[Leadman]

Has anybody build a TT Lummerland with 2xel84 output tubes? I would like to keep the same cathodyne phase inverter (2x12ax7 and a 2xel84)

I am going to change de power supply section with more nodes for a better filtering but what changes should be done in the phase inverter section to feed the 2xel84? And in the conjuntive filter?

Thank you in advance.

Best regards.

[Leadman]

It seems Lummerland is based on blues express but the phase inverter looks different.

[Dirk]

Hi,

a 18 Watt version with 2 x 6V6 will be available soon.

Best regards, Dirk

[JTM]

Hi,

a 18 Watt version with 2 x 6V6 will be available soon.

Best regards, Dirk

Great news!!

[Dirk]

Hier schon mal ein Bild vom Bub

[JTM]

Hier schon mal ein Bild vom Bub

Stark, bin gespannt! Mit NFB?

[Leadman]

2x6v6 Lummerland is here!

[Leadman]

What is the purpose of R14(220k) in the phase inverter of the LummerLand? This resistor don´t exist in the original Blues Express el84 desing.
It´s the first time I see that resistor in a cathodyne phase inverter and I am curious about it.
Maybe it attenuates the signal before de push pull triodes? because the original desing use pentode tubes and not triode....

[iefes]

R14 provides the grid of the cathodyne with a (self-adjusting) bias voltage. Typically the value would be 470k to 1M. Indeed, I would have guessed that the values of R14 and R28 are actually swapped. This would yield a more typical setup but to be honest I'm not very familiar with those small dual-triode push-pull stages and I'm sure Dirk knows his stuff 

[Leadman]

Ah! the r28 acts like a grid stopper for prevent blocking distortion in that desing, and maybe de r14 has been lowered to 220k for match with the push pull triode power section.

Thanks!