 6922 / 7308 / Cca
6DJ8 :
This is the standard incarnation of this tube. It was made both in the USA and in Western Europe. GE and Sylvania both made USA versions, and are fairly good quality. The GE tubes have an RF shield sprayed on inside the glass, making the inside look dark. This is NOT an indication of a burned out or used tube. RCA tubes were often made by either Mullard or Amperex in Britain or Holland. The most popular NOS vintage tubes are those made by Telefunken, Amperex, Siemens or Mullard, and are usually also labelled ECC88. See the next paragraph for this description.
ECC88 :
This is the European designation for the 6DJ8 type tube. It is the same tube as a 6DJ8 and often the tube has both type numbers on it. The popular vintage tubes here are those by Telefunken, Amperex, or Mullard. The Telefunken are said to sound the best, and are the most difficult to find of all of these brands. All Telefunken tubes have a tiny diamond shape molded into the glass on the bottom, and have a very chalky ink on the surface which often is partially wiped off. Beware! These tubes are being reproduced in China, and look like the real thing, complete with diamond mark. The tipoff is the label: the fake labels will not wipe off.
The Amperex can be found with a white label and the treble clef logo (rare), the Bugle Boy cartoon tube logo, Amperex in white ink, and the orange world logo. The orange world logo is the newest, and can be found in both standard "L" bracket top getter, and the rarer (and said to sound better) "A" frame top getter. The A-frame looks like a little metal "A" holding up the getter element on the top of the tube internal structure. I have also seen the A frame getter on some Mullard and Genalex (G.E.C.) tubes. The Bugle Boy is the most popular, almost to being a "designer" label, which has driven the price up and supplies down. See note below about Bugle Boy 6DJ8 tubes. I believe any of the Amperex / Philips Holland 1960s and 1970s 6DJ8 tubes are excellent, no matter which one you use. The tubes made with the plain white label (Amperex, DuMont, Hewlett-Packard, Beckman and others but all labelled "Holland") were made in the same factory as the Bugle Boy tubes and sound the same, but are often bargain priced due to low demand. Beware! The Bugle Boy tubes are being reproduced today! The box of the new tubes is even an identical green-and-yellow like the original, but it says "Bugle Boy" on it, and some even show the cartoon tube on the box. Original Amperex tubes NEVER had the words "Bugle Boy", or the cartoon tube, on the box. The Bugle Boy moniker is a slang name that audiophiles coined for the the little cartoon tube on the tube's label. The new tubes have fooled even some seasoned audiophiles! These are junky Chinese made tubes with the old label. The company vending them says they have the original burn-in racks from the old Holland factory. Big deal!! The old burn-in racks are not going to help a crappy tube. Stick with the vintage tubes while you still can!
Mullard 6DJ8 tubes are excellent as well, but are more difficult to find. They often made 6DJ8 tubes for other labels, like RCA, Zenith, and other USA brands. They have several seams molded into the top of the tube.
6922 :
This is one of two premium versions of the 6DJ8 tube. First of all, it is the same tube as the 6DJ8, and will work wherever a 6DJ8 is needed. It has premium features such as low noise, low microphonics, and usually a longer lifespan. Sylvania made a version that is JAN military spec without gold pins. Amperex made all of theirs with gold plated pins and most have the PQ shield logo, standing for Premium Quality. See note below about Amperex 6922 and Bugle Boy tubes. Some of the later gold pin Amperex have the orange world logo. I have seen both orange and white PQ logos. Some of the early versions also have a number etched into the glass, like the 7308 tubes. These were also made for other manufacturers, and will have that makers name labelled in white, but these are the same gold pin tubes. Amperex opened a factory in New York to make these for the US military (since the government contract specified only USA constructed products) and cranked these and 7308 tubes out. A "made in U.S.A." Amperex tube is not a fake! In fact, these tubes are really excellent. A few were made in Holland for non-military industrial use, but these are rare. Also rare are the "pinched waist" versions of this tube. This is actually a molding flaw which made the glass bottom slightly fatter around the outside than the rest of the tube, and the center of the tube actually dips inward and touches the metal elements inside. Clients report these are incredible sounding tubes, and the upward spiral of prices for the rare pinch waist types seem to bear this out. Finally, Philips (the parent company of Amperex) owned a number of tube brands, and many were never seen outside of Europe. Most were actually made in the same Heerlen, Holland factory that turned out the Bugleboy 6DJ8 and PQ 6922 Amperex. Watch for tubes labeled E88CC with brands like Valvo, R/T, RTC, Miniwatt, Dario, Philips, and Adzam. These tubes are identical to the Amperex PQ and Philips SQ (Special Quality) types more often found in America, and are perfect if the Amperex is not available. Also rare in America are these same brands made at the Philips-owned Mazda factory (La Radiotechnique) in Suresnes, France. These usually have a capital "F" in the second line of the date code. They are sweet like the Holland tubes, with a bit better detail and punch at the top end, and still have nice balanced warmth. We are one of the very few worldwide tube dealers to offer these rare NOS French Philips tubes.
