My little 6DJ8/6922 shootout

organ

OK, there was interest in the Siemens CCa sound quality in my other 6DJ8 thread so I thought I'd post it here along with a few others.

I've been working extra nights, and getting home around midnight. So what's the bored and lonely Organ supose to do from mid-night to 5am for the past few weeks? Tube roll in my GTA pre amp.

I have a lot more extra tubes to try. So here are the ones I've spent quality time with so far.

Amperex "Bugle Boy":
This is one of the best 6DJ8 tubes I've heard. It does lack minute detail, bass and high freq extension but it's the most musical tube in the 6DJ8 family I've heard. And no, the bass and HF extension doesn't suffer as much as some Mullards. Whatever bass is there is very powerful and robust. It has so much energy in the mid-bass compared to the others.
The soundstage is incredible. It has the most depth and most holographic imaging from the bunch. Image size is huge. The sound is also the smoothest and warm (not as warm as one of my Mullard). It has this body and adds this "bubbly" sound around vocals and instruments that's extremely musical. This tube can even make bad recordings sound more musical.
The 3D imaging is so sweet, it has that 'reach out and touch' quality to it. I feel this tube gives me the most intimate feel with the artist.

I also have an older version with the grey vertical shield that many claim is better. I can't say there's a big difference but the the earlier grey shield version seems a little bit warmer with slightly bigger images. No night and day difference. Just very small from what I can tell. I need more time to compare the two.


Amperex "Orange Globe, dimpled disc getter":
This one seems to be right there in between the BB and A frame (coming up next). The mids is richer and more vibrant. Less warmth than the BB. The thing that really seperates this tube with the BB (other than construction and year of production) is the imaging. It's there but won't give you that 'reach out and touch' feel. The sound won't shoot out of the speakers as much as BB and also has less depth. It has better low and high freq extension. Upper bass doesn't have as much energy as the BB. It also has more detail than BB which is most noticable in the mids and highs. I'm making this sound a little rough, but believe me, it's not. This tube is more similar to the BB than different. It's just that I prefer the imaging, image size, lushness and upper bass warmth of the BB.

Amperex "Orange print, A frame, dimpled disc getter Mullard made":
Aaah, I'm really enjoying this tube. This is probably the most neutral from all the Ampex tubes I've tried. The presentation is more forward and has more zing to the highs than the orange globe. It's also has more detail than the above two. Front to back imaging is not like the BB, but what is there is very good. This tube makes me feel more like being in a concert where you can almost visualize the stage and performers. What it lacks in 3d imaging, it makes up for it in the size of the soundstage. The depth is very nice too. I need to spend more time with this tube but so far I like quite a bit more than the orange globe. One thing that really stands out with the sound of this guy, is the transients and dynamics. It's very energetic with an excellent sense of "snap". It's a very fast sounding tube. Makes sense due to the neutral sound. Vocals sound excellent. Not as much tube magic but very realistic and still able to sound smooth.
This tube was made at the Mullard Blackburn plant. The first indication is the Made in England print and the etched code conforms this. From what I've read around the net, this tube was made on the Amperex tooling by Mullard for Amperex. That's why it's labeled Amperex.
But I doubt there will be any differnce between the Ampex and Mullard made A frames.

Siemens CCa:
This is one of the most sought after and expensive tube in the 6DJ8/6922 family. The CCa tubes are selected 6922. They were selected for having better section to section balance, low noise and long life. They're suppose to provide 10 000 hrs of life minimum. All CCa along with every 6922 by Siemens have gold pins.
I have the older and better vintage (Siemens & Halske logo, not plain Siemens, grey vertical shield).

Ok now the sound. I had high hopes for this one. I wanted to know why they command so much $ and why many people are going crazy for them.
The sound is right there in the Siemens "House Sound" which I find to be similar to other German made tubes like Telefunken. It's very neutral with great control and fleshes out a lot detail. Bass and high frequency extension seems to be the best of the bunch. Soundstage is wide but probably equivalent to the A frame Amperex above. So I still like the soundstage of the BB more. Mids is very, very detailed but not as smooth as the BB. One area this tube is lacking compared to the BB is the mid range tube magic. Actually, not sure if lacking is the right word because I think the BB adds that sweetness to the mids and upper bass. So yeah, it doesn't sound as sweet as the BB and it has less mid bass bloom. But it beats the BB in bass extension. It is able to dig deeper with more authority. This is a very neutral tube, which is the complete opposite of the BB.
So why am I finding it pretty hard to enjoy this tube as much as the BB? It's too damn accurate! I find the sound to be too analitycal on most cd's. Everything sounds sweet on the BB but onlly the best recordings will make the CCa shine. And when it does, it's an amazing sounding tube. Problem is, only a small percentage of my cd collection can make the CCa sound this musical. Most of the time I'll be analizing the sound instead of enjoying the music. The BB makes it so easy to relax and let the music take a hold of you. So the CCa, imo, is the more accurate tube and the BB is tube magic to the max. Just like the truth vs beauty thing we all know about.



