Class D single power upgrade product. CLASS AB DC12-18V 50W 4R 4channel TDA7850

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ljm_ljm

Member
Joined 2006
#1
I always publish something unpleasant.
I'm sorry for this first. But isn't all ascension the result of comparison.
I think I should stand up and tell others.
Class AB dc12-18v amplifier. Very cheap. It's simple. Maybe it will last for a year. It will pay an extra $0.5 for electricity.
I've heard of it. Many people use the tda7850 to upgrade the class D amplifier that comes with their cars.
The result is a big improvement. I think home should also be OK. I found that many people use dc12-18v DC power supply to make household amplifiers.
It is much better than tpa3116. I think it also exceeds tpa3255 or ma12070
The total cost of the amplifier is less than $10.
It includes 4 channel amplifiers.

The TDA7850 is a breakthrough MOSFET
technology class AB audio power amplifier in
Flexiwatt 25 package designed for high power car
radio. The fully complementary P-Channel/NChannel output structure allows a rail to rail
output voltage swing which, combined with high
output current and minimized saturation losses
sets new power references in the car-radio field,
with unparalleled distortion performances.
The TDA7850 integrates a DC offset detector
DC supply voltage 12-18V
Max. output power VS = 14.4 V; RL = 4 R 50W
,VS = 14.4 V; RL = 2R, 85W
THD Distortion Po = 4W 0.006%。 Po = 15W; RL = 2R 0.015%
SVR Supply voltage rejection f = 100 Hz; Vr = 1Vrms 75DB
 

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#5
CharlieLaub said:
Both the TDA7850 and TPA3116 are not very good. Why waste your time with them?
Click to expand...
You're right. I also know to use dual voltage. The amplifier will be better.
For example, I have seen the lm4702 amplifier that can achieve the lowest distortion under DIY conditions.
Or other discrete component amplifiers.
But there are some use occasions. Such as cars. Or only some charger power supply. But people who need to make amplifiers. Only DC12V amplifier is selected.
Relatively speaking, the performance of tda7850 is better than that of tpa3116. The price is cheaper. (very few components. Very simple)
It's more powerful, and it has four channels
 
#6
ljm_ljm said:
But there are some use occasions. Such as cars. Or only some charger power supply. But people who need to make amplifiers. Only DC12V amplifier is selected.
It's more powerful, and it has four channels
Click to expand...
You are right though, it can be a good alternative to the tpa3116 in automotive applications, especially because it has 4 channels (for 4 door speakers). However I personally don't think it is really a good choice in home audio unless you are trying to power a pair of bookshelf speakers biamped and using a active high pass/low pass filter before the input of the amplifier. It could work in low power applications with high sensitivity speakers but there are better options for home audio especially where input voltage doesn't matter.

For example, the TPA3116 has a higher input voltage (around 21 to 24V) because it could put out more power before distortion. The tda7850 is rated 30W 4Ohms at 10% distortion (which is very bad) and only 55W at 2Ohms (again at 10% distortion). The TPA3116 can put out 50W at 4 Ohms because of the higher rail voltage. It is always a good idea to look at the Output power vs. supply voltage graphs rather than looking at the advertised output.
 
#9
ljm_ljm said:
...tda7850 ... is much better than tpa3116.

THD Distortion Po = 4W 0.006%。
Click to expand...

TDA7850 and TPA3116 are not comparable at all - they are designed for different voltage supplies in mind.

TDA7850 is designed for cars, for low voltage supply up to max 15 Vdc. Maximum power output with 14.4 V supply is 23W/4ohm with 1% THD.

TPA3116 is designed for higher voltage supply, up to max 25 Vdc. Maximum power output with 24 V supply is 60W/4ohm with 1% THD. At 4W output, THD = 0.02%.
You can use it with 14.4 V supply and in that case maximum power output will be 22W/4ohm with 1% THD - but why would you use voltage supply much lower than optimal?

TDA7850 has lower THD than TPA3116 (0.006% vs 0.02%, at 4W output) and maybe has better sound quality, but also has much lower maximum power output (23W vs 60W).
 
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#11
Con: Price for 4 x LM3886 is much higher than 1 x TDA7850, also need dual voltage pover supply.
Pro: 4 x LM3886 can output 4 x 68W/4ohm, 1 x TDA7850 can output 4 x 23W/4ohm.

TDA7850 is voltage supply limited, bu it and can work with 2 ohm loads.
LM3886 is output current limited, so in reality can output max 40 W at 4 ohm loads.
 
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#14
EUVL said:
So you want low distortion, or low cost ?


Patrick
Click to expand...
This was always the most deceptive question in everything, not just audiophooling.
Kenwood ka-1000 cost at its release in Germany in 1980 was 500 DM, about 300 dollars...It sold very poorely cause Mark Levinson was a few good thousands bucks and reviewers and bussiness guys's margins were too low on 300 bucks products.
Today , when we have a purely technical review of that amp , we fully understand why, after decades of selling mega quality products for 10 times cheaper than the top dog audiophooling competition , kenwood dumped their manufacturing to Accuphase which improved the sellers margin by 3...10 fold over the competition! They only needed some champagne paint on their amps mimiquing Luxman while using sometimes even cheaper or more common components and designs than old good Kenwoods.
Last time I saw a technical review on Ka-1000 they couldn't measure its distortions on AP equipment below 50 watts...and that was a 1980 product which measured 3 times higher distortions than the top Kenwood products sold in Japan.
Apparently amps with much higher thd like Accuphase sold for 10...100 times more money....
I don't have great philosophical expectations from a guy selling discrete op amps in 2022 though!
In 2022 we generally see 10 fold lower quality products than the top ones of the 80's selling for 10...100 times more money.
Keep up the good work on fooling people with cheap universal trading quotes and the diy community will love you!
 
#15
thebiasbios said:
You are right though, it can be a good alternative to the tpa3116 in automotive applications, especially because it has 4 channels (for 4 door speakers). However I personally don't think it is really a good choice in home audio unless you are trying to power a pair of bookshelf speakers biamped and using a active high pass/low pass filter before the input of the amplifier. It could work in low power applications with high sensitivity speakers but there are better options for home audio especially where input voltage doesn't matter.

For example, the TPA3116 has a higher input voltage (around 21 to 24V) because it could put out more power before distortion. The tda7850 is rated 30W 4Ohms at 10% distortion (which is very bad) and only 55W at 2Ohms (again at 10% distortion). The TPA3116 can put out 50W at 4 Ohms because of the higher rail voltage. It is always a good idea to look at the Output power vs. supply voltage graphs rather than looking at the advertised output.
Click to expand...

:wave:

"Low power applications with high sensitivity speakers", and active filters as you wrote, is what I'm after. I watched this review and I think that the disappointing distortion that the author found was what the datasheet predicted for the watts he was measuring. ≈ 13.3W and ≈ 1% at 4Ω and 12v PSU. So this is a great data-point.

View attachment 1165791

I need at most 7w from the amp for every channel. Drivers with Re 4Ω and 6Ω.

I was looking at the TDA7297 but I think the chips they sell here are fake, way too cheap. I ordered this one at 13.53USD, hopefully it works well 🤞Pretty excited about testing an A/B amp.

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