ESL Direct Drive

Hi,

i would never put my fingers on such high voltage sources, by doing on my own, but its interesting.

In about 4 weeks i will listen to my ESL driven by:

www.innoxx.com

Capaciti

Hi,

had not the sand boxes but the KR845-Tube running at 2kV and will probabely soon modify the anode resistor to an active current source and later the tube to a new 5kV-KR tube. 😀
Besides beeing faster, working without global feedback and not needing any fancy cascading of transistors -which is notorious against breakdown- the tube can deliver higher currents into the load! The rather small 25mA of the Inox will only drive rather small capacitances, hence small or segmented panels. The current defines the power bandwidth limit of the amp which can be as low as 5kHz!! To achieve sufficient power bandwidth is one of the key-problems of solid state HV-amps! So I assume, that the amp might work with the capacitis -which are of the segmented type-, but its a way not sufficient amp to drive something like a MartinLogan-style panel. You need something more beefy to drive those babies. This issue is adressed in the McKean/Lucas articles, you can find in an older thread here.
The 1kV anode voltage and the low current of 12mA of the Lucas-amp are designed to drive headphones with their low voltage and current needs. A loudspeaker panel needs more than that, typically >2kV and >25mA. Without a beefier output stage design the Lucas would only be able to drive a speaker panel to a middle volume level, before heavy distortion sets in.

jauu
Calvin

Calvin:

Searches are turning up nothing. Can you provide a reference to this article?

For about 15 years, I ran a Sanders-like amp with a 2400 volt B+ into Dayton-Wright elements in an array and later, Dayton-Wright speakers. If a table radio is a 5, good speakers a 10, then ESL with transformers at a 20 and direct HV drive is a 25... to my ears.

Direct drive is clearly the better way. Clearly, at least with Dayton-Wrights and their otherwise pretty good transformers. But even with transformers, you are way ahead of the dynamic speaker crowd.

Of course, dangerous! But I never had a shock that I can recall.

Hi,

i thought of amp in the thread "horizontal deflection (or high voltage type) transistors to direct drive ESLs", opened by bigwill in 2006.

jauu
Calvin