Hi.I bought a LLC SMPS from China.It is here HIFI Audio Soft Switching Power Supply Board For Power Amplifier +-36V +-48V 500W | eBay
I thought the price is good but i am a bit disappointed.It did not come with Rubycon caps at input and also output.It also seems it is made a bit low quality.Poor soldering I have a limited information about SMPSs and also LLC.As i heard LLC is very sensitive about L and C values and resonant frequency. As a capacitor seller i have much more quality than the caps at input and output caps( 120uF 450v and 2200uf 50v) Especially 2200uf 50v seems very low quality. Can i change them without problem?Is there any need of adjustmens ? (altough it seems there is no adjustment trimmer or sth like that) I am using it with iraudamp7s in bridged mode for my 6ohm subwoofer.(SB34NRX75-6) SMPS Voltage is +-48v Plays music and cinema good.Good dynamics.But i want to improve Thank you in advance.
I thought the price is good but i am a bit disappointed.It did not come with Rubycon caps at input and also output.It also seems it is made a bit low quality.Poor soldering I have a limited information about SMPSs and also LLC.As i heard LLC is very sensitive about L and C values and resonant frequency. As a capacitor seller i have much more quality than the caps at input and output caps( 120uF 450v and 2200uf 50v) Especially 2200uf 50v seems very low quality. Can i change them without problem?Is there any need of adjustmens ? (altough it seems there is no adjustment trimmer or sth like that) I am using it with iraudamp7s in bridged mode for my 6ohm subwoofer.(SB34NRX75-6) SMPS Voltage is +-48v Plays music and cinema good.Good dynamics.But i want to improve Thank you in advance.
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No i wont change tuning caps of course.I can easily hear differences when i change caps on regular power supplies and i just wondered if an improvement may happens on Smps
They have to cut corners somewhere to get the price down.
LLC SMPS are very good. As the transformer primary sees a sine wave and not a square wave there is much less radiation from the SMPS.
The resonant frequency is very important. If you move it by changing caps then you can shift the frequency into the capacitive high current mode and possibly destroy it.
LLC SMPS are very good. As the transformer primary sees a sine wave and not a square wave there is much less radiation from the SMPS.
The resonant frequency is very important. If you move it by changing caps then you can shift the frequency into the capacitive high current mode and possibly destroy it.
Background: I designed the LLC in the Benchmark AHB2 amp.
Be careful. LLC power supply can be done very well, but can also be botched pretty easily. I wouldn't hazard changing any parts. The designer may be relying on a specific capacitor value or ESR for stability.
It's risky business modifying power supplies as there are often multiple dependencies.
I get scared thinking of how many DIYers are using SMPS' in the first place (400-600 Vdc doesn't tickle!), and especially SMPS that are of either unknown origin or don't have any safety testing.
Does anyone have links to DIY SMPS that solve some of these issues?
Be careful. LLC power supply can be done very well, but can also be botched pretty easily. I wouldn't hazard changing any parts. The designer may be relying on a specific capacitor value or ESR for stability.
It's risky business modifying power supplies as there are often multiple dependencies.
I get scared thinking of how many DIYers are using SMPS' in the first place (400-600 Vdc doesn't tickle!), and especially SMPS that are of either unknown origin or don't have any safety testing.
Does anyone have links to DIY SMPS that solve some of these issues?
You can replace the output caps. LLC isn't very sensitive to cap ESR so replacing with lower ESR cap will not reduce its stability by too much. I don't think replacing input cap will help much besides potentially increasing its lifetime.
As for frequency, don't bother. It has a feedback control loop that automatically tunes and detunes it for output voltage regulation. An LLC almost never operates at resonant frequency anyway, otherwise it won't be able to regulate output voltage when input voltage changes.
Regarding to shock hazard, this one seems to be well designed -- clearances and creepages are decent, maybe not the best. Transformer has physically isolated bobbin islands for pri and sec windings, which is good. If the optocoupler and Y cap are certified, this should be good enough.
Primary side EMI filter choke seems to be not that well implemented in terms of insulation, there's no physical separation between L and N windings, this could be a fire hazard if magnet wire insulation is compromised due to being rubbed against toroidal core. This is not a big deal if the core has reliable insulated coating, but I can't say that for sure without having the SMPS physically in my hand.
Reference: I hold an MSEE in electric power system engineering, and a PhD candidacy in power electronics.
As for frequency, don't bother. It has a feedback control loop that automatically tunes and detunes it for output voltage regulation. An LLC almost never operates at resonant frequency anyway, otherwise it won't be able to regulate output voltage when input voltage changes.
