The closest US tube to the ECC99 I've found is a 5687, but it's a different pinout. The Soviet 6N6P is another alternative.
Hi Kay,
Yes, the heaters were moved to a location for lower hum pick up. Since the 6EU7 doesn't have a direct sub, different pinouts are fine. I'll have to look at the ECC808 and the 6KX8 as well.
Hi kodabmx,
Interesting, a 5687. I'll have to look at that and the Russian 6N6P. I have to admit I have zero experience with Russian tubes beyond New Sensor's current manufactured product. I will say I am very happy with New Sensor so far.
Thanks everyone for the 6EU7 replacements.
-Chris
Yes, the heaters were moved to a location for lower hum pick up. Since the 6EU7 doesn't have a direct sub, different pinouts are fine. I'll have to look at the ECC808 and the 6KX8 as well.
Hi kodabmx,
Interesting, a 5687. I'll have to look at that and the Russian 6N6P. I have to admit I have zero experience with Russian tubes beyond New Sensor's current manufactured product. I will say I am very happy with New Sensor so far.
Thanks everyone for the 6EU7 replacements.
-Chris
Hi Chris,
no need for that. As I said before, this tube has become obscenely expensive, and it really isn't that much better than a ECC83/7025 (not to be confused with the 12AX/7)!
Maybe the Russian 6N2-P could be the better option?
Best regards!
I find Soviet tubes to be an amazing value... new Sensor is using the Reflector plant I believe. Good quality from there.
Yes, it's the old Reflektor plant which New Sensor now owns. It's currently known as (E)xpo-Pul.
EHX.com | Peek Inside One of the World’s Great Tube Factories | Electro-Harmonix
I find the quality of surplus Soviet era mil-spec stuff to be substantially better than most current production.
Note that the production technology is very typical of what you would have seen in the late 1940s through the early 1960s. Work areas seem clean, tidy and the process well organized. I suppose the bake during evacuation will deal with contamination during assembly as I noted that it is all done bare handed. (No cots on fingers even)
EHX.com | Peek Inside One of the World’s Great Tube Factories | Electro-Harmonix
I find the quality of surplus Soviet era mil-spec stuff to be substantially better than most current production.
Note that the production technology is very typical of what you would have seen in the late 1940s through the early 1960s. Work areas seem clean, tidy and the process well organized. I suppose the bake during evacuation will deal with contamination during assembly as I noted that it is all done bare handed. (No cots on fingers even)
Hi Kay,
The 12AX7A is identical to a 7025. The 12AX7 isn't, being more noisy for one.
Hi Kevin,
I have found that the New Sensor Electroharmonix is better (more consistent tube to tube) than the NOS stuff. The worst that comparison gets is equal. As I've said, I would happily sell all my NOS tubes for the going rate that I could replace with Electroharmonix. That would make me a very very happy guy in fact.
-Chris
The 12AX7A is identical to a 7025. The 12AX7 isn't, being more noisy for one.
Hi Kevin,
I have found that the New Sensor Electroharmonix is better (more consistent tube to tube) than the NOS stuff. The worst that comparison gets is equal. As I've said, I would happily sell all my NOS tubes for the going rate that I could replace with Electroharmonix. That would make me a very very happy guy in fact.
-Chris
Perhaps they are improving, but a couple of years ago I bought more than a dozen of Sovtek 12AX7LPS and ended up with about a quarter of them that I deemed unusable, and most of the rest had rather low transconductance and very poor matching section to section. These are all made in the same plant so I am puzzled by your glowing reports of EH consistency.
I have an AVO160 in good working order and a uTracer to test and characterize these parts. My NOS stuff is comprised of various European brands and Sylvania, Raytheon,Tungsol or RCA often mil spec., consistency in these tubes has been very good. I have some Russian stuff as well which is where my preferences tend to lie these days
I have an AVO160 in good working order and a uTracer to test and characterize these parts. My NOS stuff is comprised of various European brands and Sylvania, Raytheon,Tungsol or RCA often mil spec., consistency in these tubes has been very good. I have some Russian stuff as well which is where my preferences tend to lie these days
Not so. The key difference between the 7025 and a 'X7 or 'X7A is the presence of a spiral wound, hum bucking, heater. The difference between a 'X7A and a 'X7 is controlled heater warmup time. Please notice that RCA called for the 7025 in the famous passive EQ RIAA preamp. While difficult to implement, AC heating 7025s can yield tolerable hum levels. The Sovtek 12AX7LPS is a genuine 7025 equivalent.
Some 'LPS specimens suffered from cathode "sleeping sickness", which could be corrected by "cooking" the tubes for a while under an above spec. heater voltage.
