I like the Penta Lab KT88SC's. The bass is good and tight.
They reveal lots of detail and nuance without ever being harsh or bright. Probably original Tung Sol 6550's are better, but the cost is out of sight. The Penta Lab KT88SC's are my favorite new production KT88 or 6550. I even like them better than NOS Philips ECG 6550. Maybe the Ei KT90's are better, but only type I or II. I won't go near the type III's after several bad experiences. Hope this helps.
Jay
They reveal lots of detail and nuance without ever being harsh or bright. Probably original Tung Sol 6550's are better, but the cost is out of sight. The Penta Lab KT88SC's are my favorite new production KT88 or 6550. I even like them better than NOS Philips ECG 6550. Maybe the Ei KT90's are better, but only type I or II. I won't go near the type III's after several bad experiences. Hope this helps.
Jay