Good evening everyone,
I could use some suggestions on purchasing some 7868 tubes. I've looked on that famous auction site and their seems to be tubes coming out of Russia, I was hoping not to go that route.
So, I am seeing 4 main types of "vintage" 7868's. Those with pointy tops and those with rounded tops, those with round holes in the plate and those with square holes in the plates. I have seen combinations of these. Any suggestions on what I should be purchasing?
Thanks
Ray
I could use some suggestions on purchasing some 7868 tubes. I've looked on that famous auction site and their seems to be tubes coming out of Russia, I was hoping not to go that route.
So, I am seeing 4 main types of "vintage" 7868's. Those with pointy tops and those with rounded tops, those with round holes in the plate and those with square holes in the plates. I have seen combinations of these. Any suggestions on what I should be purchasing?
Thanks
Ray
Hi Ray,
One word. 7868EH
The Electroharmonix brand is reverse engineered from the actual North American tube. The Electroharmonix line is mostly from RCA tubes as it was explained to me. They are made in Russia and are very high quality. I use them whenever there is a choice to be made. So the other brands that New Sensor sells are copied from tubes of those respective brands. I prefer Electroharmonix over NOS tubes easily.
-Chris
One word. 7868EH
The Electroharmonix brand is reverse engineered from the actual North American tube. The Electroharmonix line is mostly from RCA tubes as it was explained to me. They are made in Russia and are very high quality. I use them whenever there is a choice to be made. So the other brands that New Sensor sells are copied from tubes of those respective brands. I prefer Electroharmonix over NOS tubes easily.
-Chris
> tubes coming out of Russia, I was hoping not to
ALL US and west-Europe tube factories shut-down 1970-1990s.
Much of the machinery was transferred to friendlier countries in East Europe. As eact-bloc tube demand fell, some of that gear moved to China. Russia had fine tube factories from the 1930s onward long past all tube use ended in most of the world. Still running.
Any tube maker can make as good or bad as the customer demands. The Russian tubes made for internal military and industrial uses are as good as any ever made. The Chinese can do wonderful work. BUT when you complain about the staggering price (really good tubes were never cheap! Most tubes today are cheaper than in 1972, considering money inflation.) most will offer lower-price alternatives. Some distributors buy the cheapest, and get junk.
> 7868EH
Yes. Mike has been hanging around the Russian factories for decades. Working with and against politicians and gangsters. Tubes bring hard Dollars so control of the factories is messy. EH has generally been very good about getting good Russian tubes, and the prices are fine.
> types of "vintage" 7868's.
7868 is not a Golden Age type. 1963, a runt hi-gain 6L6 for too-compact stereos. While tube production was still strong, it was clear the End Was Near. Production standards on consumer tubes slackened.
Moreover I would be very sure nearly "all" old 7868 on the market today have been picked-over and all the cream skimmed. I would expect (maybe wrong) to get mostly rejects. Yes, some tubes test poorly and play fine. I would fear, though, getting hard-rejects that burned up the amplifier. Plate-holes is no guide to that.
At least get 7868EH for reference.
I assume you can't re-bias for 6L6 type. Many 7868 apps are too compact. The lower gain of the proven 6L6 type may reduce NFB which is bad for hi-fi.
ALL US and west-Europe tube factories shut-down 1970-1990s.
Much of the machinery was transferred to friendlier countries in East Europe. As eact-bloc tube demand fell, some of that gear moved to China. Russia had fine tube factories from the 1930s onward long past all tube use ended in most of the world. Still running.
Any tube maker can make as good or bad as the customer demands. The Russian tubes made for internal military and industrial uses are as good as any ever made. The Chinese can do wonderful work. BUT when you complain about the staggering price (really good tubes were never cheap! Most tubes today are cheaper than in 1972, considering money inflation.) most will offer lower-price alternatives. Some distributors buy the cheapest, and get junk.
> 7868EH
Yes. Mike has been hanging around the Russian factories for decades. Working with and against politicians and gangsters. Tubes bring hard Dollars so control of the factories is messy. EH has generally been very good about getting good Russian tubes, and the prices are fine.
