PRECISION MATCHED QUAD of RCA 12Ax7 -- all matched from the year 1960 (see exhibit A,C,D) , these are super early production RCA 12AX7's ... they are all 17mm tall grey plates, with square getter's. They feature the longest grey plates RCA ever produced ... grey w/ribs and a tilted "D" , crimped-on getter.
These tubes are very musical and render excellent sound in all preamps and musical instruments. The real McCoy, with original boxes ... 53years old! They sound so musical, with an extremely well centered tone and clarity / detail you don't often hear in vintage short plates. I think of them as USA's version of Mullard's 17mm long...
And getting quite scarce! These are the hard-to-findlong grey plates -- made a very brief time -- a transitional 12Ax7 model made just after the original late 1950s black plate! You don't see them too much, as RCA very quickly tooled up to make the short-14mm plate. (7025/ 12Ax7 rendition that is) ...
Exhibit B, shows actual tube under test, dynamic emissions at full load for easy reference. All (4) tubes / all (8) sides read a STRONG 120% or so... they are all well balanced & with matched halves. An ideal & perfect QUAD set ready for use any amp or preamp circuit calling for the 12ax7, 12AX7A , 7025, or ECC83!
They test (and sound) strong, quiet and are decently current matched (plate currents & GM, calculated using the strictest fixed bias tests, see included reports) on a 2nd lab tester at full plate 250V.
In original RCA boxes where they've been stored carefully for years. Very old tubes, quite low hours , they have lots of life left -- from early HiFi estate. Just throughly checked using multiple testers and played with music. Working well; quiet and matched, detailed and sounding great! Guaranteed no problems. See my detailed, 100% feedback regarding these old RCA tubes.
This is it ... the oldest incarnation of the grey plate RCA 12Ax7. Designed back in the late 30's / 40s before WWII and found inumerable audio uses post war..... .
Contrary to the much repeated confusion... in practice the 12Ax7 usually works exceedingly well in any circuit specifying the 12Ax7A or ECC83 -- all the same tube electrically ... the 12Ax7A has shorter refined plates that (can sometimes) allow for lower mechanical noise, and less situational hum.. NOT always a preferred thing... you should always own both new & old types.... And, you should first try and always own in your collection some nice tall plate originals -- like these. They sound like nothing else .... with incredicble musicality and tonal range and great detail. I like to refer to these as USA's take on a Mullard -- which they are brighter and edger than .. but oh - so - terrific tone! If you are using a very old preamp that's dark or a bit soft ... these early black plates can really bring out the clarity & detail. They have been a favorite of Marantz owners for years...who swap out their old Tele 12Ax7's for a while to enjoy this very much more Americanized sound....early Marantz can be dark (and wonderful still) and these tubes are a perfect match!
The most throughly tested, closest matching QUAD you will see anywhere! Very hard to find gems like this --- they will sell very quickly (last quad sold within 12hrs!).
Because, dealers all over can no longer find them. These are the early RCA's, and they haven't been made for more than 50 years. For guitar amps -- they are some of the very best tubes you can use ...
this QUAD; is totally matched also. Plates are performing incrediblely close, and strong functioning at full operating 250 volts eP -- .. they're are also all very close dates of production (see exhibit C&D for dates -- all from about 1960). This era kicked off the dawn of 12Ax7's for HiFi use ... The 1950s & early 1960's encompassed RCA's first and second generation of the 12Ax7.
Cosmetics are very nice .... flashing is very shinny & thick, idicative of gentle, some use, but VERY low hours and a long life ahead. A couple of the tubes have worn ink letters, they really present beatifully and all but one have etched RCA letters in glass.. Strong and super quiet (no microphonics), no gas or shorts. They were carefully checked and played with music -- for full details please read the reports in exhibit A,C,D,E below for date codes and exacting test results.
Again, this is the super cool early version of the RCA 12AX7 Tall, GREY plate ..... just made a few years and getting pretty famous now with audiophiles and musicians ... if you're collecting or planning to use in your older instrument or hifi's preamp -- and it calls for the low noise ECC83 / 12Ax7A / 7025 --- you are fine to try these .. you may be VERY pleased with results too...... probably the earliest & best matching set you'll see on here for a very long time - hefty tall GREY plates.... 1x top D getter, and thick flashing . With closely matched ip & mhos & dates -- you just don't see'em like this very often.
Study the included tube test results in photos and you'll see just how nicely fussed over, clean and well tested these originals are!
If you're currently a user of modern tubes then these will make a world of difference in your sound — a real upgrade and a treat for your ears -- clean, clear and more overall detail you can really hear.
These are the real thing made in USA ... from 1960! They sound wonderful and will sell very quickly.
Buy Now to avoid a bidder’s war.
Check my 100% feedback (check over what buyers have to say ... they love these vintage US tubes and I get allot of repeat customers, who don't hesitate) ...always fast shipping, and always super safe double box packing !!
100% happiness assured on all tubes and old audio items. Guaranteed NO DOA.
