Hi, all. I have just assembled a 3e audio tpa3255, my first ever DIY amp. I'm a little confused by the output as I was expecting a lot more, so I'm not sure if there's a fault or if something is wrong.
The power supply I'm using is a meanwell LRS 350-48. I don't have a potentiometer connected at the moment so it is just running full power from my dac and I have been controlling the volume in Windows. The amp is connected using RCA cables.
As soon as I turn the volume up a little too high, one channel cuts out (same channel every time) and the fault light on the board comes up. I'm confused as I was expecting it to be a lot louder than it is, especially before cutting off. The last amp I used on these speakers was a marantz pm6005 which is only 35 or 45w per channel and that went a lot louder from memory.
Does anyone have any advice or am I expecting too much?
The power supply I'm using is a meanwell LRS 350-48. I don't have a potentiometer connected at the moment so it is just running full power from my dac and I have been controlling the volume in Windows. The amp is connected using RCA cables.
As soon as I turn the volume up a little too high, one channel cuts out (same channel every time) and the fault light on the board comes up. I'm confused as I was expecting it to be a lot louder than it is, especially before cutting off. The last amp I used on these speakers was a marantz pm6005 which is only 35 or 45w per channel and that went a lot louder from memory.
Does anyone have any advice or am I expecting too much?
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Measure the output voltage from the PSU while it cuts out. These chips cut out like this when the power supply is insufficient to its specifications, be it voltage or ripple
I think the issue is that you're not using a balanced signal to drive the amplifier. On this board there is no SE->DIFF conversion of unbalanced signals so if an unbalanced signal is used one side of the full bridge tries to remain at mid supply and this weird behavior occurs.
I think kipman725 is on the right track, from what I can see the amplifier board seems to be configured for a balanced signal (the jumper located behind the input header).
I would try setting the two jumpers, one for each channel, to the SE mode. The jumper pin configuration is printed on the back of the PCB. Once you have set the input to SE mode, disconnect the IN1- and IN2- cables from the RCA input jacks and tidy them away somewhere where they make no contact with the case or anything else for that matter.
I would try setting the two jumpers, one for each channel, to the SE mode. The jumper pin configuration is printed on the back of the PCB. Once you have set the input to SE mode, disconnect the IN1- and IN2- cables from the RCA input jacks and tidy them away somewhere where they make no contact with the case or anything else for that matter.
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Thanks for your responses. My father has had a look at it and I believe the balanced/unbalanced thing is the issue. I haven't heard it yet but he's changed the wiring now for the unbalanced cables and it no longer cuts out. It's a little louder now, still not as loud as we were expecting (he has told me), but I haven't had a chance to hear it for myself. Maybe my expectations are too high still, but I thought it was somewhere around 100w per channel with the 48v PSU. The speakers we are using are the kef iq7, and I don't have any other speakers to test as this is a holiday home
The Kef speaker you have is 8 ohm and 90 db.
Mine Purifi is 88.7 db and 4 ohm and still not screaming high with 48v with same amp as you.
But is sounds very good! 🙂