RCA 6922 tubes were made by Siemens in Germany, and also have gold pins. These are great tubes, but are not as plentiful. Since the military and some large industries (Tektronix) bought the Amperex made tubes in huge batches, that is what is on the surplus market today.
E88CC and E88CC/01 :
This is the European equivalent to the 6922, and is a quality step up from the standard 6DJ8 or 7DJ8. Telefunken made a fantastic version of this tube, complete with gold pins. Other vintage brands are available, but Telefunken, Philips, Siemens and Mullard are all I have ever seen in several years of tube hunting. Virtually all European brands have gold pins. Most are factory screened for tight internal matching and low noise. The E88CC/01 type (I have only seen these in Mullard brand) has even more factory testing. It is rather like a Cca type tube, with essentially military specs. It's the same as the CV2493, some have both types on the label. The /01 type is rare and worth seeking out if you like the warm British sound. There are some types out there, like "Golden Dragon" just to name one, but these are recent manufacture Chinese tubes, and can't hold a candle to the quality of the Telefunken or even any of the vintage 6922 types. There are also some nice USA made military and industrial types available with either gold or standard pins, and even these sound better than the current production tubes, and are usually priced the same or less.
CV2493 :
A rare military version of the E88CC/01. Some have both types on the label, some only the CV2493. This can be considered the British or Dutch version of the German Cca. Very low noise, carefully matched triodes, and these are batch tested to meet military specs. Usually only available in the Mullard brand, I have seen some with the Amperex Heerlen, Holland factory codes on them, even though they have the Mullard label. Scarce in the USA, and not found in the later Yugoslavian versions like the more common CV2492. It is possible only the UK and Holland made these tubes and were discontinued by the mid 1970s. Probably one of the best choices for tube microphones and mic preamps, or any other high gain, low noise use.
CV2492 :
This is a European military (usually British) version of the 6922 / E88CC type vacuum tube. Unlike the US military version, these tubes were never made in the USA. Most of the older examples were made in either the Mullard Mitcham, UK factory, or the Philips/Amperex Heerlen, Holland factory. These are fine tubes that have passed various demanding military specification tests regarding ruggedness, heat and shock resistence, and heater life. Like their civilian/industrial counterparts, they have the four molded seams on the top, heavily plated gold pins, a halo top getter with a splatter shield below it (with slight raised indentations at the 3 and 9 o'clock positions on the shield), and the standard Mullard/Philips factory date codes printed near the bottom of the glass side. Care must be taken, however, when buying these tubes if they are merely identified as "CV2492" tubes. These tubes were made well into the 1980s, and later examples are not as valuable or as desirable as the earlier varieties. Later versions were made in the former Yugoslavia and then in Russia. The Yugoslavia versions can be spotted by their lack of gold pins, and the halo getter mounted low, almost touching the splatter shield. The Russian versions are even easier to spot, as they have a fatter glass bottle, a top mounted cup shaped getter, no top mold seams, and sharp pointed pins which may or may not be gold plated. These are not bad tubes, but should only be worth one half to one fourth of what the UK or Holland made tubes are retailing for. Give the CV2492 a try, the older versions are sweet sounding and long-lived, and are a step up from the garden-variety 6922 / E88CC, and prices are generally a little lower.
