What 6L6 tubes do you recommend?

[Cornholio Farquarth III]

I need to retube my Sunn Model T Reissue head.

[Daehtihs]

Groove tubes matched them well.

[Phil O'Keefe]

Groove Tubes are fine... if you can find a good set of NOS GE 6L6GC's, those are the ones to go with IMO.

[1001gear]

Can it use KT66?

[daddymack]

Can it use KT66?

well you have the diameter issue [KT66 is larger, which keeps them out of some Fenders and some Marshalls, I'm not sure about Corny's Sunn], and the plate voltages are different, so a complete re-bias would be needed.

[1001gear]

well you have the diameter issue [KT66 is larger, which keeps them out of some Fenders and some Marshalls, I'm not sure about Corny's Sunn], and the plate voltages are different, so a complete re-bias would be needed.

 

Thanks. Figured as much. The one Sunn amp I heard had those and a very cool, jagged breakup.

[WRGKMC]

I had groove tubes in my Bassman for about 10 years and they were still working when I replaced them.

 

I tried out a set of Ruby tubes. They are branded Chinese tubes and ruby just matches them with a tube tester. After putting them in I tried to set the bias but they started popping and crackling so bad I had to power down and send them back for a refund.

 

Next I tried a set of JJ's. I had a set of EL34's in my Music man that sounded good, so I figured the 6L6's would sound similar.

They worked but pretty much sucked for tone. Anyone wants a new set I have a set I can give you half price. They may work out better on some other amp but the 10 year old Groove tubes sounded better then the JJ's new.

 

Lastly I bought a set of Electro Harmonix. The difference was like day and night. They have the tone and power of the old RCA tubes I used to use back in the 60's 70's. Big sound and full frequency. I changed out the preamp tubes too and that head rocks as good as the day I bought it 50 years ago. I had done a comparison with over a dozen different types of 12AX7 tubes too. The EH blew the doors off all of them in both normal and starved voltage circuits.

 

 

Tung Sol has a new production tube out I wouldn't mind trying but when an amp is running properly I found its best to leave it alone. Why look for trouble when it doesn't exist.

[1001gear]

Tubes are just bits in a vacuum right? Why can't they be cloned?

[AJ6stringsting]

I had groove tubes in my Bassman for about 10 years and they were still working when I replaced them.

 

I tried out a set of Ruby tubes. They are branded Chinese tubes and ruby just matches them with a tube tester. After putting them in I tried to set the bias but they started popping and crackling so bad I had to power down and send them back for a refund.

 

Next I tried a set of JJ's. I had a set of EL34's in my Music man that sounded good, so I figured the 6L6's would sound similar.

They worked but pretty much sucked for tone. Anyone wants a new set I have a set I can give you half price. They may work out better on some other amp but the 10 year old Groove tubes sounded better then the JJ's new.

 

Lastly I bought a set of Electro Harmonix. The difference was like day and night. They have the tone and power of the old RCA tubes I used to use back in the 60's 70's. Big sound and full frequency. I changed out the preamp tubes too and that head rocks as good as the day I bought it 50 years ago. I had done a comparison with over a dozen different types of 12AX7 tubes too. The EH blew the doors off all of them in both normal and starved voltage circuits.

 

 

Tung Sol has a new production tube out I wouldn't mind trying but when an amp is running properly I found its best to leave it alone. Why look for trouble when it doesn't exist.

 

Wow, I'm a devoted Euro Tubes Customer, I got tubes for my Marshalls, Carvins, Fender, Mesa Boogies and VHT amps and was very satisfied.

I spoke to one of the salesmen at Euro Tubes, talked to him what I wanted from a 1986 Carvin X-100B with 6L6's and 12AX7's, Iwanted my clean channel to have a classic Fender clean and my overdrive channel to have Marshall JCM 800 / Mesa Boogie Mark 2c kick .... Holy Moly ! , I put in the tubes and it was spot on.

