Helo Hardbop,
First of all, I assume you got matched octet power tubes. All of the CAT amps are easy to bias. I am very fortunate to own both the JL-2 Sig MK2 and the JL-3 Sig Mk2 monos. I have changed tubes on the JL-2 a couple of times. Just make sure you turn down the bias somewhat and turn the amp on. From the manual " Set the selector switch to any of the bias positions and adjust the bias control knob so that the built-in LCD meter reads 37. This indicates an average plate current of 37 milliamps per tube. This control should be adjusted slowly, because the bias control reacts very slowly to changes. Be sure the bias never gois above 50". Repeat the procedure for the other channel.
You also have to adjust the balance. Set the selector switch to balance and adjust the small black knob so that the balance reads 0.0. This knob reacts very quickly. Repeat for the other channel. Be sure to check the bias and balance say 30 minutes later and re-adjust if needed. It might take a day or two to get the tubes to settle down. According to Ken Stevens once the tubes are stable then leave them alone and don't re-bias them. The JL-2 or JL-3 are very stable amps and can be adjusted with or without a load connected to them.
I changed the input tubes on my amps to RAM labs super low noise. They are expensive but do lower the background noise and sound better than stock tubes. I have some of the same tubes you got from Kevin but use them in the preamp and tube DAC. I also got them from Kevin. Good luck and happy listening.
First of all, I assume you got matched octet power tubes. All of the CAT amps are easy to bias. I am very fortunate to own both the JL-2 Sig MK2 and the JL-3 Sig Mk2 monos. I have changed tubes on the JL-2 a couple of times. Just make sure you turn down the bias somewhat and turn the amp on. From the manual " Set the selector switch to any of the bias positions and adjust the bias control knob so that the built-in LCD meter reads 37. This indicates an average plate current of 37 milliamps per tube. This control should be adjusted slowly, because the bias control reacts very slowly to changes. Be sure the bias never gois above 50". Repeat the procedure for the other channel.
You also have to adjust the balance. Set the selector switch to balance and adjust the small black knob so that the balance reads 0.0. This knob reacts very quickly. Repeat for the other channel. Be sure to check the bias and balance say 30 minutes later and re-adjust if needed. It might take a day or two to get the tubes to settle down. According to Ken Stevens once the tubes are stable then leave them alone and don't re-bias them. The JL-2 or JL-3 are very stable amps and can be adjusted with or without a load connected to them.
I changed the input tubes on my amps to RAM labs super low noise. They are expensive but do lower the background noise and sound better than stock tubes. I have some of the same tubes you got from Kevin but use them in the preamp and tube DAC. I also got them from Kevin. Good luck and happy listening.