E188CC :
A bit rarer than the E88CC, the E188CC is usually found labelled as such by Siemens or Telefunken. Amperex and other makers (Sylvania for example) used the industrial 7308 marking, Amperex Holland and France used the E188CC label. It is basically the European equivalent to the 7308. The E188CC has gold pins, and is near the top of the 6DJ8 food chain. The Siemens version from the 1960s is quite rare, and is rated by many audiophiles as a jewel on par with the best Cca tubes, or the cryo-treated 7308s. It has low noise to the vanishing point, and a wonderful, airy top end and soundstage. This early version Siemens has a small halo top getter, and is labelled E188CC in white ink. Versions made in the Philips Holland plant are similar, and have the SQ logo. If you find some, grab 'em while you still can! Finally, Philips (the parent company of Amperex) owned a number of tube brands, and many were never seen outside of Europe. Most were actually made in the same Heerlen, Holland factory that turned out the Bugleboy 6DJ8 and PQ 6922 Amperex. Watch for tubes labeled E188CC with brands like Valvo, R/T, RTC, Miniwatt, Dario, Philips, and Adzam. These tubes are identical to the Amperex PQ and Philips SQ (Special Quality) types more often found in America, and are perfect if the Amperex label is not available. Also rare in America are these same brands made at the Philips-owned Mazda factory (La Radiotechnique) in Suresnes, France. These usually have a capital "F" in the second line of the date code. They are sweet like the Holland tubes, with a bit better detail and punch at the top end, and still have nice balanced warmth. We are one of very few worldwide tube dealers to offer these rare NOS French Philips tubes. Finally, watch for Siemens or Telefunken German made E188CC/7308 tubes, most having the E188CC label in white, with the Telefunken having the distinctive diamond shape in the bottom glass. Siemens are usually more plentiful, and a huge savings over their Cca tubes.
7308 :
This is probably the ultra 6DJ8 type tube commonly available. It has all of the features of the 6922, but the triode sections are also matched to each other, and the tubes all fit within very tight specifications. Therefore, any 7308 should match any other 7308 within the same brand. The Amperex versions were again made in New York, complete with gold pins, and often have a number etched into the side of the glass. Amperex made these for industry as well as the military. The Amperex versions have the PQ label, the military type usually is labeled "USN-CEP", but I have seen versions made for Stromberg-Carlson and Hewlett-Packard, with white ink labels. These all had the numbers etched into the glass, and all are the same tube. The USA made military white label types have been rated "Best of All", over other 7308, 6922 and even Cca tubes, in several well-documented 6922/7308/Cca listening tests. Therefore this particular type is becoming scarce and prices are rising. There were a few of these made in Holland, but most were made in the USA, therefore the Holland tubes are RARE and usually command a higher price. The Holland PQ versions have the PQ with stars on either side of the letters, and the words "Premium Quality", where the USA types have the PQ inside of a shield logo. Again, there are some nice vintage USA made standard pin military and industrial types available from Raytheon and Sylvania, just to name a few, and these are quite good at a price currently far below the European vintage labels. Finally, Philips (the parent company of Amperex) owned a number of tube brands, and many were never seen outside of Europe. Most were actually made in the same Heerlen, Holland factory that turned out the Bugleboy 6DJ8 and PQ 6922 Amperex. Watch for tubes labeled E188CC with brands like Valvo, R/T, RTC, Miniwatt, Dario, Philips, and Adzam. These tubes are identical to the Amperex PQ and Philips SQ (Special Quality) types more often found in America, and are perfect if the Amperex label is not available. Also rare in America are these same brands made at the Philips-owned Mazda factory (La Radiotechnique) in Suresnes, France. These usually have a capital "F" in the second line of the date code. They are sweet like the Holland tubes, with a bit better detail and punch at the top end, and still have nice balanced warmth. We are one of the very few worldwide tube dealers to offer these rare NOS French Philips tubes. Finally, watch for Siemens or Telefunken German made 7308 tubes, most having the E188CC label in white, with the Telefunken having the distinctive diamond shape in the bottom glass. Siemens are usually more plentiful, and a huge savings over their Cca tubes.
E288CC :
This unusual tube is basically a 7308 / E188CC in a slightly taller bottle. The filament current draw is also slightly higher but for most applications it is plug and play compatible with the 6922, 7308, Cca, or even the 6DJ8. Physical space is a consideration, since the tube is about one-half inch taller than the rest of the tubes on this page. It features gold pins, factory screened triodes for low noise, 10,000 heater life, and all the other great features that make the 7308 and the Cca such high-demand tubes. Since it is a relative unknown, the prices are about the same as good 6922 tubes, and far below that of most 7308 or Cca types! I have only seen this tube in Valvo, Telefunken, or Siemens brands. Worth giving a try if you want the best but cannot afford the soaring costs of NOS 7308 or Cca tubes.
