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New Aiyima A07 with unknown stock Capacitor?

restorer-john

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so if you're getting "ok caps" from shenzen well then, 'ok' i guess??? at least its not false advertisment... not great caps, just ok

You can get any brand you want as long as you buy enough of them.
 

diablo

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I've bought three of these over the last six months. Out of curiosity I had a look at the caps.

20230128-135108-2.jpg

Lelon 50v
Rubycon 63v
Samyoung 50v

All three are marked 105C.

None are actually in use at the moment. I'm never going to use them with anything bigger than the standard power brick, so not particularly concerned. :)
 
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diablo

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I ran a test on the three amps pictured in previous post. Just a REW sweep using the same speaker and microphone to check for any differences. This pic shows the three graphs -

Screenshot (107).png


No differnces at all. o_O
 

Wolf11Man

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Just got my Aiyima A07 delivered to my doorstep from China to Germany in just 11 day's. Surprisingly fast. Price was €38 all expenses included. Somehow they combined some discounts I did not quite understand. Anyway, normal price is €52 today.

I hooked it up to my test speakers and gave it a listen. To tell the truth, sound was a complete fail. Not a little bit "not so good", but all dull and somehow distorted, from the first note. Nothing you would like to listen to longer than a minute. It did not improve at all, even after a few hours, no burn in magico...

So I opened it up and found two 2.200uF 50V caps inside, from a Aishi WH series. So a new variety? Seems to be one of the better China capacitor brands. Not much for a 2x300W amp, but maybe OK for 2x 100W or less.
Build quality of the whole thing is fine, no obvious faults, better than the Chinese average IMO. So how could they mess up that poor amp so completely? Are the people raving about it all deaf idiots?

On a second sight, the NE5532 op-amps looked like the TI-logo had been hand lasered by a talent free artist. Nothing like you do if you are proud to originate from Texas...

To give the amp a chance before sending it back, I dropped in some NOS NE5532 I still got from pre eBay times and hooked it up again.
Sound is 100% different, clear, dynamic and pleasant. A completely new amp. It makes the small medium quality DIYS speakers sound like something much more expensive. The bass they suddenly deliver is impressive. This is the sound you can expect from a 2x 130W amp powering some 40W speaker's.

It would be interesting to know which op-amp really is under the fake logo. What can make a good amp sound so bad? Must be some industrial, non audio op-amp.

Just for the record: Power supply is a naked 36V 7A SMPS from eBay screwed into an aluminum case, nothing special. Amp and SMPS do not even get warm after hours of playing.
 
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D

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Just got my Aiyima A07 delivered to my doorstep from China to Germany in just 11 day's. Surprisingly fast. Price was €38 all expenses included. Somehow they combined some discounts I did not quite understand. Anyway, normal price is €52 today.

I hooked it up to my test speakers and gave it a listen. To tell the truth, sound was a complete fail. Not a little bit "not so good", but all dull and somehow distorted, from the first note. Nothing you would like to listen to longer than a minute. It did not improve at all, even after a few hours, no burn in magico...

So I opened it up and found two 2.200uF 50V caps inside, from a Aishi WH series. So a new variety? Seems to be one of the better China capacitor brands. Not much for a 2x300W amp, but maybe OK for 2x 100W or less.
Build quality of the whole thing is fine, no obvious faults, better than the Chinese average IMO. So how could they mess up that poor amp so completely? Are the people raving about it all deaf idiots?

On a second sight, the NE5532 op-amps looked like the TI-logo had been hand lasered by a talent free artist. Nothing like you do if you are proud to originate from Texas...

To give the amp a chance before sending it back, I dropped in some NOS NE5532 I still got from pre eBay times and hooked it up again.
Sound is 100% different, clear, dynamic and pleasant. A completely new amp. It makes the small medium quality DIYS speakers sound like something much more expensive. The bass they suddenly deliver is impressive. This is the sound you can expect from a 2x 130W amp powering some 40W speaker's.

It would be interesting to know which op-amp really is under the fake logo. What can make a good amp sound so bad? Must be some industrial, non audio op-amp.

Just for the record: Power supply is a naked 36V 7A SMPS from eBay screwed into an aluminum case, nothing special. Amp and SMPS do not even get warm after hours of playing.
It may be useful to see some pictures of your specimen for reference? Close up of components etc. :)
 

dashu

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Hi guys! First post on this forum,

I think i have 2 of those "new and improved" version Wolf11Man was talking about. They were bought last month, not in the same time, but from the same official seller on Ali. Funny stuff, on one of them, those two 2200uF capacitors have different temp rating. On the other, the small caps (near OAmp) are almost touching the heat sink (i guess caps like cozy warm heat sinks to heat them in winter months).

