LM1875 or TDA7498 For good clean sound (Boards shown in the post)

[r_kalar_2]

I have already orderd following TDA7498 Board. But I am not sure it will reach me or not.
Aiyima TDA7498 Amplifiers Digital Stereo Power Audio Amplifier Board 2X100W Amplificador Dual Channel Speaker Impedance 8 ohms-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group

Now I am planning to get the following LM1875 board. Any one have any experience with it? Or does it have any major problem?
Free Shipping!!! CG / LM1875 lower distortion and more resistant to listen / amplifier board /Electronic Component-in Integrated Circuits from Electronic Components & Supplies on Aliexpress.com | Alibaba Group

I want 20-30w clean power. Which of those boards will be better? If you have any other suggestions, please mention it. Thanks.

Edit: I have ordered the following board.
Aiyima Classic LM1875 20W+20W Audio Power Amplifier Board With Speaker Protection Warm Sound Bile Fever Circuit DIY KITS-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group

Pictures of the boards.

 

[AndrewT]

There are dozens, no thousands of Threads mentioning lm1875.
Did you look at any?

 

[r_kalar_2]

Yes, I have read and am reading. But my questions is about this board particularly. Looks like they have regulated the supply. Is it good or bad for lm1875? And, again how do you rate lm1875 against a class d ic like tda7498? I haven't found till now any detailed comparison between two.

 

[Fast Eddie D]

I haven't found till now any detailed comparison between two.

That's because it's silly to compare a digital amplifier to a legacy device like the 1875. Although similar in application they're completely different.

It's like comparing a 1962 Maserati to a Prius. The comparison is nonsensical. Both can get you from point A to point B, both have unique and valuable virtues, but the comparison doesn't tell us anything useful.

 

[r_kalar_2]

I am not asking about technology. I am asking about your experience. My title clearly stated 'for good clean sound'. It's upto you if you want to share your experience or not, or share your view about that particular lm1875 boards. Thanks.

 

[FauxFrench]

My a priori expectation would be that the LM1875 will win moderately because it has a THD of 0.015% while the TDA7498 0.1%. You are explicit about "clean sound" and class AB normally has a better THD in the mid- and high range. TDA7498 is a well performing chip and may offer better bass punch.
Questions about "what sounds best" are always facing very subjective replies.

 

[adason]

Op do not forget that result depends mainly on the speakers you will be driving.
Lm1875 does not like low impedance, so if your speakers misbehave and have dips to too low resistance, it will distort. Your fault. Otherwise it may sing beautifully.

 

[r_kalar_2]

Thanks FauxFrench and Adason. My speaker is rated at 8 ohm. So, there shouldn't be any problem. I have decided to buy the kit. But, my concern is if the IC is original or not.

 

[asuslover]

Yes, I have read and am reading. But my questions is about this board particularly. Looks like they have regulated the supply. Is it good or bad for lm1875? And, again how do you rate lm1875 against a class d ic like tda7498? I haven't found till now any detailed comparison between two.

this lm1875 board does not have regulated power supply, at least not for the power ics.

 

[taita]

I received two Aiyama tda7498's yesterday. I connected one of them on a cheap smps 240W 24V power supply and a pear of two way speakers I just finished. The sound is very easy and effortless. Very good detail and a massive bass. Good stereo image and focus as well, so I'm quite confident. Astonishing how much value for a couple of euro's. I intend to use them for a 2 or 3 way active system. Hopefully they keep playing (I had a failing Sure amplifier earlier).

 

[r_kalar_2]

this lm1875 board does not have regulated power supply, at least not for the power ics.

The board has one MC 7812CT regulator. See attached images.
Following is an updated board according to them. It also has that regulator.
Aiyima Classic LM1875 20W+20W Audio Power Amplifier Board With Speaker Protection Warm Sound Bile Fever Circuit DIY KITS-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group

 

[r_kalar_2]

I received two Aiyama tda7498's yesterday. I connected one of them on a cheap smps 240W 24V power supply and a pear of two way speakers I just finished. The sound is very easy and effortless. Very good detail and a massive bass. Good stereo image and focus as well, so I'm quite confident. Astonishing how much value for a couple of euro's. I intend to use them for a 2 or 3 way active system. Hopefully they keep playing (I had a failing Sure amplifier earlier).

I have also heard very good things about this board. I think my speaker will be the limitation to hear any difference between lm1875 and tda7498. Still I want to try these out and will keep the one I like most.

 

[FauxFrench]

I received two Aiyama tda7498's yesterday. I connected one of them on a cheap smps 240W 24V power supply and a pear of two way speakers I just finished. The sound is very easy and effortless. Very good detail and a massive bass. Good stereo image and focus as well, so I'm quite confident. Astonishing how much value for a couple of euro's. I intend to use them for a 2 or 3 way active system. Hopefully they keep playing (I had a failing Sure amplifier earlier).

I am very happy that you are pleased with your TDA7498. Yes, it is amazing how much you get for very little money. I know you have two defect SURE amplifiers.
I have bought more than 20 class D amplifiers from the cheapest suppliers and they all work (one I haven't tested yet because the onboard power supply is designed such that the supply range is narrow and does not fit my current power supplies). You have been particularly unfortunate with your Sure amplifiers.
Be aware that a class D amplifier may be destroyed by not operating with a loudspeaker load (or a similar dummy load). This is not an issue for class AB amplifiers.

 

[Mark Whitney]

The board has one MC 7812CT regulator. See attached images.
Following is an updated board according to them. It also has that regulator.
Aiyima Classic LM1875 20W+20W Audio Power Amplifier Board With Speaker Protection Warm Sound Bile Fever Circuit DIY KITS-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group

The 12V regulator is probably for the speaker protection circuit. Now you need the right transformer.

 

[r_kalar_2]

I have a dual rail 18V 2A transformer laying around. Though it's not a toroidal one. I'll buy one if needed.
Edit: Multimeter shows 20v. I think it will be ok.

 

[AndrewT]

The kit in post 11 says transformer to be dual 12V to dual 22V and then explains

(Referring to the Transformer output voltage, such as 18V-0-18V)

To me that means you can use upto 22Vac-0-22Vac as the supply transformer.
Your 18Vac is well inside that maximum and your open circuit voltage is also below the maximum.

It would be worth Emailing Ali and asking them to confirm the ambiguous dual 22V. Is that Dual 22Vac or dual 22Vdc?

 

[AndrewT]

I have a dual rail 18V 2A transformer laying around. Though it's not a toroidal one. I'll buy one if needed.
Edit: Multimeter shows 20v. I think it will be ok.

a small EI transformer rated @ dual 18Vac 2Aac will have a much higher regulation than you are measuring.
Expect regulation around the 20% value. This will give an output voltage of:
Vout = Mains voltage / Rated primary voltage * rated secondary voltage * (1+regulation)
If you feed in a mains voltage that equals the rated primary voltage the output is likely to be around 18*1.20 = 21.6Vac
If you feed in mains at maximum tolerance, the secondary voltage will be higher.

 

[r_kalar_2]

Yes, 22v ac for sure. Yes, The transformer is a small ei one. Probably I have to replace it once everything else are sorted out.

 

[r_kalar_2]

This is the picture of the transformer. I think the size is ok for a 18v transformer.

 

[AndrewT]

It's an older 240Vac transformer which is 10Vac higher, than a modern 230Vac designed for the harmonised EU mains supply. This reduces the maximum voltage when mains is at highest tolerance.