6DJ8 (6922) Types The "EH" version of the 6922 is the only tube of this type still in manufacture. Suitable for everything from pre-preamp, through phono to power amps, it is affordable and sounds very nice. This tube offers consistenly good value in terms of tonal balance, musical involvement, transient "punch," bass impact, warmth and freedom from glare and "hash." I purchase these tubes in large lots and sort them, measuring noise, susceptibility to microphonics, gain and grid leakage. About half are not suitable for much of anything. Those left over I offer in four levels for these applications. If you are seeking the very best sound, this article on my Aria Audio website might be of interest. Grade Price   6922AAA - Reference Grade For Pre-Preamps. The quietest tubes with the lowest microphonics in the bunch. Fully tested for low noise (less than 10uV noise and no microphonics), both halves tested for matched transconductance. These tubes are exceedingly rare, only about 4 out of every 100 tubes make the cut. They are suitable for the lowest noise applications and for test purposes, as there are no 6922-type tubes (including 7308, 6DJ8, ECC88, E88CC, ECC288, etc.) that are quieter than these hand-selected gems. They are as quiet as is theoretically possible for this type of tube. $120   6922AA For Phono Stages. Not as quiet as "AAA" tubes, and not as impervious to vibrations, but don't "ping," or "ring" when tapped. Less than 16uV noise and very low microphonics, Both halves tested for matched transconductance. Suitable for phono stages and other very low noise applications.. $70       6922A For Line Stages. A bit noisier still, but well below 22uV of noise. More likely to "ring" when tapped, but in a line stage application it will not be noticeable -- unless you tap it. Less than 22uV noise, both halves tested for matched transconductance.. $45   6922B For Power Amps. Less than 28uV of noise. These tubes will "ring" when tapped, but given that a power amp is not followed by any further amplification, it will not likely be audible. $10   NOTE: These descriptions are guidelines only. If you are using very efficient speakers, and/or are sensitive to microphonics or ringing, always use the next higher grade of tube.

 

Alternatives to the 6DJ8/6922 for Line Stages and Power Amps. For different sonic preferences I can suggest several other choices. I do not stock these other tubes, you'll need to hunt them down yourself.

• 7308/E188CC/8223/E288CC, CV5358, 6922-WA, CCa, CV10320, CV2492, CV2493, CV8065, E88CC, E88CC/01, ECC868, CV5231, CV5354, E188CC tubes are equivalent to 6DJ8/6922 types and can be used in place of them in all Counterpoint equipment. They are usually too noisy and/or microphonic for phono stages.
  
  
• Neither the Russian 6N1P nor the 6N(H)30 tubes are good choice -- they require much more filament current, 600mA and 825mA respectively, than the 350mA that the 6DJ8-type tubes require. This increased load on the filament supply would likely damage the filament voltage supply circuit.
  
  
• 6CG7/6FQ7 tube can also be used in place of the 6DJ8 in line stages and power amps. Usually presenting a softer, more rounded, classic triode sound with fat, deep bass. However, the RCA "clear top" is very well-balanced and nice to listen to. Again, these tubes are generally too noisy and/or microphonic for phono stages.
  
  
• For a good review of the many 6DJ8-type tubes, see Joe's Tube Lore on Audio Asylum at http://www.audioasylum.com/audio/faq/joes-tubes.html#6DJ8

12AX7 Types. There are dozens of 12AX7 type tubes available. I have two types that I stock.

• Chinese 12AX7A. A perfectly fine-sounding tube. $15 each.
• Sovtek 12AX7LP is extremely nice. This tube has a nice fat neutral sound. You can also get them from the New Sensor site at www.newsensor.com .

 

6CA4 and other 9-pin rectifier types that can be used. Just as aftermarket AC power cords, which go between your product and the wall outlet, affect the sound, sometimes dramatically, rectifier tubes (which go between the audio circuitry and the power transformer, which then goes to your expensive aftermarket power cord then to the wall outlet) can make a huge difference in the sound quality.

      There are several types of 9-pin rectifier tubes available. If your Counterpoint product used a 9-pin vacuum-tube rectifier (was I the first in high-end to use a tube rectifier? 1981, the Counterpoint SA-2 pre-preamplifier) then it would have originally come with a 6CA4/EZ81.

Important points about 9-pin rectifier tubes: 

1. In Counterpoint gear which uses 6CA4's, you can also use 6V4/EZ80's, which can be plugged right in.

2. 6BW4's can also be used but they require modification to the tube socket wiring (pin 3 needs to be connected to pin 9 -- don't do this yourself unless you know exactly what you are doing!).   

3. Some rectifiers sound a lot better than others, but you can't go by tube type or brand. There are good-sounding 6CA4's and bad-sounding 6CA4's. There are good-sounding 6BW4's and bad-sounding 6BW4's. There are good-sounding 6V4's and bad-sounding 6V4's.

4. As of December 2005, I have found 24 different versions of these three types of tubes. They are all built differently internally. Tubes with different inner construction all sound different.

