I would like to introduce and recommend a neglected 6SN7 substitute, the Raytheon
5694. It's a made for the military dual AF power triode. The 5694 = premium 6N7 GT
with separate cathode leads, like a 6SN7. It is similar electrically to a Mullard ECC32 /
CV-181, BUT with a different pin-out. The Raytheon tube actually is closer electronically to a 6SN7 than the ECC32s are. The Vfil = 6.3V @ 800ma, versus 950ma for the ECC32s and 600ma for a 6SN7 GTB. These tubes although rare can still be found for between $15 to $50 each delivered. My yield of platinum (5%) matched and balanced pairs and a single quad brought my price per tube to about $100, still a great bargain considering the fact that they are far superior to the $500 to $600 plus a pair of Mullard ECC32 / CV-181, when and if you can find them.
Raytheon has accidentally and unknowingly given the audio world a great gift.
These tubes are far less noisy than the ECC32s and deliver details like a Jazz piano with no close rival. The silent passages are as mute as you have never heard. They are also much easier on the ears, allowing for longer, more pleasant listening periods. I found the Mullard ECC32 lacking in bottom end response. My previous
6SN7 favorite flavor was the "holy grail" of the 6SN7 world, the Tung-Sol 1940s
6SN7 GT, black glass, black plates, round getters, fetching $400 to $500 a pair, when and if you can find them. Not being sentimental or indecisive, my barely used quintet quickly fetched $1,000 on the slightly used NOS market.
They require adapters or re-wiring of the octal sockets they are going into, but it's more than worth it. The required pin-out follows: Pin # 1 Cathode, 2 & 7 Filament,
3 Plate, 4 Grid, 5 Grid 6 Plate 8 Cathode. IF your making adapters, use the following pin-out. Tube base number / Tube socket number: 1 / 4, 2 /3, 3 /1, 4 / 5,
5 / 6, 6 / 8, 7 / 7, 8 / 2.
Good luck treasure hunting, I humbly await your opinions.
5694. It's a made for the military dual AF power triode. The 5694 = premium 6N7 GT
with separate cathode leads, like a 6SN7. It is similar electrically to a Mullard ECC32 /
CV-181, BUT with a different pin-out. The Raytheon tube actually is closer electronically to a 6SN7 than the ECC32s are. The Vfil = 6.3V @ 800ma, versus 950ma for the ECC32s and 600ma for a 6SN7 GTB. These tubes although rare can still be found for between $15 to $50 each delivered. My yield of platinum (5%) matched and balanced pairs and a single quad brought my price per tube to about $100, still a great bargain considering the fact that they are far superior to the $500 to $600 plus a pair of Mullard ECC32 / CV-181, when and if you can find them.
Raytheon has accidentally and unknowingly given the audio world a great gift.
These tubes are far less noisy than the ECC32s and deliver details like a Jazz piano with no close rival. The silent passages are as mute as you have never heard. They are also much easier on the ears, allowing for longer, more pleasant listening periods. I found the Mullard ECC32 lacking in bottom end response. My previous
6SN7 favorite flavor was the "holy grail" of the 6SN7 world, the Tung-Sol 1940s
6SN7 GT, black glass, black plates, round getters, fetching $400 to $500 a pair, when and if you can find them. Not being sentimental or indecisive, my barely used quintet quickly fetched $1,000 on the slightly used NOS market.
They require adapters or re-wiring of the octal sockets they are going into, but it's more than worth it. The required pin-out follows: Pin # 1 Cathode, 2 & 7 Filament,
3 Plate, 4 Grid, 5 Grid 6 Plate 8 Cathode. IF your making adapters, use the following pin-out. Tube base number / Tube socket number: 1 / 4, 2 /3, 3 /1, 4 / 5,
5 / 6, 6 / 8, 7 / 7, 8 / 2.
Good luck treasure hunting, I humbly await your opinions.
Hi!
Thanks for pointing out this tube! I use the 6N7 a lot and this is an alternative worthwhile to check.
However I would not advice to use it as a substitute for a 6SN7. It has three times the plate resistance as the 6SN7 and a much higher mu. While it might work in some circuits designed for 6SN7, it certainly will not work well in all of them
Best regards
Thomas
Thanks for pointing out this tube! I use the 6N7 a lot and this is an alternative worthwhile to check.
However I would not advice to use it as a substitute for a 6SN7. It has three times the plate resistance as the 6SN7 and a much higher mu. While it might work in some circuits designed for 6SN7, it certainly will not work well in all of them
Best regards
Thomas
Hi!
5694 mu = 35 according to this site:
NJ7P SQL Tube Database Query
6SN7 mu = 20
Very different tubes.
I would not use it to drive large triodes like the 845. Works well as driver for 45 or 801A for which I use 6N7 a lot.
Best regards
Thomas
5694 mu = 35 according to this site:
NJ7P SQL Tube Database Query
6SN7 mu = 20
Very different tubes.
I would not use it to drive large triodes like the 845. Works well as driver for 45 or 801A for which I use 6N7 a lot.
Best regards
Thomas
Hi!
