Strange Noises

[bighud]

I just got my J99's up and running. I didn't build them, built them pre assembled(not from here). They sound great, but the closest to the psu has crazy oscillating noises occuring when the gain is in stage 3-5. Every other setting is fine. The other J99 next to it, makes a crazy but much quieter sound when in gain stage 3, but did not make this sound initially and doesn't always make the sounds.

I am just curious what areas I should be troubleshooting. I am in the process of building more SCA pres.

Thanks,

[tpryan]

What op-amps are installed at U1/U8 and U2/U9?
Are load isolators or jumpers installed at L1 or L2?
Are caps installed at C6 and C12?

[bighud]

I will look into those and double check everything. Right now I am in the middle of tracking and am actually using these right now. They sound amazing by the way! I will get to checking this out as soon as I can.

[bighud]

Sorry for not responding sooner. I figured out the problem with the pres. It was just a simple problem with leads grounding to the chassis. I fixed that and all is well now.