5. You can't tell if you have a good-sounding version or a bad-sounding version by reading the brand label printed on the tube. The only way to tell one tube type from another is to inspect the internal construction visually and ignore the printing.

6. Read this again: The printing on 9-pin rectifier tubes bears no relationship to what's inside. I've found identical tubes (as determined by inspecting the inner parts like plate structures, getters, etc.) labeled with totally random brand names. I have many different tubes (with completely different inner parts) that are branded the same. The names "Mullard," "Sylvania," and so on mean nothing on 9-pin rectifiers as far as I can tell. It is impossible to determine the original manufacturer of the different types.

When I receive a batch of tubes I inspect them, identify them by their inside parts (I keep examples of each variety on hand), and sort them. New tube varieties (one's I've not seen before) are listened to as soon as possible to evaluate how good they sound. I update the quantities on the chart (below) to try to keep it current.

I offer 9-pin rectifiers in six grades. The very best grade sounds far better than any of the tubes originally used in the Counterpoint equipment. The lowest grade can be used to keep a unit running, but are not upgrades. The higher a tube is in the chart, the better I think it sounds.

TO ORDER: Just tell me the "order number" of the tube you want. Order numbers are on the chart below. "C" refers to 6CA4/EZ81 types, "V" refers to 6V4/EZ80 types, and "B" refers to 6BW4 types. "C" and "V" tubes can be used in Counterpoint gear without modification; "B" tubes require modification.

6CA4 and other 9-pin rectifier tube options for Counterpoint

Note the new "V8" type -- so good that it has received an AAAAA rating! Grade Order Number* Description Qty. In Stock Price AAAAA (amazing) C 8 6CA4/EZ81. The V8 tube, below, was the best rectifier tube, by far starting Nov 2005. I was able to provide the V8 type to customers until May 2007, when we ran out. I found what I thought were the same tube from the same vendor, but when they arrived, we noticed that they were labeled "EZ81,"and while they the same exact internal construction as the V8 type (see below), they are taller. I was concerned that they would not sound as good as the V8 tubes, but careful listening shows that they sound every bit as good as the V8 tube. Same manufacturer, same materials, same construction. Got lucky this time: like the V8, the most natural sound I've ever heard. Cables costing 10 times as much won't improve your Counterpoint as much as this tube will. (Can be used in all Counterpoint gear that use 6CA4 rectifiers without product modification.) ADDED 30 May 2007 9 $135 AAAAA (amazing) V8 6V4/EZ80. Until hearing this tube, no other rectifier sounded nearly as full and present as the AAAA tubes (below). But this one left us with dropped jaws. Totally engrossing sound: full, round, detailed, and extremely present -of all the rectifier tubes, this offers the most natural sound I've ever heard. Is is an odd-looking 9-pin 6V4-type rectifier with a fat bottle & plates stacked at right angles to each other. Cables costing 10 times as much won't improve your Counterpoint as much as this tube will. (Can be used in all Counterpoint gear that use 6CA4 rectifiers without product modification.) ADDED 19 November 2005 0 $135 AAAA (excellent) C7 Best 6CA4 ever. Extremely good, possessing all the attributes of the C6 but with a smidge more presence and 3-D imaging, and a little less sibilance than the B4 variety. EXCELLENT. (Can be used in all Counterpoint gear that uses 6CA4 rectifier tube without modification.) ADDED 12.18.05 10 $70 C6 WAS best-sounding 6CA4 ever until C7 came along. Great balance and space, detailed, full bass. Good breath/body balance, very 3-D. EXCELLENT. (Can be used in all Counterpoint gear that uses 6CA4 rectifier tube without modification.) ADDED 12.3.05, courtesy Steve Durso who found this gem. 0 B5 An outstanding 6BW4 variety. Very articulate, more relaxed-sounding and less sibilance than B4 variety. Lacks only a teeny bit of presence to be as good, or better, than the C6.EXCELLENT. Note: "B"-type rectifiers (6BW4) cannot be used in Counterpoint gear without first re-wiring tube socket. ADDED 12.18.05 2 B4 6BW4,Very similar to C6, above.EXCELLENT. Note: "B"-type rectifiers (6BW4) cannot be used in Counterpoint gear without first re-wiring tube socket. 1 AAA (very good) V14 6V4. Very like B1 (below) but with noticeably heftier bass. (Can be used in all Counterpoint gear that use 6CA4 rectifiers without product modification.) ADDED 12.3.05 16 $60 B1 6BW4, Buttery, warm, natural-sounding. VERY GOOD. Note: "B"-type rectifiers (6BW4) cannot be used in Counterpoint gear without first re-wiring tube socket. 10 V9 These four 6V4-type rectifiers all sound pretty much alike. A little more mechanical than the B1, but less top-end edge than the B2. VERY GOOD. (Can be used in all Counterpoint gear that use 6CA4 rectifiers without product modification.) ADDED 11.19.05 0 V12 0 V7 0 V13 Branded as "Groove Tube" 0 B2 6BW4, Sounds like B4 type, but not as full or smooth. VERY GOOD. Note: "B"-type rectifiers (6BW4) cannot be used in Counterpoint gear without first re-wiring tube socket. 8 V6 6V4, Warm, involving sound with nice detail. VERY GOOD. (Can be used in all Counterpoint gear that use 6CA4 rectifiers without product modification.) 2 V1 6V4, Involving sound with nice detail. VERY GOOD. (Can be used in all Counterpoint gear that use 6CA4 rectifiers without product modification.) 0 V3 6V4, Sweeter, relaxed, more organic than V4. VERY GOOD. (Can be used in all Counterpoint gear that use 6CA4 rectifiers without product modification.) 7 AA (good) V4 6V4, Very similar to V2 but slightly teeny bit sweeter. Has drive, detail. GOOD, (Can be used in all Counterpoint gear that use 6CA4 rectifiers without product modification.) 1 $40 C5 6CA4, round holes in micas. Very fast, detailed highs with no shrillness or hash. Excellent depth. (Can be used in all Counterpoint gear that use 6CA4 rectifiers without product modification.) 0 V2 6V4, Very lively, forward sound, quite dynamic. Prominent upper mids, taut bass. Loud-sounding, punchy tube. GOOD. (Can be used in all Counterpoint gear that use 6CA4 rectifiers without product modification.) 0 V5 6V4, Not as forward-sounding as V2, a little nasal-sounding. GOOD. (Can be used in all Counterpoint gear that use 6CA4 rectifiers without product modification.) 0 V10 6V4, A little more mechanical-sounding than the V5.. GOOD. (Can be used in all Counterpoint gear that use 6CA4 rectifiers without product modification.) 0 C4 6CA4, black background, sweet-sounding. GOOD. (Can be used in all Counterpoint gear that use 6CA4 rectifiers without product modification.) 7 A (okay) C2 6CA4, Airier-sounding than B3. OKAY. (Can be used in all Counterpoint gear that use 6CA4 rectifiers without product modification.) 2 $35 B3 6BW4, sounds like B1 but with added hash, not was warm as B4. Least good-sounding version of 6BW4. OKAY. Note: "B"-type rectifiers (6BW4) cannot be used in Counterpoint gear without first re-wiring tube socket. 4 no grade ("it works") V11 6V4, Fairly edgy and grainy. According to some sources, this version MAY be the Telefunken EZ80. (Can be used in all Counterpoint gear that use 6CA4 rectifiers without product modification.) 0 $18 C1 6CA4, slow-sounding, boring and confusing. Not much drive, airy but hashy. (Can be used in all Counterpoint gear that use 6CA4 rectifiers without product modification.) 2 C3 (GE) 6CA4, "GE" (this one we can positively identify by the distinctive acid-etched GE date-code dots). Prominent upper-mids, hashy-sounding. Worst-sounding 6CA4 ever. (Can be used in all Counterpoint gear that use 6CA4 rectifiers without product modification.) ADDED 11.19.05 2

