[phase0]

I don't fully understand what/why of all this extra effort. As far as I know you're the only one going to these lengths. So this power thing soft-start-resister will let the tubes live longer? What's the difference between your other mods to the WA5 versus stock upgraded WA5? Are you planning to run any of the newer 300Bs for comparison? I don't have the electronics background to really appreciate what you are doing here.

 

[ghhf]

  I don't fully understand what/why of all this extra effort. As far as I know you're the only one going to these lengths. So this power thing soft-start-resister will let the tubes live longer? What's the difference between your other mods to the WA5 versus stock upgraded WA5? Are you planning to run any of the newer 300Bs for comparison? I don't have the electronics background to really appreciate what you are doing here.

 
That makes sense in my case, as I like playing the tube rolling games (I would change tubes for some every 3-4 listening sessions) with substantial power-on/ power-off cycles, and in fact, during the past 3 months since open box my WA5, I already had my WA5 run over 100 cycles (yes, I almost turned on my WA5 everyday in the past few months).

 
And I will definitely go heavy rolling with beloved WE300B pairing with some other vintage tubes (signal and rectifier) for many and various sonic impressions in the coming months and years, that should make significant difference in long run for saving tube life.

 
I don't consider that are necessary mods for everyone, but trial and error for the result fit myself better, that is a matter of application and personal taste . They did make a difference to me, even though I always follow the rule "If it ain't broke, don't fix it"

 

 

[ghhf]

Had the parts ready for DIY the external AC power switch for my WA5, it would take some weeks work,  I could not find an alum case in black colour, anyway, hope it would not look odd when putting aside WA5 PSU.
 

 

 

 

 

 

 

 

 

 

 

[ghhf]

For better sonic effect, the circuit for full AC power connections related to SW1 will use special SCC wire.
 

 
Also for safety, replaced the Soft-Start resistor with two 1K Ohm, 50W alum shell resistors to be connected in parallel (effective as a single 500 Ohm resistor).
 

 

[ghhf]

And finally managed to get an alum case in black at the right size with sockets for a IEC inlet and 4 US power outlet. I am going to add the soft-start resistor,  SW1 & SW2 and power indicators inside this lovely case. It seems smart and consistent with my WA5 in black

 

 

 

[ghhf]

Planned to have the alum case pairing with a Furutech IEC and two US type sockets .....

 
 

 

 

 

[Thenewguy007]

Did you get rid of the hum?

 

[ghhf]

Did you get rid of the hum?

 
Note that the “hum” appeared only when WA5 connected to AC power and power OFF, it just gone after power up WA5. That is not a big problem,  in fact no impact on sonic effect or quality during listening but just annoying.
 
In my previous experiment, disconnected the Neutral wire from AC power source could get rid of the "hum". The problem was resolved, just make sure the external power switch also disconnected the Neutral wire (normally only disconnected the Live wire) when WA5 is OFF.

 

[ghhf]

A refined diagram for the external power switch, added SW3 to further limit the startup current which could be usable for my WA22/ WA6 SE and other lower power Woo amps (ON=WA5, OFF=WA22/ WA6 SE). The AC OUT green indicator now also only shines when the Soft-Start Resistor was bypassed by the SW1 and disconnected by SW2, so it tells a truth full power and safe operation condition.
 

 
Further added safety alert beep when SW1 is OFF and SW2 is ON.
 

 

[ghhf]

Got my Alum case delivered today, not in top quality, but nice enough

 

 

 

 

 

 

 

 

[ghhf]

I ended up getting one Furutech AC IEC Inlet, one Furutech FPX CU and one Synergistic Research TESLA Plex SE duplex receptacle

 

 

 

 

 

 

 

 

 

 

 

[ghhf]

Have all parts ready, look nice, it is a tight arrangement with this compact box 

 

 

 

 

 

 

 

 

 

 

 

 

 

[ghhf]

While I am working with the WA5 external AC power switch，got the C3G tubes delivered and test drive run, the tubes in sliver grey pins and look brand new in original box.

 

[ghhf]

In addition to the C3G, I am also adding some of other signal tubes the RCA/ NU 6F8G, RCA/ Sylvania 5692 for test drive listening on my WA5

 

 

[ghhf]

And have wires ready .....