I received my Tpa3255 from china and tried to boot with a 48v 3amp switching p/s. Killed the power supply and the next one two. Built a power supply from old denon transformer and two audio grade 10000uf caps, filter caps, rectifiers and all. 49.2volt dc output. Now amp works and sounds amazing. But clip and fault led on and still works. Played through 4 inch full range dayton audio reference then 10 inch Audio Nirvana full range. Any thoughts about leds???
Wanted to know more about the dead p/s . Any idea if it is build quality or it simply burned when power on?
Any pictures of the p/s as a reference ? Do you have web link of the p/s ?
Thanks
Is this the only way to fix it?
I have the blue douk board and a connex SMPS600RS and a terrible Pop on power up also on power down.
Best regards from switzerland
Hans-Peter
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Hi all.. I'm following this thread for a while and in the meantime I ordered TI TPA3255EVM so while I'm waiting for that board to arrive, I'm searching for other parts to assemble full amplifier. I have some questions:
1. Which power supply (SMPS) you can fully suggest that would operate with minimal noise and without any pops and clicks during power ON/OFF process?
Which SMPS has best price/performance ratio?
2. Can I add one ALPS Stereo pot to reduce input volume level and use it as a main volume? like this:
More Information Page
Thanks in advance..
1. Which power supply (SMPS) you can fully suggest that would operate with minimal noise and without any pops and clicks during power ON/OFF process?
Which SMPS has best price/performance ratio?
2. Can I add one ALPS Stereo pot to reduce input volume level and use it as a main volume? like this:
More Information Page
Thanks in advance..
I would not go for 100k, but for 10k pot. Gives better noise performance and frequency response. And choose the logarithmic characteristic for your master vol.
selecting a power supply (SMPS) for tpa3255; also, on/off noises
Guidelines I follow for power supplies:
1. Voltage is far more important than amperage or total watts output power. Choose a PSU with a minimum of 48V. Recommend a minimum of 2A, or ~100W to allow for dynamic headroom. Also recommend an adjustable PSU so you can increase voltage beyond 48V.
2. Choose wattage based on the speakers driven and typical listening level. With lower-efficiency speakers (<90dB) or subwoofers or low-resistance speakers, you could use up to 750W psu to drive the board up to its full rated power of 315Wpc (@10%THD!). But it makes no sense to run this chip beyond 260Wpc because of the THD. So 500W is more practical than 750W. There are many considerations and a lot of flexibility in choosing wattage.
3. I hate fans because they are noisy and leech power, but PSUs over 200W usually need one. Even if you buy a PSU without a fan, you probably need one in the case. A PSU runs more efficiently when it is not hot. Running hot stresses all the components and makes the PSU less efficient than it is designed to be. Many PSUs adjust the fan speed based on load, but many do not. If you get a PSU that has a loud fan or a fan that runs 100% all the time, you can replace the fan with a quieter model.
4. If you leave your amp turned on most of the time, consider idle power usage. For example, tpa3255evm with my 48V/100W PSU @ 53V consumes 8.2W. With my 48V/500W PSU @ 50V consumes 17.5W.
5. I prefer PSUs with efficiency spec of 85% or higher, the higher the better! Beware lower efficiency PSUs in the 75% range...they will generate more heat and require more cooling (i.e., fan). Also, please choose a PSU that has PFC (power factor correction). A PSU with PFC uses the AC waveform from the electrical grid more efficiently.
6. tpa3255evm has negligible turn-on noises unless you switch power too quickly. So it is usually not a problem. But to prevent turn-on noises, use a delay relay to startup with RESET enabled, then switch to NORMAL after a few seconds.
7. tpa3255evm has turn-off noises with every SMPS I have tried. The easiest and least complex way to prevent turn-off noises is to use a 3-pole switch for on/off, and switch V+, AC hot, and AC neutral together.
8. If you turn on PSU first, then turn on tpa3255evm with a separate switch, the tpa3255evm won't start up with some PSUs because it trips the overcurrent protection. There are several ways of dealing with this, but the easiest is to buy a PSU that has an active inrush current limiting circuit.
