29v is only 4v above 25v nominal rating. At 2A per rail that’s only 16w more dissipation. If your heat sinks can handle it, that will give you about a 32w amp! Well worth having that extra bit of headroom for crescendos. What size case and heatsink is on USSA5?
Wow, sound like good news to me!
My heatsink is from Conrad Engineering Australia. The size is 155 x 350mm
Currently temp is 51 degC , very stable thru out.
Can i just connect My M2X directly, i m more concern if the front end Daughter Card smoke out due to the extra voltages.
My heatsink is from Conrad Engineering Australia. The size is 155 x 350mm
Currently temp is 51 degC , very stable thru out.
Can i just connect My M2X directly, i m more concern if the front end Daughter Card smoke out due to the extra voltages.
If M2X front end is one that uses a Zener diode to control voltage you are fine. Also, make sure your electrolytic caps are rated for the higher voltage as this is above 25v rating.
M2X now sings beautifully with SLB, running +/-30.5Vdc rail.
Heatsink temp went up another 5 degC, currently stabilized at 56 degC.
I will bench set my USSA5 on bench first for these voltages before hooking up.
Will do a ps ripple check soon.
Thanks everyone whom make these possible.
Heatsink temp went up another 5 degC, currently stabilized at 56 degC.
I will bench set my USSA5 on bench first for these voltages before hooking up.
Will do a ps ripple check soon.
Thanks everyone whom make these possible.
Strangely my 500va trafo from RS Components output 26Vac no load, and it is actually a 24Vac written on its label. Is this normal?
That’s why I was curious about your Mains voltage, is 235vac typical for your area or running a bit high? This will effect your transformer secondary voltage.
Depending on the season and time of the day my Mains voltage variation is between 114 - 125vac.
Depending on the season and time of the day my Mains voltage variation is between 114 - 125vac.
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Hope the secondary voltages are still safe for the amps, if not i may have to go for custom winding of the trafo locally.
My initial thought was to build 2 monobloc SLB for USSA5. Looks like one SLB is more than enough for the USSA5, so now i change my mind, one go to M2X too.
My initial thought was to build 2 monobloc SLB for USSA5. Looks like one SLB is more than enough for the USSA5, so now i change my mind, one go to M2X too.
That sounds like a good plan, a single SLB psu will be fine for a stereo build.
Looking forward to see your progress 🙂
meanie,
Which model did you get from RS components?
As Vunce has already pointed out, your mains voltage is higher than typically what we see.
If you look at transformer specs, a lot of the are rated for 230V mains.
If you carefully look at output voltages assuming you have 24V secondaries, some transformers will specify "24V under full load" - so with less than full load, you will get higher voltages. So with zero load, you might get 25V-26V.
Today,I ran the other set of SLB with my existing trafo with was originally meant for the M2X.
I connected both 300VA 18Vac trafo in parallel, then fed into SLB.
Final voltage was +/-22.7vdc rail. Measured 616mV across the 0.47 resistor, so each Mosfet is pulling about 1.3A.
Strangely my M2X sounded sweeter than it was on +/- 30.5Vdc rail.
Will test out all my PS when i got more time.
a) CRC
b) CRCRC
c) SLB with 18Vac (2x300VA)
d) SLB with 24Vac single 500VA
I connected both 300VA 18Vac trafo in parallel, then fed into SLB.
Final voltage was +/-22.7vdc rail. Measured 616mV across the 0.47 resistor, so each Mosfet is pulling about 1.3A.
Strangely my M2X sounded sweeter than it was on +/- 30.5Vdc rail.
Will test out all my PS when i got more time.
a) CRC
b) CRCRC
c) SLB with 18Vac (2x300VA)
d) SLB with 24Vac single 500VA
Hi meanie,
Thanks for sharing your results.
Maybe a measure of THD and the harmonic profile would have given more insights.
Look forward to your findings with other PSU/transformer combinations.
Are you planning to try out the USSA-5 with the SLB?
Thanks for sharing your results.
Maybe a measure of THD and the harmonic profile would have given more insights.
Look forward to your findings with other PSU/transformer combinations.
Are you planning to try out the USSA-5 with the SLB?