2002 Svetlana EL34 vs 1959 Mullard EL34 vs Genelex Gold Lion KT66 Comparison In a 30 Watt Amplifier
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- Опубликовано: 27 май 2019
- A quick comparison of Svetlana (Circle C built 2002) EL34 vs Vintage 1959 Mullard EL34 vs New Genelex Gold Lion KT66 in a accurate built version of a McIntosh MA230 channel vacuum tube amplifier rated at 30 watts.
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A little off topic but further to your comments about your uncle in WW2 I noticed that your wattmeter was made by Bayly Engineering in Canada.
Pat Bayly was an intriguing guy.
He was 2nd in command of Camp X, the WW2 Allied secret spy camp on the north shore of Lake Ontario just east of Toronto and director of communications there. He re-purposed a huge commercial AM transmitter and turned it into the Hydra; the communications system that received and transmitted Allied radio signals all over the world. He also invented the cipher system known as the Telekrypton or colloquially the Rockex. It used Telex like paper tapes as one time encoding and decoding keys for messages. Unlike the German Enigma, it was fast to use and never hacked. Supposedly it got the Rockex name after the engineers paid a visit to Radio City Music Hall in New York and saw a performance of the Rockettes dancers. He later formed Bayly Engineering in Ajax, Ontario, a town between Camp X and Toronto created to build munitions and other supplies for the war effort. He served as the first mayor of Ajax as well. Ajax as named in honor of the HMS Ajax, the flagship of a group that took out the German pocket Battleship the Graf Spee.
I think it's important to remember guys like your uncle & Pat Bayly; not to glorify war but to remember their contributions. The freedom we all enjoy today came with the huge price so many of them paid.
Thanks for this info. I believe that Camp X was mentioned in " A Man Called Intrepid" by William Stevenson. Fantastic book which I highly recommend.
great video!! always check bias when changing tubes. EL 34 is a pentode and the KT 66 is 6L6 5881 tetrode tube. My amp Fender 2 X KT66 . got the super with Kt88 as well. I do have heathkits as well. KT 88 and 4- 6BQ5 stereo bookshelf amp sounds great!! working on stereo KT88 6 tube per ch. has 6SN7 driver and 2 6SL7 per amp per ch. just repair for a friend re capping filter caps.The transformers make yours look small. 3 pc amp. very heavy!! was a custom build.
I really enjoy watching your videos. I have my computer at my bench, so I actually follow along with some of your measurements on amplifiers I have built. I'm actually learning quite a bit, thank you! Wondering if KT120's would be a possible candidate for this amplifier project? I am currently adapting a Luxman 3045 pair to use them. So far with good results. Looking forward to more videos! Dan
Hi Dan, I have not tried the KT120's yet although I have seen a couple of amps that use them that were sold in kit form by, I think, Triode Electronics. I am including a link below of some measurements made by others on these amplifiers. I can not speak to how they sound in a system as I only tested them on the bench.
audiokarma.org/forums/index.php?threads/kt120-amp-mk-3.828722/
My personal experience with the only two that ever showed up in my shop was less impressive than they were supposed to be according to my measurements. I never dug into the amplifiers and tried to see the details but I am going to guess the main issues are in the output transformers which is usually the case.
I wonder how KT77s would have fared? Anyway cool video. I hope you do some more of these comparisons. I'm liking the New Sensor Svetlana EL34s. Maybe you could test those along with some JJs and Shuguangs sometime.
Many thanks for a great video. I would love to see you repeat this video but this time look at the effect on thd when your tubes are deliberately mis- matched and produce a graph of persentage mis-match against harmonic content. Although I only use a good quality scope to look for distortion, I have seen tubes where the bias has been out be 25% and still not been able to see any notisable distortion on the output waveform.
Also on the subject of Mullard tubes of the early 60's continuing to perform well, I believe the reason relates to the thickness of cathode material used in those days compared to current tubes. Your comments would be appreciated.
I certainly agree with you on the performance of the tube depending primarily on the quality of the cathode and is in my opinion, the reason some of the vintage tube are still around and working so well. Unless there is a real defect in the tube, the tube that runs the hottest is most likely the best and strongest tube. I have seen it many times.
