The layout of the new version seems better than previous one, using less leadwire connection. That makes me interest to dismantle my 300B to re-construct it again.
I saw that you are using a long silver like ground bus as ground wire. Can you tell me what wire gauge it is? Is it Jensen silver wire??
Regards,
Allan作者: william 時間: 2006-11-8 09:51
Yes, it is Jensen 1mm/1.5mm pure silver wire. modi put a lot of effort in designing the route of wiring so you can see the layout is more neat and tidy. You can always dismantle yours and re-construct / upgrade your 300B, just let me / KK know if you need any help!作者: superallan 時間: 2006-11-12 22:38
Hi William,
Thanks for your information and support. I have already changed it. I spent half day to dismantled the old layout and one day to construct the new one.
The new one is now being run-in and it seems better in transparency and sound-stage improved, after using the silver wire as ground and HT line.
Besides, I can rotate one of the 300B socket by 180 deg and I can see the brand name of the tube now.
In order to get better result on 300B performance, I changed the supply tranx output to 400Vdc. It is better in dynamic. However, the plate voltage of 2-stage 6SN7 has risen up, too. Then I changed the R8 from 2.7k to 3.3k, now the plate voltage is about 260~280V depending on the quality of 5U4G.
Original plate voltage of 2-stage 6SN7 is 210Vin Gramo Audio layout, but I refered to JE lab's circuit that is 280V in this plate voltage. Should I further adjust it to go back to 210V? or can you advise the sonic difference between 210V and 280V on 2-stage of 6SN7??