Hello,
I have a unmodified ST-70 that came with no tubes. I plan on modifying the ST70 and getting some better tubes for it later but would like to pick up a quad of current production tubes to run it with so that I know all the tubes are good and in case I blow some stuff up I am not tossing out a good vintage tube. From what I have seen for choices under $100.00 bucks a quad I have seen:
EL-34 Mullard Reissues quad 70$
Shuguang EL34B quad 45$
EL34 SED SVETLANA winged quad 80$
Quad 6CA7 ELECTRO HARMONIX EH EL34 Fat bottle 55$
Quad EL34 ELECTRO HARMONIX EL34EH 6CA7 50$
Is there any EL34's under 100 bucks a quad new that are worth buying or does anyone have any good things to say about the tubes in this list. The Fat bottle electro's sure look pretty but that does not mean they sound ok.
Thanks for your constructive opinions in advance.
I have a unmodified ST-70 that came with no tubes. I plan on modifying the ST70 and getting some better tubes for it later but would like to pick up a quad of current production tubes to run it with so that I know all the tubes are good and in case I blow some stuff up I am not tossing out a good vintage tube. From what I have seen for choices under $100.00 bucks a quad I have seen:
EL-34 Mullard Reissues quad 70$
Shuguang EL34B quad 45$
EL34 SED SVETLANA winged quad 80$
Quad 6CA7 ELECTRO HARMONIX EH EL34 Fat bottle 55$
Quad EL34 ELECTRO HARMONIX EL34EH 6CA7 50$
Is there any EL34's under 100 bucks a quad new that are worth buying or does anyone have any good things to say about the tubes in this list. The Fat bottle electro's sure look pretty but that does not mean they sound ok.
Thanks for your constructive opinions in advance.
Go with the SED =C= EL34. It's a nice tube that's not too far behind the Mullard original.
IMO, you should forget about NOS Mullard. They are SCARCE and COSTLY. You will surrender enough body parts to become terminally ill.
IMO, you should forget about NOS Mullard. They are SCARCE and COSTLY. You will surrender enough body parts to become terminally ill.
not got experience of any other brands EL34's but I just got some JJ E34L's - maybe more than your $100 though
Nice tubes and I recommend them I bought them specifically because I perceived that they might suffer a bit of abuse. In fact they are currently running JUST outside spec
Otherwise the EH tubes havent let me down generally. Whats a "Sovtek" quad cost? I had nice results with their EL84
Maybe that puts your "fat bottle" varieties a little further forward? Really I'm suggesting you go for the ruggedest ones you can. Whilst youre tweaking. It'll be on and off a lot, with no HT delay these tubes will suffer.
Andy
Nice tubes and I recommend them I bought them specifically because I perceived that they might suffer a bit of abuse. In fact they are currently running JUST outside spec
Otherwise the EH tubes havent let me down generally. Whats a "Sovtek" quad cost? I had nice results with their EL84
Maybe that puts your "fat bottle" varieties a little further forward? Really I'm suggesting you go for the ruggedest ones you can. Whilst youre tweaking. It'll be on and off a lot, with no HT delay these tubes will suffer.
Andy
It looks like the Sovtek's go for about 16$ a tube which is right in the price range. I have an Audio Research ST-70-C3 that has 6L6GC's and I have a quad of the Sovtek's for testing when I make any changes to it. They are kinda cool as they glow purplish when they are on. The only reason I got them as they had them in stock at an electronics store I goto.
The SED =C= EL34's do look pretty good.
The fat bottles look good as worst case I ruin 50 bucks worth of tubes and I can stick them to either side of my neck for a Halloween costume.
I do plan on turning it on and off a lot during testing and tweaking so it may be a good idea to buy something disposable. I have a Variac but still fear turning it up and smelling smoke.
The SED =C= EL34's do look pretty good.
The fat bottles look good as worst case I ruin 50 bucks worth of tubes and I can stick them to either side of my neck for a Halloween costume.