As for the THD, that is a good experiment and I will try it. I actually hope to make a video today using the stereo amplifier I built a few years back and posted seven videos on. In this case, I will be testing with Tung Sol. 5881 and Gold Lion KT66 without the cathode balance pot, then add the pot and balance. I also want to test with and without the small RC circuit almost all amplifiers have off the grid of the second stage to, I suppose, increase HF stability. All I have ever seen it do it increase THD in the upper frequencies. I think a square wave test is appropriate also. Thanks for your comments.
I also have a quad of Mullard EL34 in mint condition that I swap in my amp 'only on holidays' as not to ware them... P.S. EL34 were always over 6L6, just saying, expected result :) Thank you!
Boy, wouldn't mind having a couple of those OPTs. Would make a great system. Do you have any single ended amps? Seems most are PP. You must like the power.
I just can't get in to the SE amps. I do like a reasonable amount of power. At least 20 watts. The only SE amp I have attempted in the last few years is a 833A amp but my transformer was a huge PP transformer and with the quiescent current necessary for the 833A (150mA) the transformer core saturated and the primary inductance dropped to a few mH... I found out the hard way that PP transformers (they don't have the air gap in the core) do not work for SE amps.
With that said, there obviously is a charm in listening to the full-spectrum (as I will call it for lack of a better phrase) of harmonics generated by SE amplifiers. A spectral display of any SE amplifier is going to look triangular (all odd and even harmonics in descending amplitude) instead of like a beautiful sine wave and the harmonic profile is going to prove it. Trying to get THD low on a SE amplifier basically isn't going to happen and LF response at more than a few watts is going to be poor as the transformer core (even with the air gap) is going to tend to saturate easily and make the bass sound poor and distorted. We definitely do not like distorted bass. Basically it takes a 100 pound SE amplifier to perform like a 20 pound PP amplifier even at 10 watts. I am not slamming SE amps - to each their own but once again, I want at least a good 20-40 watts rating from my amplifiers and I don't have the room for a couple of 200 pound SE amplifiers... I would like to have two of those Triad transformers also...
My late father carried the M1 Garand - he held that weapon in very high regard.
I enjoy these videos because of the real-world, real-time aspect to your testing. As a pair of EL34s / KT77s require about 3.4K primary impedance and 6L6s / KT88s and the like, require around 4.2K primary impedance, do you perceive or hear any significant difference in audio quality when both are used with the same OT? The Dynaco A-431 (4.3K primary) is often used with both tubes. Your opinion is much appreciated. Thanks for your input.
One thing I have always wondered about is why McIntosh never used the 6CA7/EL34. They used the 7591 which I never liked as they run deliciously hot. Of course, the amplifier in this video is built exactly to the schematic of the Mac MA230 which uses 7891A's. With that said I made the bias supply variable on a wide range which let me use pretty much any "6L6" family of tube I wanted to. I mentioned that about Mac because for some reason, I prefer the EL34 in that amplifier. I guess I like the way is sounds - whatever that means. As we know, the EL34 is a true pentode and not a beam power tube like the rest of this family of tubes. I don't know but I dare say we are influenced by many things we don't even realize.
@@ElPasoTubeAmps Thanks for your response. Fisher, EICO, Knightkit (remember them?) and several other high fidelity component manufacturers used the 7591s. Some say it's too many elements packed into too small an envelope! They were made as "space-savers". Nonetheless, many enthusiasts think the 7591 is a wonderful-sounding tube. I like your comment that they run "deliciously hot". Beam tetrodes ( some prefer to say beam pentodes, but that's up for debate) generally are clean and detailed with good headroom. True pentodes though, have that mid-range bloom that gives "presence" and body to music. In guitar amps when driven, EL34s just sing - rich in harmonics and delicious saturation. In HiFi amps (ST-70) they give a complex and sumptuous midrange detail to female voices and stringed instruments. We are influenced by the weather, our wives and what's for dinner. The variables are legion! Thanks again.
