Suitable alternat for SED wing = c= ?

[bandit2013]

I tend to be wordy.

It would be very difficult to say one tube is better than another. They all have unique character and tones. Perhaps I need a guitar lobotomy to cure me of the itch of trying to get a perfect sound and just sit down and take time to just play the dang thing. Trying out new power tubes, preamp tube rolling, is almost like changing pickups in your favorite guitar since there will always be something to like or dislike and it just goes on and on and on...... :shock: I can stop...., or can I ? :wink:

 

[bandit2013]

The JJ6CA7 tubes sounded great for about a month. Not a bad price but the life span of the tube is this short :evil: , perhaps the SED =C= price is a bargain. Ran the wing c 6L6 for nearly 8 months without an issue . As for one of the Matched JJ6CA7 started to make some popping noise then decided to shut down completely I was really enjoying the tone from these tubes. The tube in question was in the V9 position. I noticed it did not have the typical blue glow to it like the other 3, so I swapped V8 and V9 and put the channel power modes to 45W. Powered the amp up all seemed fine. Then it went out completely. Heater was still glowing. I swapped the JJ6CA7s with the EH EL34 just to see if there would be any difference, all was fine with them. I do know that the tubes do not need to glow blue and it is not an indication if there is anything wrong if they do not. Since I can see the grid through the side slits on the plate, they were not glowing bright either when playing the guitar. Also when I moved the tube to the other position is was much cooler than the other three.

When I drive the EH EL34 to a get the sound I like, they plates will be glowing almost in entirety. Well before I burn up any more money on tubes to fry in the Mark V, best to find out what the story is. This amp may be hotter than it should be. Guess I will drop in the SED wing C 6L6GC for the time being. They may get hotspots at the seam of the plates but they go completely cherry like the stock Mesa 6L6GC. I am considering Gold Lion KT77 but they cost a bit more than SED =c= (EL34 or 6L6GC).

I did try the SED wing c 6L6 paired with the TAD6L6GC-STR in the Mark IV, that was a sinister tone. I will have to try it in the Mark V. The TAD6L6GC-STRs did not reveal any hot spots on the plates but that may be a result of the black coating.

 

[R_ADKINS80]

I just repaired a B52 combo that had one tube with heaters on but no blue glow. Threw my bias probe on it and it wasn't passing any plate current. An open screen grid resistor was the culprit. Replaced not of.the "cinder block" grid resistors with quality resistors.from the tube depot and it was an IMMEDIATE improvement in tone. If anyone has ANY amp that uses those brick resistors, do yourself a favor and spend the $.99ea on some good resistors. Thank me later!

 

[bandit2013]

I am not sure there is a grid resistor issue since the defect stayed with the tube when it was moved to a different location. I do believe that the amp may be running a bit hotter than it should. From what I gathered, the Mark V runs on the hot side for a fixed bias amp, where as the other Mesa amps have a cold bias. As for the EL34, they all had the blue glow but not as abundant as the large bottle 6CA7 or 6L6GC types. Since I was preamp tube rolling to tune in the 6CA7 for CH3 (the JJ6CA7 have an early onset of distortion) in an attempt to gain more headroom from the power tubes. The popping issue was going on for about a week along with the crackle of the glass while the tube warms up. It would go away once temperature was optimum. I did not realize that when the tube reached proper temp it was shutting down. That would explain the higher than normal saturation since one half of the A/B was only driving one tube and not two.

I have the SED =C= back in, bias switched to 6L6 and everything is kosher. Still I need to get a bias probe and meter so I can be assured that plate voltage and current are not out of whack. I did study the schematics on the Mark V, not sure how complete or incomplete it is (more incomplete since all of the relay switch circuits are missing, contacts are there but no parts for switch logic are available). If one of the relays used to alter bias are not working would account for the issue. Relays are used to change bias for the 10W mode. So there is not just one resistor that can be changed if the bias requires altering. I still cannot rule out a grid resistor, it is common for carbon comp to become open circuit when the get thermally saturated. There are two carbon comps, the rest are metal film resistors which can take the thermal stress better than the carbon comp. If I continue to have issues then I will have the amp serviced. As for the grid resistors, I can replace them at work since my solder station is much better than the single solder iron I have at home.

In addition, after running the TAD6L6GC-STR (pins are much thicker) the socket clips may be on the loose side. Before installing the SEDs, I used a dental pick to close the gap on the connectors. SED tubes have much thinner pins than the 6CA7 and the TAD6L6GC-STR. It may have been a loose contact, but the problem followed the tube when it was moved to different location. Rules out amp for the moment.