9. Ripple on most SMPSes is negligible, <250mV. From 48V, 250mV is 0.005% and 100mV is 0.002%. Also, there is good PSRR on tpa3255evm.
10. Finally, be sure to check the grounding scheme for the PSU. At 48V, earth-grounding is preferable to floating/isolated ground.
11. Linear? Given an SMPS with the correct voltage and sufficient amperage, any reason to use an LPS with a switching amplifier? Not for me, considering an LPS is perhaps 60% efficient it wastes a lot of power.
12. Switching frequency: I haven't measured this, but my theory is that higher switching frequency is preferred, in order to push any switching noises further outside the audio spectrum. 100KHz switching is great, 40KHz less great.
Mean Well PSUs are good quality, reasonably priced, and there is a large selection to choose from that meet my guidelines and work well with tpa3255evm. Here are some to read more about:
100W fanless
* HRP-100 90% efficient
* if you need 5V standby for other uses HRPG-100
* lower profile but specs largely the same RSP-100 88% efficient
200W fanless
* HRP-200 89% efficient
* with 5V standby HRPG-200
* lower profile RSP-200 88% efficient
* zero-voltage switching, "resonant" USP-225
300-400W fanless, without inrush current limiting
RPS-300, RPS-400
EPP-300, EPP-400
350W fanless with inrush current limiting, zero-voltage switching
USP-350
500W fanless with inrush current limiting, zero-voltage switching
USP-500
600W with fan & 5V standby
HRPG-600
750W with fan & 12V standby
RSP-750
Guidelines I follow for power supplies:
1. Voltage is far more important than amperage or total watts output power. Choose a PSU with a minimum of 48V. Recommend a minimum of 2A, or ~100W to allow for dynamic headroom. Also recommend an adjustable PSU so you can increase voltage beyond 48V.
2. Choose wattage based on the speakers driven and typical listening level. With lower-efficiency speakers (<90dB) or subwoofers or low-resistance speakers, you could use up to 750W psu to drive the board up to its full rated power of 315Wpc (@10%THD!). But it makes no sense to run this chip beyond 260Wpc because of the THD. So 500W is more practical than 750W. There are many considerations and a lot of flexibility in choosing wattage.
3. I hate fans because they are noisy and leech power, but PSUs over 200W usually need one. Even if you buy a PSU without a fan, you probably need one in the case. A PSU runs more efficiently when it is not hot. Running hot stresses all the components and makes the PSU less efficient than it is designed to be. Many PSUs adjust the fan speed based on load, but many do not. If you get a PSU that has a loud fan or a fan that runs 100% all the time, you can replace the fan with a quieter model.
4. If you leave your amp turned on most of the time, consider idle power usage. For example, tpa3255evm with my 48V/100W PSU @ 53V consumes 8.2W. With my 48V/500W PSU @ 50V consumes 17.5W.
5. I prefer PSUs with efficiency spec of 85% or higher, the higher the better! Beware lower efficiency PSUs in the 75% range...they will generate more heat and require more cooling (i.e., fan). Also, please choose a PSU that has PFC (power factor correction). A PSU with PFC uses the AC waveform from the electrical grid more efficiently.
6. tpa3255evm has negligible turn-on noises unless you switch power too quickly. So it is usually not a problem. But to prevent turn-on noises, use a delay relay to startup with RESET enabled, then switch to NORMAL after a few seconds.
7. tpa3255evm has turn-off noises with every SMPS I have tried. The easiest and least complex way to prevent turn-off noises is to use a 3-pole switch for on/off, and switch V+, AC hot, and AC neutral together.
8. If you turn on PSU first, then turn on tpa3255evm with a separate switch, the tpa3255evm won't start up with some PSUs because it trips the overcurrent protection. There are several ways of dealing with this, but the easiest is to buy a PSU that has an active inrush current limiting circuit.
