tube rolling... 6l6's

[dp1954]

I've had my mc240 and mx110 back from Terry's now for a couple of months and have spent the last few weeks rolling tubes in the 240 trying to find the combination that I like the best. The 240 came with a new quad of Groove Tube kt66's. My musical tastes are varied.. anything from country to metal, classical to blues. I listen to and like most everything except opera and old style country. All the tubes in the mx110 are teles.... Small tubes in the 240 are telefunken 12ax7's with the rest being rca black plates. While I was having the equipment rebuilt I started picking up various 6l6 tube varieties to try. These are MY observations... YMMV, done in the order of testing.

1. Grey plate sylvania 6l6gc's. These came out of a Marshall bass amp and tested out at about 87% new. Definitely not my cup of tea. No bass, no treble, weak mid, made me wonder who stole my stereo. Not a setup I could live with.

2. New quad of EH 6l6gc's. Better bass than the sylvania but about the same otherwise. I put about 10 hours total on this setup and even though the 6l6's improved over time I just don't think these are where its at. The highs did improve over time to the point that I'd choose these over the sylvania's.

3. NOS quad of RCA blackplates. test at 103% of new. Stuck these in and cranked up some Buffet. Now I was starting to get somewhere with these tubes. Better bass, midrange and treble with a much better soundstage. These are much better than #1 or #2. If I didn't know anything else I could live with this combo.

4. Groove Tube kt66's.. These are the quad that came with the 240 and have about 30 hours on them. These were the first tubes I tried when I purchased the 240 and before it was rebuilt. These tubes are actually not bad. Very good bass although a little loose way down low. Very nice midrange and decent treble although the highs were not as clean as I'd like. These tubes have the first three beaten in spades though.. they are just bigger, louder and .... more.

5. Valve Art kt66's.. I picked up this quad based on some remarks I'd heard on the forum. These now have about 20 hours on them. And these things are just fantastic. The 240 opened up on all fronts.. highs, lows, soundstage, separation. These are a great buy. They are clean/clear, the best I have heard so far. I really can't say enough about these tubes,, I'm just really impressed. I have ordered another quad just to keep for the future. At 90 bucks a quad these are a no brainer.

These are all just my thoughts/observations. I'm very happy with the VA kt66/240/110 setup, but because I'm a junky and can't leave well enough alone I've order a quad of VA 350B's just to try. I'm curious to see the diffenrence between them and the 66's.

Aint it fun?

Dave

[Allan Songer]

I've rolled just about every 6L6 variant you can imagine in my MC30s (and 240s in the past) and here is where I ended up:

The WE 350B brings an amazing lifelike quality to an already amazing midrange in the MC30 without sacrificing anything in the bass department. The GEC KT-66 has the firmest, tighest bass, but the WE 350B bass is close. And in the midrange NOTHING comes close to the 350B.

[dp1954]

Allan. I can't see the pic you've included, but assume its a quad of either GEC 66's or WE 350b's. I am aware of these tubes and there following, but at the price you can't beat the VA's 66's. I'd be interested in hearing the setup with a quad of either of the above. I may start picking up a tube hear/tube there..

dave

[Allan Songer]

I'm buying one of Craig's new stereo amps for my office system. He's setting it up with VA 350Bs--can't wait to hear them!!!

[Audible Nectar]

I am revisiting some of the output tubes for my MC-30s as well. Since these amps were rebuilt, I'm getting "new light" with some of these tubes that I didn't think so much of before.

The SED Winged-C 6L6GC is a pretty good value priced tube for these. Balanced, smooth, and clean sounding, the only problem with these tubes is the hella long break in time......about 200-250 hours before they "clear up" from NOS state. Other than that, it's hard to say much bad about them. If you are seeking a reliable and cheap 6L6 for these amps, this is a good choice. No particular exceptionalities, but good all around. Been using these for the last few months.

The RCA blackplates were a favorite in both before and after rebuild versions of this amp, but not quite as balanced overall. A KILLER midrange tube for guitar oriented stuff.....you will think that the notes are jumping out of your speakers! There are other tubes I prefer for other material outside the rock realm, and at times a bit too much midrange emphasis and a looser bass.....but it does some things really well.

I am getting an opportunity to audition some GEC KT66 soon, a tube that I really want to revisit with these recent rebuilds. The added bass authority and sweeter throat should be an asset this time. Was not impressed pre "rebuild", but expect better with the new, clear, and "wide open" caps.

And of course, the GE 6L6GC is a tube I really want to try out again. I think the smoother, richer tone of this tube will be a really good selection for one of my MC30 pairs long term. This is another "midrange" tube, which is to say it's really good at that while not being "perfect" at the extremes, but great for bringing old, dead recordings back to life. I have two sets of MC-30s (one set to be rebuilt), and think the GE would have a home in one of those two pairs. I just need to get some of my own....the prior listen were loaners.

350B.....well, I've got so much to do already that I'm not worried about these for now. Might try the Valve Arts at some point later.....the WE version being a tube I'll likely never own.

[jbsl]

I just got a quad of the SED Winged-C 6L6GC and have put around 40 hours on them and so far I like them. Did not know it will take that long to break in. I also went ahead and ordered a quad of SED EL 34s to try out. Also ordered some 5751s.

May have to try the VA KT 66.

[jbsl]

Where can you buy a quad of Valve Art kt66's?

[Audible Nectar]

Kevin at Upscale Audio has the VA KT66, as well as Jim McShane (Citation II rebuilder and tube seller).

And yes, the SED Winged C will become more liquid/fluid/clear as you use them from NOS state. It's kinda funny, because I have had these in now for three months, and have had no desire to change them. I've fiddled with the smalls a bit (mostly the phase splitter) but have left my outputs alone as of late. Pretty good for a $20 NOS tube.

[Mick Bell]

Anybody tried Genalex Golden Lion KT66?

[jbsl]

The only KT 66 Upscale has on the website is Chinese KT66 Genalex Copy. I did not see the VA KT66. Jim does have them.

[WopOnTour]

I just got a quad of the SED Winged-C 6L6GC and have put around 40 hours on them and so far I like them. Did not know it will take that long to break in. I also went ahead and ordered a quad of SED EL 34s to try out. Also ordered some 5751s.

May have to try the VA KT 66.

I didnt care for the SED 6L6GCs in my Harmon Kardon.They sounded gruff despite being used for 100 hrs or so in another amp.I've also tried some Groove Tubes GCs in there but they were quite weak/thin sounding.

The RCA black-plates that came with my amp actually sound quite good, although it's probably a toss-up between them and the quad of NOS General Electric 7581A that I found on eBay- depending on the music you listen to. The 7581 definately have much better bass extention and are really ROCK the Lascalas (hence they've in there a LOT) but for more subtle tunes, blues, and jazz the RCAs seem a bit superior (detailed?) in the mids.

I've only had this amp for a few weeks and basically have only recapped the main output couplings so far (McShane power supply upgrade is enroute) but once I'm done I may order a set of these EH KT66 to try .

For $100 they would be hard to beat if they sound that good. I've been looking for a "steal" on some WU/WE 350Bs but...

WopOnTour