 

[bandit2013]

I will just have to bit the bullet and order some SED wing C 6L6GC. While I am at it, I may as well get the SED EL34 too. Considering the cost of the Gold Lion KT77, why not. I have found some resources that will do platinum matching, prices are a bit lower than the Canadian resource.

I also found a resource for the NOS Svetlana Groove Tubes GT6L6R-2 gold series which is what I have at the moment that I bought through Doug's Tubes. Too bad about the JJ tube, I really liked the tone I was getting from them. I tried to pair up two of the JJ with the EH EL34, did not sound all that great. The EH EL34 sound much better in the Mark V since I have put some hours on them in the Mark IV. The EH EL34 sound okay in the V, however, they seem to perform better as an integrated quad in the Mark IV. Since I was missing that 6CA7 tone, I gave the EH EL34s another go in the Mark V. It is hard to believe they are the same tubes I started with since they do not sound as thin now as they did when I first tried them. For now, the SED wing C 6L6GC will be back where they belong, in the Mark V. I did try them with the TAD6L6GC-STR, they did not mix well in the Mark V but that combination sounded killer in the Mark IV.

My long term plan, find a suitable alternate for the Mark V running EL34 type tube. I love this amp and have no plans on getting rid of it. I am just having a hard time finding a happy medium. 6CA7 are perfect for that vintage crunchy tone for CH2. Cleans are nice too. But CH3 (Pentode or Triode makes little difference) is overly compressed. 6L6GC seems to be the best overall tube for this amp. The Mesa RA100 should satisfy the Vintage itch. Still need to try the KT77, SED EL34, and maybe EH6CA7.

 

[shimmilou]

...I also found a resource for the NOS Svetlana Groove Tubes GT6L6R-2 gold series which is what I have at the moment that I bought through Doug's Tubes..

If you're not worried about them selling out, I would like to get a couple of pairs myself. Care to share the source?

 

[bandit2013]

Last report on JJ6CA7: After one of the tubes decided to become an open circuit, the three remaining tubes sat in a box for a while. I attempted to operate just two paired with the EH EL34 tubes. That did not have the same magic as the full quad of the JJ6CA7. The Mark V has been running on the SED 6L6GC. (I did put in the TAD6L6GC-STR for a few days but prefer the old and tired SEDs which seem to have new life with a new rectifier tube installed.) Back to the JJ6CA7. I wanted to use them up, and I did just that. Installed them in the my Mark IV combo (after swapping the Fane Speaker for the MC90 there was more room to install any sized tube.) Note: I have installed a pair of the JJ6CA7 into the Mark IV a few times and they worked fine but tone was not as nice as in the Mark V. Powered up the amp, tubes warmed up just fine. The second I switched out of stand-by, they turned into arc welders. Both of them went into continuous meltdown. I know I did not install the dead tube since it was marked the second I removed it from the Mark V. Now I have two others to toss, may as well toss the remaining one. I am glad I did not stock up on the tubes. I did not expect a short life span of two weeks at best. I can understand one tube, but three? After that event I checked over the amp internals, tested all of the grid resistors, connections, traced out the circuitry, and checked the OT windings. No issues to be found. Installed a quad of Svetlana 6L6 everything works. Tried the pair of EH EL34 in the outer sockets, all is good. All I can say about the JJ6CA7, they sounded really good when they worked. Unfortunately, my SEDs are not current production. They are relabeled Svetlana from the early 90's before Svetlana became SED. (Groove Tube Gold Series GT6L6R-2).

The TAD6L6GC-STR sound good, they have some interesting harmonic content but I get tired of them easily. When driven hard enough they do seem to have similar character as the JJ6CA7. Makes me wonder if these are truly a 6L6GC tube since they seem to lack the hyper sonic high end. For the time being, they will remain as back up for the GT6L6R-2 (Svetlana/SED) when they bite the dust.

 

[shimmilou]

bandit2013,

Were all of the other brands of tubes that you have been testing, rated for use in Mesa amps? In other words, do you know if the current draw was in the acceptable range so as to be biased properly? If not biased properly, that would tend to skew the results of the listening tests, and could also be the reason some tubes didn't last very long. :?:

 

[bandit2013]

All of the tubes I have bought though either "Doug's Tubes" or "the tube store". Each order I placed had emphasis for use with Mesa Boogie Mark V. The only exception were the EH EL34's. I bought those from Sam Ash as a matched set. They are still working very well. I am currently using them in the Mark IV. Periodically I will install them in the Mark V.

