Does anyone know what the deal is with lopsided tubes? I get the minor differences, but some seem pretty extreme. Wondering if something like this is still considered normal.
Thank You!But they are sold i waited too long.....
Nathan have you tried it with a different input tube I know you run the E80cc does it behave the same with the 12au7? The only tubes I have experienced something similar with are the Bendix 6080 graphite plates and they only did it a few times on start up soon after shipping. Once I had put a few hours on them they settled down and the problem went away.
I use a old set of cheap old phones for any initial testing be it new tubes, burning in caps or after making circuit mods.
Sounds defective to me. Cold, the tube seems to work, but as it heats up to operating temperature, internal metal parts expand, something inside shifts position slightly and the left channel drops out. These are wonderful tubes and you have my condolences...
If the seller offered a warranty then I'd inform him and return it as soon as my feet could scurry to the post office. Bummer for both parties involved of course but given the price these typically sell for you have the right to expect a functioning tube if it was sold as such. Assuming the amp and cans work fine with any other tubes of the same basic construction I guess that thermal expansion makes something shift and lose contact, this clearly goes beyond 'pinging' tubes during warmup. Good tip to check the heaters.
Just a short side note to share my excitement about one of the new tube types I'm currently testing in my DV 337 amp: a pair of Sylvania 7236 power tubes. To my ears these sound extraordinarily good. I'll definitely do a more detailed comparison later on but some impressions while listening to classical on the 337 and paired with TS 6SJ7 mesh plate drivers:
- Extraordinarily clear and crisp sounding, much clearer than any 6080 and 6AS7(G) I've heard.
- Very detailed
- Deep soundstage
- Dead silent, no microphonics at all on this NOS pair, and this from the first moment.
I'd compare them to my TS 5998 but a bit less 'wide' in soundstage, though deeper and more detailed. Bass is good, not very pronounced (caution: the type of music I'm listening to right now is not bet for bass let alone bass punch evaluation), less 'boomy' than the TS 5998.
These are not warm sounding tubes, rather more SS like to my ears but very, very detailed and really nice with orchestral music and brass (listening to some trumpet concertos by Purcell, extraordinary).
You don't see these too often online but even at this stage I'd say, grab a pair if you encounter them. Best of all, I paid less than half than the price for 5998.
As always, everything 'IMO' and based on my taste.
The Sylvania 7236 has a flat plate structure like a 6AS7G. It sounds pretty good, but it's nowhere near as good as the TS7236.
Here's a quick pic of the Sylvania 7236 playing in my amp, don't know if it helps you for the structure. Apologies for quality but hey, it's 5:30 AM here :-)
Once again, I haven't heard the TS version but these do sound very, very nice if you like a tight, clear, controlled and not overly warm sound that most would term more ss than tubey. Have just been rolling them to compare with RCA 6AS7G and for my taste the 7236 play in a different and far superior league when listening to classical. Have BWV 1068 on (Bach's suite Nr. 3 in D for orchestra) and it's magic. But remember my caveats about bass (haven't tested them with it yet) and the fact that I'm really a fence-sitter and prefer a warm SS sound or a cool-neutral sounding tube amp, not the favoured by many 'lush' or 'liquid' / warm tube sound. Will do a detailed comparison with the TS 5998 later, wouldn't surprise me if these came out on top for me.