My A04's overall volume seems to be getting abit lower for both channels(not by much, may be 10% at given position of pot), after a few hrs of burn-in.
I checked, both channels working, all caps seems ok except one of the 2200uf feels slightly bulged. (never checked as new kit, so am not sure it's like that from beginning or i am feeling placebo about bulging)
Will it cause the volume to go down? or will there be any other cause?
I checked, both channels working, all caps seems ok except one of the 2200uf feels slightly bulged. (never checked as new kit, so am not sure it's like that from beginning or i am feeling placebo about bulging)
Will it cause the volume to go down? or will there be any other cause?
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Thank you for the reply bushellj. I'll have to try to find one premade or are there other OPA recommendations? I have updated my profile, I am in US.
Hi,
When I reviewed my TPA3251 based on 360 Customs implementation, I noticed a 30% difference in volume with my Aiyima. With a good clean implementation and PFFB eneabled; the TPA3251 is really excellent.
With that implementation worthy of the name, it is neck and neck with my Hypex Ncore and my double Mono Pascal (which are worth a lot more)
I have two Aiyima A04's, is there any clear proof that PFFB is used in this product?
Toku said:
No PFFB on Aiyima or any known TPA32XX Chinese Amplifier.
As I explained, PFFB is used only on high ends TPA32XX (XRK Audio / 360 Customs for instance).
Benefits of PFFB is described and measured here :
https://www.ti.com/lit/an/slaa788a/slaa788a.pdf
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Just as a side note...
I guess those doing it know it already, but just in case...
It is not because you turn the potentiomter to max (and modulate the volume elsewhere or not) that you do bypass the poor volume pot. That's not the way a pot works.
In short, if it is true that these pots behave exceptionaly badly at low positions, they do still rob in term of music, stage, dynamic etc. at other volumes and also at max volume. In fact, you would need to take the pot off the unit and connect directly (or via resistors to adjust the load) to get things right.
I hope this helps
Claude
I guess those doing it know it already, but just in case...
It is not because you turn the potentiomter to max (and modulate the volume elsewhere or not) that you do bypass the poor volume pot. That's not the way a pot works.
In short, if it is true that these pots behave exceptionaly badly at low positions, they do still rob in term of music, stage, dynamic etc. at other volumes and also at max volume. In fact, you would need to take the pot off the unit and connect directly (or via resistors to adjust the load) to get things right.
I hope this helps
Claude
In the US, you can buy the chips quite cheaply from the major TI distributors - We get totally screwed in Europe with import duties and carriage costs !!
Maybe worth finding someone who could do the soldering for you and just purchase some of the Adapters (SOIC to DIL8/DIP8) off ebay.
Yes I had planned to order from Mouser but I don't think I'll be able to find someone to do the solder work if its not something you advise a beginner to do.
I may be able to source premade OPA1656 DIP8 for around $7 US, I am not sure if that is too much..
Does anyone have experience with OPA2134 with this amp? Are there any recommendations in a DIP8 package? I have seen others mentions AD827 and others but not sure what the consensus is.
I may be able to source premade OPA1656 DIP8 for around $7 US, I am not sure if that is too much..
Does anyone have experience with OPA2134 with this amp? Are there any recommendations in a DIP8 package? I have seen others mentions AD827 and others but not sure what the consensus is.
Would properly bypassing the poor potentiometer yield significant improvement? I don't believe anyone has tried this mod yet, I would be curious how it is done on this particular amp. Also, would bypassing the OP amps also produce further results?
Bypassing a poor potentiometer (or replacing it with a good one) makes a significant improvement with integrated amps and preamps, as outlined many many times "on this forum and elsewhere" but perhaps indeed not yet on this admittely not (yet?) very technicaly minded thread.
If you browse into other sections here you will find many infos regarding this topic, but also elsewhere on the net not to mention what manufacturers are doing in top line products to address this topic - Luxman with his top range being the more recent one (see LECUTA, a different approach to the same problem), but Accuphase and Pass are of course already "there"... as many others.
