June 3, 2012
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Tung-Sol Solid Grey Plate
Moving backwards in time, this review covers the Tung-Sol solid grey plate tubes manufactured between 1960 and 1963. The matched quad of output tubes under review were made in August, 1962 (3226236-3). They have the hallmark ST bottle shape with a top getter and two side getters projecting from the upper half of the plate structure. There are four hexagonal, transparent mica spacers holding the transparent splatter shield and they have a chrome-colored collar with a brown base.
The tubes were OEM (original export manufactured) for Stromberg-Carlson, a telecommunications equipment and electronics manufacturing company, who, in turn, packaged them for sale to General Dynamics.
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The set is well broken-in and has seen hundreds of hours of playing time prior to review. Although these tubes exhibit the usual Tung-Sol 6550 “house sound,” they are not identical sonically to the three-hole grey plates previously reviewed. The Listening Impressions section that follows will, therefore, highlight these differences.
Listening Impressions:
- The overall presentation is smooth, refined and extremely natural.
- Detail is reference-level with sharp and clear initial transients. Steel guitar strings zing.
- Percussion instruments played by slapping the hand against the drum head are almost life-like.
- Images are larger but not diffuse.
- The ocarina on American Acoustic by Tingstad & Rumbel is piercing without being shrill.
- Dynamics are borderline reference quality.
- Sound stage cues are easily apparent. I was able to tell depth differences depending on whether the vertical venetian blinds behind my listening seat were in a closed and flat position (less depth) or closed but perpendicular (more) to the glass patio doors.
As you may be able to tell, these are among my very favorite output tubes. While listening to the CD entitled Chet (the Keepnews Collection version) by Chet Baker, the only thing missing was a very cold vodka martini.
Comments (3)
I, too, have found the solid plate Tung-Sol 6550s to sound different from the later three-hole plate. Yep, the lack of coloration allows these tubes to track sources in honest fashion. Those low-level clues, such as hands slapping drum skins, aren't as distorted, buried, muffled, warped, or obscured.
I'm very scared to ask but I shall. How much was this quad of tubes? My guess is about $600. Off to find your review on current Tung Sol 6550s to compare reviews. Keep up this awesome work. It is helping this tube newbie and is appreciated.
@JD -
Thank you for the kind words.
I honestly don't remember how much I paid for them and even whether I bought them from an online vendor or at an auction at E-bay. I did find a transaction for a matched quad of NOS grey smooth plate Raytheon 6550s that I won at E-bay and their price was $555. And that was in 2005. I'm guessing that the Tung-Sols were at least that much.
There is a seller now on the Audio Asylum Trader who's asking $960 for a quad of NOS three-hole grey plate Tung-Sols. The earlier smooth grey plates, were they available in NOS condition, would most likely be even more. There are very good quality current production tubes that are reasonably priced and even vintage GE 6550s which are excellent, can be found for around $125 each, I believe.
Please keep in mind as you peruse these reviews, that they're only my opinion. Nothing more, nor less and that your system, room acoustics, and personal preferences may lead you to different impressions and conclusions.