 

I was cleaning out a warehouse at a Hardware Store, that I worked at and I found a box of old RCA and some Mullards tubes; 6L6's, 12ax7's, El84's and EL34's.

I broke a deal with my boss and I had to go 3 stories up, clean some pigeon crud off the store sign and I got 3 boxes of the aforementioned tubes and the tubes were mine for free !!!!. Man it was worth the climb , just like when my friends would rib me about dating a 6 foot goddess back in the 1980's .... she was worth the climb too !!!! Mullards are not that bad either.

RCA tubes are very very dynamic, especially the 6L6's, they are extra sensitive to the volume knob.

Turns out, that the tubes were ordered in October of 1969 and where obstructed from view until I discovered them. Lucky me !!!!

You're darn tooting when you say RCA Tubes rule !!!!

[WRGKMC]

I should also note, there were American made tubes back then that sucked just as badly as some of the ones made today too.

A couple of things to keep in mind. Tubes were invented in 1904 and were pretty much perfected by the mid 60's when many of the loudest tube amp designs were built.

 

Many of the tubes had decent designs and used similar materials, but given the fact musical instrument amps got really loud and caused the tubes to vibrate, and because the amps were driven around by bands from gig to gig, most Hi Fi vacuum tubes weren't up to the task and had big problems with durability and microphonics. I used to get 6 months out of most of them before the elements began to rattle bad enough to affect the sound and that was with an amp head that sat on the cab. Combo's were far worse and its a main reason so many amps blew up back in the day.

 

Manufacturers did respond by making an industrial GC version of the 6L6 tubes. They typically held up longer to the constant vibrations and transportation. I remember having allot of noise issues with Sylvania tubes. GE tubes were real popular in amps. That had mediocre durability and tone. They rattled badly and became microphonic when they got old. Tung Sol were great for Hi Fi, but they were horribly microphonic in guitar amps. Same with the Telefunken preamp tubes that came from imported German radios like Grundig and Blaupunkt.

 

Philips made some decent tubes. They were a Netherlands company that got into making radio tubes in the 20's then escaped to the US during WWII then moved back to Europe after the war. I don't think most Americans knew the tubes were no longer made in the US and the company knew better then to advertise it. The tubes themselves were very durable and decent sounding. You found them in many imported amps and many repair shops carried them as replacement tubes along with Mullards, RCA, GE and Sylvania.

 

There were a tone of branded tubes back then just as there are today. Everything from Ampeg, to Magnavox to Zenith had tubes branded tubes made for their Hi Fi gear. Even Fender, Ampeg, Gibson had tubes branded for them back in the 60's through the present.

 

There were many Tube manufacturers who didn't make audio tubes too, or at least didn't make good or popular ones. Raytheon, Westinghouse, Western Electric for example were huge radio TV tube manufacturers, but you didn't normally find them in guitar amps. It may be the companies were sold off or they simply saw that market as small potatoes (which it was) Radio, then Military made most of those companies huge fortunes.

Some built the first Tube based computers which were the size of a city block just to calculate missal trajectories.

 

They all became obsolete shortly after 1947 when transistors were invented. Took about 10 years for SS to become durable enough to challenge most tube applications, but by 1970 most of the US based Tube manufacturers either sold out or move on to bigger and better things. By the late 70's most of the tubes being sold for amps were either NOS or imported. Today, finding actual NOS is quite rare. Most electronics repair shops went out of business when buying new was cheaper then the cost to repair. I used to buy allot of the leftover stock at flea markets during the 80's. Then after the 90's places like eBay ruled for buying NOS.

 

Today? Forget it, Tubes are made of glass and don't visually show you how many hours they've burned. Its like buying a light bulb. you aren't going to know if its fresh out of the box or its been burning for thousands of hours. I see people pay insane prices on used tubes and I simply laugh. The tubes being made today are as durable if not much more so then anything made in the past. Some match or exceed the audio fidelity too. You simply have to try some out and find the best match for the amp circuits.