Cca :
Whew, these babies are so scarce there isn't even much info out there about them! Mentioned by audiophiles, usually in a reverent whisper, these gold pinned gems are about as good is it gets in 6DJ8-land. Matched triode sections, low noise screening, 10,000 hr. heater life expectancy, carefully controlled frame grid winding, low microphonics......the list goes on and on. This is regarded as one of the most detailed and three-dimensional sounding tube ever made in this family of tubes. Most of what is available is Siemens or Telefunken made, although there are a few very rare examples of Philips or Amperex Holland made out there. Since this was a tube made specifically for the German goverment and military, all that I have seen carry a German brand label, even those made in Holland. Even rarer are the Holland made Cca tubes with the pinched waist indented glass midsections, said to be the most sonically "3D" tube ever made, of any type. Finding these is akin to finding a 1795 gold piece in your attic! I don't believe there were any of these Cca tubes made in the USA. Awesome audiophile tubes!
6H23 :
This is a Russian made equivalent to the 6922 or E88CC, but will work in place of any 7308 or 6DJ8 type as well. Ordinarily the Russian tubes are just not of a high enough quality to go head-to-head with NOS German, Dutch, or UK tubes. These are a possible exception. The so-called "rocket logo" type from the 1970s and early 1980s seems to hold it's own against NOS tubes costing 3-4 times as much. These NOS Russian rockets have been critically acclaimed in several online discussion boards for their detail and smoothness. At current prices, these are about one-third to one-fourth the cost of NOS Western Europe types, and so their value is enhanced even more.
7DJ8 / PCC88 :
This is an unusual tube that must have had a limited range of specific uses. It is virtually identical to the 6DJ8 except for the heater rating, which is 7 volts. I have seen Siemens, Valvo, Telefunken, Philips, Ultron and Matsushita (Japan) brands of this tube. It probably makes a good sub for the 6DJ8 and may last longer due to the higher voltage heater. Some are labelled with only the "PCC88" and others have both types listed on the label. All seem to be good quality. The Japanese factory was set up by Mullard, and these tubes even flash orange at the bottom of the filaments when first energized, like most European triodes do. Most of the European types were made at the Munich Siemens factory, the Hamburg Valvo factory, the Heerlen Holland Amperex Factory, or the Blackburn, UK Mullard factory. These sound just like the best 6DJ8 tubes, the German tubes being mostly neutral, and the Dutch and British tubes having a touch of midrange warmth. Watch for the very rare D-getter types and even rarer pinch waist types, often at bargain prices (compared to 6922 types in these categories) when you can find them. You may want to try a 7DJ8 for the longer heater life in a 6.3 volt circuit, and the lower price!
- The 6922 is designed to handle higher power than the 6DJ8, and for longer life. Otherwise, they're the same. A 6922 will work in a 6DJ8 circuit. The converse is not always true, as a circuit that pushes a 6922 hard may overload a 6DJ8. Usually they are interchangeable.
- In order of longevity and toughness of the tubes the order goes like this: 6DJ8 - 6922 - 7308. I think it is something like 2500 hour longevity for the 6dj8; 5000 for the 6922 and about 10000 for the 7308.
Other than that they are the same exact design and pinout. The higher the longevity the more the tube can handle voltage wise, so replacing a circuit specifically designed for a 7308 tube with a 6dj8 will DRAMATICALLY reduce your tube life. You might only get a few hundred hours out of your 6dj8 in this case for example.
- these were the best sounding tubes of the entire 6dj8/6922/7308 family. I bought two pairs of early 60's tubes, the ones with the dull grey all around the middle section, and thought that they were absolutely incredible sounding tubes. A little dry sounding, but very detailed and nice. I had mine cryo treated and that gave them a little longer life and a slightly different sound. (In a good way different.)