I didn't catch that, I agree $100 is hardly a bargain, especially since they can be had NOS for $12. No matching justifies $100 no matter if it is 'platinum' or whatever.
Another alternative to 6N7 would be the 6A6 which goes for $5 for NOS, it has a UX7 base instead of octal but is electrically equivalent.
Thomas
I didn't catch that, I agree $100 is hardly a bargain, especially since they can be had NOS for $12. No matching justifies $100 no matter if it is 'platinum' or whatever.
Another alternative to 6N7 would be the 6A6 which goes for $5 for NOS, it has a UX7 base instead of octal but is electrically equivalent.
Thomas
For $120 I would buy ten and match them up myself although I would guess a 5% match is unnecessary and two or three would yield a good pair.
But it does look like an interesting tube with a mu=35; it could be a useful driver for a small triode. I like the separate cathodes compared to a 6N7; that really makes it more useful.
But it does look like an interesting tube with a mu=35; it could be a useful driver for a small triode. I like the separate cathodes compared to a 6N7; that really makes it more useful.
I understand that tubes are not linear and will sound different in different circuits. However I would like to confirm WS Traders opinion of the 5694 as a 6SN7 sub. It is the most dynamic tube I have ever used in my Oppo BDP-95 Modwright player. They have spoiled me to the point that I won’t listen to anything else. My 3 hole bad boys, round plate tung-sols, etc., all sound restricted to me now that I have played my system with these Raytheon’s. If I have the funds, I will pay the current NOS prices of the “Holy Grail” round plates for a low-microphonic NOS pair of these tubes. They do everything my VT-99’s do except better. They are more extended without adding any harshness. I have nothing to gain from this and thought I would jump in and give another opinion. I wonder how many other tubes is out there that sound better/ same as current expensive NOS tubes that we have yet to discover?? Diana Krall’s Temptation sounds like she is playing in front of me. I can feel the snare drum hit as if I were in front of it live. The best way I can describe them is extremely dynamic. They do have quite a bit more gain than the 6SN7. It allows me to attenuate the input of my amp lowering my noise floor. I absolutely love these tubes. I have a feeling that a lot of them are microphonic. I have several NOS pairs that have at least one triode that is overly microphonic. Currently, I have two matched pairs that are perfect. Unless something catastrophic happens I will never let go of these tubes.
Cheers!
Steve
Cheers!
Steve
Hi Steve,
these tubes are not the same. The 5694 cannot be regarded as general alternative to the 6SN7! It can degrade the performance if the circuit around if that cannot work well with the much higher plate resistance. The higher mu can be a benefit in some circuits but also a disadvantage in others.
Also important to note that they have a different pinout. Otherweise unexperienced readers might just try to plug these into their 6SN7 sockets.
Best regards
Thomas
these tubes are not the same. The 5694 cannot be regarded as general alternative to the 6SN7! It can degrade the performance if the circuit around if that cannot work well with the much higher plate resistance. The higher mu can be a benefit in some circuits but also a disadvantage in others.
Also important to note that they have a different pinout. Otherweise unexperienced readers might just try to plug these into their 6SN7 sockets.
Best regards
Thomas
Thank you Thomas. Understood and point taken. Yes, just like the 6F8G an adaptor must be used. The difference of course is the specs are virtually the same as a 6SN7.
That is OK because I know that for me, in my Oppo BDP-95 w/Modwright mod, I have run these tubes for hundreds of hours and they are the cream of the crop in my set-up.
That is OK because I know that for me, in my Oppo BDP-95 w/Modwright mod, I have run these tubes for hundreds of hours and they are the cream of the crop in my set-up.
On the recommendation for the 7N7, it is the loktal equivalent of early 6SN7GT and because of the loktal base it is still far cheaper than comparable vintage 6SN7.. Don't get fooled by the "7" it is in fact a standard 6.3V filament type. IMVLE there are no bad 7N7..
There is talk about matching tubes for Gm.
Well, the expensive way is by testing tube after tube and selecting the one or two odd best matches.
In a popular magazine of the 1950’s (popular engineering or such) I read tha it is possible to fine-tune the Gm by changing the heater voltage .
The suggestion given there was a trim pot of say 1 ohms that allowed to slightly change the voltage between two halves or two tubes.
Similarly, I have today matched tubes (non-feeback output of a WE91A design) within 0,1 dB per channel by changing the screen voltage slightly, of the 6SJ7 driver tube.
It works like a charm!
Thos way you do not need an expensive cash layout.
Well, the expensive way is by testing tube after tube and selecting the one or two odd best matches.
In a popular magazine of the 1950’s (popular engineering or such) I read tha it is possible to fine-tune the Gm by changing the heater voltage .
The suggestion given there was a trim pot of say 1 ohms that allowed to slightly change the voltage between two halves or two tubes.
Similarly, I have today matched tubes (non-feeback output of a WE91A design) within 0,1 dB per channel by changing the screen voltage slightly, of the 6SJ7 driver tube.
It works like a charm!
Thos way you do not need an expensive cash layout.
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