@bushelj
All 4 inductors on this board have to be of the same value. So you read the wrong number on the PCB or it is written wrong.
The absolute value is not that important, if you take it (much to) serious, you would match it to the load. Which is nonsense if you use speakers, as their impedance (Ohm) changes with frequency. So a nominal 8 Ohm speaker may have a static resistor value of 6 Ohm, which first peaks to 25 Ohm at resonance frequency and then increases with frequency. This is to the speaker being no static load, but a complex system. At high frequency the voice COIL is off course, an inductor it self.
So calm down, nothing wrong with the board.
All 4 inductors on this board have to be of the same value. So you read the wrong number on the PCB or it is written wrong.
The absolute value is not that important, if you take it (much to) serious, you would match it to the load. Which is nonsense if you use speakers, as their impedance (Ohm) changes with frequency. So a nominal 8 Ohm speaker may have a static resistor value of 6 Ohm, which first peaks to 25 Ohm at resonance frequency and then increases with frequency. This is to the speaker being no static load, but a complex system. At high frequency the voice COIL is off course, an inductor it self.
So calm down, nothing wrong with the board.
Hi Turbowatch. I was not referring to the 4 big Inductors on the output. I was referring to the two inductors that are part of the low voltage power supply at the front of the board nearest the front panel. One is marked as 101 and the other is marked as 220 on the board.
These Amplifiers have been sold under various names but the main PCB appears to be identical with the same part number silk screened onto the board so I don't believe there have been any changes during the life of this product.
So although all the PCBs for the TPA3255 model appears to be the same part number from all the photographs I have seen the early models appear to have the right inductors installed - ie. 101 and 220. The later production models seem to have 101 inductors installed in both positions.
The later models also have the SAMWA Caps installed in the signal path whereas the earlier models had other (better?) makes. All models appear to have Nichicon Caps installed in the primary Power Supply (the big ones). These caps being Nichicon are also included in the sales literature so probably more difficult to substitute !!
The Chinese tend to build these amplifiers in batches and probably use whatever components they have available at the time !! Often some devices might get substituted with other non-equivalent devices - Lower Quality, Different Value, Lower Voltage rating etc. - Whatever basically costs less !!
Hi guys,
reading a the late posts and about the 220 or 101 inductors: I've not such a chinese amp on hand (but the TI EVM one) and it looks like this inductor is used locally by a buck conveter to generate one DC rail used locally: in such case, rising he inductor from 2.2µH to 10µH would not worry me at all -I would say there are reasons for it to be even better in fact-
Cheers
reading a the late posts and about the 220 or 101 inductors: I've not such a chinese amp on hand (but the TI EVM one) and it looks like this inductor is used locally by a buck conveter to generate one DC rail used locally: in such case, rising he inductor from 2.2µH to 10µH would not worry me at all -I would say there are reasons for it to be even better in fact-
Cheers
If we had a circuit diagram it would be most useful !! The 100uH one is part of the buck circuit but I don’t have a clue what the other one does unless it is part of the filter for the 12volt supply.
Just plugged in my TPA3255 Amp and it sounds pretty good out of the box ! Running it from a 24volt Mean Well Switching Power Supply. Have a 48volt Mean Well as well so you try this later once it has run for a bit.
Switch on thump is minimal - more of a nasty sharp click. Power down is much more noisy but not as bad as expected from other comments.
Indeed, there's one 10µH for it on TI's EVM board. that's the only other choke -except for output filtering- I could see on the schematic.
Tu es de Trévoux cool ) Je suis d Ambérieu lol ) Un Français ça fait toujours plaisir
Yep Daniboun...Ambérieu en Dombes ou en Bugey?
Has anyone seen a current phase measurement of any of the tpa3255 builds? Too me transient response like a snare crackle is less sharp with the 3e tpa3255 vs the LJM IRS2092 board I just went from. It might be that the tweeter got slightly more delayed with the tpa3255. I've tried a lot of tilt angle on the speakers and transients sounded really good with the LJM. The 3255 sounds a bit more laid back in comparison and I wonder why?
LOL ! it means that French people are always wrong
Which is not so wrong when we hear the lies of our president on TV about the health crisis ....
are you referring to the Pop sound at startup ?
Hi Daniboun.
If you apply power from the external power supply and then switch on the amp with the switch on the front you get a distinct Pop but not too loud (at least with my current 24volt Mean Well supply). If you turn off the switch you get a nasty crack through the speakers which I think is unacceptable for a so called finished amplifier.
My solution is to leave the switch on the amplifier in the on position and turn the supply to the Mean Well Power Supply on and off. Doing this there is no pop at start up or turn off presumably because the voltage takes time to build at start up and fades away gradually when you remove the supply.
What a pity the front switch is not the reset switch for the TPA3255 so you could apply power first and then switch it on after power had been applied. Same with turning off.
I have also noticed some very faint white noise (hissing) at the speakers when there is no input. The white noise stays at the same level regardless of the position of the volume control. This seems very odd for a digital amp which should be completely silent ?