I do plan on turning it on and off a lot during testing and tweaking so it may be a good idea to buy something disposable. I have a Variac but still fear turning it up and smelling smoke.
I bought a bunch of different EL34 tubes when I was developing my Simple SE amp so I could evaluate several different tubes for reliability. I am known for testing tubes at and above the spec. I got a quad of all of the low cost brands from Antique Electronic Supply (JJ, Winged C, and Valve Art) I also got a quad of Sino - Shuguang from ESRC. In a seperate deal I purchased a large box of "pre auditioned" Russian tubes cheap. This included 8 Electro Harmonix EL34's, and one Elecro Harmonix 6CA7. I have used other tubes from these suppliers and manufacturers in the past with good success. I tested all of them in 2 different SimpleSE amplifiers at supply voltages from 325 to 465 volts.
I have always had good luck with old Svetlana / Winged C tubes, but not this time. One of the Winged C tubes had a clearly mis alligned screen grid which glowed brightly at 325 volts. It distorted badly and I did not want to try it at higher voltages. Another tube exhibits a glowing grid wire (only one) at voltages over 350 volts. The other two work fine and can handle everything that I throw at them. 2 out of 4 is not good odds, maybe this is an anomaly.
The JJ tubes can take every thing that I throw at them. All 4 are identical, they just start to show plate glow at 32 watts of total (plate and screen) dissipation, no grid wire glow at max voltage. These sound the best of all the EL34's too.
The Valve Art and Shuguang tubes are very good for the price. All 8 behave the same. Plate just starts to glow at about 33 watts total dissipation. No grid wire glow at max voltage. The sound is good, but maybe not as detailed as the JJ's.
The Electro Harmonix EL34's are the smallest EL34 tubes. They can handle about 30 watts before glowing. No grid wire glow in 8 tubes at max voltage. The sound is similar to the Shuguangs, maybe a little brighter.
I have one of the fat bottle EH 6CA7 tubes. Be aware that this tube is actually a beam tetrode so it is not exactly identical to an EL34. I tested it with good results. I could crank 35 watts through it without glow and it rocked. It is the loudest and has the best bass of all of the tubes tested. I only tested one tube, but it draws more current than the other types.
Which ones do I use in my amp? My amp uses any of several tubes, EL34, 6L6, KT88 and 6550. I change tubes depending on my mood, and what type of music I play. When I use EL34's, I use the JJ's.
I have always had good luck with old Svetlana / Winged C tubes, but not this time. One of the Winged C tubes had a clearly mis alligned screen grid which glowed brightly at 325 volts. It distorted badly and I did not want to try it at higher voltages. Another tube exhibits a glowing grid wire (only one) at voltages over 350 volts. The other two work fine and can handle everything that I throw at them. 2 out of 4 is not good odds, maybe this is an anomaly.
The JJ tubes can take every thing that I throw at them. All 4 are identical, they just start to show plate glow at 32 watts of total (plate and screen) dissipation, no grid wire glow at max voltage. These sound the best of all the EL34's too.
The Valve Art and Shuguang tubes are very good for the price. All 8 behave the same. Plate just starts to glow at about 33 watts total dissipation. No grid wire glow at max voltage. The sound is good, but maybe not as detailed as the JJ's.
The Electro Harmonix EL34's are the smallest EL34 tubes. They can handle about 30 watts before glowing. No grid wire glow in 8 tubes at max voltage. The sound is similar to the Shuguangs, maybe a little brighter.
I have one of the fat bottle EH 6CA7 tubes. Be aware that this tube is actually a beam tetrode so it is not exactly identical to an EL34. I tested it with good results. I could crank 35 watts through it without glow and it rocked. It is the loudest and has the best bass of all of the tubes tested. I only tested one tube, but it draws more current than the other types.
Which ones do I use in my amp? My amp uses any of several tubes, EL34, 6L6, KT88 and 6550. I change tubes depending on my mood, and what type of music I play. When I use EL34's, I use the JJ's.
In my current amp I have used Ei, Shuguang and SED Winged 'C' EL34 tubes and by far the best are the SED.
