6DJ8/6922/7308 Sound Performance Analysis – Chimera Labs 09/01

I have been recording my customer’s feedback on the sound performance of the 6DJ8 tubes they are using. I combined that with my own listening opinions. Let me add the that the best sounding tube for your needs will probably only be found when you try different types until you own ears tell you which tube is best. Use this information to help you narrow down your search.

In my opinion the Amperex types are some of the best sounding 6DJ8 types. For audio applications there are ECC88/6DJ8 types that sound better than some of the E88CC/6922 or E188CC/7308 types, Yes, even those made by Amperex.

Lets’ cover the current production tubes and then move on to the good stuff. I will cover the vintage tubes in Alphabetical order. This list has left out a lot of 6DJ8 types, if you have a favorite let me know, maybe it will make the revised list.

Current Production:

Sovtek 6922 (Russian) - A very soft sounding tube, a bit lifeless, slow in transient performance and back of the hall in dynamics, frequency response just OK with a warm rolled off Bass and a sterile sounding midrange. But its sins are mostly those of omission. It has proven to be quiet and reliable

Russian 6H23N – I am told it was made by many different manufacturers and the earlier the production date, the better it sounds. I have heard several different types and it does sound better than the Russian 6922. Better Bass, better dynamics more life to the midrange. The ones I listened to were nice and quiet. But, so far, even the Sylvanias offer better performance.

Russian 6NP1 – This tube does not have the same Operating Characteristics as the 6DJ8 tube types. I would check with the manufacturer of the equipment before substituting a 6NP1 in place of a 6DJ8 type. This is what Svetlana the importer recommends as well. The customers I talked to that tried it, went back to the vintage types. If you are building something, use it at the right voltages and operating points, and it should work well.

Vintage Tubes

Amperex ECC88 – Early White Label, made in Holland, D type Getter, rare and expensive. I have only heard a few of these and they didn’t test all that great. So I don’t have an opinion, guys that have them love them.

Amperex ECC88 – Bugle Boy, made in Holland, Round Getter with shield, a great tube. Wide and deep soundstage, a lot of air and ambience, not as fast and dynamic as some of the other Amperex types. Bass is a little warm and rolled off. Currently it is in great demand, certainly a “To Try”, but some of the other Amperex ECC88s sound a little better to me. But very sweet and non fatiguing.

Amperex ECC88 – Orange globe logo, made in Holland, Round Getter with shield, one of the best Amperex tubes, better than the Amperex 6922 Orange Label(non PQ). Nice rich harmonic structure, fast with good dynamics, not edgy like most of the 6DJ8s, good bass and highs. Put it on your “To Try” List.

Amperex ECC88 – Orange Label, made in Great Britain, “A frame” construction. Definitely more “up front” than the Bugle Boy, Great highs with no edge, the instruments sound a little bigger(like you are sitting up front in the hall) but maybe not quite as much air as the Bugle Boy. Great Bass and fast, another “To Try”, and it seems to love phono stages.

Amperex ECC88 – Orange Label, made in Holland, “A frame” construction. Middle of the hall presentation with very good frequency response. Sweet top end and midrange, excellent low level detail resolution wide soundstage but a little more up front than the Bugle Boy, a customer favorite, and definitely a “TO Try”, one of my personal favorites.

Amperex ECC88 – PQ Orange Label, made in Holland, “A frame” construction. Why is it the PQs always sound better. Same sound signature as the Orange Label covered above, just cleaner, faster, and a little better in every way. This is one of Amperex’s best. Definitely one “To Try” and my favorite ECC88.

Amperex ECC88 – Globe Orange Label, made in Holland. Solid dimpled round getter. This is a sleeper, I haven’t seen that many of them. Very quiet, can sound a little soft compared to some other Amperex types, but everything sounds right. Good frequency response, nice soundstage, no edginess, nice tone and timbre, it does everything pretty well. The price is right on these since there isn’t a lot of talk about these. I would put on my “To Try” list, but I like the “A Frames” or Round Getters a little better.

Amperex 6922 – JAN, White Label, made in the USA. Yes, Amperex had a tube manufacturing plant in New York. At that time you could not qualify to bid on US military orders, unless you built tube in the US. This is a very good tube, quiet, great speed and dynamics and very wide bandwidth. Might not have as much harmonic structure as the best of the Amperex ECC88s, it sounds jut a tad lean. Hard to find and expensive but always in demand.

