Rerurn to Romy the Cat's Site

Referring to my very recent acceptance of the 6E6P as a tetrode to drive the tweeter:

http://www.GoodSoundClub.com/TreeItem.aspx?PostID=5329

I decided to today to stick my beloved 7721/D3A in place of the 6E6P – thanks God they have the same pins layout. I dropped bias to 1.5V and fired up the amp driving 20mA though the D3A’s plate. The 6E6P is has transconductance 35mV/A +/- 5FRT. I measured 5 D3A and all of then has exactly 36mV/A – virtually the same. So, I lighted the amp on and … it worked. I did direct some differences but I have 6dB per octave now in tweeter and when I will have 12dB, and particularly in the slope, I doubt that any difference will be observable. I wish I have a 9 pin tube like this with 50mV/A…

Rerurn to Romy the Cat's Site