Yes, I was fortunate. Picked up 16 for about €20 if I remember, off a Swiss auction site. It is the first time out of the boxes for them, and one looks like it has been used so I will need to match them a bit with a tester. Also have a factory box of 50 7B6s that will probably outlive me.
This incarnation of the BH will be using pentode mode with Sowter OPTs also cheap off the same site, the rest is junk box. The OPTs only have 8R taps, but are 8K so should be a good match.
I am using 270R for the cathode bias of the EBL21 since the data sheet had 135R for a pair in PP. I have tied all the diodes to the cathodes for both driver and output tubes. We will see how that works. It was quite nice having a lot more space to work with than trying to do everything with 9 pins on one tube.
This incarnation of the BH will be using pentode mode with Sowter OPTs also cheap off the same site, the rest is junk box. The OPTs only have 8R taps, but are 8K so should be a good match.
I am using 270R for the cathode bias of the EBL21 since the data sheet had 135R for a pair in PP. I have tied all the diodes to the cathodes for both driver and output tubes. We will see how that works. It was quite nice having a lot more space to work with than trying to do everything with 9 pins on one tube.
It always has been good practice to tie unused diodes etc. to the cathode in order to avoid unwanted impact. I also think that a PP transformer designed for a pair of EL84's will work with the EBL21's. Maybe the plate dissipation ratings will be exceeded some bit when driven harder, but who cares...
Btw, somewhere deep in the WWW there's a schematics, most probably by Philips, also showing a pair of EBL21's in PP, but driven by two ECH21's.
Best regards!
Btw, somewhere deep in the WWW there's a schematics, most probably by Philips, also showing a pair of EBL21's in PP, but driven by two ECH21's.
Best regards!
PP EBL21 in old radio: https://www.google.com/url?sa=t&rct...usg=AOvVaw3RL2ecr456pyX8iFhDaKRe&opi=89978449