Perhaps its time to post on the manufacturers forum?If you're wiring a point to point TDA7297 chip...
I prefer to run a PG connection to connect on the wire headed to the SG pin from the SG input, but I connect the PG wire before the capacitors.
Yes I know it sounds weird, but the amplifier sounds better this way.
If you want to buy a PCB from me I have a few right now. PM me if you like. (free BC337 with board)
Bridged? Mono-Block? Balanced?
I have several of these lunch money amps. Some are bone stock, most have Upgraded caps and pot removed.
I have converted a pair of IEMs to balanced for use with my Pono player. The
results are impressive.
Now I would like to try balanced mode using a separate amp for each channel. I'm open to suggestions as to how to utilize a pair of these amps as mono-blocks in balanced mode.
The subs are powered by iNuke 1000dsp that has a balanced mode.
I have several of these lunch money amps. Some are bone stock, most have Upgraded caps and pot removed.
I have converted a pair of IEMs to balanced for use with my Pono player. The
results are impressive.
Now I would like to try balanced mode using a separate amp for each channel. I'm open to suggestions as to how to utilize a pair of these amps as mono-blocks in balanced mode.
The subs are powered by iNuke 1000dsp that has a balanced mode.
There's no point. You can't bridge a bridged amplifier, first off. Second if you parallel the channels it may decrease actual sound quality a little bit at the price of maybe no power gain.
Lastly, they separate units are not going to be much of an increase in quality.
Your best upgrade would be a better PSU for the current boards you posses. Well and a STMico chip instead of reject chip.
I'd like to address this perseverant fuss over the "fake" vs. "real" componentry.
I constantly see references to "fake chips" or "fake caps" here.
Is this a wild assumption? Or are there facts? Now, I do remember someone taking photos of one capacitor vs. another and pointing out differences in printing, etc.
Just because a company like Mouser or Digikey sells a product doesn't mean it couldn't be questionable. And just because something from say Nichicon or STMicro appears slightly different doesn't necessarily make it "fake". They could have contracted a different manufacturer to fabricate it and hence the difference.
Of course, I'm not dumb and do recognize knock-offs are part of the way Asia, Inc. operates and I suppose other countries as well. And I'm not being critical of any one person, so please get that out of your heads. (I haven't paid attention to who has or has not made these statements.)
But I think this "fake" vs. "real" talk should be based on facts and not be just loose talk.
Mark
I constantly see references to "fake chips" or "fake caps" here.
Is this a wild assumption? Or are there facts? Now, I do remember someone taking photos of one capacitor vs. another and pointing out differences in printing, etc.
Just because a company like Mouser or Digikey sells a product doesn't mean it couldn't be questionable. And just because something from say Nichicon or STMicro appears slightly different doesn't necessarily make it "fake". They could have contracted a different manufacturer to fabricate it and hence the difference.
Of course, I'm not dumb and do recognize knock-offs are part of the way Asia, Inc. operates and I suppose other countries as well. And I'm not being critical of any one person, so please get that out of your heads. (I haven't paid attention to who has or has not made these statements.)
But I think this "fake" vs. "real" talk should be based on facts and not be just loose talk.
Mark
I broke a few transistors and the fake ones have a smaller die (usually).
The discussion is not really on fake parts, rather on those that did not meet the producer's standard. Some say that instead of discarding to the trash, they sell them cheap to get back some of the cost.
This way it makes sense why someone could make money with a 2$ populated pcb amp, while only one chip is more expensive than that on the normal market.
The discussion is not really on fake parts, rather on those that did not meet the producer's standard. Some say that instead of discarding to the trash, they sell them cheap to get back some of the cost.
This way it makes sense why someone could make money with a 2$ populated pcb amp, while only one chip is more expensive than that on the normal market.
Mouser and Digikey can only guarantee the products they sell 1st time. They accept returns, and there some fakes can/will enter their sales channel, if they decide to sell these returned products like any other.
So yes, nothing is certain these days. US government defence department warehouses are full of fake parts, you might have seen documentaries about that.
So yes, nothing is certain these days. US government defence department warehouses are full of fake parts, you might have seen documentaries about that.
Well that's the thing, they are made by the producer, they are the same as the "original" ones.
I think price should be the main area to look out for, and also a reliable supplier.
I would not trust ebay for this.
Even so, one could get a few and get an ideea on the chip, but if you want to create something nice, instead of dumping cash in caps and whatnot, you're better off with a good pcb design, new chip and whatever caps you wish. This has higher chances of wielding better results.
The price difference tells us something.
But really the fact that the ones on Ebay go bad from rated voltage specifications being applied, from the PDF, should be plenty. They've even lowered the input voltage in their ads.
A clear indication would be that they aren't overheating when they go, as well.
Probably all of the ones on eBay where meant for something such as TV's being made in China, but didn't pass inspection.
