Rolling 6SN7s

[Laudanum]

Nick ... Supposedly, most 6CG7's have an internal shield.  6FQ7 does not.   I have a few of these tubes and I believe that all of mine are labeled as "6CG7/6FQ7", none are shielded.   Also read that supposedly they all sound the same.
 
Anyway ... IF the tube is not shielded the quick and dirty wiring option is to cut the existing connection between pins 4 and 5 on the 12AU7 9 pin socket and then jumper over from pin 9 to whichever pin, 4 or 5 which is no longer connected to heater voltage.   If you have a shielded 6CG7, ground pin 9, seperate pins 4 and 5 and the connection from heater supply that was going to pin 9 (black wire) goes to the now electrically unconnected pin (4 or 5).   In other words,  on the 6CG7 and 6FQ7, pins 4 and 5 get the heater connection and pin 9 is open if the particular tube has no shield, or grounded if it does.    Safest bet is to ground pin 9 which allows for all 6FQ7's and both shielded or unshielded 6CG7's.

The quick and dirty option makes it easier to go back to 12AU7's or subs with same pinouts if you just want to try an unshielded 6CG7/6FQ7.  

[Nick Tam]

I don't have a single 6CG7... the point I was making was that I was sent a wrong adapter from the seller for the 6CG7>6SN7 instead of the 12AU7>6SN7 one and was wondering if I could just use this as a 12AU7 adapter since the 6SN7 doesn't have that 9 pin, the 12AU7 socket to 6CG7 adapter basically has no connection and is technically free floating.

I'm just impatient to rolling in the 6SN7s I've ordered and I don't have the correct adapter.

12AU7 socket > 6CG7 adapter to 6SN7 pinouts > 6SN7 tube

Seller just said he'll send out the correct adapter and I don't have to return the old one... no questions asked. Although it's probably because he's just going to overlook the loss since the actual adapter was merely 5 dollars in value plus that 2 dollars shipping... basically breakeven since I bought the adapter for 15.5USD with shipping. What a nice seller...

[Laudanum]

Sorry Nick, thought you wanted to try a 6CG7 while waiting on a new adapter.

[lextek]

I picked up one of the Ebay adapters.  I had some nice 6SN7s from a previous amp hanging around.  Nice to have some more options to stick in your Crack.  Yes the 6SN7s sound very, good.

[Nick Tam]

They are indeed. Now I don't want to go back to the 12BH7/E80CCs I was using. They do music justice. They don't have the technicalities of the good E80CCs but that vintage sound that's just superior to the musicality of the 12BH7/12AU7s.

[Natural Sound]

I set up my crack amp to use 6SN7's from the beginning. Started by punching the front hole allowing me to install a second octal socket. From there all I had to do is make the necessary wiring changes during assembly. I really love the way it sounds. But I couldn't help wondering what the circuit sounded like with a 12AU7 up front. Basically I went the opposite way and bought an adaptor that converted the 6SN7 to a 12AU7. After some seriously critical tube rolling sessions I decided to stay with the 6SN7. Both tubes sounded really good. The 12AU7 actually did a better job at what I would call "micro detail." As good as that sounds there is a downside to having such good detail. That is to say that the 12AU7 really revealed all the nasties in poorly recorded material or poor analog to digital transfers. The 6SN7 is a lot more forgiving when listening to less than optimal source material.

Anyway, that's my 2 cents. As they say, "your mileage may vary." There are a lot of variables to consider. So have fun experimenting and set your amp up the way YOU like it.

[Nick Tam]

Yep they are forgiving. They also sound far more vintage than the 12BH7 or E80CC which I love for microdetail. They all have their pros and cons

[adamct]

 Question: I have a 6SN7 (tube) to 6DE7 (socket) adapter from my Woo Audio WA6. Can I use that adapter to run 6SN7s with my Crack+Speedball with the stock sockets and wiring?

Any advice is greatly appreciated!

Best regards,
Adam