Word to the wise: avoid the Electro-Harmonix 12AX7 tubes

[Whoopysnorp]

I just bought six of the EH 12AX7s to replace what was in my Boogie Studio Preamp, and also just to have some extras around. Well, after a few hours of fooling around, I decided only four of the six were acceptable. One of them had a really annoying constant crackling sound, and another was too microphonic to use for any high-gain application. I know they're pretty cheap tubes, and they are current production (and therefore quality control problems are the norm) but damn, 4 out of 6 isn't encouraging.

The ones that worked did sound good, at least.

[clineaudio]

Originally Posted by Whoopysnorp

I just bought six of the EH 12AX7s to replace what was in my Boogie Studio Preamp, and also just to have some extras around. Well, after a few hours of fooling around, I decided only four of the six were acceptable. One of them had a really annoying constant crackling sound, and another was too microphonic to use for any high-gain application. I know they're pretty cheap tubes, and they are current production (and therefore quality control problems are the norm) but damn, 4 out of 6 isn't encouraging.

The ones that worked did sound good, at least.

svetlanas opened my marshall up like you wouldn't believe. Now they are...
"SED Winged C, St. Petersburg

A major Russian power-tube manufacturer. Formerly a part of the huge Svetlana collective factory, now independent. SED tubes are now distributed in North America and Europe by PM Components. Types in production: EL34, SV6L6GC, SV6550C, 300B, EL509, EF86, 6BM8, 6AS7, 3CX300A1, 6D22S, GP-5, and a long list of large power types for amateur radio, broadcast and industrial uses. KT88 and 12AX7 are have been recently introduced.

Note: there is no "Sovtek" factory. "Sovtek" is only an American brand name owned by New Sensor. New Sensor now owns the Svetlana brand name and is using on tubes manufactured by Reflector."

(sorry for the pasting, but it's good info, nonetheless)

[Whoopysnorp]

Yeah, all I know is that the tubes branded Sovtek, Svetlana, and Electro-Harmonix are all made by the same factory. Yeah, the SEDs are what used to be Svetlanas, and I hear nothing but great things about those.

I like some JJ/Tesla tubes, like their E34Ls for example, but their preamp tubes seem a little ho-hum to me.

[lukedavo]

I dont know, try the groove tubes, maybe they will work a little better for you. They got a 12ax7 that is the same price as the svetlana ,which coincidentally I have heard bad things about their consistancy in manufacturing, ie.. 2 out of 6 are bad.

[Whoopysnorp]

What I really like are the reissue Tung-Sol 12AX7s. I have a pair of those in V1 and V2 of my Rivera and they have a great tone. They are a bit more expensive than most 12AX7s though--around 14 or 15 bucks.

[smopo24]

why is there such inconsistencies in the manufacturing of tubes anyways? it seems like they should have gotten the kinks out of the process by now.

[Nubus]

Originally Posted by Whoopysnorp

I just bought six of the EH 12AX7s to replace what was in my Boogie Studio Preamp, and also just to have some extras around. Well, after a few hours of fooling around, I decided only four of the six were acceptable. One of them had a really annoying constant crackling sound, and another was too microphonic to use for any high-gain application. I know they're pretty cheap tubes, and they are current production (and therefore quality control problems are the norm) but damn, 4 out of 6 isn't encouraging.

The ones that worked did sound good, at least.

Hey Whoops- EH should have replaced those defective tubes. I'm sure that they offer some sort of guarantee for situations like that.

[Whoopysnorp]

I wound up getting replacements for them but haven't had a chance to try them yet.

Basically, I think the reason that tubes are such a crap shoot is that they are manufactured for cheap in third world countries using cheap raw materials, and they aren't made to military or medical specs anymore.

[smopo24]

Originally Posted by Whoopysnorp

I wound up getting replacements for them but haven't had a chance to try them yet.

Basically, I think the reason that tubes are such a crap shoot is that they are manufactured for cheap in third world countries using cheap raw materials, and they aren't made to military or medical specs anymore.

yes, they wouldn't want happy customers and a good reputation, now would they? unfortunately that's the cost of doing buisness these days; cheap parts and labor for a niche-market product will assure more profit.....but i'm sure customers would be willing to pay more for better quality control; look at the market for NOS tubes!

[Whoopysnorp]

Originally Posted by smopo24

yes, they wouldn't want happy customers and a good reputation, now would they? unfortunately that's the cost of doing buisness these days; cheap parts and labor for a niche-market product will assure more profit.....but i'm sure customers would be willing to pay more for better quality control; look at the market for NOS tubes!

I definitely agree, and I'm surprised that nobody already does it. There are some current production tubes that are a cut above the typical quality--the reissue Tung-Sol 12AX7s come to mind--but that is a rarity.