In Reply to: RE: It may not be the tube posted by astrostar59 on July 24, 2013 at 07:15:55:
The kit one is great! The problem is that the mesh plate tubes can't handle the same dissipation level as solid plates. I bought the mesh plates because they had a good reputation and they looked cool, but I have since discovered that they must be run at a lower bias power. The bias points of kit one are indeed optimum and I have very happy with my kit-1. The folks at Sophia upgraded me to Carbon Princesses and they sound excellent. The bias point of Kit-1 is:
B+ ~450 w/ 5U4GB
B+ ~430 w/ 5U4G
V-plate ~360 w/ 5U4GB
V-plate ~340 w/ 5U4G
I-plate ~85mA w/ 5U4GB
I-plate ~82mA w/ 5U4G
V-cathode ~77V w/ 5U4GB
V-cathode ~73V w/ 5U4G
All these measurements were made with Sophia Carbon Princesses. JJ 300B's gave a slightly lower I-plate. If you calculate the power dissipation at these levels you get:
W-Plate ~31 Watts w/ 5U4Gb
W-Plate ~28 Watts w/ 5U4G
Notice that I included numbers for both 5U4G and 5U4GB. The 5U4G is a better choice in my opinion but the GB version is usually included in the kit, so I included these numbers for reference.
From what I have read, the mesh plates can't handle this continuous power. All the solid plates can, and I have had no problems with Shuguang, Psvane, JJ, and Sophia Carbon Princesses. I am currently running the Carbon Princesses. They seem to open up the sound a little more.
kit-1 is indeed a great circuit and I am very happy with it. I only ran into trouble with Sophia Mesh Plates.
here are a few pics of my build. Notice that the mesh plates are indeed running a little hot:
https://dl.dropboxusercontent.com/u/109856281/17-Finished%20A0.jpg
https://dl.dropboxusercontent.com/u/109856281/17-Finished%20A2.JPG
https://dl.dropboxusercontent.com/u/109856281/AN-K1-2.jpg
https://dl.dropboxusercontent.com/u/109856281/IMG_0255.JPG
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Follow Ups
- RE: It may not be the tube - rlyach@yahoo.com 07:47:15 07/24/13 (0)