I just recapped a Fender 135 watt TR. The amp came to me with a very high noise level at idle. It had recently been retubed with all JJ tubes and they all test to be good. So, I recapped the amp and replaced the plate resistors. The amp idles very quietly now and sounds great at lower volumes. But, now if you dig in on a chord the amp easily goes into OD. It's actually a very pleasant sounding OD, but my customer plays country and wants it clean. What could possibly cause this amp designed for ultra cleans to push into overdrive so easily?