Sherod
I put in my CCa's about the same time you did, turn the preamp off when not using and have it on about 6 hours per day and the cca's still test very well on my tester and best I can tell no degrading of the sound. I picked up a B&K Model 606 tester for about $100 on ebay in excellent condition at the time I got the cca's and find it perfect for my purposes and easy to use. Hope this helps
Joe
I put in my CCa's about the same time you did, turn the preamp off when not using and have it on about 6 hours per day and the cca's still test very well on my tester and best I can tell no degrading of the sound. I picked up a B&K Model 606 tester for about $100 on ebay in excellent condition at the time I got the cca's and find it perfect for my purposes and easy to use. Hope this helps
Joe

