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Joined 2018
Hi gandolf-San,
Thanks for your comment, Well, I choose 1.2MHz switching frequency in the point of view of my board's sound characteristics. I don't know why TI didn't show the difference of PWM frequency vs Measured performances
I'm wondering if the switching frequency is high enough, we'll have a chance to use Air inductors, something different from ordinary Core Inductors. Especially dual tone (20kHz + 18kHz) performance will be different (Just my guess..., Not tested yet)
Once I met terrible sound and burning heat accident on Magnetically saturated Toroidal Core Inductors (Core saturation was not disappear even if the mains power off, It required to degauss for fixing problem) So I hate to use these kind of cores if I can....
TPA3116D2 has an internal NFB loop, so I think the clock jitter is not a big matters. (SS feature is welcome! >> TI) But still I'm considering small output power waveform resolution will be different between 400KHz PWM (20times of 20KHz) and 1200kHz PWM(60 times of 20KHz).
I'd like to measure these differences, but I need to build sharp cut-off and low-distortion LPF to measure these differences. I'd like to make sure them some day
HILO
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Hello, I was checking the datasheet, how come removing the 100k resistor switches the gain to 20dB? According to the datasheet, you must use 2x51k resistor to set 20dB slave mode or 5.6k and open to set 20dB master mode.
One question. which one is better to use, slave or master mode using only one chip?
Thanks
Yes, as FauxFrench said you only need one resistor for 20dB in master mode, and it has been mentioned on this forum several times that the remaining resistor value doesn't matter. I did not want to try soldering a 5.6k on for no benefit!
Another part of my amp jigsaw arrived yesterday - a little 2.1 pre-amp board that runs from DC, so it's easy to power from the laptop brick. NE5532 2.1 Channel Subwoofer Low Pass Filter Pre AMP Amplifier Board DC12~24V xi 8760701639276 | eBay
This has fixed the hiss that I was getting from my Delta 192. I've got the YJ blue/black board connected to the subwoofer output and the Sanwu on the main stereo. All powered from my Toshiba 15V brick. Working pretty well but there is a high pitched quiet squeal in the tweeters that I think is coming from the YJ. I have got another red/orange Sanwu (SW-HF23 V2.0) on the way to use in PBTL mono for the subwoofer so I will see if that makes any noises.
Edit: found another version of the Sanwu board. Blue this time, with ceramic input caps, an op-amp (?) and no easy PBTL mod links underneath. TPA3116 PBTL DC 11-26V Dual Channel 2x100W Digital Power Amplifier Board 2 Chips Stereo High Power Amplifier Board Audio Input 2.54mm 3 Pins Socket Sale - Banggood.com
Edit: Ah it is two chips! I was only looking at the top pics, the money shot is further down the page.
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The description for that pre-amp board doesn't make it entirely clear, but am I correct in assuming that it functions like a crossover & that the main stereo output does not have the subwoofer frequencies in it?
If so it looks like the perfect solution when coupled with three of something like this to make a very simple/minimalist 2.1 setup? Total would be £14.10 delivered... plus power supply & case, but not needed for testing purposes.
TPA3116 D2 DA DC 12V 24V 100W Mono Channel Digital Power Audio Amplifier Board 192090279548 | eBay
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I'm interested in this, but it I suspect it passes full range on to the main speakers and acts only as a variable low pass filter to bass. Hopefully chopchop can clear this up.
Also, it looks like the bass output is stereo, although it states that it is mono - how do you connect to the amp? Do you bridge L&R or use either or?
Also, it looks like the bass output is stereo, although it states that it is mono - how do you connect to the amp? Do you bridge L&R or use either or?
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Probably mono mixed sub, which is good. I ordered this board as well and hope it has a hp filter for the tops.... I can test it in about 4 weeks or so........
Hi sskloss-San, FauxFrench-San,
I had same kind of feeling something like this TPA3116D2 board.
The signal input part audio coupling MLCC capacitor changes sound characteristics a lot. So I changed them to ordinary Electric Caps. (I believe Film caps will be the best choice for this part). As a result of this, the sound was changed to plain normal. But I met a big power ON/OFF Pops Noise
HILO
Did you increase the value of the input capacitors over the original MLCC SMD caps?
Come on guys, I really worked hard on this as a first time noob and really hoped someone would react positively
(Or reacted at all...
)Member
Joined 2018
Hi millstonemike-San,
I did not checked the capacitance of MLCCs.
It seems not so much. I increased them to 10uF.