As of me, I played with various pots and reported last year on the results when I tweaked my Pass B1 Korg - and pots alone made a significant improvement.
I see no reason why this amp should be different as it has a similar volume control implementation, unless it would be sounding so bad that one wouldn't hear any differences to modifications, which it is clearly not. Admittely on low HIFI stuff you may pass on all that: too many bottlenecks to hope to improve significantly anything just replacing one item.
Re "would bypassing the OP amps also produce further results?" is quite a rhetoric question as OPAs (or a similar functioning more complex set up) would be required anyway to move on this amp from a non symmetrical signal at the input to the required symmetrical signal to feed the amp chip at his heart...
Having said that, if you have a symmetrical source output it is indeed quite easily feasible and we exposed how to do that already in this thread, enabling a quick and easy reversible try thanks to the OPAs sockets. Search function top right of this screen is your friend... but as you raised the question - hence me perhaps wrongly assuming your are not that experimented - may I humbly advise you to dig deeper into the topic to make sure you know what you are doing before grabing your soldering iron? If you are experimented or you digged into that topic meanwhile, then please ignore my last comment: my sole intention is just to protect you and your unit, nothing else
Have fun and good muck whatever you may go for
Claude
If you browse into other sections here you will find many infos regarding this topic, but also elsewhere on the net not to mention what manufacturers are doing in top line products to address this topic - Luxman with his top range being the more recent one (see LECUTA, a different approach to the same problem), but Accuphase and Pass are of course already "there"... as many others.
As of me, I played with various pots and reported last year on the results when I tweaked my Pass B1 Korg - and pots alone made a significant improvement.
I see no reason why this amp should be different as it has a similar volume control implementation, unless it would be sounding so bad that one wouldn't hear any differences to modifications, which it is clearly not. Admittely on low HIFI stuff you may pass on all that: too many bottlenecks to hope to improve significantly anything just replacing one item.
Re "would bypassing the OP amps also produce further results?" is quite a rhetoric question as OPAs (or a similar functioning more complex set up) would be required anyway to move on this amp from a non symmetrical signal at the input to the required symmetrical signal to feed the amp chip at his heart...
Having said that, if you have a symmetrical source output it is indeed quite easily feasible and we exposed how to do that already in this thread, enabling a quick and easy reversible try thanks to the OPAs sockets. Search function top right of this screen is your friend... but as you raised the question - hence me perhaps wrongly assuming your are not that experimented - may I humbly advise you to dig deeper into the topic to make sure you know what you are doing before grabing your soldering iron? If you are experimented or you digged into that topic meanwhile, then please ignore my last comment: my sole intention is just to protect you and your unit, nothing else
Have fun and good muck whatever you may go for
Claude
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Claude, thank you for your reply. As you have already assumed, I am not as versed as you in the specifics of diy amplifiers. My apologies if my questions were poor and gave the impression I was taking a hacksaw to the amp. My intentions were to dig deeper and ask questions on things I could not find a definitive answer to. You need not worry, I have already been steered away from the soldering iron by bushellj. I only wanted to know if it was a possibility in the future as I know the discussion about this amp will pass with time.
I do understand the frustration of senior users and the tendency to point at the search button.. but searching "bypass op amp" yields random results that is hard to narrow down. I've read about this being done on with other amplifiers and did not know if it applies here.
Again, thank you for the insight, it cleared up my questions.
I do understand the frustration of senior users and the tendency to point at the search button.. but searching "bypass op amp" yields random results that is hard to narrow down. I've read about this being done on with other amplifiers and did not know if it applies here.
Again, thank you for the insight, it cleared up my questions.
No prob at all asking, on the contrary, there is no poor question...and I am not wanting any senior position ;-)
Search has an advanced section where you can select posters and threads and so find posts by a given poster inside a specific thread - I find that quite useful and was in fact refering to that. I belueve Danyboun had a similar question as yours...