I found the SED's took as much beating as the Ei fat bottles whilst delivering a great deep punchy bass.
I found the SED's took as much beating as the Ei fat bottles whilst delivering a great deep punchy bass.
another vote for the SED...
Surprisingly enough, I've also had good luck with the Svetlana 6L6GCs in the stereo 70. Another good 'NOS' bet is the 1970s Matsushita EL34 (often labeled RCA, GE, El Menco, etc) - these can still be found for a decent price, but the word on them seems to be out and prices have gone up.
Surprisingly enough, I've also had good luck with the Svetlana 6L6GCs in the stereo 70. Another good 'NOS' bet is the 1970s Matsushita EL34 (often labeled RCA, GE, El Menco, etc) - these can still be found for a decent price, but the word on them seems to be out and prices have gone up.
The SED EL34 is my choice for audio use. It is generally well made, and is very nice sounding.
Someone mentioned JJ - do what you think is best, but the build quality is so poor on the JJ octals that you need to be VERY careful about using them. There are a lot of issues besides the undersize pins that were a big problem.
The large bottle EH 6CA7s are very good tubes, but sound more like a "baby 6550" than an EL34. The fat bottles have more energy at the frequency extremes it seems.
Someone mentioned JJ - do what you think is best, but the build quality is so poor on the JJ octals that you need to be VERY careful about using them. There are a lot of issues besides the undersize pins that were a big problem.
The large bottle EH 6CA7s are very good tubes, but sound more like a "baby 6550" than an EL34. The fat bottles have more energy at the frequency extremes it seems.
I`ve heard that if you need a thighter sound than SED, the Golden Dragon i sa good choice. Norw. idealers of MingDa use them as an upgrade for their products. I bought a quad for my amp when it is ready.
I like the SED the best. EH fat bottle sound very close to my RCA fat bottle and work very well in my Bassman 100 but lack detail in both of my ST. 70's (1 stock and 1 modified)
Sounds like the consensus is the the SED. I will for sure try out a set of them.
Thanks for all the info tubeland.com, I checked out your site, it looks great. You definitely know what your talking about.
kstagger, what sort of setup do you have to run 6L6gc's in your St-70, do you have a ST-70-C3 too?
Shane
Thanks for all the info tubeland.com, I checked out your site, it looks great. You definitely know what your talking about.
kstagger, what sort of setup do you have to run 6L6gc's in your St-70, do you have a ST-70-C3 too?
Shane
Colored me confused, but I thought SED was the defunct joint stock company that New Sensor acquired a few years ago? I believe (perhaps mistakenly) that most of the tubes currently sold under the SED label here are made by New Sensor's ExpoPul plant in Saratov.
=C= (Winged C) is the brand that Svetlana SPB of St. Petersburg sells under in the United States and anywhere outside of the old eastern block where New Sensor controls the rights to the SED name.. It also appeared on all tubes made prior to the existance of SED.
The Svetlana SPB tube is built on different tooling in a different plant. I like the =C= EL34 as well as their 6550C which last time I knew was both good sounding and reliable.
Personally I would go for the =C= EL34..
Incidentally before powering up this old ST-70 you might just as well recap it, (Quad cap, bias supply caps, and coupling caps) and replace the selenium rectifier if it is still present. Simple resistance measurements will tell you which resistors in the driver circuit are suspect. There is no reason I can think of to destroy a set of output tubes or the power transformer in one of these amplifiers when all of the issues with it are so well known.
I have not had good luck with Russian made 7199, IMHO you would be better off buying a couple of good used ones on eBay.
=C= (Winged C) is the brand that Svetlana SPB of St. Petersburg sells under in the United States and anywhere outside of the old eastern block where New Sensor controls the rights to the SED name.. It also appeared on all tubes made prior to the existance of SED.
The Svetlana SPB tube is built on different tooling in a different plant. I like the =C= EL34 as well as their 6550C which last time I knew was both good sounding and reliable.
Personally I would go for the =C= EL34..