I see no sense in wanting to fake a $2 chip, the setup cost involved would make it a ridiculous venture. The idea that somehow reject chips get funnelled to those board producers selling on Ebay is just as ridiculous. I think someone is trying to drum up business by trashing what most are quite happy with.
These little chips burn out because you guys are trying to driving inefficient 4 Ohm speakers at hifi levels, it has nothing to do with voltage.
My lunch money amp, can drive my vintage, very efficient 15 Ohm speakers with 18v and the chip remains cool. Switching to a smaller pair of less efficient 6 Ohm speakers, the chip get quite hot.
One can diddle around with all sorts of configurations of board layout but there is no escaping that the chip can only supply a few watts of power before distortion set in.
These little chips burn out because you guys are trying to driving inefficient 4 Ohm speakers at hifi levels, it has nothing to do with voltage.
My lunch money amp, can drive my vintage, very efficient 15 Ohm speakers with 18v and the chip remains cool. Switching to a smaller pair of less efficient 6 Ohm speakers, the chip get quite hot.
One can diddle around with all sorts of configurations of board layout but there is no escaping that the chip can only supply a few watts of power before distortion set in.
I have no business in this area...
Also to be honest I didn't even mess with the original chip. It's not worth my time. For 2.5-4$ for a legit one.
Could it be the chip is long redundant and the surplus is being sold off cheap because they are no longer used in TV's? The ST technical document was issued in 2003 and states the 7297 chip was developed for TV and portable radio applications. Now, 2003 was well before we all got our large screen digital surround sound TV's.
The ST technical document also states that at 15W there is a 10% THD and at 5W the THD is 1% and at 1 watt the THD is .1%. So taking the hifi standard, anything above 1% THD is not high fidelity.
How many modern speakers can happily rock with 5W?
It's 100% normal for different companies to purchase dies for different semiconductors and manufacture them. You can buy this service if you want to. Also who knows where the chips are from, TV is a speculation, maybe hundreds of thousands of boomboxes only sold in Asia were the original reason for someone other than STMicro to make chips.
No matter what the case in China happens to be, they aren't the same. And, Radiosmuck, if you're making a sly one at me I'll let you know I've sold 9x boards that were leftover from a build (at a discount, too). There is no business venture. There's a failed IndieGoGo. Originally there were requests for a kit but so far I've spent my own money without a return, and I've made multiple modding guides. Please stop your unwarranted jabs. If you're satisfied please let everyone else whom enjoys discussion and modifications continue without a guilt trip.
For the record, despite the distortion figures, it sounds flat out awesome. Yes it's limited, yes 15w isn't that high. Perhaps Radioschmuck you should take a look/closer look at the review I posted, using a TDA7297. But to note, we often listen at 1-2w, even if a peak can hit 200w at the same level.
No matter what the case in China happens to be, they aren't the same. And, Radiosmuck, if you're making a sly one at me I'll let you know I've sold 9x boards that were leftover from a build (at a discount, too). There is no business venture. There's a failed IndieGoGo. Originally there were requests for a kit but so far I've spent my own money without a return, and I've made multiple modding guides. Please stop your unwarranted jabs. If you're satisfied please let everyone else whom enjoys discussion and modifications continue without a guilt trip.
For the record, despite the distortion figures, it sounds flat out awesome. Yes it's limited, yes 15w isn't that high. Perhaps Radioschmuck you should take a look/closer look at the review I posted, using a TDA7297. But to note, we often listen at 1-2w, even if a peak can hit 200w at the same level.
Hi Guys
Just wonder if anyone has any opinions on this board with 2 caps high power AC/DC 2-channel amplifier Stereo audio amp boardD class pwm TDA7297 | eBay
Simon
Just wonder if anyone has any opinions on this board with 2 caps high power AC/DC 2-channel amplifier Stereo audio amp boardD class pwm TDA7297 | eBay
Simon
Do you guys know if the TDA7297 runs in pure class A if we keep the power output low, say below 650mW? I have heard that class AB amps run in class A at low power. The reason I ask is that if I want to use this as a headphone amp, could it work as a class A amp? Perhaps transformers might be needed but I am pretty sure a 32ohm headphone would be able to eek 500mW out of this.
I have a feeling it won't care what the ohm level is... It doesn't care about impedance drive load of any 4 or 8 ohm speaker I've put it on. "Current hungry" or not.
But, I'd also say who cares if it stays in class A because the sounds is so good... It sounds closer to class A than most AB amps in a lot of its characteristics.
That new one from China looks like it might have a better chip. Sadly the diodes are going to be bad. But this looks like a better option for a few mods.
But, I'd also say who cares if it stays in class A because the sounds is so good... It sounds closer to class A than most AB amps in a lot of its characteristics.
That new one from China looks like it might have a better chip. Sadly the diodes are going to be bad. But this looks like a better option for a few mods.