I will have to take 2 of these little amps apart for my friend in order to tweak them - now he has purchased them I guess I have no way back ;-)
I will have to dig deep inside them. If there is interest here, I may post my findings and mods, for whatever they are worth. Not saying it is the ultimate but the goal is to push the ball as much as reasonably acceptable. Might take some time though, quite busy at the moment and still on some of my very own HIFI projects since ages. But well, re this amp, OPA and pots are of course on the menu among other things and whatever I might discover inside and also hear...
Might give you some useful ideas on what to give a try... and on what not to waste any time if I did it already trying my luck
Claude
Search has an advanced section where you can select posters and threads and so find posts by a given poster inside a specific thread - I find that quite useful and was in fact refering to that. I belueve Danyboun had a similar question as yours...
I will have to take 2 of these little amps apart for my friend in order to tweak them - now he has purchased them I guess I have no way back ;-)
I will have to dig deep inside them. If there is interest here, I may post my findings and mods, for whatever they are worth. Not saying it is the ultimate but the goal is to push the ball as much as reasonably acceptable. Might take some time though, quite busy at the moment and still on some of my very own HIFI projects since ages. But well, re this amp, OPA and pots are of course on the menu among other things and whatever I might discover inside and also hear...
Might give you some useful ideas on what to give a try... and on what not to waste any time if I did it already trying my luck
Claude
I am certain there is plenty of interest of any findings you may come across. Many others not just myself would be excited for any results with mods on this amp. I've seen the inductors being replaced but no info regarding bypassing the pot. Switching out the pot has been discussed but size constraints seem to be an issue which led me to my question about the difficulty of bypassing it altogether.
Perhaps you could advise me on a mod that seems more on the introductory level. I've seen that some recommend replacing the wire from the amp to the binding posts. Do you recommend such a mod and if so, what materials should I be utilizing?
Perhaps you could advise me on a mod that seems more on the introductory level. I've seen that some recommend replacing the wire from the amp to the binding posts. Do you recommend such a mod and if so, what materials should I be utilizing?
The reason for your dissatisfaction with the volume POT is the adoption of the wrong characteristic standard.
The taper A logarithmic curve is used for the volume POT which adjusts the volume from old days. However, most Chinese products use a taper B linear characteristic POT for volume control POT.
Due to this, a sudden volume change at a low volume position and a gang error that causes a left-right volume difference are greatly amplified.
I sue for this every time I get the opportunity, but modern audiophiles don't really understand what this means.
The taper A logarithmic curve is used for the volume POT which adjusts the volume from old days. However, most Chinese products use a taper B linear characteristic POT for volume control POT.
Due to this, a sudden volume change at a low volume position and a gang error that causes a left-right volume difference are greatly amplified.
I sue for this every time I get the opportunity, but modern audiophiles don't really understand what this means.
I hope this post is not in response to my post, .as prentending to know better than I do what the causes of my own insatisafactions are... would require quite some supernatural skills ;-)
I am quite involved since several decades with audio and my pot comparison was just based on sonics from the 10am position on (see reasons why in the original report please) and judgement was done solely on sound quality on various items (see original report in B1K thread). Not on basics such as linear vs log response and channel imbalance probs were discarted "as much as the devices"would allow it" (say in their best range at fixed position) as another post buffer general volume control was used to adjust differences. Didn't change the conclusion though... and is not the topic here.
'Nough said, back to these amps," sadly" I will play with these devices with less constraints than most as the 2 amps will be incoporated in another existing housing, saving an old Pioneer amp somewhere, owner's nice wish. So I don't have to make parts fit inside the OEM casing. Note I could if I fancy it, and would probably like to as a challenge whenever it makes sens, but no clue if I will though yet - say it won't be my first concern anyway and wouldn't trade quality for space in my case.
For sure though I won't make the pot fit as it will have to control 2 amps so is better outside the units anyway. In my experience, if considering conventional pots, size does matter in most cases, so the better for me if I have plenty space and options left. We aren't settled on that, my friend wants some additional functions as remote control...
