Really, this thread was about complete chip amp kits.
But it became a little side tracked.
In conclusion, all I can say is that there a good and bad guys selling their stuff, you ask around or take a chance.
And for less than $50 at risk, it is pocket change for most of us.
Enjoy the music, and share your experiences so that others can benefit.
But it became a little side tracked.
In conclusion, all I can say is that there a good and bad guys selling their stuff, you ask around or take a chance.
And for less than $50 at risk, it is pocket change for most of us.
Enjoy the music, and share your experiences so that others can benefit.
Do you think a reputed vendor like Digikey sells counterfeit products? I don't think so. I always buy op-amp, semiconductors from reputed sellers like mouser, element14 and they never disappoint me.
Branded copy?! The only well known semiconductor company manufacturing LM1875 other than TI is UTC(taiwan) and is not available here in india.
That's not relevant here.
I didn't hijack this thread. This thread is about headphone amplifiers not about lm1875 authenticity.
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Audio Power Amp_华润微电子欢迎您
Audio Power OpAmps | Amplifiers | LCSC.com
These people are integrated makers from wafer stage silicon, and the MW brand is well known here along with the 3 triangle brand.
Overall, China Resources holdings has more than 400,000 employees, mostly not in electronics.
Put simply, they did not get big by selling dodgy stuff.
Audio Power OpAmps | Amplifiers | LCSC.com
These people are integrated makers from wafer stage silicon, and the MW brand is well known here along with the 3 triangle brand.
Overall, China Resources holdings has more than 400,000 employees, mostly not in electronics.
Put simply, they did not get big by selling dodgy stuff.
I was commenting about a photo posted by jbau in that the shape was different, not that it was authentic or fake.
I never said that it was a fake.
Anyway, here kits are available from Delhi, at least 2 suppliers offer Chinese and Keltron capacitors, and do not say if their chips are genuine or not.
Also, remember please that in India most people have concrete plastered walls, and in a 150 square foot room, 10 watts total audio off both channels is loud enough, at least for me.
So 2030 or 1875 is enough, 3886 is too much.
ST got the 2030 designs, rights, whatever from Philips, both have stopped making them, so UTC or others are the only choices,
And if you look at the watts vs. supply voltage graphs, at up to +/- 24 volts the 1875 and 2050 are similar, and at +/- 15 volts there is little difference in 1875 and 2030.
Price wise the Chinese chips are similar, and the 1875 can take up to +/- 32 volts, I would stay around +/- 27 on a genuine one.
At that point, the output is quite high.
So it becomes your choice, to build a genuine amp, taking four hours, or buying a pre-assembled kit for one third the price, for use in a medium sized room.
I would ask you to assemble the circuit and see how it performs against the older versions which you also have, and tell us if there is a change in performance.
I never said that it was a fake.
Anyway, here kits are available from Delhi, at least 2 suppliers offer Chinese and Keltron capacitors, and do not say if their chips are genuine or not.
Also, remember please that in India most people have concrete plastered walls, and in a 150 square foot room, 10 watts total audio off both channels is loud enough, at least for me.
So 2030 or 1875 is enough, 3886 is too much.
ST got the 2030 designs, rights, whatever from Philips, both have stopped making them, so UTC or others are the only choices,
And if you look at the watts vs. supply voltage graphs, at up to +/- 24 volts the 1875 and 2050 are similar, and at +/- 15 volts there is little difference in 1875 and 2030.
Price wise the Chinese chips are similar, and the 1875 can take up to +/- 32 volts, I would stay around +/- 27 on a genuine one.
At that point, the output is quite high.
So it becomes your choice, to build a genuine amp, taking four hours, or buying a pre-assembled kit for one third the price, for use in a medium sized room.
I would ask you to assemble the circuit and see how it performs against the older versions which you also have, and tell us if there is a change in performance.
Only $2.4 for a complete hifi 1875 kit! Strange isn't it?
It looks definitely fake to me.
20W LM1875T HiFi Stereo Player DIY Audio Amplifier Board Kit Power Mono Channel | eBay
It looks definitely fake to me.
20W LM1875T HiFi Stereo Player DIY Audio Amplifier Board Kit Power Mono Channel | eBay
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TDA2030A Audio Power Amplifier Module buy online at Low Price in India - ElectronicsComp.com
Rupees 98 + 18% GST
Fully assembled 2030A board, says 18 watts output.
That is about 1.6 US Dollars, in India.
Enjoy
Rupees 98 + 18% GST
Fully assembled 2030A board, says 18 watts output.
That is about 1.6 US Dollars, in India.
Enjoy
This is a sample of what is available in India
The picture has a ST chip, at that price I would not say anything about fake or real.
But it works, don't expect too much.
No, I did not buy it and try.
But these good quality chips are available, may not be ST, I can't say either way.
The picture has a ST chip, at that price I would not say anything about fake or real.
But it works, don't expect too much.
No, I did not buy it and try.
But these good quality chips are available, may not be ST, I can't say either way.