Tubes from Doug's Tubes, requested for use with Mesa Mark V.
Groove Tubes (relabeled Svetlana NOS) GT6L6R-2, rated #4, Still sound great and are in current use.
Tung Sol 7581: bought these to replace stock Mesa 6L6GC, originals redplated within first 2 months of use. They sounded really good for about same time period, then suddenly went flat. These tend to reach verge of red plating in the Mark V. Sound good after warm up, but loose tone quickly after playing. They do not seem to have the same character in the Mark IV and almost sound like new.
JAN/phillips 5U4GB, never worked. Blew fuses the second I turned the power switch on, Sent back to Dougs Tubes under RMA, no response from Doug. $40.00 wasted. Not too happy with that.

Svetlana (new sensor/ Reflektor): bought these about the same time I got the Mark V. Intended use was for the Mark IV. I do not remember where I bought them. May have been the Tube Store. I do remember requesting tubes suitable for Mesa Boogie Mark IV.

purchased from The TubeStore. Requested for use with Mesa Boogie Mark V
JJ6CA7: (Blew out one tube, did not red plate, it just began popping than stopped. Tube failed in V10 while using 90W mode. )
TAD6L6GC-STR: These sound great. A bit dark but not bad.
EH 5U4GB. No issues. Replaced original Mesa 5U4GB.

 

[bandit2013]

bandit2013,

Were all of the other brands of tubes that you have been testing, rated for use in Mesa amps? In other words, do you know if the current draw was in the acceptable range so as to be biased properly? If not biased properly, that would tend to skew the results of the listening tests, and could also be the reason some tubes didn't last very long. :?:

I will be getting a bias meter soon. At least with that I may be able to specify a bias range for my amp.
All of the tubes I bought online were requested to be suitable for Mesa Mark V. If I could indicate plate current with good tubes, that may be better. Seems that tubes get eaten up quicker in the 45W mode than in 90W. I have two surviving tubes from the original Mesa set, red plated two of them in 45W mode on the Variac power setting. The surviving originals work just fine with the Mark IV. I have tried them in the Mark V more recently with the Tung Sol tubes in V10 and V11. It does not take long for the plates to begin to glow (not just at the seams). They do not get cherry red like the Mesa tubes that got smoked on me, just an overall faint orange glow on the complete plate surface. It is possible that the tubes that came with the amp may have been swapped at the showroom. I did not buy the amp I tested as it looked a bit dirty. I took the clean one that looked like it just came out of its shipping carton.

Considering the EH tubes, after they have had some burn time with the Mark IV, they actually sound better and not as thin in the Mark V. In all honesty, the JJ6CA7 had the best tone. If you do a search on jj tubes, many have had issues with them (primarily premature failures). I will definitely need to give the EH6CA7 a try. I am also considering the Gold Lion KT77 (also made by Reflektor = new sensor). I do not mind paying a premium if the tubes last. I will be ordering SED 6L6GC and the EL34. The Tung Sol when new did have the similar complex harmonics as the GT6L6R-2 (NOS in this case stands for New Old Svetlana), however, they had supersonic tones that really added the ice pick effect. The SED or in my case GT6L6R-2 also have the hyper upper but not as harsh. After 8 months of use they sound perfect when compared to everything I have tried. In addition, the GT6L6R-2 are the only tubes that equally distributed blue glow in 90W mode in all 4 tubes. Considering that the outer tubes are biased differently than the inner tubes. Perhaps the tubes I have used other than the GT were not quite matched.

 

[shimmilou]

Thanks for that. I would definitely get some good bias probes. I always check the bias when installing new output tubes, just to be certain that they are biased properly, and matched. Definitely CDO about my tubes.

Of all output tubes that I've used, I find that the EH are always among my favorites in whatever amp that I put them in, for both sound and toughness. The EH sound great and are as tough as nails, without a doubt are my favorite 6V6, and the 6CA7 and EL34 are excellent also. Conversely, EH preamp tubes are not often my preferred choice. By far, the vast majority of the tubes that I prefer, come from the Reflector factory in Russia (New Sensor brands), especially the Mesa and GT labeled, due to the extra testing/screening.