Amperex 6922 – PQ White Label, made in the USA. Yes it is one of the best Amperex 6922 White Labels, very musical, fast, excellent timbre and low level detail resolution, no edginess, and quiet. Worth every penny, although it is getting expensive out there.

Amperex 6922 – PQ White Label, made in Holland. To me the midrange is a little larger than life but still it is very musical and sounds a lot like the US versions. Many people considerate the best and it is getting very expensive.

Amperex 6922 – Jan or PQ Orange label, made in the USA. Very clean with good frequency extension but it can sound edgy in the upper midrange in some equipment. Some Amperex ECC88s offer better performance at much better prices.

Amperex 7308 – Jan or PQ White Label, made in USA, This is one of the best, slightly better than any of the 6922s and ECC88s. It does not have the rich harmonic structure of some of the Amperex ECC88s, but overall it is very good. Using some of the best ECC88s in the phono stage and these 7308s in the line or amp stages is a recipe for Great Music. Some people prefer the Holland White Label 7308s, I have not listened to enough of them to have an opinion, save it sounds very similar. Definitely a “To Try” Tube.

Amperex 7308 – Jan or PQ Orange Label, made in the USA. Sound a lot like the Amperex ECC88 Globe Orange Labels with the Round Getter, a little quieter and cleaner. Not quite as live sounding, another “To Try” Tube.

Amperex 7308 – Green Label, made in the USA, close in sound to the Amperex 7308 Orange Label, but it seems to work better in high gain applications like phono stages and may be quieter. I don't think this tube is as good as a lot of people say it is but, certainly a “To Try” Tube.

Mullard ECC88/6DJ8 – made in Great Britain, using Amperex Tooling, you can find a lot of them labeled RCA at very reasonable prices. I consider this an Amperex tube, the construction and sound is identical to the Amperex Globe Orange Label Holland. For some reason the Mullards seem to sell for more than the Amperex…if there is a difference in sound performance, I can’t hear it.

Mullard E88CC/6922 – made in Great Britain, another clone of the Amperex tubes, very good sound performance, good frequency extension, ambiance, sound stage and harmonic structure not as good as the best Amperex types.

Mullard CV2493 – made in Great Britain with a dimpled solid disc getter like the Amperex Orange Label ECC88. Doesn’t sound the same. I have only listened to about 6 of these, so maybe I got a bad batch. All they seem to do is midrange and it does it very well. If for some reason you want less frequency extension, then this is the tube for you.

Siemens ECC88/6DJ8 – made in West Germany, many labeled RCA, pretty good tube and the RCA ones are usually at good prices. Nice dynamics and music presentation, a little light on the top end, but good bass and decent soundstage. Not my choice for symphonic music but with Jazz and Vocals more its OK. Not in the Amperex performance range but for the right price you could be happy.

Siemens E88CC/6922 – made in West Germany, many labeled RCA, sounds a little softer and the midrange is sweeter than the Siemens ECC88. Highs a little recessed and I guess the tube doesn’t have the best low level detail presentation, sort of a vintage sound.

Siemens E188CC/7308 – made in West Germany, many labeled RCA and some labeled Telefunken, this is getting you close to the sound of the better Amperex tubes. Very Musical, nice speed and dynamics, still has a sweet sound with nice ambiance. This makes my “To Try” Tube list.

Sylvania 6DJ8/6922/7308 – JAN Green Labels, made in the USA some later production labeled ECG Phillips. The sound signature of all these types is so close, I am not going to separate them. You can include the commercial yellow labels in here as well. These are better tubes than the any of the Russian types and easy to find at good prices. Maybe that’s the reason they are being relabeled Mullard and Siemens. Musical, nice dynamics, decent bass, a little edgy and forward but they are not soft and they offer decent low level detail resolution. The later production ECG Phillips doesn’t sound quite as good as the earlier ones. They are quiet and reliable too, but they don’t make my “TO Try” Tube List.

There is a lot of tube counterfeiting going on, I hear the Sylvanias are now available with Bugle Boy Labels. All the Amperex tubes have very small production codes etched in the bottom side of the glass.
The tubes also have four little edges you can feel at the top of the glass, the Sylvanias don’t.

Remember to search the web, go to Audio Asylum at http://www.audioasylum.com/audio/tubes/bbs.html
Do a search for counterfeit tube in the Text to Find window at the top right of the page. When you buy a batch of “fake” tubes, go to the audio newsgroups and let everyone know.

Vintage Tube Sound Performance and Information