HILO
I would bet the MLCCs were less than 1 uf, maybe 0.1 uf. It takes time for the caps to come up to the half Vcc bias to support the AC signal on a DC only system. By using 10 uf caps, that time is increased considerably, more than the TPA3116's built in power up delay. And that may be the cause of your power on pop.
I think it just splits the audio and mono sums and low-passes for the subwoofer output. The three knobs are filter cutoff, subwoofer volume and overall (sub and main out) volume. The pots are detented and seem quite good. The subwoofer out is in mono but I think it uses those 3 pin connectors for ease of connection to many of these amp boards.
A high-pass on the stereo outs would be nice but my stereo mains are sealed and roll off at a 12dB slope from about 100Hz so I'm just using this to allow the subwoofer to fill in what's missing. If your main speakers produce a lot of bass then a proper crossover might be better. This is pretty amazing for the price though.
I've got hold of another Sanwu to use in mono for the sub. The two amps do make some quiet but annoying whistling interference on the tweeters so I've added diodes to the power supply wires and that has cut it down. I used 1N4001 but I read on this forum that Schottkys would be better.
I've ordered another simple sub filter board to play with, just two knobs of this one. I'm going to see if I can mod it to a high pass. Low-pass Filter NE5532 Bass Tone Subwoofer Pre-Amplifier Preamp Board 12-24V UK 958748772515 | eBay. Single sided, the circuit could be quite easily drawn out from the photos unlike the 2.1 one.
Also ordered one of these to put on the DC supply to see if it will get rid of the whistle traces that remain. 6A EMI DC Power Supply Filter Board For Car Speaker Power Amplifier Filtering | eBay
It's mono, they just like using those 3 pin connectors.
what about TVS diodes, are they good as well for lowering any white noise caused by DC input ?
I got 1.5KE27A TVS - AFAIK it should be ok for 24v DC - but the question is whether TVS work just as fine as Schottkys diodes for noise reduction.
Also - I presume that you connect them against the current path (i.e connect the + of diode to the + of DC current ).
I don't know anything about TVS diodes. I think the noise performance is quite good with these amps. I can hear white noise and interference if I crank the volume up but any music played at that volume would probably break my speakers or ears! I think Schottkys were suggested due to the lower voltage drop compared to silicon.
Yes postive wire to the anode of the diode and the reverse for the ground wire.
Is there some inherent feature of the NE5532 that explains why there are dozens of different cheap low pass filters on eBay/Alie/etc. but not a single high pass filter? It seems crazy that if I want a low pass I can buy a preassembled unit for £3-4 but if I want a high pass filter my only option is to buy something literally ten times the price?! Is the world just so saturated with small 'satellite' systems that high passing the main L/R outputs has become too niche of a market to design products for?
This is only ten pounds and it's British: NEW ! ! 2.1 24dB/oct stereo active crossover single sub output Buttkicker PCB. | eBay
Needs parts and soldering but it does the whole lot for a 2.1 system. The only gotchas are the frequencies are fixed and it needs a split supply or a special chip to run it off a single supply.
I think there are some Chinese boards around, I think they call them "Tone boards" or "Audio dividers" rather than crossovers.
I saw those, but the price & the need for a symmetric power supply put me off. The seller has kits for £33 or assembled units for £40. Then you add the shipping cost & the cost of power supply components & you end up spending £50 on a crossover for £10 worth of amplifiers (& it won't even run from the same power supply).
If you come across one, I would be very appreciative of a link. I've been searching ebay, Aliexpress, banggood, etc. plus trawling forum posts & Google image searches & simply cannot find any cheap, DC powered 2.1 crossover at all.
I'm using an old dbx 223xl at the moment, but I'm trying to downsize from 19" rack equipment!
Yes, I've been thinking about a Behringer CX2310 but even a 1U rack is a bit of lump compared to the size of these amps.
This one at least has the power supply on it so all it needs is a transformer: Linkwitz-Riley Crossover 3-Way Electronic PCB Board Replacement Craft Tool 1 Pc 6086083950832 | eBay
The little 2.1 board does an acceptable job for the money if your stereo speakers don't go very low. Maybe a simple fixed 6dB high pass could be bodged onto it: RC High-pass Filter Design Tool
My filter & three of £3.37 amp modules arrived today, much sooner than I was expecting! The thermal adhesive on one of the amp modules failed & the heatsink was loose, so I'll have to reattach that. The solid capacitors are labelled 'Elna' but somehow I doubt they're legit considering the price...