 

[bandit2013]

Perhaps I should point out a few things to avoid misleading conclusions:

Power Tubes that have failed in my quest for tone in the Mark V:
Original Mesa 6L6GC STR440. Two red plated within the first 2 months of ownership. Speaker cabinet used: Mesa Rectifier 412 slant cab with 4 V30's. After that, only replacements I had were the 13 year old and used Mesa 6L6GC STR 420 that I pulled out of the Mark IV.
Mesa 6L6GC STR 420 (borrowed from my Mark IV which were replaced with Svetlana 6L6GC). These redplated within a week of use in the Mark V. I did not expect much out of them. Sounded great to the end.
JJ 6CA7 . One tube just quit functioning. 2-3 weeks of use.
Jan 5UGB. Was dead on arrival. Anode was shorted to cathode on one diode.

Power Tubes that sounded Awesome out of box, but suddenly changed tone (loss of highs).
Tung Sol 7581. They did not fail. I suspect the ailing rectifier tube to contribute to tone loss. I would still be using them if they sounded the same in the Mark V. At the same time I replaced all of the V30 with EVM12L Black Label speakers. Use in the Mark IV seems to give them new life. Replaced these with the NOS Groove tubes GT6L6R-2 (relabeled Svetlana/SED). Case with the Mark IV combo, it makes no difference between the SED, Tung Sol or new sensor Svetlana branded tube. Best tone combination is with EL34 mixed with the Tung Sol.

Tubes that are similar but darker tone: TAD6L6GC-STR. They sound great but I get tired of the tone easily. There is more wealth of harmonic content created by the SED 6L6GC that is hard to beat.

Tubes I am now considering: EH6CA7. Gold Lion KT77. Of course I will get SED 6L6GC. I may even get the SED EL34 too. I may forgo purchase of the EH6CA7 and the Gold Lion KT77 and stock up on the SED 6L6GC's.

 

[jnoel64]

When I ordered a new set of Tung-Sol EL34s for my Dyne, I did not specify to the vendor what I was putting them in (I believe I used Tube Depot). It's been almost a year, and the tubes are still going strong. In fact, the tone just gets better every time I play the amp. I figured the next time I order tubes, I would specify what I am putting them in. So, maybe I was just lucky this first time?

On another semi-related topic, I contacted Doug's Tubes for his pre-amp tone kit. I told him exactly what I was using them for, and he gave me the same generic kit for 7 tube preamp sections. Not all Mesa preamp sections are alike (not to mention other manufacturers), so I really question the validity of a generic kit for any amp that has a certain number of tubes.

 

[shimmilou]

That sounds like Eurotubes also. You see the same lineup of tubes listed several times, with a different description each time, as if the different description somehow gives you a different sound. :lol:

 

[bandit2013]

I did get the preamp tube kit from Doug's tubes at the same time I bought the TS7581. I also bought 7 TS12ax7 from TheTubeStore. Needless to say, since the TS7581 were super bright with really defined deep bottom, I needed a V1 tube with lower gain such as the Jan/GE 5751 which is a really sweet tube. I gave away two of the TS to some friends to try out. When I got the SED tubes, the Jan/GE was no longer needed. So I gave that to a friend who had a vintage 65 twin to try with the TS. The only tube I am currently using from the tone kit in the Mark V is the Sovtek LPS. All of the remaining TS tubes I have are in the Mark IV which makes the clean channel really nice. That did not effect the tone of the other channels either. The Penta labs went microphonic on me.

After trying the old Mesa 12ax7a tubes I had from the 90's (all of which had only 3 months of use) they worked the best in the Mark V. I did not have enough of them to put in the Mark IV.

What may be classified as a good driver tube (used for reverb, PI, effects loop etc...) should be the same quality as the tube you would use in V1 (does not mean it has to be the same tube). It depends on the amp. TS and EH tubes are good tubes (EH are considered the low end of the Reflektor brand). However, in the Mark V, I was getting hum with no input signal when I had TS or EH in V3, V4, V6 which are AC heated tubes. Using a smaller plate tube eliminated the noise (old Mesa tubes performed the best on electrical noise reduction and still sounds killer with the high gain channel).
Oddly enough, the Penta Labs tubes look identical to the old Mesa tubes but have a round halo getter where as the Chinese made Mesa tubes have a square getter. Also sorting by Mesa is more refined than the other brands.

A point on the Mullard reissue, if it was not for the mechanical noise issue I would probably use them. They are similar to the Sovtek LPS (same plate design) but tend to translate mechanical vibration into audible noise. Makes the power tubes sound like they are rattling. The Sovtek version is a better quality tube than the Mullard reissue.

