[S Clark]

The Dodd battery Pre is has had rave reviews over the last year or so and is known to have a clear, open sound with a totally black background.  Noticing that I had begun to have a small collection of 6dj8 type tubes, I decided to sit down for an evening of comparison.

Tungsram 7308
All things in their place, with nothing overly accentuated.  However, percussions have a soft edge, vocals recessed in the soundstage, and the attack and decay of the pluck of an acoustic guitar a bit muffled.  4th place as I like more detail

Valvo 7dj8 w/ D getters
This was the tube I just bought with very high hopes.  Of the five tubes listened to this evening this one finished last.  Lack of edge or detail like the Tungsram without the musicality.  Perhaps the extra volt compared to the 6dj8 just doesn't like my Dodd.  With all the hoopla about "D" getters, it was a disappointment.

JJ 6dj8
Actually, this did a nice job overall.  Good seperation of notes, good attack and decay of guitar, vocals sounded real.  Percussion ok, detail fair, soundstage reasonably wide and deep.  3rd place and definitely not a bad tube

Amperex/Seimens made 7308
very good seperation of notes on guitar. Vocals clear.  Excellent soundstage depth and width.  Bass and percussion detailed and clean.  Tie for first

Amperex Orange Globe Holland 6dj8
Attack and decay on everything outstanding, vocals extremely clear-almost in your face,  guitar notes separate, backup vocalist clear and defined, instruments appear that weren't quite there with the other tubes.  Sounds like a clear first, but there was one glaring flaw.  Although the soundstage was wide, there was absolutely no depth.  Everything came at you from the distance of the speakers.  Why oh why couldn't it have the depth of the Seimens7308.  Tie for first because is it is soooo damned clear.

[S Clark]

I forgot to ask if anyone has a 6dj8 type that they are using and recommend.

[S Clark]

Hey guys, I know that there are lots of fans of these tubes... so chime in.  What are you using and why?

[bunnyma357]

I am using some Voskhod 6n23p's that I really like in my Onix SP3, and is my current favorite.  Right now I'm running all NOS Russian/East German tubes and this has given me the best mix of airiness/delicateness combined with more beefy authority.

Others I've tried and liked, before winding up with the Voskhods  (In rough order of preference):

Amperex US PQ 6922
Amperex Holland 6DJ8's A-Frame
Amperex Holland PQ 6922
Tesla E88C
Reflektor 6n23p-ev


Jim C

[S Clark]

Can you describe what you liked about the Voskhods? 

[johnzm]

s clark,

i also have a dodd pre and have so far tried amprex goldpin 7308, and early amprex 6922, along with the stock JJ's.

i do agree the JJ's are not bad at all..

i am still breaking it in so i am swapping tubes between the jj's and the 7308/6922 depending on what im listening to.

how do you like your dodd so far and what is your setup?

[S Clark]

Along with the Dodd Pre is an old pair of Knight KB-85 amps with Sonicap upgrades, a Cambridge 640cd, a JVC QL-6 turntable, GR research AV3's, Neo2X, and a pair of the Mighty LS-9s in the latter stages of assembly.  Power cord is the Electra 7 strand, and interconnects are Electras and DIY.  Everything in my system can be replaced except the Dodd pre.

[BobM]

The Amperex's 6922's of most any NOS pedigree are generally really nice, but mucho expensive for a matched pair in good shape. I found that the Russian "Rocket Logo" tubes from Ultimate Audio to be very good for their very modest price, with maybe just a hair less "body" than the better NOS tubes but plenty of extension and detail.

[bunnyma357]

The Amperex's 6922's of most any NOS pedigree are generally really nice, but mucho expensive for a matched pair in good shape. I found that the Russian "Rocket Logo" tubes from Ultimate Audio to be very good for their very modest price, with maybe just a hair less "body" than the better NOS tubes but plenty of extension and detail.

The "Rocket Logo" are Voskhod tubes, that's the symbol for their factory. 

I can't give a direct comparison of the 6n23p's because I ordered a bunch of Russian Tubes from eBay and swapped multiple tube slots at the same time - so I can't really attribute what changes relate to which tubes. The end result was a more natural sound, perhaps a little less detailed, but more fullbodied, with richer harmonics, so voices & instruments sound more natural. Also the soundstage became more realistic, before, some instruments like guitars seemed to move to the front, and vocals moved to the back - now the placement seems correct with all the instruments more in line with each other, but still with a sense of depth.

I had been swapping around tube configurations about every two weeks, but this one has just sounded right enough that it's been months - and I've just been enjoying music rather than thinking about improving one aspect of the performance.

