C12 with 6S6B-V triode

[Papa Tango Charly]

Thank you all. Tbone PSU 2000 heater is 6,5 V and B+ is now 120 V (56 V et 62 zener).after being replaced

 

[Papa Tango Charly]

The bias in the schematic you posted will work fine with 6s6b-v. I don't know how it will match T14 soundwise. You will get closer to the C12 sound with a high quality low noise old stock ECC81 and the original schematics with fixed bias. The capsule will as always be the most determining part.

Apparently 6072 tube are 43 mu and 6S6B-V around 25 mu. 7:1 and 6.5:1 should be better for triodes 6S6B-V. Is that right? best. I have somme beautiful C12 from taskar i bouhght from VAMI. I don’t know if I need to place this optional filter cap. The tbone 2000 is a very clean Psu

 

[HerbertR]

Only if the device ends up getting plugged into a non-earthed mains socket. Then, via the 2-4 Y-class capacitors in said mains filter, the chassis could end up floating around half-mains-voltage. Those capacitors (sub-10nF) can "only" pass single-digit mA currents at 50-60Hz, but that'll still be noticeable...

OK. That definitely makes sense. Theoretically, only the amount of HF should be drained from the filter via the ground connection and remain on the housing when disconnected. According to official requirements and proper grounding, a lack of it is an absolute no-go and grossly negligent. Therefore, I personally think that a properly filtered main voltage should be an improvement in quality. A non-existent mass connection may not be present in any way. Therefore this case should not be relevant. But maybe I lay wrong with my opinion and information and other companies neitger shouldn't use them if not really required and only for "problem" treatment.

 

[tomas.borgstrom]

Apparently 6072 tube are 43 mu and 6S6B-V around 25 mu. 7:1 and 6.5:1 should be better for triodes 6S6B-V. Is that right? best. I have somme beautiful C12 from taskar i bouhght from VAMI. I don’t know if I need to place this optional filter cap. The tbone 2000 is a very clean Psu

I've used 6S6B-V with 10:1 BV11 and it sounds great.

 

[Papa Tango Charly]

Yes thank you so much! i have made the M49 with your schematic. it works beautifully!

 

[Moby]

I've used 6S6B-V with 10:1 BV11 and it sounds great.

Also with the 7:1 it works fine, of course depending from the operating point of the tube.

 

[Tubetec]

Maybe someone might explain how tube MU and anode impedence determines the best choice of transformer ratio .

 

[gyraf]

don't expect predictability beyond rule-of-thumb ranges - there's a heck of a lot going on in the details, and I always found that the empirical way would show you answers completely uncorrelated to the expected values And as always: if it sounds right, it is right..

 

[Moby]

Maybe someone might explain how tube MU and anode impedence determines the best choice of transformer ratio .

It's possible to explain but I would like to add that "ratio value" does not help here. What really matters is the primary impedance value.

 

[kingkorg]

It's possible to explain but I would like to add that "ratio value" does not help here. What really matters is the primary impedance value.

Primary inductance?

 

[Moby]

Primary inductance?

Yes, the side what directly corresponds with the tube. Also, the reflected impedance of the primary is derivate of the preamplifier impedance and the ratio of the transformer. To cut the long story short, what is written as the nominal impedance pri/sec isn't the real number.
Best way to determine the numbers is to measure the unit and define it from the measuring result.

 

[Papa Tango Charly]

Thanks guys!