6922 & 7308 Tube rolling results

24.4.254.70

Posted by Rafe on April 25, 1999 at 16:34:12

I've just finished doing comparisons of the 6922 and 7308 tubes I have. I've listed them is order of my preference, from least favored to most favored. These are just my opinions and I do not claim to have made as detailed a study as Joe S.

I rolled the tubes in my BAT VK-30 preamp. The rest of the system:

BAT VK-D5 CDP (with Amperex USA 7308 gold pins)
Classe CA-150
AQ opal XLR interconnects
AQ Midnight double bi-wire cables
Sonus Faber Concerto Grand Pianos on the marble stands

1. Sovtek 6922 - Pretty much concur with Joe S's comments. Sterile, thin, and SS sounding (although this isn't really apparent until after doing some tube rolling).

2. Phillips JAN 6922 - Boxes labeled 1/87. Slight improvement over the Sovteks. Soundstage lacks depth and height. Highs sound a little harsh. Another ho-hum tube.

3. Siemens (Germany) E188CC/7308 gold pins. Suprisingly, this tube did not place higher in my list. Initially, I was impressed with the excellent bass performance, deep and tight. Best bass of all the tubes I tested. The soundstage was wider than the Amperex's and the images seemed more precise. However, I soon began to notice an edginess, especially on the mids and highs that became quite annoying. Voices seemed to lack warmth and body. Tonal quality was un-natural and artificial. Brass instruments were shrill. Probably an excellent tube is some systems, but not a good match for my system.

4. Amperex 6922 PQ USA white label, gold pins. A good tube. No real problems. Good soundstage, imaging and tonal balance. Female vocals are slightly forward. Bass is slightly loose. Overall, a tube I can live with.

5. Amperex JAN 7308 (green label, single supported halo getter) 4/72. Good sounding tube. Slightly better in all respects than the Amperex 6922 in #4. A little more warmth in the mids, slightly deeper and tighter bass.

6. Amperex USA 7308 orange label, polished steel pins, single support halo getter. This tube did not pass all of Joe S's identification tests as an Amperex tube. They do not have gold pins. Tube diameter is slighly wider than the other Amperex's I have, but narrower than the Sovteks. It does have the 4 ridges on the top of the tube, the characteristic shield with the raised squares, and plate assembly. Whatever it is, it is a wonderful sounding tube in my system. Considerably more dynamic than my number 1-5 tubes. Lush, warm and full bodied mid-range. Noticeably lower noise. Smooth brass and female vocals. Very sweet and musical.

7. Amperex USA 7308 orange label, polished steel pins. This is now the reference tube in my system. Again, this tube did not pass all of Joe S's identification tests as an Amperex tube. No gold pins, but 4 ridges. Wider than other Amperex's. But the internals are really strange. The plate assembly looks like standard Amperex, but the standard Amperex shield or halo getter is not visible. There is an "A" frame supporting a circular plate with a number of round "rings" on the underside. This is at the very top of the tube, so I can't see what, if anything, is on top of it. But..WOW! The sound is AMAZING! My jaw dropped the minute I turned on the preamp after inserting these tubes. This tube delivers everything that tube #6 does, but more so. Rich, smooth, sweet, and lush, but still wonderfully detailed and natural. Everything I could ask for in terms of performance. This tube makes up for not having a tube amp. I don't know if this is really an Amperex or not. Frankly, I don't care. I'm looking to accumulate a lifetime supply of these.

Well, these are my impressions. I gotta go and look for some more of my favorite tubes. Happy listening!

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Topic - 6922 & 7308 Tube rolling results - Rafe 16:34:12 04/25/99 (27)

Re: 6922 & 7308 Tube rolling results - PeteG 20:45:31 04/28/99 (3)

Re: 6922 & 7308 Tube rolling results - Rafe 22:10:03 04/28/99 (2)

Re: 6922 & 7308 Tube rolling results - PeteG 05:44:18 04/29/99 (1)

Re: 6922 & 7308 Tube rolling results - Rafe 08:43:13 04/29/99 (0)

Re: 6922 & 7308 Tube rolling results - Joe S 16:47:06 04/25/99 (22)

Re: 6922 & 7308 Tube rolling results - Rafe 20:42:53 04/25/99 (21)

One thought.... - Joe S 06:36:07 04/26/99 (20)

Re: One thought.... - Jack G 09:23:45 04/26/99 (19)

So how do you guys keep/store your tubes? - Edp 10:48:20 04/26/99 (18)

Well.... - Rod M 11:48:01 04/26/99 (3)

Re: Well....; LOL - Rafe 12:25:42 04/26/99 (0)

Sounds good, now - Edp 11:52:54 04/26/99 (1)

ROFLOL! ;) - Rod M 12:04:57 04/26/99 (0)

Re: So how do you guys keep/store your tubes? - Joe S 11:22:24 04/26/99 (0)

Re: So how do you guys keep/store your tubes? - Jack G 10:59:34 04/26/99 (12)

Re: So how do you guys keep/store your tubes? - Sherwood 07:53:12 04/27/99 (11)

Re: So how do you guys keep/store your tubes? - Jack G 08:39:02 04/27/99 (10)

Re: So how do you guys keep/store your tubes? - Joe S 12:32:12 04/27/99 (9)

Re: So how do you guys keep/store your tubes? - Jack G 12:44:56 04/27/99 (8)

NOS 2A3 monoplates? - Quest 09:52:45 04/28/99 (3)

i thought that would get someone's attention:-) - Jack G 10:05:23 04/28/99 (2)

thank you Jack (nt) - Quest 11:48:17 04/28/99 (1)

Also try Angela intruments not as cheap tho. (nt) - Jack G 12:11:06 04/28/99 (0)

Re: So how do you guys keep/store your tubes? - Joe S 14:37:27 04/27/99 (3)

The number just dropped... - Jack G 06:14:49 04/29/99 (2)

Your dog? - Stephen 10:17:46 04/29/99 (1)

Re: Your dog? - Jack G 10:52:09 04/29/99 (0)

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