When i first powered them (Fiio E10K+A07+Wharf 9.1) i was thinking... meh, dunno what's the hype, except low price. Maybe my E10K is not quite on the level of other DACs but shouldn't be that bad (i really like it paired with HD58x). I'm not a believer on burn-in amps but i was thinking i should try it anyhow. I'm not sure how legit are those 5532. I could guess different fabs have slightly different markings on TI chips. I'm planning to get from mouser some real NE5532, and because i read here some nice things with noise improvement, some LM4562 and OPA1656. I'm also planning to change those caps to some proper low-esr ones (most probably chemicon ky with just 16mm dia, i don't like caps to close to heat sinks). In the mean time i'm trying to find some mods other people like & make sense.
 

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Joe Smith

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I replaced the op-amps in mine to 4562's, added a thermal pad between the top of the heat fins and the case to transfer more heat to the case. Really happy with the sound. Not buying another one as I hold out some hope that Aiyima will do a true "v2" of this amp with better heat displacement, more separation for the caps from the heat sink, better volume pot, etc. Or, I may try a SMSL A300 for a bit more power, it's still very affordable.
 

DVDdoug

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I hooked it up to my test speakers and gave it a listen. To tell the truth, sound was a complete fail. Not a little bit "not so good", but all dull and somehow distorted, from the first note.
I could be defective, but I'll believe that when I see the distortion measurements or the results of a level-batched, blind, ABX test. ;) I've never heard distortion from a DAC. (I don't claim to have "golden ears".) In fact I've NEVER heard distortion from ANYTHING that wasn't broken except when an amplifier (or preamp, etc.) was overdriven into clipping, and I've heard distortion from vinyl records.

I HAVE heard bad frequency response, but not from a DAC. And, I HAVE heard noise (hum, buzz, hiss, whine) from various equipment.

Capacitors in power supplies aren't critical at all (again, unless they are defective). And for those that don't know, the voltage rating is simply the maximum rating. The designers should leave a little safety-margin, but a 500V capacitor in a 25V circuit is no better than a 50V capacitor in the same circuit. And that safety margin is for reliability, not for "performance".

Most capacitors in an audio device are NOT in the signal path. And if they aren't used in filters or "tone controls", they aren't THAT critical either.
 

Wolf11Man

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Your first, major mistake say's it all: The A07 is not a DAC but an amp. Sorry, so the rest of your post is far off as well. A DAC is no amp.
Capacitors have a lower resistance if they have a higher voltage rating. Small capacitors limit dynamic headroom. These are fact's, not audiophile fantasies.

Concerning the specific amp I experienced: It does not matter for me why the build in NE5532 sounds so much worse then the NE5532 from my NOS. They "should" sound identical. Maybe the Aiyima part was defective, maybe fake.
This is just a hint that changing stock parts for two cheap, real NE5532, may explain to why some have very different impressions of the same amp.
A NE5532 is around 1$. This is no expensive no sense op-amp rolling.
 

Wolf11Man

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Hi guys! First post on this forum,

I think i have 2 of those "new and improved" version Wolf11Man was talking about. They were bought last month, not in the same time, but from the same official seller on Ali. Funny stuff, on one of them, those two 2200uF capacitors have different temp rating. On the other, the small caps (near OAmp) are almost touching the heat sink (i guess caps like cozy warm heat sinks to heat them in winter months).

When i first powered them (Fiio E10K+A07+Wharf 9.1) i was thinking... meh, dunno what's the hype, except low price. Maybe my E10K is not quite on the level of other DACs but shouldn't be that bad (i really like it paired with HD58x). I'm not a believer on burn-in amps but i was thinking i should try it anyhow. I'm not sure how legit are those 5532. I could guess different fabs have slightly different markings on TI chips. I'm planning to get from mouser some real NE5532, and because i read here some nice things with noise improvement, some LM4562 and OPA1656. I'm also planning to change those caps to some proper low-esr ones (most probably chemicon ky with just 16mm dia, i don't like caps to close to heat sinks). In the mean time i'm trying to find some mods other people like & make sense.
Your amps are exactly the same as mine, except that they mixed a WH series and a WA cap (105°c and 85°C) up in yours. I see no benefit from changing these out, as they are the largest you can fit in that place. If you still use the amp in a few years simply exchange them if you don't feel well with them getting a little warm. The amp does not get very hot during normal listening.
If you look close, the writing on the two NE5532's is not exactly on the same spot. TI doesn't place it so-so on their products. Replacing them with a known real NE5532 may be really worth a try. The NE5532 is a very good, hard to beat op-amp. If real it should not have any negative impact on sound quality at all. It is very questionable if you will hear any difference by switching to an LM4562 or OPA1656 from a real NE5532.
 

dashu

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I've considered ordering just 2x OPA1656, but then again shipping (on mouser) was more than just the ICs. I decided to reach the "free shipping" threshold. So why not testing the real NE5532? If am still at it, just add LM4562 and some caps (1.5$ for a proper low esr cap with 10k hours @105c).

I could check on TME, digikey & others but i don't think it will be an significant price difference. Would I hear any difference between those ICs? Probably not, but at least i will know.
 
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