> types of "vintage" 7868's.
7868 is not a Golden Age type. 1963, a runt hi-gain 6L6 for too-compact stereos. While tube production was still strong, it was clear the End Was Near. Production standards on consumer tubes slackened.
Moreover I would be very sure nearly "all" old 7868 on the market today have been picked-over and all the cream skimmed. I would expect (maybe wrong) to get mostly rejects. Yes, some tubes test poorly and play fine. I would fear, though, getting hard-rejects that burned up the amplifier. Plate-holes is no guide to that.
At least get 7868EH for reference.
I assume you can't re-bias for 6L6 type. Many 7868 apps are too compact. The lower gain of the proven 6L6 type may reduce NFB which is bad for hi-fi.
new production 7868 tubes have fat pins than the original
i had to loosen the socket pins to get the new tubes in....
i had to loosen the socket pins to get the new tubes in....
OS 7868s were built with Novar bases. The EH 7868 is built with a Magnoval base. The pin circles are identical, but Magnoval pins are fatter. I suspect that New Sensor could not source Novar bases.
Once EH 7868s are installed, there is no going back to OS tubes, without replacing the sockets. The whole issue is "academic", as the New Sensor product is, for all practical purposes, the only option.
Once EH 7868s are installed, there is no going back to OS tubes, without replacing the sockets. The whole issue is "academic", as the New Sensor product is, for all practical purposes, the only option.
i learned that the hard way, when the costumer brought back his fisher 400
receiver with the output tubes not properly seated in their sockets...
a suitably sized safety pins took care of that, i wanted to replace the
sockets but the owner would not agree, so i did what i had to do...
i told him, he can not go back to his old tubes...
I've restored a few Fisher 400s and used the EHs in them, worked out great.
Pins are larger so once you use these, might be difficult to go back to small pins without adjusting sockets.
Mark
Pins are larger so once you use these, might be difficult to go back to small pins without adjusting sockets.
Mark
If one were designing a new amp for their own use and could use the electrically equivalent 7868 Electro Harmonix or the 7591A Electro Harmonix what would you all recommend? The 7591A appears to have different guts inside as the plates are larger (maybe a good thing?). It is also slightly cheaper in price.
I'd be using the 7591A. At least it's socket is a standard octal. But then, why wouldn't you just use a 6L6GC and be done with the funny stuff?
I thought a 7868 and 7591A were the same tube with different bases.
-Chris
I thought a 7868 and 7591A were the same tube with different bases.
-Chris
i would go for octals, lots of choices and tubes...
why even the JJ 6V6 i bought could pass as a 6l6GC, i have no complaints..
i fact we used that on an amp using the EL34 and could not know any better...
why even the JJ 6V6 i bought could pass as a 6l6GC, i have no complaints..
i fact we used that on an amp using the EL34 and could not know any better...
Because the 7591 is as easy to drive as "12" W. tubes. Also, it doesn't hurt that the 7591 family is very good sounding.
Hi Eli,
They are easier to drive, and I had that in mind when I posted. However, the 6L6 isn't that hard to drive really. I also like the sound of 6L6GC tubes, or the 7581A's. 🙂 What I was looking for is a tube type that will be here "forever".
I have an int. amplifier that uses 7591A's. I was bummed out for years until New Sensor re-issued the 7591A. That amp was headed for a 6L6GC conversion otherwise. Yes, they sound good. The 7868 re-issue saved a ton of Bogen PA amps!
-Chris
They are easier to drive, and I had that in mind when I posted. However, the 6L6 isn't that hard to drive really. I also like the sound of 6L6GC tubes, or the 7581A's. 🙂 What I was looking for is a tube type that will be here "forever".
I have an int. amplifier that uses 7591A's. I was bummed out for years until New Sensor re-issued the 7591A. That amp was headed for a 6L6GC conversion otherwise. Yes, they sound good. The 7868 re-issue saved a ton of Bogen PA amps!
-Chris
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