Having said that, the pot can be replaced in situ with a small one (Panasonic was suggested, never tried it, Alps and TDK are other possibilities not to mention volume chips solution à la Muses but these are $ and usualy require some space), possibly with some skills a bigger one could fit "arranging" the surrounding parts differently - thinking caps and connections mainly. Again, won't be my problem as my friend has different needs that lead us to other paths.
For those would could make with an external quality volume control, there is no harm simply taking the original pot completely out and connecting the required connections as if there would be no pot inside the unit. It seems the input of the following stage has a high enough impedance to allow that as AOP...
Regarding binding posts, that idea was by Rich, so whoever might ne interested better ask him.
If time allows, I will report once I am done and try to make things as clear as possible then... will take some time though until then...
Enjoy the summer
Claude
I am quite involved since several decades with audio and my pot comparison was just based on sonics from the 10am position on (see reasons why in the original report please) and judgement was done solely on sound quality on various items (see original report in B1K thread). Not on basics such as linear vs log response and channel imbalance probs were discarted "as much as the devices"would allow it" (say in their best range at fixed position) as another post buffer general volume control was used to adjust differences. Didn't change the conclusion though... and is not the topic here.
'Nough said, back to these amps," sadly" I will play with these devices with less constraints than most as the 2 amps will be incoporated in another existing housing, saving an old Pioneer amp somewhere, owner's nice wish. So I don't have to make parts fit inside the OEM casing. Note I could if I fancy it, and would probably like to as a challenge whenever it makes sens, but no clue if I will though yet - say it won't be my first concern anyway and wouldn't trade quality for space in my case.
For sure though I won't make the pot fit as it will have to control 2 amps so is better outside the units anyway. In my experience, if considering conventional pots, size does matter in most cases, so the better for me if I have plenty space and options left. We aren't settled on that, my friend wants some additional functions as remote control...
Having said that, the pot can be replaced in situ with a small one (Panasonic was suggested, never tried it, Alps and TDK are other possibilities not to mention volume chips solution à la Muses but these are $ and usualy require some space), possibly with some skills a bigger one could fit "arranging" the surrounding parts differently - thinking caps and connections mainly. Again, won't be my problem as my friend has different needs that lead us to other paths.
For those would could make with an external quality volume control, there is no harm simply taking the original pot completely out and connecting the required connections as if there would be no pot inside the unit. It seems the input of the following stage has a high enough impedance to allow that as AOP...
Regarding binding posts, that idea was by Rich, so whoever might ne interested better ask him.
If time allows, I will report once I am done and try to make things as clear as possible then... will take some time though until then...
Enjoy the summer
Claude
Is aiyima using original Ti opamps?
I have taken detailed pics of the Aiyima opamps vs Mouser originals. I used as much light as I could to highlight the difference. I am not a supply line expert on TI semiconductors so I cannot tell you if the marking codes are as expected (not made up).
Bottom line: to my eye they look fake, but there is no way to tell for sure without decasing and microscope inspections.
Marking are consistent on both units.
Machining marks are similar but it seems that the Mouser(Ti originals) are more refined that the Aiyima
Back stamping. Similar, not really a measurable difference.
Laser etching markings: fortune 500 companies spend fortunes promoting their brand and brand awareness. Logos should be consistent within products, marking should have the same logo and sizing and colors should match to a pantone accuracy. This is not the case
I have seen several pics of original TI products and the logo is shiny and very defined. The laser etching of the Aiyuma Ti op-amp follows a different path. Lines that are supposed to be straight are not. The logo and fonts are visibly darker and the thickness of the font lines and font separation is not the same. Logo is definitely not the same, tool-path for the laser is different and some lines are wrong (the end of Texas should be straight in Aiyima is crooked).That leads me to believe that they are counterfeit. Note that that was consistent on all the Aiyima and Mouser opamps
IC manufactures strive to a level of consistency and quality from fab to fab to make all the product match the look and performance regardless of the fab they were made. This is not the case. The markings are really different. I am not claiming that Aiyima is trying to fool their customer, as in today supply line is almost impossible (unless you pay the premium of tier one distributors) to get real originals. Me, I have return countless Intel CPU over the years as the marking were so bad that it was clear that they were polished and relabeled .