- If you go to Audio Asylum to the FAQ section and look under Joe's Tube Lore, http://www.audioasylum.com/scripts/d...oes-tubes.html you will find a good bit of information regarding these as well as other small signal tubes. Also Vacuum Tube Valley http://www.vacuumtube.com/ publishes a magazine and under back issues you can order Issue 7 from Spring/Summer 1977. The lead article is "The 6DJ8 and other Frame Grid Tubes" which also gives you a good overview of what was made and the differences between the different tube types. ServinginEcuador summed it up well though in terms of the evolution. The latter tubes (7308) were made to be more durable than the earlier versions.
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> 6DJ8 / ECC88 / 6922/ 7308 Tube List
- 6DJ8 / ECC88 is the "standard grade" of this family. They normally have steel pins.
- 6922 / E88CC is a "premium grade" version of the 6DJ8. Most have gold plated pins, but many Sylvania manufactured 6922's have steel pins (a few Sylvania's are gold pin).
- 7308 / E188CC is "generally the highest quality tube" in the 6DJ8/ECC88 family. Most have gold pins. Sylvania's are steel pin. They are designed with low microphonics and low noise. Sections are usually pretty closely matched.
- 7DJ8 / PCC88 These are "7 volt filaments" which were designed to be used in series string circuits. However, they work well in standard 6DJ8 circuits and can generally be used as direct substitutes. You can some some money using these.
- CCa This is a "special version of the 6922 / E88CC" which is usually only found as Siemens or Telefunken. These are very rare tubes and usually not in stock. But as for everything else, call or email to make sure.
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> 6DJ8 / 6922 / 7308 / Cca
6DJ8 :
This is the standard incarnation of this tube. It was made both in the USA and in Western Europe. GE and Sylvania both made USA versions, and are fairly good quality. The GE tubes have an RF shield sprayed on inside the glass, making the inside look dark. This is NOT an indication of a burned out or used tube. RCA tubes were often made by either Mullard or Amperex in Britain or Holland. The most popular NOS vintage tubes are those made by Telefunken, Amperex, Siemens or Mullard, and are usually also labelled ECC88. See the next paragraph for this description.
ECC88 :
This is the European designation for the 6DJ8 type tube. It is the same tube as a 6DJ8 and often the tube has both type numbers on it. The popular vintage tubes here are those by Telefunken, Amperex, or Mullard. The Telefunken are said to sound the best, and are the most difficult to find of all of these brands. All Telefunken tubes have a tiny diamond shape molded into the glass on the bottom, and have a very chalky ink on the surface which often is partially wiped off. Beware! These tubes are being reproduced in China, and look like the real thing, complete with diamond mark. The tipoff is the label: the fake labels will not wipe off.
The Amperex can be found with a white label and the treble clef logo (rare), the Bugle Boy cartoon tube logo, Amperex in white ink, and the orange world logo. The orange world logo is the newest, and can be found in both standard "L" bracket top getter, and the rarer (and said to sound better) "A" frame top getter. The A-frame looks like a little metal "A" holding up the getter element on the top of the tube internal structure. I have also seen the A frame getter on some Mullard and Genalex (G.E.C.) tubes. The Bugle Boy is the most popular, almost to being a "designer" label, which has driven the price up and supplies down. See note below about Bugle Boy 6DJ8 tubes. I believe any of the Amperex / Philips Holland 1960s and 1970s 6DJ8 tubes are excellent, no matter which one you use. The tubes made with the plain white label (Amperex, DuMont, Hewlett-Packard, Beckman and others but all labelled "Holland") were made in the same factory as the Bugle Boy tubes and sound the same, but are often bargain priced due to low demand. Beware! The Bugle Boy tubes are being reproduced today! The box of the new tubes is even an identical green-and-yellow like the original, but it says "Bugle Boy" on it, and some even show the cartoon tube on the box. Original Amperex tubes NEVER had the words "Bugle Boy", or the cartoon tube, on the box. The Bugle Boy moniker is a slang name that audiophiles coined for the the little cartoon tube on the tube's label. The new tubes have fooled even some seasoned audiophiles! These are junky Chinese made tubes with the old label. The company vending them says they have the original burn-in racks from the old Holland factory. Big deal!! The old burn-in racks are not going to help a crappy tube. Stick with the vintage tubes while you still can!
Mullard 6DJ8 tubes are excellent as well, but are more difficult to find. They often made 6DJ8 tubes for other labels, like RCA, Zenith, and other USA brands. They have several seams molded into the top of the tube.
