12AX7 is for guitar amps while 12AU/T7 or 12BH7 = hifi
ZMF Aegis Official Thread
- Thread starter AnyDave
- Start date
12AX7 is for guitar amps while 12AU/T7 or 12BH7 = hifi
Yeah those are pretty different tubes so not surprising they would sound very different. From a design standpoint, any DIY application where I would consider using 12AX7 I would rather use a pair of 6F5G/6SF5GT, which are single triode octal equivalents with better linearity. Any commercial application where I would consider using 12AX7, I'd rather sacrifice 30% gain for half the plate resistance and better linearity by using 6SL7. So for me, 12AX7 has no place, just my opinion.
AnyDave
Previously known as EtyDave
Sponsor: ZMFheadphones
Member of the Trade: Dark Matter Audio Labs
- Joined
- Apr 20, 2016
- Posts
- 2,692
- Likes
- 8,116
I think that there are quite a few folks that prefer octals for hifi vs any 9-pin mini.
Yeah their closest octal counterparts tend to be higher performing. And in this case it's not even a subjective evaluation, they are lower distortion. With that said, there are still some excellent 9-pin tubes that have no octal counterpart.
Just checking back in, after last night's heavy weight bout between the Cossor ATS25 and Mullard 807. First off, both of these tubes are absolutely fantastic, with each having their own special magic. That being said (spoiler), if I had to pick only one it would be the Cossor. I am going to attempt to describe how magical the Cossor is, and then describe how the Mullard 807 compares for reference.
The Cossor ATS25 has so much magic going on it's insane. The sound is weighty and lush, yet highly detailed and dynamic, with nuances galore. I am hearing more detail and nuances than I have ever heard before. This tube is amazing in how warm and harmonically rich it is, while also still being super quick, dynamic and detailed at the same time. The bass hits hard and digs extremely deep, and can actually be a bit startling when it first hits. This tube brings the most grip and explosiveness of all the 807's, and makes the amp sound "super charged". The mids are forward and present, and euphonic with extremely lifelike timbre. The highs are well extended and smooth. As for the staging, that's where this tube is very unique. The staging with this tube very much reminds me of the 300B, with vocals front and center, and then all the instruments are a bit further back and layered perfectly with each having it's own space. This tube gives the song exactly what it calls for, and can be super intimate, or deep and expansive depending on the track. The sound is very holographic, and it doesn't even sound like it is coming from the cups. Next is the decay, and this is where some serious magic is happening. The notes just seem to hang around a bit longer while floating in space and fleshed out completely with this tube. This in turn really brings on the realism, and I feel like I can reach out and touch the notes. The Cossor ATS25 no doubt brings "Holy Grail" level performance, and is a tube I can't recommend enough. All that being said, I feel like I am still not doing this tube justice, as it's hard to put into words the magic this tube brings.
On to the Mullard 807 Black Plate Foil Getter, and this tube is not quite as warm, harmonically rich and forward as the Cossor. The sound is still weighty and very punchy, with excellent bass that goes deep and hits hard. This is just a tad less bass than the Cossor, and still is very much at basshead level. The mids are not quite as forward and involving, but are still fantastic, with lifelike timbre and really good euphonic texture. I actually think their is more texture in the mids compared to the Cossor, and this seems to make the notes sound electrified. The highs are pretty similar to the Cossor, being extended yet smooth without any harshness. Overall, this tube is just a bit behind in detail and nuances, yet also a bit more open and balanced as well. The Mullard still reminds me of the 300B, and is one heck of tube that will stay in my rotation.
Having both heavy weights in my rotation, I am finding I like the Mullard the most with Electronica, and I like the Cossor more for Folk, Rock and Acoustic stuff. That being said, both tubes do all genres extremely well, and one will want for nothing while listening.
All listening has been done with the Caldera Closed in stock configuration, with RCA 5691 for input and Phillips Sittard GZ34 as the rectifier.
Happy Hunting, Rolling, and Listening.
The Cossor ATS25 has so much magic going on it's insane. The sound is weighty and lush, yet highly detailed and dynamic, with nuances galore. I am hearing more detail and nuances than I have ever heard before. This tube is amazing in how warm and harmonically rich it is, while also still being super quick, dynamic and detailed at the same time. The bass hits hard and digs extremely deep, and can actually be a bit startling when it first hits. This tube brings the most grip and explosiveness of all the 807's, and makes the amp sound "super charged". The mids are forward and present, and euphonic with extremely lifelike timbre. The highs are well extended and smooth. As for the staging, that's where this tube is very unique. The staging with this tube very much reminds me of the 300B, with vocals front and center, and then all the instruments are a bit further back and layered perfectly with each having it's own space. This tube gives the song exactly what it calls for, and can be super intimate, or deep and expansive depending on the track. The sound is very holographic, and it doesn't even sound like it is coming from the cups. Next is the decay, and this is where some serious magic is happening. The notes just seem to hang around a bit longer while floating in space and fleshed out completely with this tube. This in turn really brings on the realism, and I feel like I can reach out and touch the notes. The Cossor ATS25 no doubt brings "Holy Grail" level performance, and is a tube I can't recommend enough. All that being said, I feel like I am still not doing this tube justice, as it's hard to put into words the magic this tube brings.