@@radiojet1429 LOL.... deliciously hot - don't you just love spell checkers - maybe ridiculously hot is more like it. :-)
hi i have a question .i have 4 mullards el34 with xf2 b2f4 on all of them .can you tell what year they are.please?are they worth some money??
They can be pretty valuable if they are good and strong I am no expert on the markings but if all the logo is on the tubes along with some data, I think you can tell the place and approximate date of manufacture. I can only suggest an Internet search as I don't know all of these markings. Good luck.
Svetlana (current), Genalex, and Mullard are all produced at the same factory... it's interesting to see that there design differences do have effect.
he mentioned that only the Genalex are current production.
@@BretFrohwein The Svetlana's date is 0602 - I assume that is 2002. But per the comment above, it would be really interesting to have a brand new set of tubes produced in the same factory but branded differently to see if any differences could be measured. We all know that the vintage tubes of yesteryear were done the same way and GE, RCA, Mullard, Amperex, etc produced and sold to one another under different brands. A comment was made on one of my videos many years ago about the production of vacuum tubes which stated that there was a pretty wide margin of performance in the manufacture and performance of vacuum tubes (made in the past few years and today) and, in general, the lower performing tubes did not end up in the recycle bin but were sold all over the world. So, to me, this means that they definitely can "grade" tubes and sell the very best under different names for premium prices so we should take that into account with some of the off-brand and cheaper tubes. They may "work" but performance may be at the lower level.
St. Petersburg made EL34s are now OS too. :>( Current production branded Svetlana is New Sensor product out of Saratov.
The Triad's 4000 Ω primary is a bit "tall" for KT88s. Maybe full pentode mode with regulated g2 B+ and 550 or so V. anode B+. Mullard style circuitry is "idiot resistant". However, the numbers for that Triad "iron" seem promising enough to make Williamson style feasible.
If you're going too use 5881's, I would recommend Tung-Sol. Even though they're not the Tung Sol we remember, They are excellent sounding tubes and pretty rugged. The past 3 years, I've been having a lot of problems with other Tung-Sol tubes, especially the 12AX7's. Been getting dud after dud, right out of the box. Not only have I been dealing with microphonics, but H2C shorts out of the box. Most newly manufactured tubes nowadays are a dice roll. Sometimes you get a good run, other times its dud after dud. But, once you nail a good batch, you're in. Its frustrating when you're servicing a lot of guitar amplifiers as I do. We both know, tubes have a shorter life in a guitar amp than they do in Hi-Fi amps. PS: The original Tung-Sol tubes were made about 13 miles from my shop here in New Jersey.
I agree that the new Tung Sol 5881's can be very good. I have had great luck with them also. I also had a fantastic set of Tung-Sol KT66's - absolutely beautiful and maybe a year later ordered another pair and all four were total junk. Unbelievable... I sent them all back to TubeDepot and got a full refund. I was not willing to take another chance with anything associated with a batch close to them. I even sent them color printouts of the measurements I made for what ever that was worth. I have no issue with TubeDepot - they are good.
I recently purchased a quad of new Gold Lion KT66's (you have seen them recently on YT) and even though I have not critically tested each one and as pairs, they seem very good. As for 12AX7's and that family of tubes, not long ago I attended a few estate sales and have ended up with a lifetime supply of those vintage tubes. I commented the other day to a good gentleman that I probably have more and better vintage 12xx7's than all of Ebay. Oddly enough, I now like to build with 6SN7's. Oh well...
For triode mode or ultra linear mode, why not try the KT77s!
I have a Lafayette 236 A amp with 4 EL84 Lafayette branded tubes.
How are these tubes completely?
They can be branded Lafayette but they were manufactured by some vacuum tube company and labeled for Lafayette. They very well may be high-end Mullard or other premium tubes.
@@ElPasoTubeAmps Thanks for the response, That is really good to know!
I don't get it. If the Max dissipation of an EL34 is 25w per tube, a pair being ran at Max of 100%" which no one would do", it would be 50 watts. So getting 45 watts out of them means you are running them at more than 80% dissipation. Is there something I'm missing here?
