Originally Posted by mordy
Did anybody compare the Pinnacle style side getter 6AV6 with the GE 6AV6 top getter?
I have not directly compared these, but my general feeling is that the RCAs are a bit more forward and bright.
And I can provide a little more guidance regarding which GEs to purchase....
Currently, my go-to tube is the 1958 GE 6AV6. It has superb clarity and transparency, sweet mids and a punchy, detailed bass. Actually, I have had this tube for some time now, but initially felt that it wasn't all that great, so had put it aside. When I received the FIVRE and Toshiba tubes, I noticed how similar the construction of these tubes were to the GE and pulled it out for comparison. In the meantime, I had purchased new headphones and upgraded my op amp, and boy was I surprised when I heard these again! Finding an overlooked treasure in my "not good enough pile" was very sweet. :)
However, the fact that Audiofanboy reported that he was not all that impressed by his GE 6AV6 was somewhat disconcerting. And further, I have seen several versions of this tube on eBay that look quite different. So in an attempt to get to the buttom of this, I ordered two more GE 6AV6, each with different internal construction. (And I should point out that that there also exist RCA and Sylvania manufactured tubes with GE paint. Typically, the classic sandblasted GE pattern with the tube number and dots is conspicuously missing on these tubes.)
1958 GE 6AV6
1974 GE JAN 6AV6. The metal box-like structure on the top mica is gone. It has a side-mounted square getter, located above the top mica. Compared to the 1958 GEs, it is as if the bass has been sucked out, leaving a rather shrill presentation. Not good.
1980 GE JAN 6AV6. Halo getter, top mounted. But sound is similar to the 1974 GE with a rather shrill presentation. Not good.
The specific changes in these newer tubes that make them sound like crap are likely undetectable to the naked untrained eye, but they appear to coincide with the removal of the box-like structure located on the top mica. So my recommendation is that if a GE 6AV6 doesn't have a metal box-like structure on the top mica, do not buy it.
But there is more.... Apparently, the 1950s GE 6AV6 design was adopted and implemented by a number of other manufacturers, such as FIVRE and Toshiba (Multivox) below. Notice that both of these have the metal box-like structure on the top mica and diodes that resemble GE's plates with a rather steep peak. And more importantly, the sound of the FIVRE and Toshiba tubes is indistinguishable from my 1958 GEs. So if you see a 6AV6 that looks like a 1950s GE with peaky diodes and a box on top of the mica, there is likely a very good chance it will sound like a 1950s GE. And that is a good thing. :)
FIVRE 6AT6/EBC90 (1950s)
Toshiba (Multivox) 6AV6/EBC91 (1970s)