The 5651s are not expensive. About $8 each. I bought some because I had a problem with one amp where the 5651 went dark. When I looked inside, the internal fuse had blown.
Replaced the 5651 and the internal fuse and it worked for 20mins and the fuse blew again. I ran in mono for a while, thinking I had to send the amps to Lamm - which was a bit of a logistics issue. But finally I contacted Erina and she told me what to do.
The problem was that the 6C33C voltage regulator was old and not doing its job. I had a spare set of 4 x 6C33Cs from Lamm (all correct numbered parts for the amps) sitting in the cupboard. I replaced the whole set - they were all quite used up, one significantly so. These were the original valves, except for 1 - so they had done some miles (I bought the amps second hand).
There was actually nothing wrong with the 5651 voltage reference tube so I put it back in.
I've replaced the 6N6Ps once and will do so again in January. I use Pvane 12AX7s.
Regards,
Replaced the 5651 and the internal fuse and it worked for 20mins and the fuse blew again. I ran in mono for a while, thinking I had to send the amps to Lamm - which was a bit of a logistics issue. But finally I contacted Erina and she told me what to do.
The problem was that the 6C33C voltage regulator was old and not doing its job. I had a spare set of 4 x 6C33Cs from Lamm (all correct numbered parts for the amps) sitting in the cupboard. I replaced the whole set - they were all quite used up, one significantly so. These were the original valves, except for 1 - so they had done some miles (I bought the amps second hand).
There was actually nothing wrong with the 5651 voltage reference tube so I put it back in.
I've replaced the 6N6Ps once and will do so again in January. I use Pvane 12AX7s.
Regards,