Regarding to shock hazard, this one seems to be well designed -- clearances and creepages are decent, maybe not the best. Transformer has physically isolated bobbin islands for pri and sec windings, which is good. If the optocoupler and Y cap are certified, this should be good enough.
Primary side EMI filter choke seems to be not that well implemented in terms of insulation, there's no physical separation between L and N windings, this could be a fire hazard if magnet wire insulation is compromised due to being rubbed against toroidal core. This is not a big deal if the core has reliable insulated coating, but I can't say that for sure without having the SMPS physically in my hand.
Reference: I hold an MSEE in electric power system engineering, and a PhD candidacy in power electronics.
This is not an accurate statement. The radiated EMI from the transformer (magnetic field) comes from voltage drop across leakage inductance. In conventional push-pull, forward or flyback SMPS leakage inductance must be as low as possible. In LLC SMPS leakage inductance is higher and is used as a ballast, there is the option to include leakage inductance in the transformer or to use an external inductor. The 1st option is adequate for small power adapters, but radiated EMI is higher. The 2nd option is adequate for audio SMPS.
Hi.I connected it to 500w class d amp and 13 inch subwoofer.I already can not open max sound at home because it shakes glasses so i can say it is powerful enough but it would be better seller sends item with Rubycon output capacitors as same as his item picture(received amp with china made output caps) May be average performance for money.( i am using it for subwoofer,maybe i do not use for stereo and try linear PS for stereo system)
I did not use it much.I am listening music with my HD6xx and hi end dac with headphone amp.
I did not use it much.I am listening music with my HD6xx and hi end dac with headphone amp.
Hansueli,
I bought the same supply recently and I'm looking forward to your measurements. Waht I'm in is not only the ripple on main output but also the quality of the +/- 15V rails and the EMI on the input side. For the transformer a shielding would be necessary, that's clear from the previous posts.
heinrichh
I bought the same supply recently and I'm looking forward to your measurements. Waht I'm in is not only the ripple on main output but also the quality of the +/- 15V rails and the EMI on the input side. For the transformer a shielding would be necessary, that's clear from the previous posts.
heinrichh
This is one downside of SMPS.
A transformer, bridge and smoothing is more hardy.
I have transformer test rig which gets shorted quite often and has lasted me 10 years so far !
Hi Hansueli.I put this smps and L15DX2 500w class d amp in this case(I am using it bridged).It plays well since 2 days.But there is a small sound (tırrrrrrr) from smps transformer.(not audible over 30cm)
It plays well now.For your information.I did not open a ventilation hole on top and bottom because it is not heating up.
I hope it will not break down.
It plays well now.For your information.I did not open a ventilation hole on top and bottom because it is not heating up.
I hope it will not break down.
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Hansueli,
with a bit reengineering I found out that the auxiliary supply has its own winding on the transformer and is completely separated from the rest, even the center tap. There are only two diodes and two small electrolytes, that's it. Shorting it will kill the transformer because the power of the auxiliary winding is too small for triggering the protection ciruit if there is any.
Do you still have the SMPS? I have tried to figure out how much power can be taken from the auxiliary winding, but the manufacturer can not be determined even with lots of hours googling and the various dealers know nothing about. We could at least estimate that if we could measure the wire diameter of the winding. For this I would have to destroy my power supply, but yours is already broken. Can you measure it for me?
TIA Heinrich
with a bit reengineering I found out that the auxiliary supply has its own winding on the transformer and is completely separated from the rest, even the center tap. There are only two diodes and two small electrolytes, that's it. Shorting it will kill the transformer because the power of the auxiliary winding is too small for triggering the protection ciruit if there is any.
Do you still have the SMPS? I have tried to figure out how much power can be taken from the auxiliary winding, but the manufacturer can not be determined even with lots of hours googling and the various dealers know nothing about. We could at least estimate that if we could measure the wire diameter of the winding. For this I would have to destroy my power supply, but yours is already broken. Can you measure it for me?
TIA Heinrich
Dear heinrichh
Sorry but I have no possibility to measure the wiring diameter.
The wire are already at the recycling :-(
When I take the wire away from the transformer the wires were connected to the high voltage side. So for me it’s not really galvanic separation. It could be used for powering the L6599
Sorry but I have no possibility to measure the wiring diameter.
The wire are already at the recycling :-(
When I take the wire away from the transformer the wires were connected to the high voltage side. So for me it’s not really galvanic separation. It could be used for powering the L6599
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