*Note: "C" refers to 6CA4/EZ81 types, "V" refers to 6V4/EZ80 types, and "B" refers to 6BW4 types.

6LF6 Tubes. This tube, used in the output stage of the SA-4, are no longer available in matched octets. Some modification of the SA-4 circuitry is necessary to allow unmatched tubes to be used. Information about this modification for do-it-yourselfers is viewable here, or if you want us to do it, see the SA-4 Upgrades Page . We don't stock the tube, but you can find GE 6LF6's at www.tubesandmore.com as well as other online tube vendors.

6SN7 Types. I can provide tested Sovtek 6SN7's for your SA-11, and later models of the NP220 and NP100 for $22 each. Equivalent tubes that will certainly work in the NP amps and may work in the SA-11 (the unmodified SA-11 is very sensitive to any grid leakage) are: 6SN7GT, 6SN7GTA, 6SN7GTB, 6SN7WGT, 6SN7WGTA, ECC32 (but not if the tube is light-bulb-shaped: that's a relabled CV-181 and is not a good equivalent), 5692, 6180, VT-231 (the amazingly great-sounding WWII military version of the 6SN7, but good luck finding a pair!), CV1986, and CV1988.

6SL7 Types. I can provide6SL7 triode tubes for your high-sensitivity NP amplifiers for $37 each. Equivalent tubes that will work in the NP amplifiers are: 6SL7GT, 6SL7WGT, ECC35, 5691, 6113, 6188, CV1984, CV1985, and the Russian equivalent type 6N9S (their Cyrillic "N" looks like an "H,"so you may see it advertised as a "6H9S").

5651. I have been called several times by people who are concerned that their 5651 must be failed because it is glowing red hot. Touch it -- it is cold, cold, cold. This is not a vacuum tube, although it looks like one. It is filled with neon gas and glows orange during normal operation. It is the voltage reference for the high-voltage regulators. This is a very reliable device -- we've only seen one fail in thirty years.

Other Types. The other tube types used in Counterpoint gear, like the 12AY7, 6080, 6GC5, 6BQ5, 6JC6A, 5651, 5R4 and 6FS7 are available. E-mail me to inquire about price and availability.

How We Test Our Tubes. (just kidding).

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