6922 :
This is one of two premium versions of the 6DJ8 tube. First of all, it is the same tube as the 6DJ8, and will work wherever a 6DJ8 is needed. It has premium features such as low noise, low microphonics, and usually a longer lifespan. Sylvania made a version that is JAN military spec without gold pins. Amperex made all of theirs with gold plated pins and most have the PQ shield logo, standing for Premium Quality. See note below about Amperex 6922 and Bugle Boy tubes. Some of the later gold pin Amperex have the orange world logo. I have seen both orange and white PQ logos. Some of the early versions also have a number etched into the glass, like the 7308 tubes. These were also made for other manufacturers, and will have that makers name labelled in white, but these are the same gold pin tubes. Amperex opened a factory in New York to make these for the US military (since the government contract specified only USA constructed products) and cranked these and 7308 tubes out. A "made in U.S.A." Amperex tube is not a fake! In fact, these tubes are really excellent. A few were made in Holland for non-military industrial use, but these are rare. Also rare are the "pinched waist" versions of this tube. This is actually a molding flaw which made the glass bottom slightly fatter around the outside than the rest of the tube, and the center of the tube actually dips inward and touches the metal elements inside. Clients report these are incredible sounding tubes, and the upward spiral of prices for the rare pinch waist types seem to bear this out. Finally, Philips (the parent company of Amperex) owned a number of tube brands, and many were never seen outside of Europe. Most were actually made in the same Heerlen, Holland factory that turned out the Bugleboy 6DJ8 and PQ 6922 Amperex. Watch for tubes labeled E88CC with brands like Valvo, R/T, RTC, Miniwatt, Dario, Philips, and Adzam. These tubes are identical to the Amperex PQ and Philips SQ (Special Quality) types more often found in America, and are perfect if the Amperex is not available. Also rare in America are these same brands made at the Philips-owned Mazda factory (La Radiotechnique) in Suresnes, France. These usually have a capital "F" in the second line of the date code. They are sweet like the Holland tubes, with a bit better detail and punch at the top end, and still have nice balanced warmth. We are one of the very few worldwide tube dealers to offer these rare NOS French Philips tubes.
RCA 6922 tubes were made by Siemens in Germany, and also have gold pins. These are great tubes, but are not as plentiful. Since the military and some large industries (Tektronix) bought the Amperex made tubes in huge batches, that is what is on the surplus market today.
E88CC and E88CC/01 :
This is the European equivalent to the 6922, and is a quality step up from the standard 6DJ8 or 7DJ8. Telefunken made a fantastic version of this tube, complete with gold pins. Other vintage brands are available, but Telefunken, Philips, Siemens and Mullard are all I have ever seen in several years of tube hunting. Virtually all European brands have gold pins. Most are factory screened for tight internal matching and low noise. The E88CC/01 type (I have only seen these in Mullard brand) has even more factory testing. It is rather like a Cca type tube, with essentially military specs. It's the same as the CV2493, some have both types on the label. The /01 type is rare and worth seeking out if you like the warm British sound. There are some types out there, like "Golden Dragon" just to name one, but these are recent manufacture Chinese tubes, and can't hold a candle to the quality of the Telefunken or even any of the vintage 6922 types. There are also some nice USA made military and industrial types available with either gold or standard pins, and even these sound better than the current production tubes, and are usually priced the same or less.
CV2493 :
A rare military version of the E88CC/01. Some have both types on the label, some only the CV2493. This can be considered the British or Dutch version of the German Cca. Very low noise, carefully matched triodes, and these are batch tested to meet military specs. Usually only available in the Mullard brand, I have seen some with the Amperex Heerlen, Holland factory codes on them, even though they have the Mullard label. Scarce in the USA, and not found in the later Yugoslavian versions like the more common CV2492. It is possible only the UK and Holland made these tubes and were discontinued by the mid 1970s. Probably one of the best choices for tube microphones and mic preamps, or any other high gain, low noise use.
