Hi,
I have purchased the new Sense G3 headphone amplifier (formerly Phenix) that is an Earmax clone.
It came with these Chinese tubes:
Driver: 1 x 12AT7
Output: 2 x 6N11
I have doubts about the possible tube substitutions. I have 2 Siemens ECC801S, 2 Phillips E88CC and 1 Valvo 6201. I am wondering if the 6201 can substitute the 12AT7 at the driver, and the two couples of ECC801S or E88C the 6N11 at the output.
BTW: I love the sound.
I did buy it with the idea of tweaking it, but I will wait before I cannibalize it. I’ll just try some tube rolling at the moment.
I have purchased the new Sense G3 headphone amplifier (formerly Phenix) that is an Earmax clone.
It came with these Chinese tubes:
Driver: 1 x 12AT7
Output: 2 x 6N11
I have doubts about the possible tube substitutions. I have 2 Siemens ECC801S, 2 Phillips E88CC and 1 Valvo 6201. I am wondering if the 6201 can substitute the 12AT7 at the driver, and the two couples of ECC801S or E88C the 6N11 at the output.
BTW: I love the sound.
I did buy it with the idea of tweaking it, but I will wait before I cannibalize it. I’ll just try some tube rolling at the moment.
Hi SY. Thank you for the answer.
I am going to try the Valvo 6201 replacing the 12AT7
What do you think that can be a better substitute?
I have seen Mullard E81CC for $95, Mullard 6201 for $75, and Telefunken ECC801 for $59.
I am willing to pay more if there are really good options, but I am afraid to buy something unnecesarily overpriced.
I am going to try the Valvo 6201 replacing the 12AT7
What do you think that can be a better substitute?
I have seen Mullard E81CC for $95, Mullard 6201 for $75, and Telefunken ECC801 for $59.
I am willing to pay more if there are really good options, but I am afraid to buy something unnecesarily overpriced.
I don't know if they have triple mica.
They are labeled Siemens ECC801S. This are the details that the seller gave me:
2xNOS Siemens ECC801S 12AT7 ECC81 Munich Germany NIB 1981. Etched date code. A perfectly matched pair. Long lived version at least 20,000 hours. Made for German army. Excellent resolution in the bass. Falcon logo on box. Tested on Amplitrex AT 1000. Brand new in original boxes.
Date codes:
C PHI
6 Not Equal To
1I
Triode emissions;
tube # 1 13.4 [mA] / 13.2 [mA]
tube # 2 13.1 [mA] / 13.3 [mA]
NOS is 10.0
I am impatient to start heating them
They are labeled Siemens ECC801S. This are the details that the seller gave me:
2xNOS Siemens ECC801S 12AT7 ECC81 Munich Germany NIB 1981. Etched date code. A perfectly matched pair. Long lived version at least 20,000 hours. Made for German army. Excellent resolution in the bass. Falcon logo on box. Tested on Amplitrex AT 1000. Brand new in original boxes.
Date codes:
C PHI
6 Not Equal To
1I
Triode emissions;
tube # 1 13.4 [mA] / 13.2 [mA]
tube # 2 13.1 [mA] / 13.3 [mA]
NOS is 10.0
I am impatient to start heating them
Hi SY. Thank you for the answer.
I am going to try the Valvo 6201 replacing the 12AT7
What do you think that can be a better substitute?
I have seen Mullard E81CC for $95, Mullard 6201 for $75, and Telefunken ECC801 for $59.
I am willing to pay more if there are really good options, but I am afraid to buy something unnecesarily overpriced.
If you're interested in performance rather than prestige... JJ for $10.
For $10 I will try it for sure. Now I am starting to remember that many years ago I used to have a Marshall JMP1 preamplifier, and the sound dramatically improved when I replaced the stock 12AX7 for a JJ. But I don't know if what is juicy for guitar may be good for audio.
What a memory lapse!!. Do we get older?
What a memory lapse!!. Do we get older?
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Yes. I tested multiple samples of quite a few alternatives and the JJ was head and shoulders better. Half the distortion of a 6201, for example.
I have already tried both the Siemens ECC801S (not triple mica) and the Valvo 6201 substituting the Chinese 12AT7 at the input stage, and my impression is: WOW! The bass player is alive!. Great bass, warm middle, sweet treble. I still cannot tell much about the differences. Both offer a giant improvement.
The Valvo produced noise when I moved the volue pot, but it is being reduced after 30 hours burning. I hope that it will dissapear completely.
Silly question: can the ECC801S substitute the 6N11 at the output stage? The only 6N11 data sheet that I have is in Chinese.
The Valvo produced noise when I moved the volue pot, but it is being reduced after 30 hours burning. I hope that it will dissapear completely.
Silly question: can the ECC801S substitute the 6N11 at the output stage? The only 6N11 data sheet that I have is in Chinese.
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Before swapping tubes around it would be good to have a schematic. For example if by chance the 12AT7 is inside a local NFB loop and the effective gain is near unity then you'd be embarrassed if you claimed a difference between different tubes. On the other hand it might be running open loop.
If you want to change the sound moving the bias around will have more effect and will be less random. Also tubes are not precision devices many times when people roll tubes the reason they like one over the other is because it is a good match to the cathode bias resister in the amp. In other words they are in effect moving the bias around in an indirect way.
I have found this schematic, but my unit is a Sense G3, not a Phenix G3. I am going to trace the circuit for possible differences.
G3 Tube Amp Review
And the Morgan Jones circuit:
http://gilmore2.chem.northwestern.edu/projects/cmoy5_prj.htm
G3 Tube Amp Review
And the Morgan Jones circuit:
An externally hosted image should be here but it was not working when we last tested it.
http://gilmore2.chem.northwestern.edu/projects/cmoy5_prj.htm
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