Recheck your cabling and inputs/outputs. If it was me, I'd put everything back the way it was in the P10 system and see what happens. You are playing with too many variables. Ensure tubes are seated fully.
- 13 posts total
- 13 posts total
Yes, had everything back to original.
I located a pair of JJ ECC802-S tubes and replaced the 12AX7LPS Sovteks out of the rearward position of the L/R channels of the Ares.
No more noise! No electronics expert here but I know (or I think I know) that 1 tube failure can effect both channels - it seems.
As I recall, the JJ's needed a lot of gain to get the system going.
Thanks guys for you help!
desalvo, Do I understand correctly that you replaced 12AX7s with ECC802? The ECC802 is equivalent to a 12AU7, which is a much different tube electrically, compared to a 12AX7, as noromance already suggested. You made some remark about needing more gain, and I am not surprised; the 12AU7 is much lower in gain than the 12AX7 and would not suffice as the gain tube in most phono stages. The right thing to do is to replace 12AX7s with 12AX7s or ECC83s or ECC803s. However, you mention that the tubes were in the "rear" position on the Ares. Does that mean they are near to the output jacks? If so, the circuit may use 12AX7 as a cathode follower. (A tube that converts voltage to current and reduces output impedance, essentially.) 12AX7s are not a really good choice for cathode follower; 12AU7/ECC82/ECC802 is a better choice, but to make full use of the latter tube, you would need to change some resistors in that stage. So, it's still best to stick with 12AX7 or its congeners.