CV2492 :
This is a European military (usually British) version of the 6922 / E88CC type vacuum tube. Unlike the US military version, these tubes were never made in the USA. Most of the older examples were made in either the Mullard Mitcham, UK factory, or the Philips/Amperex Heerlen, Holland factory. These are fine tubes that have passed various demanding military specification tests regarding ruggedness, heat and shock resistence, and heater life. Like their civilian/industrial counterparts, they have the four molded seams on the top, heavily plated gold pins, a halo top getter with a splatter shield below it (with slight raised indentations at the 3 and 9 o'clock positions on the shield), and the standard Mullard/Philips factory date codes printed near the bottom of the glass side. Care must be taken, however, when buying these tubes if they are merely identified as "CV2492" tubes. These tubes were made well into the 1980s, and later examples are not as valuable or as desirable as the earlier varieties. Later versions were made in the former Yugoslavia and then in Russia. The Yugoslavia versions can be spotted by their lack of gold pins, and the halo getter mounted low, almost touching the splatter shield. The Russian versions are even easier to spot, as they have a fatter glass bottle, a top mounted cup shaped getter, no top mold seams, and sharp pointed pins which may or may not be gold plated. These are not bad tubes, but should only be worth one half to one fourth of what the UK or Holland made tubes are retailing for. Give the CV2492 a try, the older versions are sweet sounding and long-lived, and are a step up from the garden-variety 6922 / E88CC, and prices are generally a little lower.
E188CC :
A bit rarer than the E88CC, the E188CC is usually found labelled as such by Siemens or Telefunken. Amperex and other makers (Sylvania for example) used the industrial 7308 marking, Amperex Holland and France used the E188CC label. It is basically the European equivalent to the 7308. The E188CC has gold pins, and is near the top of the 6DJ8 food chain. The Siemens version from the 1960s is quite rare, and is rated by many audiophiles as a jewel on par with the best Cca tubes, or the cryo-treated 7308s. It has low noise to the vanishing point, and a wonderful, airy top end and soundstage. This early version Siemens has a small halo top getter, and is labelled E188CC in white ink. Versions made in the Philips Holland plant are similar, and have the SQ logo. If you find some, grab 'em while you still can! Finally, Philips (the parent company of Amperex) owned a number of tube brands, and many were never seen outside of Europe. Most were actually made in the same Heerlen, Holland factory that turned out the Bugleboy 6DJ8 and PQ 6922 Amperex. Watch for tubes labeled E188CC with brands like Valvo, R/T, RTC, Miniwatt, Dario, Philips, and Adzam. These tubes are identical to the Amperex PQ and Philips SQ (Special Quality) types more often found in America, and are perfect if the Amperex label is not available. Also rare in America are these same brands made at the Philips-owned Mazda factory (La Radiotechnique) in Suresnes, France. These usually have a capital "F" in the second line of the date code. They are sweet like the Holland tubes, with a bit better detail and punch at the top end, and still have nice balanced warmth. We are one of very few worldwide tube dealers to offer these rare NOS French Philips tubes. Finally, watch for Siemens or Telefunken German made E188CC/7308 tubes, most having the E188CC label in white, with the Telefunken having the distinctive diamond shape in the bottom glass. Siemens are usually more plentiful, and a huge savings over their Cca tubes.
7308 :
This is probably the ultra 6DJ8 type tube commonly available. It has all of the features of the 6922, but the triode sections are also matched to each other, and the tubes all fit within very tight specifications. Therefore, any 7308 should match any other 7308 within the same brand. The Amperex versions were again made in New York, complete with gold pins, and often have a number etched into the side of the glass. Amperex made these for industry as well as the military. The Amperex versions have the PQ label, the military type usually is labeled "USN-CEP", but I have seen versions made for Stromberg-Carlson and Hewlett-Packard, with white ink labels. These all had the numbers etched into the glass, and all are the same tube. The USA made military white label types have been rated "Best of All", over other 7308, 6922 and even Cca tubes, in several well-documented 6922/7308/Cca listening tests. Therefore this particular type is becoming scarce and prices are rising. There were a few of these made in Holland, but most were made in the USA, therefore the Holland tubes are RARE and usually command a higher price. The Holland PQ versions have the PQ with stars on either side of the letters, and the words "Premium Quality", where the USA types have the PQ inside of a shield logo. Again, there are some nice vintage USA made standard pin military and industrial types available from Raytheon and Sylvania, just to name a few, and these are quite good at a price currently far below the European vintage labels. Finally, Philips (the parent company of Amperex) owned a number of tube brands, and many were never seen outside of Europe. Most were actually made in the same Heerlen, Holland factory that turned out the Bugleboy 6DJ8 and PQ 6922 Amperex. Watch for tubes labeled E188CC with brands like Valvo, R/T, RTC, Miniwatt, Dario, Philips, and Adzam. These tubes are identical to the Amperex PQ and Philips SQ (Special Quality) types more often found in America, and are perfect if the Amperex label is not available. Also rare in America are these same brands made at the Philips-owned Mazda factory (La Radiotechnique) in Suresnes, France. These usually have a capital "F" in the second line of the date code. They are sweet like the Holland tubes, with a bit better detail and punch at the top end, and still have nice balanced warmth. We are one of the very few worldwide tube dealers to offer these rare NOS French Philips tubes. Finally, watch for Siemens or Telefunken German made 7308 tubes, most having the E188CC label in white, with the Telefunken having the distinctive diamond shape in the bottom glass. Siemens are usually more plentiful, and a huge savings over their Cca tubes.
