Hello!
I'm planning on replacing the power amp in my bass amplifier with a class D amp, and I'm leaning towards the TA3020 v3b with an SMPS-500. I've already built a 4-channel PA amp with those and an SMPS-1000, and they work excellently.
Now, since I'm throwing out the power supply as well (6kg of toroid is just too heavy) I'm left without +-15 volts for the preamp section. What do you suggest as a practical way of getting those voltages? Is there a way to get that from the SMPS? It doesn't really have to be particularly well regulated; the current requirements are very modest.
I'm planning on replacing the power amp in my bass amplifier with a class D amp, and I'm leaning towards the TA3020 v3b with an SMPS-500. I've already built a 4-channel PA amp with those and an SMPS-1000, and they work excellently.
Now, since I'm throwing out the power supply as well (6kg of toroid is just too heavy) I'm left without +-15 volts for the preamp section. What do you suggest as a practical way of getting those voltages? Is there a way to get that from the SMPS? It doesn't really have to be particularly well regulated; the current requirements are very modest.
Oh, excellent! I'll just hold my horses until it's available. But I'll want dibs on the first batch.
the new SMPS500R is available already, Connexelectronic
this use resonant topology, and has the output regulated. there are 110V and 230V versions available. i prefer not to use a switch for both 110V and 230V compatibility, for better efficiency and reliability.
this use resonant topology, and has the output regulated. there are 110V and 230V versions available. i prefer not to use a switch for both 110V and 230V compatibility, for better efficiency and reliability.
the SMPS250 can provide about 200mA on the aux. supply and up to 500mA when the current draw from main voltage is at least 0.5A. the required current, 1A at 5.5V is too high and will overheat the heatsink since there is a linear postregulator which make this voltage from a higher one.
Thank you, that's great!
What aux voltages does it provide at what max. current?
I would like to try to use this SMPS with several amp modules which need different votages - from +-35V to let's say +-60V. Is it somehow possible to adjust the main voltage of this SMPS within this wide range?
Thank you, I appreciate your great support!
the aux. voltage is 2x20V DC, at max. 0.5A. the main voltage is adjustable within max. +-10%, that's because the topology used requires tight output voltage to maintain the operation within ZVS range. the output voltage can have one of the following values: +-30V, +-40V, +-50V, +-60V, +-70V all +-5-10% adjustable
Hi, does A350SMPS allow minor output voltage adjustments? I think about using it with two different amp boards where one needs about +-31V and the other about +- 34V and I want to get max. possible output power.
My idea is that I would order one A350SMPS with nominal output voltage let's say +-32V with adjustable output voltage range let's say from +-29V to +-35V? Is that possible? Thank you.
My idea is that I would order one A350SMPS with nominal output voltage let's say +-32V with adjustable output voltage range let's say from +-29V to +-35V? Is that possible? Thank you.
The A350SMPS and A500SMPS has unadjustable output voltage, they use Q-R topology with 50-50% duty cycle.
if you need adjustable output, i recommend the A250SMPS which can provide more than 350W peak, or if you need more power, the SMPS500R, which use LLC resonant topology and the output voltage is adjustable within +-10% of the nominal voltage. for example, the 32V nominal output voltage can be adjusted within +-29 to +-35V range. it also have an auxilliary output of +-12 to +-20V .
if you need adjustable output, i recommend the A250SMPS which can provide more than 350W peak, or if you need more power, the SMPS500R, which use LLC resonant topology and the output voltage is adjustable within +-10% of the nominal voltage. for example, the 32V nominal output voltage can be adjusted within +-29 to +-35V range. it also have an auxilliary output of +-12 to +-20V .
Hi Cristi,
can you recommend SMPS for 4702 based amps (100W) ? How does one obtain required +/-60V as well as +/-52V DC from SMPS ? I'd like to power 4x100W amps (two boards) in total from one SMPS if possible. It does look like 500R is the one to go for, but I'm still not sure about twin voltages required.
Thanks,
Bratislav
can you recommend SMPS for 4702 based amps (100W) ? How does one obtain required +/-60V as well as +/-52V DC from SMPS ? I'd like to power 4x100W amps (two boards) in total from one SMPS if possible. It does look like 500R is the one to go for, but I'm still not sure about twin voltages required.