9. Ripple on most SMPSes is negligible, <250mV. From 48V, 250mV is 0.005% and 100mV is 0.002%. Also, there is good PSRR on tpa3255evm.
10. Finally, be sure to check the grounding scheme for the PSU. At 48V, earth-grounding is preferable to floating/isolated ground.
11. Linear? Given an SMPS with the correct voltage and sufficient amperage, any reason to use an LPS with a switching amplifier? Not for me, considering an LPS is perhaps 60% efficient it wastes a lot of power.
12. Switching frequency: I haven't measured this, but my theory is that higher switching frequency is preferred, in order to push any switching noises further outside the audio spectrum. 100KHz switching is great, 40KHz less great.
Mean Well PSUs are good quality, reasonably priced, and there is a large selection to choose from that meet my guidelines and work well with tpa3255evm. Here are some to read more about:
100W fanless
* HRP-100 90% efficient
* if you need 5V standby for other uses HRPG-100
* lower profile but specs largely the same RSP-100 88% efficient
200W fanless
* HRP-200 89% efficient
* with 5V standby HRPG-200
* lower profile RSP-200 88% efficient
* zero-voltage switching, "resonant" USP-225
300-400W fanless, without inrush current limiting
RPS-300, RPS-400
EPP-300, EPP-400
350W fanless with inrush current limiting, zero-voltage switching
USP-350
500W fanless with inrush current limiting, zero-voltage switching
USP-500
600W with fan & 5V standby
HRPG-600
750W with fan & 12V standby
RSP-750
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I don't think delaying power to the amp will help...and it might cause your smps to trip overcurrent protection. To eliminate power-down click, switch the V+ wire on/off along with the AC wires to the smps. This cuts the power line between smps and amp, so the the amp does not get a turn-off pop from the smps.
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Pop noise when shutting down the amp
I found this in the TI forum.
This is the link to the thread in the forum:
TPA3250 Pop Noise when power supply shut-down - Audio Amplifiers Forum - Audio Amplifiers - TI E2E Community
It is suggested to put the amplifier into reset before removing the power to reduce noise.
On our EVMs, we use a voltage supervisor (U7) to manually toggle reset if the PVDD voltage falls below a threshold set by R32 and R26. The means the amplifier will shut down automatically if power is removed before the supply voltage falls to where the amplifier will be forced to shut down and cause pop.
Look like the easiest approach is to use the reset switch. I am sure someone can come up with a way to "move the switch off the board" so that even when the amp is enclosed, an off the board switch will serve the purpose.
Regards,
I found this in the TI forum.
This is the link to the thread in the forum:
TPA3250 Pop Noise when power supply shut-down - Audio Amplifiers Forum - Audio Amplifiers - TI E2E Community
It is suggested to put the amplifier into reset before removing the power to reduce noise.
On our EVMs, we use a voltage supervisor (U7) to manually toggle reset if the PVDD voltage falls below a threshold set by R32 and R26. The means the amplifier will shut down automatically if power is removed before the supply voltage falls to where the amplifier will be forced to shut down and cause pop.
Look like the easiest approach is to use the reset switch. I am sure someone can come up with a way to "move the switch off the board" so that even when the amp is enclosed, an off the board switch will serve the purpose.
Regards,
I don't use a volume pot because I don't want anything extra in the signal path or any gaps in shielding for signal wires.
But I'm sure someone else has ideas about which volume pot goes best with this amp.
Quick question if you can help:
*What is series naming differences across Meanwell:
HRPG, RSP, USP, RPS, EPP. I also found NES, S, IRM as well.
*What differs, which SMPS series better suited for Audiophile uses?
Read some consider Meanwell average - 150~250mv ripple
Put forward EVGA Supernova 15mv ripple "resulting stiffness makes it much better than the equivelent linear supply"，as well Lambda, Murr, Siemens SMPS
Hope to leverage on any understanding.
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What criteria is lrs-350-48 falling short on? It claims No load power consumption <0.75W and is cheap
This Mean Well product listing page describes the different series characteristics:
http://www.meanwell.com/productSeries.aspx