On to the Mullard 807 Black Plate Foil Getter, and this tube is not quite as warm, harmonically rich and forward as the Cossor. The sound is still weighty and very punchy, with excellent bass that goes deep and hits hard. This is just a tad less bass than the Cossor, and still is very much at basshead level. The mids are not quite as forward and involving, but are still fantastic, with lifelike timbre and really good euphonic texture. I actually think their is more texture in the mids compared to the Cossor, and this seems to make the notes sound electrified. The highs are pretty similar to the Cossor, being extended yet smooth without any harshness. Overall, this tube is just a bit behind in detail and nuances, yet also a bit more open and balanced as well. The Mullard still reminds me of the 300B, and is one heck of tube that will stay in my rotation.
Having both heavy weights in my rotation, I am finding I like the Mullard the most with Electronica, and I like the Cossor more for Folk, Rock and Acoustic stuff. That being said, both tubes do all genres extremely well, and one will want for nothing while listening.
All listening has been done with the Caldera Closed in stock configuration, with RCA 5691 for input and Phillips Sittard GZ34 as the rectifier.
Happy Hunting, Rolling, and Listening.
Last edited:
ATS25 has so much magic going on it's insane.
I have a pair of these VT60 tubes. I think they are identical to your Cossor ATS25.
On to the Mullard 807 Black Plate Foil Getter
Your Mullard 807 looks very similar to my Brimar 807.
Attachments
Last edited:
Anyone compared the 807 to the KT8C?
Man, I'm happy this was your finding because last night I got antsy and I ordered some of those GEC VT60 tubes @Marutks just posted. I think they are the same as the Cossors... Ebay identified them as military grade Cossor essentially. Who knows hopefully they are great.Just checking back in, after last night's heavy weight bout between the Cossor ATS25 and Mullard 807. First off, both of these tubes are absolutely fantastic, with each having their own special magic. That being said (spoiler), if I had to pick only one it would be the Cossor. I am going to attempt to describe how magical the Cossor is, and then describe how the Mullard 807 compares for reference.
The Cossor ATS25 has so much magic going on it's insane. The sound is weighty and lush, yet highly detailed and dynamic, with nuances galore. I am hearing more detail and nuances than I have ever heard before. This tube is amazing in how warm and harmonically rich it is, while also still being super quick, dynamic and detailed at the same time. The bass hits hard and digs extremely deep, and can actually be a bit startling when it first hits. This tube brings the most grip and explosiveness of all the 807's, and makes the amp sound "super charged". The mids are forward and present, and euphonic with extremely lifelike timbre. The highs are well extended and smooth. As for the staging, that's where this tube is very unique. The staging with this tube very much reminds me of the 300B, with vocals front and center, and then all the instruments are a bit further back and layered perfectly with each having it's own space. This tube gives the song exactly what it calls for, and can be super intimate, or deep and expansive depending on the track. The sound is very holographic, and it doesn't even sound like it is coming from the cups. Next is the decay, and this is where some serious magic is happening. The notes just seem to hang around a bit longer while floating in space and fleshed out completely with this tube. This in turn really brings on the realism, and I feel like I can reach out and touch the notes. The Cossor ATS25 no doubt brings "Holy Grail" level performance, and is a tube I can't recommend enough. All that being said, I feel like I am still not doing this tube justice, as it's hard to put into words the magic this tube brings.
On to the Mullard 807 Black Plate Foil Getter, and this tube is not quite as warm, harmonically rich and forward as the Cossor. The sound is still weighty and very punchy, with excellent bass that goes deep and hits hard. This is just a tad less bass than the Cossor, and still is very much at basshead level. The mids are not quite as forward and involving, but are still fantastic, with lifelike timbre and really good euphonic texture. I actually think their is more texture in the mids compared to the Cossor, and this seems to make the notes sound electrified. The highs are pretty similar to the Cossor, being extended yet smooth without any harshness. Overall, this tube is just a bit behind in detail and nuances, yet also a bit more open and balanced as well. The Mullard still reminds me of the 300B, and is one heck of tube that will stay in my rotation.
Having both heavy weights in my rotation, I am finding I like the Mullard the most with Electronica, and I like the Cossor more for Folk, Rock and Acoustic stuff. That being said, both tubes do all genres extremely well, and one will want for nothing while listening.
All listening has been done with the Caldera Closed in stock configuration, with RCA 5691 for input and Phillips Sittard GZ34 as the rectifier.
Happy Hunting, Rolling, and Listening.
How does that Phillips GZ34 compare the the Mullard GZ32? I really like this Mullard so far. The Brimar was great too. Does the Mullard GZ32 pair with the VT60s?