I have taken detailed pics of the Aiyima opamps vs Mouser originals. I used as much light as I could to highlight the difference. I am not a supply line expert on TI semiconductors so I cannot tell you if the marking codes are as expected (not made up).
Bottom line: to my eye they look fake, but there is no way to tell for sure without decasing and microscope inspections.
Marking are consistent on both units.
Machining marks are similar but it seems that the Mouser(Ti originals) are more refined that the Aiyima
Back stamping. Similar, not really a measurable difference.
Laser etching markings: fortune 500 companies spend fortunes promoting their brand and brand awareness. Logos should be consistent within products, marking should have the same logo and sizing and colors should match to a pantone accuracy. This is not the case
I have seen several pics of original TI products and the logo is shiny and very defined. The laser etching of the Aiyuma Ti op-amp follows a different path. Lines that are supposed to be straight are not. The logo and fonts are visibly darker and the thickness of the font lines and font separation is not the same. Logo is definitely not the same, tool-path for the laser is different and some lines are wrong (the end of Texas should be straight in Aiyima is crooked).That leads me to believe that they are counterfeit. Note that that was consistent on all the Aiyima and Mouser opamps
IC manufactures strive to a level of consistency and quality from fab to fab to make all the product match the look and performance regardless of the fab they were made. This is not the case. The markings are really different. I am not claiming that Aiyima is trying to fool their customer, as in today supply line is almost impossible (unless you pay the premium of tier one distributors) to get real originals. Me, I have return countless Intel CPU over the years as the marking were so bad that it was clear that they were polished and relabeled .
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The OP amplifier NE5532 is an extremely inexpensive product at 20 to 30 cents. What are the benefits of making a copy of such a product?
The famous OPA627 makes a lot of money, but I think the NE5532 just makes a loss. So I think two of the photos are real.
There are a lot of second hand intel CPU fake products in the market. Many fake products are also exhibited at Yahoo auctions in Japan. They will be sold one after another. Since the profit is large, fake listings will not disappear.
The best way to prevent damage is to increase your knowledge or not buy used ones.
The famous OPA627 makes a lot of money, but I think the NE5532 just makes a loss. So I think two of the photos are real.
There are a lot of second hand intel CPU fake products in the market. Many fake products are also exhibited at Yahoo auctions in Japan. They will be sold one after another. Since the profit is large, fake listings will not disappear.
The best way to prevent damage is to increase your knowledge or not buy used ones.
Sadly, there is a lot of benefit to substandard counterfeit chips. A counterfeit ne5332 is about 5 cents (probably less if you buy 100,000 of them at a time). That is about 20 cents less per chip (assuming 25 per from the original).
I have an Aiyima A03 with three ne5532, so if the manufacturer is planning to make a run of 20000 units, that will be 12,000 thousand dollars saved. That pays the salary of an Aiyima engineer for more than a month, or reduces your BOM cost.
So, assuming that BOM accrues 20 dollars, and I sell for $30 wholesale, I can use those $12000 saved to manufacture an extra 600 units, for a total run of 20600 units. Assuming that I sell them all, that is an extra profit of $18000 (600 x $30). Or when units came back to RMA, replacing does not came out of the profit.
Now, add fake elna and nichickon caps, substandard counterfeit connectors and relabeled relays and soon you have saved $2-5 from the cost while giving the customer the illusion of purchasing a quality product.
So, now you can see how profitable can be to use five cents counterfeits.
I have an Aiyima A03 with three ne5532, so if the manufacturer is planning to make a run of 20000 units, that will be 12,000 thousand dollars saved. That pays the salary of an Aiyima engineer for more than a month, or reduces your BOM cost.