E288CC :
This unusual tube is basically a 7308 / E188CC in a slightly taller bottle. The filament current draw is also slightly higher but for most applications it is plug and play compatible with the 6922, 7308, Cca, or even the 6DJ8. Physical space is a consideration, since the tube is about one-half inch taller than the rest of the tubes on this page. It features gold pins, factory screened triodes for low noise, 10,000 heater life, and all the other great features that make the 7308 and the Cca such high-demand tubes. Since it is a relative unknown, the prices are about the same as good 6922 tubes, and far below that of most 7308 or Cca types! I have only seen this tube in Valvo, Telefunken, or Siemens brands. Worth giving a try if you want the best but cannot afford the soaring costs of NOS 7308 or Cca tubes.
Cca :
Whew, these babies are so scarce there isn't even much info out there about them! Mentioned by audiophiles, usually in a reverent whisper, these gold pinned gems are about as good is it gets in 6DJ8-land. Matched triode sections, low noise screening, 10,000 hr. heater life expectancy, carefully controlled frame grid winding, low microphonics......the list goes on and on. This is regarded as one of the most detailed and three-dimensional sounding tube ever made in this family of tubes. Most of what is available is Siemens or Telefunken made, although there are a few very rare examples of Philips or Amperex Holland made out there. Since this was a tube made specifically for the German goverment and military, all that I have seen carry a German brand label, even those made in Holland. Even rarer are the Holland made Cca tubes with the pinched waist indented glass midsections, said to be the most sonically "3D" tube ever made, of any type. Finding these is akin to finding a 1795 gold piece in your attic! I don't believe there were any of these Cca tubes made in the USA. Awesome audiophile tubes!
6H23 :
This is a Russian made equivalent to the 6922 or E88CC, but will work in place of any 7308 or 6DJ8 type as well. Ordinarily the Russian tubes are just not of a high enough quality to go head-to-head with NOS German, Dutch, or UK tubes. These are a possible exception. The so-called "rocket logo" type from the 1970s and early 1980s seems to hold it's own against NOS tubes costing 3-4 times as much. These NOS Russian rockets have been critically acclaimed in several online discussion boards for their detail and smoothness. At current prices, these are about one-third to one-fourth the cost of NOS Western Europe types, and so their value is enhanced even more.
7DJ8 / PCC88 :
This is an unusual tube that must have had a limited range of specific uses. It is virtually identical to the 6DJ8 except for the heater rating, which is 7 volts. I have seen Siemens, Valvo, Telefunken, Philips, Ultron and Matsushita (Japan) brands of this tube. It probably makes a good sub for the 6DJ8 and may last longer due to the higher voltage heater. Some are labelled with only the "PCC88" and others have both types listed on the label. All seem to be good quality. The Japanese factory was set up by Mullard, and these tubes even flash orange at the bottom of the filaments when first energized, like most European triodes do. Most of the European types were made at the Munich Siemens factory, the Hamburg Valvo factory, the Heerlen Holland Amperex Factory, or the Blackburn, UK Mullard factory. These sound just like the best 6DJ8 tubes, the German tubes being mostly neutral, and the Dutch and British tubes having a touch of midrange warmth. Watch for the very rare D-getter types and even rarer pinch waist types, often at bargain prices (compared to 6922 types in these categories) when you can find them. You may want to try a 7DJ8 for the longer heater life in a 6.3 volt circuit, and the lower price!
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