..... disclaimer: high voltage circuits; info posted should be used for entertainment purpose only ....
LS165w-2T power supply, with dual transformers. Brand is "spring thunder audio"
Price (including shipping to the US) is usually $20 ~ $30 (the lowest I saw was $18 on aliexpress during holiday sale season). Search "100-265V 6P3P EL34 low Noise Switch PowerSupply for Tube Single-end” to see the listings.
workmanship looks ok enough, see photos for physical dimensions. The print on silver label rubbed off easily.
The power supply has two independent outputs
-- HV is switchable ("300v" and "280v" settings) by installing a jumper. The jumper must be installed to get HV output.
-- LV is 6.3v.
-- HV and LV grounds are both tied to the chassis/power gnd. (so this one is not suitable for srpp)
upon applying AC power, the LV output turns on right away, HV output turns on ~20 seconds later (no obvious ramping, not a soft start type). Light/heavy loads don't seem to affect output voltages much.
(Input power measured using a kill-a-watt P3)
All is not great though. The HV output is very noisy, and you can't just add a big capacitor bank to kill the noise --the (very sensitive) over-current protection would trip and prevent the HV from powering up. some test results below:
(LS165w-2t powering an appj 6ad10 (amp-section only), driving a pair of fostex T50rp)
** Use as-is : loud ripple noise
** HV --> small transformer primary winding ( kind of serve as a choke, 230 ohm DCR) --> 60uf ASC Polyprop cap: will not turn on (over-current tripped)
** HV --> small transformer (230 ohm DCR)--> 332 ohm resistor --> 60 ASC PP --> works, no back ground noise, (even when driving Beyer T1, which is the most sensitive phones I have).
Shorting out the 332R resistor after powered up: no background noise
Shorting out both the resistor and the choke, after powered up --> HV stays on, but loud ripple noise.
as long as there is a choke (any small junk transformer will do) followed by a reservoir capacitor, there is no back ground noise, perfectly quiet. This does require using a current-limiting resistor to allow power up, then use a timer relay to short out this current-limiting resistor. (555 timer relays are ~$3 on ebay or amazon).
With the large aluminum shell serving as heatsink, the temp rise was minimal. With ~100mA draw on HV and ~1A draw on LV, the shell was barely warm to the touch after running over night. I don't plan to use it for heavy loads, 150mA HV and 2A LV will probably be the max it will see. If more power is needed.... just add another one, make it one per channel. the price is low enough.
LS165w-2T power supply, with dual transformers. Brand is "spring thunder audio"
Price (including shipping to the US) is usually $20 ~ $30 (the lowest I saw was $18 on aliexpress during holiday sale season). Search "100-265V 6P3P EL34 low Noise Switch PowerSupply for Tube Single-end” to see the listings.
workmanship looks ok enough, see photos for physical dimensions. The print on silver label rubbed off easily.
The power supply has two independent outputs
-- HV is switchable ("300v" and "280v" settings) by installing a jumper. The jumper must be installed to get HV output.
-- LV is 6.3v.
-- HV and LV grounds are both tied to the chassis/power gnd. (so this one is not suitable for srpp)
upon applying AC power, the LV output turns on right away, HV output turns on ~20 seconds later (no obvious ramping, not a soft start type). Light/heavy loads don't seem to affect output voltages much.
(Input power measured using a kill-a-watt P3)
All is not great though. The HV output is very noisy, and you can't just add a big capacitor bank to kill the noise --the (very sensitive) over-current protection would trip and prevent the HV from powering up. some test results below:
(LS165w-2t powering an appj 6ad10 (amp-section only), driving a pair of fostex T50rp)
** Use as-is : loud ripple noise
** HV --> small transformer primary winding ( kind of serve as a choke, 230 ohm DCR) --> 60uf ASC Polyprop cap: will not turn on (over-current tripped)
** HV --> small transformer (230 ohm DCR)--> 332 ohm resistor --> 60 ASC PP --> works, no back ground noise, (even when driving Beyer T1, which is the most sensitive phones I have).
Shorting out the 332R resistor after powered up: no background noise
Shorting out both the resistor and the choke, after powered up --> HV stays on, but loud ripple noise.
as long as there is a choke (any small junk transformer will do) followed by a reservoir capacitor, there is no back ground noise, perfectly quiet. This does require using a current-limiting resistor to allow power up, then use a timer relay to short out this current-limiting resistor. (555 timer relays are ~$3 on ebay or amazon).
With the large aluminum shell serving as heatsink, the temp rise was minimal. With ~100mA draw on HV and ~1A draw on LV, the shell was barely warm to the touch after running over night. I don't plan to use it for heavy loads, 150mA HV and 2A LV will probably be the max it will see. If more power is needed.... just add another one, make it one per channel. the price is low enough.
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