I was going through my tube collection and came across a pair of gold pin Telefunken E80CC. I was wondering why I bought them and didn't remember what amplifier they were for. Then, I guessed I bought them for intended use in the Crack from reading the forums years ago. So, I started researching the thread about what resistors to use to make them work optimally.
I installed 470 ohm resistors in the R1 slots on Speedball and ended up around 77-80V. Holy cow do those tubes sound good! Clarity and power. Really impressed to say the least. With my Beyer T1 (V1) they are right on the border of too bright, however, they are always in control and the audio is incredible. By far the brightest tube I've used yet with Crack. I have a brand new pair of Senn HD-600 arriving tomorrow. I am thinking they will pair very good with the E80CC.
I also came across a pair of 12BH7A, I would like to give them a shot with the R1 value at 150 ohm to start. I am aware of the increased current and ordered a pair of MJE5731A transistors but they won't be here for a week. Will it hurt anything badly if I briefly try it using the stock transistors? I am aware the resistance should probably be lower but don't want to heat things up too badly right now.
Also, I have been kind of using the Crack to check various tubes for how well they are balanced. The E80CC are within 3V on T1 and T5; all 6SN7GTB's, 3-7V difference. Does the voltage on T1 and T5 need to be within a certain range before it is audibly different? The 7V difference on one of the 6SN7's had me wondering if it's a tube to reject. In listening, it sounds OK but I am wondering if there are dB differences between drivers.
One last question is ...... if the T1 and T5 voltages are higher/lower for one tube type than the other, say for instance a 6SN7, is the tube weaker or stronger?
Anyway, still having fun messing around with Crack. I did the Cree's last week and Triad C7X arrived today. That will be all I ever end up doing. Where I have arrived now has me wondering if I even need my Woo Audio WA2 any longer. I have really learned how formidable the Crack is over the past few months. Outstanding! and thank you!