I don't think you are missing anything. The EL34 actually are a nice performing vacuum tube even with a lower plate dissipation than the 6L6 family of tubes. Remember, the EL34 is a true pentode with three wire grids and the KT66's are a beam power tube with beam forming plates instead of a third grid. The beam-power tube, as I understand it, is the American version of the EL34 and back in the day, the different companies and countries had to make these little changes to be able to produce vacuum tubes because of each other's patents. I may be wrong about this but I believe the beam-power tube design is a little bit more efficient than the true pentode. Nowadays, we don't think much of having a 100 pound 10 watt huge triode SE amplifier just because it is exotic and beautiful but I think it can be safely said that in the 1940's thru 1960's , and beyond, smaller and lighter equipment was in vogue. The heavy-iron days were over so even small advances in efficiency and performance is what was selling to the public.
@@ElPasoTubeAmps Thanks for the reply. I just can't see how the Max dissipation of a tube like the EL34; being 25w can squeeze out 45w out of two tubes without major distortion and extremely short life.... also, what was the plate voltage of your amp?
@@JuanLega I think it is about 490 volts. Notice that the electrolytic capacitors are rated at 525 volts. Remember we are running two tubes so we have a max plate dissipation of 50 watts now and you can see that it certainly will do the 45 watts. I have seen EL34's in Music Man guitar amplifiers running at 800 volts on the plate and able to deliver a lot of power. I can't remember the output but it is probably well over 50 watts. Just a small breeze of air over equipment does wonders for extending the life of the components.
Do 7403/3D21WB. Cool tube simular to kt-88 in performance. I have a lot of the 3d21a and 3d21b but they are low power like 14th and 19 watts but the 3d21wb is 40 or 42 watts
1959 and I still out perform...um, I mean they. It took a few minutes to prepare my self to watch this. I had to accept...just in case...that my dogma might have to confront my cognitive dissonance head on. Were you going to destroy a myth...or confirm what I 'dogpatically' knew? (yes I have dogs...and now you get the pun :O) Anyway...WHEW! Thanks for another great vid!
I understand what you are saying. It is true that some of the lucky vintage tubes are still the best after 60+ years. But as I mentioned in an earlier comment, we have to be thankful that some crazy fellows in Russia and China love this vacuum technology as much as we do and went to the trouble to pack up and ship the factory (Mullard) from England to Russia so they could once again make these exotic glass and metal vacuum devices and be able to sell them at 1960 prices. I remember the cost of a 6L6 back in the 1960's was pretty much what it is today and that was a lot of money back then. I went to work as a NASA contractor in January 1970 and started at $125 a week and I had plenty of money. My first apartment (furnished) was $125 a month. That's $6500 per year and five times below the poverty level nowadays. My point is, we are actually pretty lucky that we don't have to strictly rely on vintage tubes for our hobby. A 12AX7 would be $1000 and the hobby as we know it, could not exist and lastly... I find that the new Tung Sol 5881's perform every bit as good and even better than most of the vintage 5881's. Must have been an ingenious design easy to reproduce. Thanks for your comments.
@@ElPasoTubeAmps I had a conversation about tube manufacturing with the ultimate tube guru Myles Rose. He stated that the only reason tubes are not made of the same quality...or here in the US...is profit (this was a couple of years ago, though). All the regulations can be met...with some expense. If some guitar players with way too much money, like Bonamassa and Hammett, were to fund a tube factory and set it up as a perpetual nonprofit we could have great tubes for many lifetimes. But then, I guess I could go back to Tesla's days and have some similar dreams, so I'm just glad I had a box of old Tungsrams, Telefunkens, GEs, Sylvanias & Mullards and such that cost me next to nothing 25 years ago. But my supplies are running low...and a few are failing at this point. Like any of us, 60 years of R&R can wear one out a bit...LOL!
@@TheDogPa I remember 40+ years ago when I was in Huntsville, AL and I would pick up radio equipment and use parts from them that was from WWII and was 30 years old and I thought at that time, that is really old... Now those parts are 75 years old and many are still working. It isn't going to be long before our vintage supply of tubes reaches 100 years and some are still going to be working - just like us - just got to power us up slowly...