So, assuming that BOM accrues 20 dollars, and I sell for $30 wholesale, I can use those $12000 saved to manufacture an extra 600 units, for a total run of 20600 units. Assuming that I sell them all, that is an extra profit of $18000 (600 x $30). Or when units came back to RMA, replacing does not came out of the profit.
Now, add fake elna and nichickon caps, substandard counterfeit connectors and relabeled relays and soon you have saved $2-5 from the cost while giving the customer the illusion of purchasing a quality product.
So, now you can see how profitable can be to use five cents counterfeits.
5532 and 5534 are amongst the most widely used AOPs in audio and at the heart of many many kits and builts. Can't comment for this amp (and it may also vary on the production line given the changes we have seen here), but there are many fakes around nowadays, as documented on various forums.
I have purchased last year 2 non expensive Chinese audio kits and they have indeed fake 5532s. Not that I could "see it" the way you did, I could just hear a difference with the original parts I had as these were mounted on a socket and easy to swap. I assumed from the start these and some expensive caps could very likely be fakes, so it wasn't a problem for me at all as I counted replacement parts in the (read "my") total price.
Hearing the difference with original 5532s was a bit more difficult with the second kit but at higher levels it became clear the fake one didn't like at all to swing voltage whereas the original was able to.
If you search a bit you will find someone who measured some nicely made fakes with an oscilloscope and given the horrible results from 10kHz on or when exceeding 10V swing / some gain no wonder one could hear the difference on these. However, at low / usual frequencies and low voltages, listening to the fake one wasn't that horrible they said.
Frabor is right, there is a business for such fakes, and I was amazed to see that even some low volume niche parts are now counterfeit... seems as long as they enjoy some popularity there is a market for it.
All this should 't detract from this amp, at the end it sounds quite good with its fake parts and so the good news is it can even improve more with genuine, easy to replace ones... or even better AOPs. TBH, for that price I consider I buy a housing, a functioning unit with a genuine heart and I do consider that most other parts are cheap. Some aren't critical at all to music quality, all these that are... are likely to be replaced anyway when we will tweak it. Still cheaper than purchasing a real unit or kit from the start, that is if you consider it to be a fun DIY project and don't count your hours of course... If I would charge time it would become the most expensive amp on Earth LOL, but this is a hobby and pleasure.
All IMHO / IME
Claude
I have purchased last year 2 non expensive Chinese audio kits and they have indeed fake 5532s. Not that I could "see it" the way you did, I could just hear a difference with the original parts I had as these were mounted on a socket and easy to swap. I assumed from the start these and some expensive caps could very likely be fakes, so it wasn't a problem for me at all as I counted replacement parts in the (read "my") total price.
Hearing the difference with original 5532s was a bit more difficult with the second kit but at higher levels it became clear the fake one didn't like at all to swing voltage whereas the original was able to.
If you search a bit you will find someone who measured some nicely made fakes with an oscilloscope and given the horrible results from 10kHz on or when exceeding 10V swing / some gain no wonder one could hear the difference on these. However, at low / usual frequencies and low voltages, listening to the fake one wasn't that horrible they said.
Frabor is right, there is a business for such fakes, and I was amazed to see that even some low volume niche parts are now counterfeit... seems as long as they enjoy some popularity there is a market for it.
All this should 't detract from this amp, at the end it sounds quite good with its fake parts and so the good news is it can even improve more with genuine, easy to replace ones... or even better AOPs. TBH, for that price I consider I buy a housing, a functioning unit with a genuine heart and I do consider that most other parts are cheap. Some aren't critical at all to music quality, all these that are... are likely to be replaced anyway when we will tweak it. Still cheaper than purchasing a real unit or kit from the start, that is if you consider it to be a fun DIY project and don't count your hours of course... If I would charge time it would become the most expensive amp on Earth LOL, but this is a hobby and pleasure.
All IMHO / IME
Claude