Sound of the 6SN7?

[Green77]

Hi!

I have finished my KT88 PP where the input tube is a 6SN7.
I have tried 2 diffrent tubes. Electro Harmonix sounded like crap and GE sounded nice but it's not mine

I have looked at Tung-Sol or TAD. Anyone have any comments on them?

Thanks // Daniel

[Globulator]

Originally Posted by Green77

Hi!

I have finished my KT88 PP where the input tube is a 6SN7.
I have tried 2 diffrent tubes. Electro Harmonix sounded like crap and GE sounded nice but it's not mine

I have looked at Tung-Sol or TAD. Anyone have any comments on them?

Thanks // Daniel

Try it in SRPP (or use 6N1P-EV if space is an issue), I found the SRPP used as a driver stage works extremely well (and possibly is more tolerant of differing tube sonic signatures).

[Tubes4e4]

Hi Daniel,

a somewhat heretical answer: Redesigning your amp in a way so it can deal with inevitable tube tolerances. That would be "good engineering". If that is not your aim, just redesign the amp so that it sounds good to you with the tubes you want to use.

Regards,

Tom

[DualTriode]

Hello Green77,
I can guess that you want to roll a few tubes before you tear your amplifier apart and start over. NOS tubes will cost a lot. I would start with a current production Tung-Sol. Tung-Sol 6SN7’s have a reputation for being top of the heap for current production.
DT
All just for fun!

[hcbonfim]

Hi dear i made my Octal Aikido with 6SN7 GTB TUNGSOL and i am very happy with the sound,
they are very cheap also,

best regards

[Globulator]

Before you do anything too drastic you may try varying the cathode and anode resistors to explore some different areas of the tube - you can get big differences here.

Then there is the application of a CCS to consider.

[ashok]

Originally Posted by Globulator

Try it in SRPP ..............., I found the SRPP used as a driver stage works extremely well ...............

Any working circuits you can suggest ?

[Globulator]

Originally Posted by ashok

Any working circuits you can suggest ?

Well they are all the same really, just divide the HT voltage by 2 and lookup the curves at the voltage. Select the current you want and it it for both cathode resistors: job done

The nice thing about the SRPP is that you don't even need anode resistors - just the cathode ones to select the grid voltage and tube current at the 1/2 HT operating point.

[ashok]

Originally Posted by Globulator

............ just divide the HT voltage by 2 and lookup the curves at the voltage. Select the current you want and it it for both cathode resistors: job done ..............

Yup , basically determine value of one resistor ! However selecting an operating point that works best ( audibly and electrically ) might not be so simple ?

[ChrisA]

Originally Posted by Green77

Hi!

I have finished my KT88 PP where the input tube is a 6SN7.
I have tried 2 diffrent tubes. Electro Harmonix sounded like crap and GE sounded nice but it's not mine

I have looked at Tung-Sol or TAD. Anyone have any comments on them?

Thanks // Daniel

By rolling tubes what you are ding is leaving the bias fixed and then hunting for a tube that works at that bias. Why not adjust the cathode resistor for best sound with the tube you have. It is far cheaper to "roll resistor values" than to roll tubes.

OK, yes roll tubes too. but each tube will have a best operating point so when you compare tubes listen to each tube at it's best setting. Simply doing a tube swap will just find the tube that is the best match for your cathode resistor. This is a good use for a resistor substitution box.

I think this is where small amounts of local feedback help. This can give you linear gain even if there are tolerances in the parts. But that would be a re-design. likely not what you want to do.