The perspicacious would opt for perspex........
I can just see the aftermarket crowd going wild with this one......
Besides the usual plethora of aftermarket cables, there will be:-
Coloware will have a range of colored covers....
There will be a plethora of different wood covers.
Edstrelow will have a pattern of sorbothane to make these Stax killers
The Hifiman HE-6 crowd will break out different felt fazor mods.
Anaxilus will have 3 different mods to get rid of the echo chamber cavern effect...
The newest mod will be to coat the inside of the covers with teflon to make sure even the sound doesn't stick...
etc, etc, ad hoc, ad addendum, ad astra. ad nauseum...........................
Bowie would have been 71 today and in two days it'll be the annie of his death.
Just noticed that Rick Wakeman played keys on Hunky Dory (Changes, Life on Mars etc).
Still seems impossible that he won't surprise us with revelation again!
Looks like Cobra King LTD driver's removable "Spaceport" made of aerospace aluminum will fit nicely into that headphone port, sure to improve sound ...
Here are my BOM for a pair of BH.
https://www.mouser.tw/ProjectManager/ProjectDetail.aspx?AccessID=b44788bc7f
for GRLV and GRHV. copied from Carbon build thread.
http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=b6d687c7f7
http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=54687aa8fa
Parts I already have or going to buy from local dealer are NOT included like LEDs, insulators, IC sockets. Someone need to check if all resistor value are correct.
I hope I could finish it at the end of April
although you certainly can (singlepower es1,es2...) when you apply high voltage with the tube cold, the cathode can strip. with the diy-T2 applying high voltage with the tubes cold does all sorts of bad to the input tube, putting +500 on the cathode with the filament grounded.
soft start on an el34 seems like a waste of time, haven't seen anyone do that. On expensive DHT's, might be a good idea, might be a waste of time.
calculate the resistors based on measured values when everything are hooked up, and tubes are running warm - depending on the transformer the spec'ed voltage might be different under load.
Not needed.
Soft START is a good thing to be easy on the tubes. T2 uses 60 seconds delay.
Some uses constant current sources to feed the filament, to avoid the high current when the tube is cold - high current is stressing the tube (and usually why incandescent bulbs fail)... some runs the filament a bit below spec e.g. 6V rather than 6.3V, (even seen 5.5V) as far as I have measured 6V is pretty safe, where as lower voltage increase the risk for "cathode stripping"
Just recomissioned my BH original - the one Kevin designed in 2000-2004 with just about every transistor in it obsolete. It has been sitting for several years after I finished the KG SRM/T2 clone.
Fired up just fine, and still sounds stunning.
( 2 channels x (2x Output stage current + 10mA for input stage )*sqrt2*360VAC + 4x 6.3VAC*1.5A ) * some_factor depending on how much overkill ~ 100VA * some_factor
I usually end up using a factor somewhere above 2 and close to 3