@@ElPasoTubeAmps Sometimes I need a Variac just to get out of bed :)
What about a HI-AMP using 4CX500 tubes and forced air cooling.
I have built and posted videos on a push-pull 3-400Z amp that would deliver over 1300 watts. I have scaled-back somewhat from the monster amplifiers since then. I think the next amplifier will be a push-pull SV572-10 amplifier. These are high-end low mu triodes for especially for audio.
The transformer you want to use.... May I suggest the following Tubes you could try....Russian 6C33.....Tungsol 7241 or 7242... .or parrellel connected 6336..... Either of these tubes will work at plate voltages as low as 200 volts
Something exotic for the transformer how about the 845
That is a good suggestion. I can't spend $1500 for some old fried tubes off of Ebay but I see some of the new one are pretty reasonable ($128). I think I will seriously revisit the Svetlana SVT572-10 tubes that I have and maybe make it parallel-push-pull to get the Z down in the plate circuit (these SVT572-10"s are not the more common transmitting 572 triode) Thank you...
I'm about to pickup a single EL-34 for my Carr Mercury Someone please recommend a mid price one Thanks )
I personally have had good performance from the Mullard or Svetlana EL34's. I buy from tubedepot.com.
@@ElPasoTubeAmps Thank you
With all the advancements in technology precision measurement equipment high-performance futuristic materials nano technology Russians and the Chinese still cannot produce or even copy a product made almost 70 years ago.
My philosophy on that subject boils down to the spirit things are built with.
While it seems like yesterday, I started working a real job in January 1970 - right at 50 years ago and I can say from my experience, we had an attitude that we wanted to build the very best equipment in the world and we wanted it to work forever and be repairable. The big mainframe computers of the day were built with 100% highest quality stainless steel nuts and bolts along with every other top-quality component.
Just look at the books on vintage equipment. Besides schematics that were beautiful, there was theory of operation documents and so much more with every piece of equipment. We were proud of what we did and we had to sign our names to documents for what we did and how we did it. No BS... I know I am sounding like an old geezer but it surely looks to me like that spirit has been traded off for cheaper and throwaway equipment. With that said, I do indeed see the advantages of some of the instruments we can all have and afford that would have cost a man twice his yearly salary back in those days so I am thankful for that advancement of today. Even today, we can buy a year 2000 Tektronix oscilloscope that cost $35,000 new for $500 off Ebay...
Lastly, and I will never know for sure but I suspect there are many millions of vacuum tubes built long ago that didn't perform very well either. The ones that are still around today and still running strong were probably the very best of the best (not necessarily know in that way at that time) and we still enjoy using them. No doubt they knew how to grade tubes 70 years ago just as well as we do today but tubes are not a mainstream item anymore and is now just for the esoteric bunch of nuts like us... :-)
All in all, I have to be grateful that there are still a few eccentric individuals out there, mostly in Russia and China, that have a love and passion for this technology and actually build factories to produce these exotic items which, as I understand it, are still very labor intensive. We sure can't produce them in the USA as labor costs would make a 12AX7 cost $400 or maybe $4000 by the time we got past all the government environmental regulations and labor laws.
I appreciate your sentiment and support, but Veteran's day is 11NOV.
I messed that one up, didn't I. I meant to say Memorial Day. Thanks for noticing and letting me know.
The new Svetlana's are so close to the Mullard's I'd take those vintage tubes to eBay in a second. About 6 new sets of tubes would be about the exchange rate for the old Mullard's at auction. Some folks just want the name to enhance their imagination.
I agree. For the price, new quality made tubes perform so close to the best of the vintage that it is hard, as you mention, to pay many times the price for an improvement in less than 0.1% THD.
@@ElPasoTubeAmps BTW thanks for all the great content! 73 de KB0NES
i agree with both you and David, however it is odd that the 60-70 yr old tubes should perform better at all. I too, as others experienced, have had extreme reliability issue's with the 12AX family of new tubes and prefer any Good used or NOS American tube, they just seem to always work.
@@ElPasoTubeAmps My svetlanas don't touch my rfts in the musicality departmemt