I assume you're using the TU-3 to share power with one other pedal then, in order to power all 6 pedals? The Biyang supplies 400mA of current, which is low but should be just enough.
Like I said, you have to try different combinations. Does the noise go away if you take out one of the delays (as in totally remove it from the signal chain)? Then swap it with the other delay to see if just one of them is faulty.
Like I said, you have to try different combinations. Does the noise go away if you take out one of the delays (as in totally remove it from the signal chain)? Then swap it with the other delay to see if just one of them is faulty.