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Well...it happened. I flipped the amps on this evening and was greeted with horrible popping out of the speaker and white/purple flashes of light from inside one of my JJ 6V6S tubes. Tube tester told me I had a short on pretty much...everything except cathode. Thumping the tube in the tester would make the short go away.
So now I'm in the market for a quad of 6V6 tubes for my Motorola HS-619. I'm currently limping on two good JJ tubes and two good 6P6S tubes. Not ideal...but the amp doesn't mind and it's probably better than running just a single output tube.
I don't feel like going NOS...especially since a whole quad of tubes wasn't in my plans. So I'm looking at going either with a matched quad of EH 6V6GT or pick up another quad of JJ 6V6S tubes.
Has anyone used the EH tubes and able to provide an opinion? The price difference between them is a toss-up.
Thanks in advance,
I have several touring guitarist customers using JJ 6V6s in their amps, and they have held up well over hundreds of miles on the road.
That said, the JJ 6V6 isn't exactly a 6V6; it's a kind of 6V6/6L6 hybrid. Some like this difference and prefer them. They don't sound exactly like a vintage RCA or Sylvania 6V6, and even those have slightly different flavors.
So, if you have liked your JJ 6V6s, you might want to get more of them. If you get a Tung Sol reissue set, they should work fine, but you may or may not like the sonic signature.
JJ's Octal production is highly suspect. The EH tube is OK, but its New Sensor "stablemate", the "reissue" TungSol is excellent.
If you want to try NOS, without surrendering body parts, make or buy adapters constructed from Loctal sockets and Octal plugs to hold 7C5s.
What Eli said - get the reissue Tung-Sols.
The datasheet I saw for the 7C5 listed a max plate voltage of 315V; my amps run higher than that. Hell, the max screen is listed as 285V and my amp is running them at 330V They look cheap enough and I'm sure I could construct adapters if I wasn't pretty sure they'd explode once the B+ hit them.
I'll have to give some consideration to the new production TungSol's; they're a little more than I really want to pay right now.
Of all the JJ octal tubes, the 6V6S seems to be the most consistently ok tube. It's just the way the 6V6S reproduces music. It's tone is not classic 6V6GT, with a rich midrange. More of a 5881 tone. Bass and treble. A little thin in the middle.
I am hoping that like...it was just a fluke that something failed and that tube went the way it did "for no good reason". I know the amps were rebuilt in 2008, I don't know how old the JJs were when I bought them back in 2011. I swapped rectifiers after I got them because the Sovtek's they came with had a hotter B+ and these things were already at what I thought a 6V6 amp should run. I'm pretty sure I may have abused those tubes before I did that.
I ran them for about 3 years before I swapped a pair of soviet 6P6S tubes in I had laying around, the datasheets indicating my voltages were way too high, but I was having one of those nights were I was like "let's see if they melt". They were much like you described the classic 6V6 tone...very rich midrange. I came to like them after 100 hours or so. I ran those until a few months ago when one developed a problem with the cathode shorting to filament; I pulled the JJs out of storage and slapped them in.
It was kind of like a slap in the face; those Soviet tubes sounded a bit muddy in comparison.
Oh well..I'll get something ordered next week.
I still have to wonder if this wasn't a sudden death but rather a bunch of stuff I didn't notice leading up to the lightshow. That very same amp "ate" a 5Y3 earlier in the week; the one I had in there decided it didn't want to make a lot of B+ after it got hot. I put a replacement 5Y3 in it; but I later wound up swapping in a 5R4GY "because I could" and...maybe with the fact my amps are a pretty light load compared to a 5R4's current handling; the B+ was a tad higher and just allowed the problems to continue....I spend a lot of my time looking at how something broke after I fix it...and doing what I can to make sure it doesn't happen again.
But it's Friday..I'm in a mood that I want my tunes at any cost; and since these amps are consumer equipment built like some of the jukebox amps I've services...I broke all the rules and split a pair of non-shorted JJs and the good pair of the Soviet tubes between the amps.
Sounds fine. No smoke. Overly large OPTs aren't hot after a few hours of use. I think I can limp along till I get a new quad in...so I got that goin for me.
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