There is a fella in the UK selling identical Cossors with the red lettering for just a tad more.
Structurally they looked the same as the red letter ones. Sonically I'm hoping the same as well. I see the UK guy, but they don't say they have matched pairs...
Yeah I noticed that as well. I ordered a pair. . . Fingers crossed they sound ok.
Nice! Just wonder where does the Fivre 807 sit among the Cossor & MullardJust checking back in, after last night's heavy weight bout between the Cossor ATS25 and Mullard 807. First off, both of these tubes are absolutely fantastic, with each having their own special magic. That being said (spoiler), if I had to pick only one it would be the Cossor. I am going to attempt to describe how magical the Cossor is, and then describe how the Mullard 807 compares for reference.
The Cossor ATS25 has so much magic going on it's insane. The sound is weighty and lush, yet highly detailed and dynamic, with nuances galore. I am hearing more detail and nuances than I have ever heard before. This tube is amazing in how warm and harmonically rich it is, while also still being super quick, dynamic and detailed at the same time. The bass hits hard and digs extremely deep, and can actually be a bit startling when it first hits. This tube brings the most grip and explosiveness of all the 807's, and makes the amp sound "super charged". The mids are forward and present, and euphonic with extremely lifelike timbre. The highs are well extended and smooth. As for the staging, that's where this tube is very unique. The staging with this tube very much reminds me of the 300B, with vocals front and center, and then all the instruments are a bit further back and layered perfectly with each having it's own space. This tube gives the song exactly what it calls for, and can be super intimate, or deep and expansive depending on the track. The sound is very holographic, and it doesn't even sound like it is coming from the cups. Next is the decay, and this is where some serious magic is happening. The notes just seem to hang around a bit longer while floating in space and fleshed out completely with this tube. This in turn really brings on the realism, and I feel like I can reach out and touch the notes. The Cossor ATS25 no doubt brings "Holy Grail" level performance, and is a tube I can't recommend enough. All that being said, I feel like I am still not doing this tube justice, as it's hard to put into words the magic this tube brings.
On to the Mullard 807 Black Plate Foil Getter, and this tube is not quite as warm, harmonically rich and forward as the Cossor. The sound is still weighty and very punchy, with excellent bass that goes deep and hits hard. This is just a tad less bass than the Cossor, and still is very much at basshead level. The mids are not quite as forward and involving, but are still fantastic, with lifelike timbre and really good euphonic texture. I actually think their is more texture in the mids compared to the Cossor, and this seems to make the notes sound electrified. The highs are pretty similar to the Cossor, being extended yet smooth without any harshness. Overall, this tube is just a bit behind in detail and nuances, yet also a bit more open and balanced as well. The Mullard still reminds me of the 300B, and is one heck of tube that will stay in my rotation.
Having both heavy weights in my rotation, I am finding I like the Mullard the most with Electronica, and I like the Cossor more for Folk, Rock and Acoustic stuff. That being said, both tubes do all genres extremely well, and one will want for nothing while listening.
All listening has been done with the Caldera Closed in stock configuration, with RCA 5691 for input and Phillips Sittard GZ34 as the rectifier.
Happy Hunting, Rolling, and Listening.
So the GEC VT60 is slightly different than the Cossor ATS25. I've been building out a Vacuum Tube GPT helper and this is the scoop on the two:
I had it isolate the technical differences:
Technical Differences Summary:
1. Maximum Anode Voltage:
• VT60: 315V
• ATS25: 300V
2. Screen Voltage:
• VT60: 225V
• ATS25: 250V
3. Control Grid Voltage:
• VT60: -14V
• ATS25: -15V
4. Transconductance:
• VT60: 4.1mA/V
• ATS25: 3.8mA/V
5. Amplification Factor:
• VT60: 8.5
• ATS25: 9
6. Plate Resistance:
• VT60: 50k ohms
• ATS25: 52k ohms
7. Load Resistance:
• VT60: 5k ohms
• ATS25: 4.5k ohms
I had it isolate the technical differences:
Technical Differences Summary:
1. Maximum Anode Voltage:
• VT60: 315V
• ATS25: 300V
2. Screen Voltage:
• VT60: 225V
• ATS25: 250V
3. Control Grid Voltage:
• VT60: -14V
• ATS25: -15V
4. Transconductance:
• VT60: 4.1mA/V
• ATS25: 3.8mA/V
5. Amplification Factor:
• VT60: 8.5
• ATS25: 9
6. Plate Resistance:
• VT60: 50k ohms
• ATS25: 52k ohms
7. Load Resistance:
• VT60: 5k ohms
• ATS25: 4.5k ohms
https://www.langrex.co.uk/products/807-ats25-cossor-ceramic-base-nos-valve-tube/
This is the eBay seller’s website, looks like they do offer matched and balanced pairs for a small fee.
Users who are viewing this thread