The ECC99 is a comparatively recent Tesla/JJ introduction, with no North American equivalent. Its advantages are pin compatibility with the 12A_7 bunch, a true medium μ of 22, and somewhat less heater draw than other "super triodes". AFAIK, of the "super triodes", only the ECC99 and 6H30Π (6n30p) are in production.
Attachments
Hi Eli,
I ran across some literature a while back that stated that the 12AX7A was a 7025, and it wasn't sales oriented stuff like a white paper. Then there are all the tubes out there branded 12AX7A/7025 from all the really good manufacturers of the day. I'm referring to the NOS, new in the day stuff. Any tube not marked with both numbers are either 12AX7 tubes, or old 7025s. I think that it's perfectly reasonable to assume they are equivalent being marked in that manner. A spiral heater doesn't even cause trouble on the production line. It slides into the same cylinder with the same coatings.
I'm not attempting to second guess you, but the truth of the matter has to lie somewhere and I can't see the large corporations of the time telling big fibs.
Best, Chris
I ran across some literature a while back that stated that the 12AX7A was a 7025, and it wasn't sales oriented stuff like a white paper. Then there are all the tubes out there branded 12AX7A/7025 from all the really good manufacturers of the day. I'm referring to the NOS, new in the day stuff. Any tube not marked with both numbers are either 12AX7 tubes, or old 7025s. I think that it's perfectly reasonable to assume they are equivalent being marked in that manner. A spiral heater doesn't even cause trouble on the production line. It slides into the same cylinder with the same coatings.
I'm not attempting to second guess you, but the truth of the matter has to lie somewhere and I can't see the large corporations of the time telling big fibs.
Best, Chris
My understanding is that the original 12AX7 had a conventional heater. Philips/Mullard made a similar valve but used a spiral heater, calling it the ECC83. Then the 7025 appeared, essentially a US version of the ECC83. Finally some later 12AX7 acquired a spiral heater too.
The net result is that if a valve is labelled ECC83 or 7025 then it should have a spiral heater - but we know that modern valve makers play fast and loose with valve naming conventions (e.g. the ECC99 on a B9A base, when '9' means B7G!). A valve labelled 12AX7 may or may not have a spiral heater.
The net result is that if a valve is labelled ECC83 or 7025 then it should have a spiral heater - but we know that modern valve makers play fast and loose with valve naming conventions (e.g. the ECC99 on a B9A base, when '9' means B7G!). A valve labelled 12AX7 may or may not have a spiral heater.
Thanks DF96 !
And so we keep going around in circles (or is that around in spirals?).
Some filaments are like the stock market, they just keep going up and down.
"Standards are such a wonderful thing that everyone has his own" (me).
Can any of you name ALL the standards for wired electronic communication . . .
IEEE-488 (GPIB), RS232 (real serial 232 ways), Firewire, etc. . . .
And so we keep going around in circles (or is that around in spirals?).
Some filaments are like the stock market, they just keep going up and down.
"Standards are such a wonderful thing that everyone has his own" (me).
Can any of you name ALL the standards for wired electronic communication . . .
IEEE-488 (GPIB), RS232 (real serial 232 ways), Firewire, etc. . . .
leadbelly,
The Random House Dictionary of the English Language, 1968:
standard (stan'derd) n. 1. something considered by an authority or by general consent as a basis of comparison; an approved model.
Yes, I am sarcastic. A standard is set and agreed to by committee; and then the variations begin.
After that, some adhere to the old standard, some adhere to the 'new' standard, some do not tell you which of the two they adhere to, etc.
Some start their own variation and do not adhere to standard 1 or standard 2.
The "standard" is no longer a standard.
You may want to check your tubes as to what they really are, before you use them.
And saying that an "equivalent" pentode that has 3x the plate resistance in a circuit that has a dominant series RC pole to ground will perform the same as the original tube is wrong.
The Random House Dictionary of the English Language, 1968:
standard (stan'derd) n. 1. something considered by an authority or by general consent as a basis of comparison; an approved model.
Yes, I am sarcastic. A standard is set and agreed to by committee; and then the variations begin.
After that, some adhere to the old standard, some adhere to the 'new' standard, some do not tell you which of the two they adhere to, etc.
Some start their own variation and do not adhere to standard 1 or standard 2.
The "standard" is no longer a standard.
You may want to check your tubes as to what they really are, before you use them.
And saying that an "equivalent" pentode that has 3x the plate resistance in a circuit that has a dominant series RC pole to ground will perform the same as the original tube is wrong.
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