Tonefiend Forum

So, having just jumped into the valve amplifier world, I have found myself facing a question: How much do different tubes affect an amplifier's tone? I know that different tubes such as El34's, 6l6's, and 6V6's all have different sounds, but I'm curious about different makes and models of the same designation. Most tube retailers post descriptions of how they think different tubes sound, but I would like someone's opinion who isn't trying to sell me something. Have you guys experimented with different brands and models? How radical where the changes? Were they revelatory or redundant?

Generally cheaply made tubes are less reliable and more prone to failure.Tesla/JJ makes less expensive tubes that work well (no issues with any I bought)There are only a few places that actually make tubes anymore.The expensive tubes are out of my price range but usually are either old or use things like gold contacts etc.When you hear a great sounding amp that has mullards or svetlanas it might just be that it is a great amp ? Tung Sol made some really good tubes in China of all places.It is one of those things that some people swear by and others just don't even think about.Welcome to the world of tubes insert credit card....... Here !

The only way I buy tubes is if they have been run for at least 24 hours (some need more like 48 to 96 hours) then matched for bias and gain (transnconduction). The reason is that tubes amazingly still are assembled by hand, this means there is a lot of variation no
matter how careful the workers are. Tubes after they run in change physically internally as the elements shift from the heat. If you do that and then set the bias correctly (60-65% for AB1-2) and tweak the resistors in the phase inverter to match any slight gain variations. If you do that the amp will sound fabulous, it is standard OP for hifi but guitar amps need it to. If the amp is cathode bias I prefer seperate cathode resistors for each output also standard for hifi. I also prefer that preamp tubes be run in to find the stinkers. You will find very few techs that can do that sort of thing unfortunately. I also have to say that most of the Groove and Mesa tubes don't seem to have the run in or matching I desire. I can't tell you how many sets of Groove and Mesa tubes I was givn to install that were sorely lacking and fell short of giving the best tone possible but that is what the customer gave me to put in. I have put Svetlana & Tesla tubes in Mesas and set them up properly the customers were amazed at the tone they got, very happy customers that gave me some great tips ( broken pedals and even old amps which I loved to get). It seems like New Sensor ( Electroharmonix) is doing a pretty decent job of tube run in and matching these days. I used to get all my tubes from Fat Willie at NBS Electronics in Denver, CO but he seems to have gone missing of late (hated his politics but loved his tubes). I don't do repairs these days since my back surgery except for me and a very select group of pals so I haven't been doing my own burn ins and matching as it requires buying at least 50-100 tubes at a time to get enough matches. I am fotunate to have squirreled away a lot of NOS tubes over the years. But it is worthwhile to learn how or find someone who can set up the amp properly.

I am still trying to figure out what to do with the 50+ 25L6's I have in my garage, they might make cool overdrives or distortions or maybe even low powered single ended amps. They don't sound like a 6L6 but are between that and 6V6's.

If you look around on you tube there are videos of a French dude that hand builds tubes for a hobby,it is fascinating and very instructive check it out.

The Eurotubes sight sounds like it's run by a bunch of grumpy old man, and scrolling quickly could give you a seizure. They seem to know what they're talking about, though, and I learned a couple things from reading what they had to say.

Quote from joe on October 11, 2012, 10:35
Usually the medium-cheap tubes work fine for me, but I have occasionally splurged for a spiffy power tube or two. My one sustained tube quest was forced on me: I THOUGHT it would be a cool idea to build a Marshall 18-watt clone from Ceriatone with an EF86, because I've never had an amp with that particular tube. I love the 18-watt, I love Ceriatone, but man, that frickin' tube! So noisy! So hard to source good ones! So expensive! So not worth the hassle!

EF86's are cool tubes but they can be very noisy and microphonic because they have a boatload of gain which contributes to their problems. It can help to put elastomer bands on the glass envelopes to help suppress microphonics, they should also be mounted in shock mount sockets with rubber isolators between the socket and the chassis. They can be used many ways besides as a conventional preamp. The gain can be varied by controlling the screen grid current so you can use it as VCA and other circuits in fact there was a Svetlana doc that detailed using it and other tubes as a vacuum tube synthesizer. They sound very different from any other preamp tubes, they made some Vox amps sound unique. I have heard some astounding phono preamps made with EF86s in the past the creators selected the tubes by hand and I was told they used less than one in 75. They actually welded wire leads to the tubes and mounted them in vibration proof, temperature controlled mini-vaults. These preamps were $20,000+ even in the early 80's and they sold piles of them.