At some point I'll do some comparisons of the specific tubes, keeping the other tubes constant, but I just haven't felt the need to do that yet. And I'm sure with my integrated, a lot of it has to do with the synergy between several tubes, as well as the performance of each tube. Plus for me price is a factor, and the Russian/East German tubes were all very reasonable.

Maybe I'm talking myself into doing a quick test today and write some impressions of the various 6922 family tubes I have in the Onix/Melody SP3.

Jim C

[Ericus Rex]

What came in 2nd?

I'm currently using the Siemens 7308 and really like it.  Used Sovtek 6922 before that.  I have some Amperex orange label 6dj8s and they are just too warm (dull?) for my system.  Don't do too much rolling.  I prefer all those greenbacks to be in my wallet.

[bunnyma357]

Here are my quick impressions of the various 6DJ8 type tubes I have running in my Onix SP3.  The other slots are:

RFT ECC81 (NOS) (12AT7 type tube in place of a 12AX7)
RFT 12AU7 (NOS)
Reflektor 6P3S-E (NOS)  (Coin base tubes 6L6 alternative, supposed to be from Reflektor factory, but there is no factory logo, so I'm sure)

Voskhod 6n23p (NOS)  -  Natural realistic sound, treble through bass sound connected, soundstage is moderately wide and deep - again sounds appropriate.

Amperex USA PQ 6922 (NOS) -  Has more detail and air, wider soundstage, but maybe a little less deep. High end seems slightly grating, increased presence seems to make solo performers sound bigger than the perspective you'd expect. More impressive, but less natural. Overall thinner presentation, lower mids and bass sound a little tinny - less harmonics and resonances.

Tesla E88CC (NOS - Not JJ)  -  Similar to the Vokshods, but with a smaller presentation both width & depth, and a little less high end "presence", cymbal crashes seem to end a little less naturally. Very nice and natural sounding, just slightly flat - not as involving as the Voskhods.

Amperex Holland 6DJ8 A-Frame (Used in good shape)  -  Wide soundstage, but less depth, sounds a little unnatural on the size of instruments - "10 ft. wide piano", not a lot of presence or sense of space or air around vocalist and instruments, sounds a little flat. A little thin in the lower mids and bass. Very forward direct presentation - not romantic or lush. Sounds really good on some recordings, and just average on others.

Amperex Holland PQ 6922 (Used - a little less matched pair than some of the others)  -  A little flat on the high frequencies, deep soundstage but some what unnatural some vocals too far back, keyboards too far forward. Width is much less than some of the others, doesn't seem to go much beyond the speakers. Again a very direct presentation, with less of a sense of space.
Also seems to work better with some recordings more than others. Seemed to take longer to warm up and become "sweet" sounding than some of the others.

Reflektor 6n23p-ev (NOS)  -  Transients seem a little crisper, sound is a slight bit grating and a little less smooth. Natural sounding presentation, soundstage depth and positioning feel correct - a little less wide than some of the others. Not a lot of presence or sense of harmonics & resonances.

Melody 6922  (Chinese tubes that came with the amp)  -  Sounds like a scaled down presentation, less depth dynamics, and less able to separate the instruments accross the soundstage. A little laidback and not the same you are there presence as the others.

After this quick test I'd rank them as follows:

1) Voskhod 6n23p
2) Amperex Holland 6DJ8 A-Frame
3) Tesla E88CC
4) Amperex Holland PQ 6922
5) Reflektor 6n23p-ev
6) Amperex USA PQ 6922
7) Melody 6922


These impressions and preferences are definitely different than when I was running the amp with GE 3MBP 5751 (NOS),  RFT 12AU7 (NOS), and Valve Art 350B's (New Production) in the other slots, so how the tubes interact is clearly a factor.

Jim C

[S Clark]

Sounds like the Voskhod 6n23p may be value leader along with the JJ. 
What about Mullards, Phillips JAN, Telefunken, etc., etc., ...?

[bunnyma357]

If you do look at Russian tubes, the labeling is a little weird since some people translate the characters and some don't. So, a 6n23p-ev  can also be called a 6H23n-eb or a 6H23π-eb or 6H23pi-eb.

Here's a link that shows what logos correspond to what factories:

http://www.ominous-valve.com/russtube.html

I've had good luck buying directly from Russia, Romania, the Ukraine, etc. from eBay for very reasonable prices.

Jim C

[FullRangeMan]

Thanks guys for sharing your impressions, I will take note.
Regards

[S Clark]

Still looking for Mullard impressions. Anyone?