1995 Cadillac SLS Air conditioning growl

My AC clutch blew up (fell apart) and was making a lot of noise. I assumed the AC compressor seized, and this caused the clutch to blow up. Surmising the worst, I purchased new AC Delco: AC Compressor, Accumulator/Drier, orifice tube, O rings. I took system apart and assumed I would have a lot of black debris on the inside. No black, two minor metal "shavings" deemed as normal wear, were found in orifice tube. I replaced all parts, oil, evacuated system, and added 2# of R134 as required. After about a week, I noticed a growling whenever the AC was on, sounding similar to a power steering pump growl (not clacking or metal on metal, but a bearing like whirring sound). I assumed it was the compressor and replaced it. Pressures on high side and low side appeared normal, no evidence of blockage prior to tear down. Upon teardown, No addl stuff in lines, no black oil, no debris noticed, clean oil. Orifice tube clean. I replaced just the AC compressor this time with new AC Delco unit. Whirring went away but after 3 days with higher heat 88 degrees outside, whirring sound is coming back. Whirring sound gets worse as HI side pressure increases. (210# HI, 35-45# LO) Pressures normal blah blah blah. I am now suspecting the "muffler" that is part of the AC discharge tube/manifold assembly. In the GM service manual, it suggests changing this if a compressor ever fails as the muffler contains filters for debris that may have accumulated. Any thoughts/suggestions/comments?

Thanx

Jim