I had a multiple-preowned DR5 preamp for three years. The DR6 was basically the DR5 with a huge outboard power supply. The DR5 was famously dark sounding, although very holographic with good ability to discern subtle dynamic shading. The DR6 was notably more open sounding on top while retaining the DR5's strengths. It also had a great phono stage. Classe' products of the Dave Reich era were built to last as they offered a LIFETIME warranty (to original owners only). There was a serious committment to lasting quality. I recently sold my DR5 and it still is operating flawlessly for its new owner. All controls remained tight and felt like new. The unit operated like brand new with no noise from pots or switches. I would have no problem recommending the purchase of a used DR6.