 

[bandit2013]

the GT6L6R-2 (SED) are beginning to reveal signs of wearing out. Not as bright as they used to be, and CH3 is becoming more compressed even with low gain settings.

on the otherhand, I installed the EH EL34 (exact same tubes I claimed to be thin and lacking character) sound completely different. They actually sound damn good! The only difference, I changed all preamp tubes a while back with the old and used Chinese Mesa 12ax7a (use on the tubes on average of 3 months, replaced them when I burned out the EL34/6CA7 tubes when I played in a garage band many moons ago, 1991-1993 I believe, was not for long but it was fun). I wish I kept all of the used preamp tubes. The new one's just don't sound as good. For tube that were not purchased specifically for the Mark V, they are sounding really good. Also changed Rectifier tube which may have been part of the improvement.

 

[DangerMoney]

I haven't read this whole thread but some places still have SEDs in stock.

http://www.boiaudioworks.com/m/sed

http://www.amplifiedparts.com/products/T-6L6GC-WC

http://www.tubesandmore.com/products/T-6L6GC-WC


I order all my tubes from BOI and am extremely pleased with their service. They burn the tubes in for 24 hours, match them and write the Ip and gm values on each individual tube box at no extra charge. They're here in San Diego. I order tubes on a Saturday and they're in my mail box on Monday. Tell them what amp you're putting the tubes in and they send the right grade.

The last two are the same company in Tempe, AZ.

 

[bandit2013]

Thanks for the resources. I believe I have come across boi before.

Yes, I am aware that there are still supplies of the SED tubes available. I am convinced the only replacement for SED tubes are SED tubes. I am basically done tying to seek out an alternate. I admit that the tone and sound quality obtained from the JJ6CA7 was awesome but that came with a price. Short life span. 3 out of 4 tubes are toast. Lost one in the Mark V, then blew out two in the Mark IV. I had them in the Mark IV a few times. When I changed out speakers and wanted to experience the difference, the pair of JJ6CA7 immediately turned into arc welders the second I flipped the standby switch.

I definitely will get a quad of SED EL34 and a complete set of 6L6GC. I have considered the Gold Lioin KT77 but at the going price, the SED is a bit lower in cost. I am currently running the EH EL34 in the Mark V at the moment. The GT6L6R-2 (NOS Svetlana from the 90's) are still working but seem to be losing the high end as well as sound more compressed with high gain settings.

My next move will be another amp. Mesa Royal Atlantic 100. Yet another amp to feed.

 

[bandit2013]

If you have not figured it out yet, I must be some kind of nut ball. :roll: I definitely have to retract all I said about the EH EL34 tubes. First off out of the box, they were amazing. One or two days of use they did seem a bit thin, lacking the type of tone I would have expected from an EL34 power tube. After burning up the JJ6CA7, I was skeptical on tubes in general. I have been switching between the EL34 and the old GT6L6R-2. The EH EL34s have blossomed into a really nice sounding tube. It helps to have the right preamp tubes to start with. A new Rectifier tube does not hurt either. It appears after some use of the EH EL34 tubes have improved with age. I actually favor the tone I am getting now with the EL34 over the old GT6L6R-2 (NOS Svetlana). I recently discovered the cause of the compression effect I was getting with them, it was a preamp tube that was the cause. I rolled in some of the old preamp tubes I had and found the one causing it. Now the Mark V sounds better than it ever has. I think I would definitely consider buying the EH EL34's again. One thing is for sure, I would like to find out where I can get some more of the old Mesa Chinese 12ax7A tubes with the square getter. I did try the stock Mesa (JJ) tubes but they created hiss / too much white noise to be desired.

EH EL34 = Well defined tones, bold and tight bottom end. shimmering highs but not ear shredding ice pick. Nice compression when pushed. Ch3 does not loose definition even with moderate to high gain setting (helps to have good preamp tubes). CH2 will create that vintage crunch that will get you lost for many hours just taking it all in. Ch1 clean is almost as pristine as a 6L6GC. Note: I am still using the same EH EL34 that I said were thin, week and needed much higher volume settings to get into clip. After a few hours of burn-in time they have opened up and sound much closer to what I remember an EL34 to sound like.

 

[shimmilou]

Good to hear about the EH EL34, they've always been good for me. As far as Chinese preamp tubes, I really like the GT 12AX7-C, they have very nice clean that sounds good warm or bright, and the distortion characteristics are pretty smooth and can get some nice grit when really pushed.