It's an OTL amp so there are probably limits as to how much you can output. Looks like it has a separate power transformer for each channel and is built well. Yo Hifi, was it modded to use different tubes?
Not for other tubes, as it already sounded really well with the tubes used...but u can get tube sockets to do that for u...BUT..it did have internal mods like bigger caps and some other higher quality stuff inside..even the two powerswitches were allocated to the back to minimize the interference into the signal...as the thick wires to them were running along the huge transformers..and according to he first owner doing this mod could mimimize interference..i bought it modded from him... And if u use TS5998 powertubes the output could be raised by 2% i understand.
About the lafigaro 339, i undersstand that the 339 has <0,6W. So at least 0,6w..but many think its same output is at least as high (or low) as the 337 as they are both built based on same design..both designers worked together at Darkvoice once.
The 337 is stated, quoting: more then 1watt of output...
Its said that those quoted poweroutputs are quoted to low..as offically a OTL tubey cant drive a planar (he500) as well as those do.. And if i understand it well..they are one of the few OTL's who do...but guys..those huge monsters look sexy at night if u use huge bendix 6080wb graphite plates or Ts 5998 powertubes! With their glow u dont even need candles to make an romantic environment
Quick find on the 337 thread:
http://www.head-fi.org/t/219504/darkvoice-337-a-review/885#post_10206485
http://www.head-fi.org/t/219504/darkvoice-337-a-review/885#post_10208697
And if u read last pages of the threads of both amps u will see they do well with a he500