You are right. Thank you!
An externally hosted image should be here but it was not working when we last tested it.
I insisted a bit with the input impedance because I think it's an easy way to filter out the low frequencies in a biamped system (without aditional xo)
E.g: Having set a gain of 20dB gives 60KOhm input impedance -> using 22nF input capacitors makes a high pass at about 120Hz.
Not sure if a 22nF between the input capacitors, right before the IC will make a low pass filter at the same about 120Hz (I'll test this)... it would be such an easy way to make a byamped system without any other xovers or expensive caps (Possibly some eq will be needed.)
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Sounds logical and may well work.
An alternative would be to use for instance a 100nF capacitor and arrange a dynamic impedance (a resistor in series with a DC decoupling capacitor to ground) at the TPA3118 input pin such that you are better in control of the impedance and, thus, the cut-off frequency.
An alternative would be to use for instance a 100nF capacitor and arrange a dynamic impedance (a resistor in series with a DC decoupling capacitor to ground) at the TPA3118 input pin such that you are better in control of the impedance and, thus, the cut-off frequency.
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Nice summary of mods photo. Only thing I'd like to know, the final value/brand/supplier of the upgraded caps and coils? I've read this thread, twice in some parts, lol, and remember JP was going to post a final mod recommendations list with component values, did I miss that? I'm using 8 Ohm speakers with a 24VDC (9A rated) p.s., connecting amps in parallel from p.s.. I'm open for suggestions, as I think I will only be doing the R27 removal to start. I'm using shielded cable for 3.5mm inputs (3 conductor) that splits (common ground) to each amp. Below is general layout,
before wiring. The upper left block is a fused &
lighted IEC 120VAC socket.
Note: this photo is simply for component layout, making sure I'll be able to fit things in a 6" x 6" x 2" steel enclosure.
before wiring. The upper left block is a fused &
lighted IEC 120VAC socket.
Note: this photo is simply for component layout, making sure I'll be able to fit things in a 6" x 6" x 2" steel enclosure.
An externally hosted image should be here but it was not working when we last tested it.
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power supply is a 24VDC, 9A unit (AC110V 220V to 24v DC 9A 150W Industrial Power Switching Supply Converter Module | eBay), as mentioned by Jean Paul (?) earlier in this thread. Enclosure is a repurposed unit that my company threw out hundreds of, I just thought it would make a good case for an amplifier. I'll add a 2.1mm power input jack to allow battery power, making this a truly portable, versatile amplifier box that can be powered by either 120VAC or a 12~24VDC battery pack(s).
Looking for comment, do the amps need to be shielded from the power supply in my layout? Will a thin metal wrap (don't have specs at the moment, thicker than tin foil
) around the power supply board reduce any noise or would it be a waste of effort?
Looking for comment, do the amps need to be shielded from the power supply in my layout? Will a thin metal wrap (don't have specs at the moment, thicker than tin foil
) around the power supply board reduce any noise or would it be a waste of effort?
Sanwulasers site is in no hurry to ship, took about a week to get my order out. By the way, they do not have the boards we are talking about here, they have a TPA3118 and TPA3110 stereo bluetooth board (also configurable as mono) and a mono TPA3110, but not the mono non bluetooth TPA3118.
Same as snubber in previous photos, just different values? Or another approach altogether?
330pF+10R on the photo I uploaded are from another forum by a user called jls001:
"The last mod that I did was to use bootstrap snubbers for the output inductor filters to reduce EMI that can arise by the switching of the output stage (sudden transients into inductive loads produce EMI). The "output" side of the inductors already have snubbers by way of the zobel network. What is added is a C and R before the signal reaches the inductor. This additional snubber cleans up the sound further. "
"The last mod that I did was to use bootstrap snubbers for the output inductor filters to reduce EMI that can arise by the switching of the output stage (sudden transients into inductive loads produce EMI). The "output" side of the inductors already have snubbers by way of the zobel network. What is added is a C and R before the signal reaches the inductor. This additional snubber cleans up the sound further. "
Changing the caps will have an immediate effect. People on many threads are using Panasonic caps... Go for some good brand, low ESR caps. I use just 1 x 1000uF Panasonic per side (2 caps per board) and it's ok. The price (a quality indicator) is about 1-2 USD/cap.
The coils should be at least 3A rated (the bigger, the better). Usually high current coils have also lower DCR (which is important - less than 0.05Ohm). I preffer shielded coils, but torroids should work well too.
thanks selwe.
I'm gonna use the Panasonic caps (part # EEV-FK1V102M, 35V, 1,000uF) and Coilcraft inductors (part # XAL5050-103MEB, 10uH, 40.9 Ohm DCR) linked below (Mouser links). Figured I'd add the supplier links for other users in the U.S who are interested in improving the Sanwu 3118 board.
capacitoprs: EEV-FK1V102M Panasonic | Mouser
inductors: XAL5050-103MEB Coilcraft | Mouser
My amps will be powered by 24VDC and driving 8 Ohm speakers.
I'm gonna use the Panasonic caps (part # EEV-FK1V102M, 35V, 1,000uF) and Coilcraft inductors (part # XAL5050-103MEB, 10uH, 40.9 Ohm DCR) linked below (Mouser links). Figured I'd add the supplier links for other users in the U.S who are interested in improving the Sanwu 3118 board.
capacitoprs: EEV-FK1V102M Panasonic | Mouser
inductors: XAL5050-103MEB Coilcraft | Mouser
My amps will be powered by 24VDC and driving 8 Ohm speakers.