Now to my conclusion. All these tubes are AWESOME and light years ahead of current production. I can easily live with just one of them if I had to.

I seriously can't say I have a favorite. They're all excellent tubes where each type possess a quality missing in the others. So depending on my mood and occassion, I'll pop in the appropriate one. I like all of them.

One thing I just began doing when evaluating sound is listening to the electric guitars. Just like what I hear in a live show, the guitar has so much power to it. When an artist strums on his guitar, you can really feel the energy and power of the sound. It's like there's a beast inside the guitar amp that growls at you. There's the fundamental note, but along with that is the under tone and over tones. They all combine to give a very powerful and big sound. This is one quality I just started looking for in tubes and all the ones mentioned above possess this. It can sound like a cat purring softly, then suddenly, as the song builds, it takes on a life of it's own. The sound becomes more powerful and you can feel the energy building up and then jumps out right at you.
Bass guitars is also sweet when the tube has excellent energy in the upper bass like the BB. On good recordings, when I hear a slide on the bass guitar, I can feel the power as it starts with a transient when the player plucks the string, then as he slides his finger down the neck, the note goes lower and I get this "sucking" effect from the speakers. I can almost visualize the air being sucked and and the floor warping.
It's hard to describe. But this is some of the qualities I find very nice in the good vintage tubes that I've yet to hear on new production.

Well, that's all I have for now. I probably have 10 other vintage 6DJ8's to try but that won't be for a while.

Please feel free to add your experience with other 6DJ8/6922/7308 tubes you've had.

Maurice

marvda1

organ, any experience with nos tesla tubes?

marvin

ND13

Maurice has been hacking into my "rate the tubes" file on my puter!!!

J/K

You've come to close to the same conclusions I did. I have at least 30 6DJ8 variant tubes. And so far, none of them can top the Amperex makes.

organ

Marvda,
Never tried Tesla yet, only JJ (made on Tesla equipment). This will be the next 6922 for me to try... http://thetubestore.com/teslae88ccgp.html

Noel,
Interesting how the Ampex tubes behave so similar even on different gear. One thing's for sure though, Amperex got the midrange magic right on their 6DJ8's.

Is there any other 6DJ8 tube or others in the family you tried that gives you the same mids and imaging as BB? I'm really enjoying this type of sound right now.

Last night, I installed a pair of Mullard ECC82 in the cd player with the BB in the pre. Whoa, tube sound overkill. Not something I'd want everyday, but very good to have once in a while.

marvda1

that brings a question to mind. if you have lets say a preamp that uses 6dj8's and a cdp or dac that uses 6dj8's is it best to use the exact same tube in each?

marvda1

anyone able to answer the question?

Blownrx7

"that brings a question to mind. if you have lets say a preamp that uses 6dj8's and a cdp or dac that uses 6dj8's is it best to use the exact same tube in each?"

That's a very good question! Will having the same tube cause too much of a good thing???
Is it better to balance out one tubes emphasis with another's de-emphasis? It can get a little crazy, but it will come down to personal taste in many cases. ymmv

Anyway, can anyone suggest a source for reasonable priced (and reliable, i.e. not at the end of their life) Amperex tubes?

organ

Marvda1 and Blownrx7,
Doing that will keep the same sound signature of the tube (+/- the sound signature of the other gear).
IMO, it's much better to experiment. That's what's so fun about tube rolliing. You could get too much of a good thing sometimes, just like what I mentioned above on my last post about having Mullard on the source and BB on the pre. For some reason, my amp always remain neutral no matter which 6SN7 or 6SL7 I roll (but haven't done many here). I can get a touch of warmth on the amps but it always sounds neutral.

You should experiment. Using something that sounds warm on the source and maybe something more neutral on the pre, or neutral on pre and warm on source. One thing I learned is that the frequency range is determined by the tubes I use in my source. So it's probably best to use the tubes on your source as the "baseline" and roll the others until your ears are happy.

I have a pair of later production Siemens that sounds awesome on oldies. This tube adds that old production grain (not the bad kind of grain) that you sometimes hear on older recordings.

Blown,
The best place for cheap Amperex is ebay. Just make sure you're getting genuine Amperex tubes. Know what to look for (seams on top, mica design, etc) so you don't get burned buying a counterfeit tube. Also, make sure the tube still tests good. Look for a seller that list the test results. Some lightly used Amperex but test as NOS can be found cheap. And once in a while, you'll just run into a killer deal. That's how I came across my CCa tube. They usually go for $300+/pair. Got a single for $50 from Germany that test higher than new. Another great deal I won was for 10 various Amperex 6DJ8's for less than $80. Some of the best deals come from pulls out of old military or industrial equipments.

tubedepot.com have used and guaranteed Amperex and Telefunkens.