Incidentally before powering up this old ST-70 you might just as well recap it, (Quad cap, bias supply caps, and coupling caps) and replace the selenium rectifier if it is still present. Simple resistance measurements will tell you which resistors in the driver circuit are suspect. There is no reason I can think of to destroy a set of output tubes or the power transformer in one of these amplifiers when all of the issues with it are so well known.
I have not had good luck with Russian made 7199, IMHO you would be better off buying a couple of good used ones on eBay.
I found SED =C= 's to be a big improvement overall upon Chinese EL34 in PP (chinese tubes' bass especially was terrible)...
Simon
Simon
Winged C SED tubes that I saw are very similar to ebay item 280082886759
Are these the recommended ones?
I am not too worried about recapping the ST-70. It looks like it was done fairly recently and with ok quality stuff. It has some sort of rectifier on it that I do not recognize. The amp works fine as it is now but I want to upgrade the driver board mostly and put better connectors and such on it.
What do you make of this rectifier?
Link to Album
Are these the recommended ones?
I am not too worried about recapping the ST-70. It looks like it was done fairly recently and with ok quality stuff. It has some sort of rectifier on it that I do not recognize. The amp works fine as it is now but I want to upgrade the driver board mostly and put better connectors and such on it.
What do you make of this rectifier?
Link to Album
AFIAK SED now = New Sensor/ExpoPul, while =C= Svetlana SPB (The real Svetlana in St. Petersburg.)
so SED and =C= are not the same vendor.. QED??
I know this is confusing, but I believe & understand that they are now two ENTIRELY separate business entities thanks to the bankruptcy of SED of Huntsville, Alabama and St. Petersburg, Russia some years ago.
So which vendor are you guys talking about?
I can vouch for =C=, but not the current SED product with which I have no familiarity.
Is New Sensor/SED actually also selling Svetlana =C= tubes in SED boxes?
😕 😕 😕
so SED and =C= are not the same vendor.. QED??
I know this is confusing, but I believe & understand that they are now two ENTIRELY separate business entities thanks to the bankruptcy of SED of Huntsville, Alabama and St. Petersburg, Russia some years ago.
So which vendor are you guys talking about?
I can vouch for =C=, but not the current SED product with which I have no familiarity.
Is New Sensor/SED actually also selling Svetlana =C= tubes in SED boxes?
😕 😕 😕
Pyre said:
I have an old 60s era '70 I rebuilt a few years ago with the SDS Power supply board and the Triode Electronics input board.
The Svetlana version of the 6L6GC is pretty tough - 30W plate/500V max
http://www.drtube.com/datasheets/6l6gcsvet1996.pdf
- so (this was in a pinch!) I biased them up like the EL34. Treble seemed a little softer than the Matsushita EL34, but otherwise an excellent sounding tube. They also served duty when I was testing a pair of rebuilt Mark IIIs and they took the abuse (biased for lower than 6550 current though).
Looking at your pictures I noticed there seem to be a lot of power supply modifications to this unit.. The C-354 choke appears to be missing and there is a lot of additional capacitance under the chassis.
I would not plug a 5AR4 rectifier into that socket without knowing a whole lot more about the mods that have been made to this amplifier. I suspect the capacitor charging inrush current would kill a 5AR4..
I would not plug a 5AR4 rectifier into that socket without knowing a whole lot more about the mods that have been made to this amplifier. I suspect the capacitor charging inrush current would kill a 5AR4..
kevinkr said:
Wrong. SED stands for Svetlana Electronic Devices, the Russian parent company in St Petersburg, Russia. They can't use the Svetlana name in the USA though, as the rights to it were bought by New Sensor in bankruptcy court when the old Svetlana USA distributor went belly up.
So SED = Winged C = tubes made in St. Petersburg, Russia
Svetlana = New Sensor (USA only) = tubes made in New Sensor's own plant
NO! They are selling Svetlana branded tubes in Svetlana boxes, which they have every right to do now. The boxes from New Sensor DO NOT have the "winged C" logo on them. The winged C belongs to SED.
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