I'm new to this forum, and new to the whole DIY audio and I hope you can help me out with something.
I bought the 3e TPA2355 some time ago, and I'm having some problems with getting good sound.
When I connect the headphone output of my phone to it I get good sound, but when I connect my tv in the same way the sound is not good.
Even at the lowest output setting of my tv the sound is quite loud, and there is a lot of white noise. The tv output is also a headphone jack (3.5mm) and I've used the same cable for testing.
I'm not sure what is causing this. Any ideas?
I bought the 3e TPA2355 some time ago, and I'm having some problems with getting good sound.
When I connect the headphone output of my phone to it I get good sound, but when I connect my tv in the same way the sound is not good.
Even at the lowest output setting of my tv the sound is quite loud, and there is a lot of white noise. The tv output is also a headphone jack (3.5mm) and I've used the same cable for testing.
I'm not sure what is causing this. Any ideas?
Apoptosed these amps are very sensitive and if your source is not very good then the sound quality will not be very good. When I first tried mine both my Mac and tv had too much background noise. My iPhone 8 was noisy too but my iPhone 5s was ok. I then got a DX160 digital audio player and the sound quality was amazing but too bright. I then tried a Khadas Tone Board DAC and this produced great sound quality and was a lot warmer sounding. You get what you put in!
A great option is a RaspberryPi + Volumio + DAC, this is not too expensive and is not to hard to set up.
A great option is a RaspberryPi + Volumio + DAC, this is not too expensive and is not to hard to set up.
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This is common to any Class D Amps. Good source = very important
Class D amps are very analytics.
The Khadas Tone Board DAC as already mentioned or some other DAC from a PC or a Mac. A DAP, Digital Audio Players have good sound quality and can store and stream music from the headphone jack line out. Audio Interfaces are similar to DAC but with extra features and used to listen to and record music using a Mac or PC. Some phones are very good too, I think there are some LG that are rated. These are the main options for HI-Res music sources.
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I have just finished setting up my new Scarlett Solo balanced DAC. I was worried about it not working out as I had bypassed the opamps and also made some balanced TRS leads. The leads were a pain, I cut them in half and fitted some 2.5 mm 3 pin plugs, the wire was so fine and I wished I had got just the plugs to make them from scratch. I need a potentiometer shaft extender as the DAC is inside the case.
It sounds very good but... it sounded very good before. Bypassing opamps and making leads is very fiddly and I will have to have a few days to listen before making any judgments.
All this went into my newest project which I started today. I got hold of a faulty Technics SU-7300 amp and plan to get it fully working with a TPA3255. I stripped it, fitted all the ac including a relay, a RaspberryPi, SMPS and the amp. I replaced 4 speaker posts and everything is working so far. Just need to sort out the volume knob and get the VU meter working.
It sounds very good but... it sounded very good before. Bypassing opamps and making leads is very fiddly and I will have to have a few days to listen before making any judgments.
All this went into my newest project which I started today. I got hold of a faulty Technics SU-7300 amp and plan to get it fully working with a TPA3255. I stripped it, fitted all the ac including a relay, a RaspberryPi, SMPS and the amp. I replaced 4 speaker posts and everything is working so far. Just need to sort out the volume knob and get the VU meter working.
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This setup is much cooler. The heat sink was hot to the touch before now it is cool. I have done three things that could have caused this, balanced input, changed the DAC or bypassed the opamp. This is excellent as it was concerning as an efficient amp should not produce excess heat. Have anyone else noticed this?
When you are doing listening comparisons between different configurations/hardware, it's a good idea to make only one change at a time!
It appears that you have gone from:
Khadas DAC + unbalanced input via opamps
to
Scarlett DAC + balanced direct input
So you are comparing not only the difference between input configurations, but also the difference between Khadas and Scarlett DAC's.
Given that your previous DAC was Khadas (which is highly regarded) it's unfortunate you didn't then buy a Soncoz LA-QXD1, because this DAC is effectively a balanced version of the Khadas (same designer).
It is more detailed, cymbals are sounding like cymbals I have never heard before. Bass has more drive to it. I was listening to Childish Gambino Awaken My Love album and thought I had a problem but it was the weird samples and effects the use.
I want to know why it is running cool now? It is producing hardly any heat!
I want to know why it is running cool now? It is producing hardly any heat!
Yes my heatsink sits at 50 something celsius at idle without a cover on. I am trying a solution of using the amplifier switch plugin for volumio which puts a rpi GPIO pin into either high or low state when music is played. I am thinking of having it switch to low state and using a resistor and transistor to pull the rst pin to gnd on the 3e 3255 amp when music not playing. I notice that even in reset mode the heatsink still sits a few degrees above ambient. I haven't have a close look at the schematic but can anyone tell me exactly what this mode does? Would be interesting to get a power usage monitor and compare idle power usage in reset mode and when on.
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One issue is that it represents a reasonable amount of wasted energy for something that i want to be able to leave on 24 hours a day. Also i don't think that it is very good for the circuitry in general to be at those temps long term including the rpi and dac. This could be helped with good cooling on course. 10 or 11 watts idle power usage that others have reported is not what i would have expected from a good class d design.