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TDA2030 IC - 18W Hi-Fi Audio Power Amplifier IC Package buy online at Low Price in India - ElectronicsComp.com
ST China marked TDA 2030A for 82 Rupees, that is a realistic price...1.10 USD
NS marked LM3886 for 295 Rupees, about US $4.00
ST China marked TDA 2030A for 82 Rupees, that is a realistic price...1.10 USD
NS marked LM3886 for 295 Rupees, about US $4.00
The question remaining unanswered is, what happens when the amp gain is lowered below the recommended 21X (26.4dB) ? Is the amp stable?
I cut the gain in half on one channel using 20k/2k2 feedback R's for 10X (20dB), and made measurements. No sign of instability on square wave edges. See noise/distortion graphs below showing the amp at 21x and at 10x, same conditions except raising the rails to 16.2V (note different vertical scales...).
At 10X, noise floor (predictably) drops by 5dB across the board. H2 is up by 2dB, but H3 drops by 9dB. Higher harmonics are all down. So yes, I'd say it is worthwhile doing. I'll listen later, and try dropping it a bit more tomorrow.
I cut the gain in half on one channel using 20k/2k2 feedback R's for 10X (20dB), and made measurements. No sign of instability on square wave edges. See noise/distortion graphs below showing the amp at 21x and at 10x, same conditions except raising the rails to 16.2V (note different vertical scales...).
At 10X, noise floor (predictably) drops by 5dB across the board. H2 is up by 2dB, but H3 drops by 9dB. Higher harmonics are all down. So yes, I'd say it is worthwhile doing. I'll listen later, and try dropping it a bit more tomorrow.
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Listening tests last night were excellent. Better overall than the JLH variant I'm working on.
Today I looked into lowering the gain further. In doing so, one consideration is the impedance matching at the amp inputs. With a 10k pot, the + input will see a source ranging from near-zero to 2.5k at the pot's -6dB point. So I think 2.5k is the maximum we would want to use as the feedback shunt R. That results in a gain of 9.
I changed one channel and remeasured. Transient response is still clean, and the amp is still stable. The distortion improved significantly; both H2 and H3 sitting right around -100dBr! I think most of this is due to the impedance matching and not the 1dB drop in gain. Either way, these are excellent results. Should sound great. And it gives a very high bar for the JLH project to reach!
Today I looked into lowering the gain further. In doing so, one consideration is the impedance matching at the amp inputs. With a 10k pot, the + input will see a source ranging from near-zero to 2.5k at the pot's -6dB point. So I think 2.5k is the maximum we would want to use as the feedback shunt R. That results in a gain of 9.
I changed one channel and remeasured. Transient response is still clean, and the amp is still stable. The distortion improved significantly; both H2 and H3 sitting right around -100dBr! I think most of this is due to the impedance matching and not the 1dB drop in gain. Either way, these are excellent results. Should sound great. And it gives a very high bar for the JLH project to reach!
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why shady sites ? Hit RS Components India
https://in.rsdelivers.com/product/t...truments20w-5-pin-to-220-lm1875t-nopb/5358736
I did not know ElectronicsComp was a shady site.
Never dealt with RS India, they tend to be more expensive in total cost compared to Mouser, in that you pay for packing and freight too, so for each part you have to consider that also.
A friend finds it cheaper to buy avalanche diodes from Mouser USA and have the material shipped in a FedEx standard box, than buy in India from Mouser.
Anyway, I buy local, as I tend to do repairs rather than buy in bulk quantities.
So my choice is limited to what is needed for repair.
Never dealt with RS India, they tend to be more expensive in total cost compared to Mouser, in that you pay for packing and freight too, so for each part you have to consider that also.
A friend finds it cheaper to buy avalanche diodes from Mouser USA and have the material shipped in a FedEx standard box, than buy in India from Mouser.
Anyway, I buy local, as I tend to do repairs rather than buy in bulk quantities.
So my choice is limited to what is needed for repair.
Lm3886 costs Rs250 each(US $3.5) here in kolkata (India). Genuine tl074, tl072, ne5532, 7815/7915, lm317/337 costs Rs10-20 Each (US $0.25). So most of the time i buy from local component dealers(offline). RS components provides excellent service but you have to buy most components in bulk quantities.
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LM 3886 over Rs. 500 each on RS India, compared to the counter delivery at a shop for Rs. 250.
So unless you are in a remote location, they are expensive.
LM1875 Rs. 282 GST paid each at RS, Mouser is 161 plus 18 % GST for the same item...I do not know the Mouser charges for freight.
So it boils down to the landed price comparison, and RS has a history of being expensive, at least anecdotally.
My usual parts buy is less than Rs. 500, so I am simply going to buy local, as I get to pay about half, and get immediate delivery, as RS ships their stuff from Delhi area, 1000 kilometers away...
RS may be popular in New Zealand, but at least here the preference is for others.
So unless you are in a remote location, they are expensive.
LM1875 Rs. 282 GST paid each at RS, Mouser is 161 plus 18 % GST for the same item...I do not know the Mouser charges for freight.
So it boils down to the landed price comparison, and RS has a history of being expensive, at least anecdotally.
My usual parts buy is less than Rs. 500, so I am simply going to buy local, as I get to pay about half, and get immediate delivery, as RS ships their stuff from Delhi area, 1000 kilometers away...
RS may be popular in New Zealand, but at least here the preference is for others.
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