Thanks,
Bratislav
Suitable SMPS's to supply the LM4702 amplfier can be A350SMPS, (one amplifier board) but the drive voltage might need to be taken from the main voltage, or the SMPS500R, which has also 2 auxilliary voltages, and they can supply the driver part of the amplifier. one smps can supply two boards, but at full power it might face clipping or overcurrent premature trip. this because the class AB amplifiers have the efficiency somewhere arround 60% and at 400W total output power this means about 670W peak drawn from smps.
for best performances, i recommend to use two SMPS500R, one for each amplifier. in this way the maximum power on each channel can also be increased up to 130W.
for best performances, i recommend to use two SMPS500R, one for each amplifier. in this way the maximum power on each channel can also be increased up to 130W.
Thanks! So if I understand correctly, 500R can provide all the voltages needed, and that is great news. No more heavy amps for me (my 2x100W class A monster is 40kg+)!
I will never run the continuous full power from all 4 amps (they will be for active open baffle speaker), so there is no chance of overload. The max power might be drawn for 2 bass units, but even then only for short peaks, as open baffle drivers can easily be overdriven.
I will never run the continuous full power from all 4 amps (they will be for active open baffle speaker), so there is no chance of overload. The max power might be drawn for 2 bass units, but even then only for short peaks, as open baffle drivers can easily be overdriven.
If I wanted to feed the MOS version of the LM4702 amp by SMPS500R then I should connect +AUX voltage in series with the main + voltage and -AUX with main - voltage to get the higher voltages for the driver?
In particular, I would order +-50V version of SMPS500R and adjust its main voltage to +-52V and use LM7808 and LM7908 to lower the +-20V AUX voltages to +-8V and connect them in series with the main voltages to get +-60V for the driver. Is my understanding correct?
If I used +-60V A350SMPS and used the same +-60V voltage for both driver and output stages, would it have any negative influence on the sound quality or anything else?
In particular, I would order +-50V version of SMPS500R and adjust its main voltage to +-52V and use LM7808 and LM7908 to lower the +-20V AUX voltages to +-8V and connect them in series with the main voltages to get +-60V for the driver. Is my understanding correct?
If I used +-60V A350SMPS and used the same +-60V voltage for both driver and output stages, would it have any negative influence on the sound quality or anything else?
I do not recommend to connect the aux. in series with the main voltages. fist, because is not possible, the Aux. is a differential voltage which have a common GND, then, even if it would have a separate GND, the voltage could be be floating as the main voltage rail consumption increase.
I recommend the following configuration: if you need +-52V for the main voltage, then on the Aux. can get +-62V without using any external regulator. this voltage ratio is given by the transformer turns ratio, in this case the main voltage winding could have 2x5 turns, and the aux. 2x6 turns. it mean about 10.5V per turn.
If you really want to do-it in the way which you explained, then the best approach will be to use the linear regulators, such as LM317/337 AFTER the series connection of the aux. and the main rails. in this way, if there is any voltage fluctuation the regulators will eliminate. why i say to use the LM317/337 instead of 78xx ? simply because they are nor referenced to GND directly, but through voltage divider, and this will not expose them to higher voltage than they can withstand. the LM78xx must be referenced to GND, so this will destroy them since the input voltage is much larger than they accept (usually 3V + Vout). still remain a delicate situation if you short the voltage rails to GND or the opposite rail. this can destroy the regulators.
I recommend the following configuration: if you need +-52V for the main voltage, then on the Aux. can get +-62V without using any external regulator. this voltage ratio is given by the transformer turns ratio, in this case the main voltage winding could have 2x5 turns, and the aux. 2x6 turns. it mean about 10.5V per turn.
If you really want to do-it in the way which you explained, then the best approach will be to use the linear regulators, such as LM317/337 AFTER the series connection of the aux. and the main rails. in this way, if there is any voltage fluctuation the regulators will eliminate. why i say to use the LM317/337 instead of 78xx ? simply because they are nor referenced to GND directly, but through voltage divider, and this will not expose them to higher voltage than they can withstand. the LM78xx must be referenced to GND, so this will destroy them since the input voltage is much larger than they accept (usually 3V + Vout). still remain a delicate situation if you short the voltage rails to GND or the opposite rail. this can destroy the regulators.
Thank you for detailed explanation, Cristi.
Actually, I do not insist on any particular solution, I am just trying to find out optimal solution. Provided I want to feed your MOS version of LM4702 based amp module by one of your SMPS, which one would you recommend and how shoud they be connected and set up to achieve optimal results?
I prefer not doing changes of number of turns of transformer windings and similar not so easy modifications. Thanks.
Actually, I do not insist on any particular solution, I am just trying to find out optimal solution. Provided I want to feed your MOS version of LM4702 based amp module by one of your SMPS, which one would you recommend and how shoud they be connected and set up to achieve optimal results?
I prefer not doing changes of number of turns of transformer windings and similar not so easy modifications. Thanks.
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