Do you have a direction you could point me that would fit something that size? I briefly looked around when I considered it but couldnt find anything reasonably priced and that wasnt huge, like a full size amp chassis.
And yes, Op-amps are definitely a subjective taste. So many factors in play. I didnt "dislike" the OPA1656's, I just wasnt as in love with them as most and found the much simpler, cheaper LM4562's more to my liking. As I continue tweaking this amp though you can bet Ill reroll all of them. Im definitely doing the opa bypass as well as the others. Not sure I can find room for 20uf under the board though. I have the .01uf Muratas already and I also have some low ESL (ESR) .01uf's coming as well to try which may be even better than the Muratas, well see. As you suggested, Im a bit of a tinkerer and as this is a super cheap hobby Im happy to "waste" some money trying a bunch of different things.
You may well be right about the larger capacitance not making a difference but as dropping to 2200uf caps did I figure its a good experiment either way.
Yep, the additional OPA PS caps are best over the board, that is around or over the OPA... need indeed to be inventive, especially if you want to roll op amps.
Regarding the size of the casing, sorry no hint as we fitted all into an existing amp. But Gilles tought me that Ali...s or other Chinese had some casings ready made in all sizes for little money. And you could still build one from scratch, or use a tin box for cookies you rework and decorate - even cheaper.
I would though wait a bit to find out what dimensions Mark's filter is going to have...
Good luck!
Claude
PS: the Muratas I used where 0.1uF (or rather 0.082uF to be precise), not 0.01uF. The latters are too small IMHO for our needs and frequency bands.
Regarding the size of the casing, sorry no hint as we fitted all into an existing amp. But Gilles tought me that Ali...s or other Chinese had some casings ready made in all sizes for little money. And you could still build one from scratch, or use a tin box for cookies you rework and decorate - even cheaper.
I would though wait a bit to find out what dimensions Mark's filter is going to have...
Good luck!
Claude
PS: the Muratas I used where 0.1uF (or rather 0.082uF to be precise), not 0.01uF. The latters are too small IMHO for our needs and frequency bands.
Greetings... I have been doing a lot of reading on the Aiyima A04 and purchased one recently (green pcb) with the intentions of doing some minor modifications initially. I like what rhing suggested on touching up soldering joints and swapping out the op amp. Soldering the 1656 op amp on a Dip-8 adapter seemed a little to detailed for me, for now at least (small space for soldering). So, I purchased a pair already mounted on adapters from eBay. What I received, well I really am shocked that someone could sell this workmanship. But, I would appeal to some input to the attached image (of many photos). My thoughts are excessive heat, limited patience was implemented; I don't know if the op amps could have been damaged with excessive heat. Thank you...
Attachments
I have some ideas for you :
I am using this case with my Jlester TPA3255 module (it is compact solid and elegant).
And if you are looking for a high end SMPS Psu with a very low ripple, I would go for the Micro Audio SMPS600 (39 > 47VDC single rail) which is a great DIYer (they also made a sublime Purifi PSU with an excellent reputation)
MicroAudio – SMPS for audio applications
Checkout :
x en maths
x en maths
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Sorry, was a typo. I ordered the .1uf's. Any insight as to why C0G capacitors max out at under 1uf? They seem to be the idea for audio.
Cool, I'll take a look. Unfortunately my super limited electronics experience means I know nothing about building a power supply, though I would definitely like to learn. That's why I was looking at the Meanwell.
thanks again for the great write up. When I bought my Aiyima Amazon was out of 32V x 5Amp power bricks, so I bought 32V x 3Amps. Is this hindering my amp sound. Is volts or amps more important to sound quality? thanks again. I will probably do all of your mod recommendations over time. Just takes me a while to find the parts. At first I was disappointed in this amp but I was streaming Spotify, lifeless, no soundstage, etc. Then I threw in a CD and my 1040 soundcard and the amp came to life! Now I am hungry for more and alass I don't have the big money for $$$$ stuff. This is great!!!
With 8 ohm speakers voltage is more important than current. I highly doubt you're missing much with a 3a vs 5a adapter.
Here is the answer with measurements, this will give you a concret idea about :
High end TPA3255 ($1500) vs Chinese TPA3255 ($50)
The TPA3255 / TPA3251 chips are not oriented for power but rather for SQ
Aiyima A07 ($50)
And now checkout the Minidsp SHD Power Amplifier with TPA3255 chip @ $1499
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Quote: Any insight as to why C0G capacitors max out at under 1uf? They seem to be the idea for audio.
Size... technology used to achieve this performance means you can't really pack a lot of uF in a small form factor which is the rule nowadays. If size doesn't matter, PPP caps have the worst capacity/size factor, but then sound excellent in demanding applications.
Size... technology used to achieve this performance means you can't really pack a lot of uF in a small form factor which is the rule nowadays. If size doesn't matter, PPP caps have the worst capacity/size factor, but then sound excellent in demanding applications.
Regarding PS and SMPS quality... IMHO when it comes to sound quality there is a lot more than the graphs that ASR likes to believe they are the last word, but anyway, won't start a debate here.
Yes, the lower the LS impedance (and that is not a constant but varie with frequency), the more you need current (amperes, A) to drive your LS withe the same power level, whereas high impedance needs more voltage so to speak. The relationship is quite simple, (at each given frequency which has (to simplify a lot as that one is complex in fact and has an imaginary number part, but well...) its own R you have :
P = (U^2)/R = R I^2
Say you want 100W and have a constant R = 1 ohm load (quite low for LS), then the equation tells you that you need 10V and 10A.
Say now you have R= 10 ohm load (a tad high for LS, but depending on frequency some show it), then you need 31.6V and 3.16A. You can see here that you need in this latter case over 3 times more voltage and 3 times less amperes / current.
Now, all this is quite academic as the chip used in this amp has of course limitations and on top I am not sure the tracks and layout quality permits really reliable long term high power output. As of bursts, short term power deliveries, they are taken care by other aspects of the PS, call it short power reserve to address quick power needs.
At the end, as stated in this thread, IMHO it doesn't really matter if you run this unit under 26V or 32V as the real perceived max loudness difference will be small. It is always good to have some A because that's what you may need depending on your speakers (if they are current hungry that is run into low impedances especialy at lower frequencies). But how much power you really need depends on your entire system and needs.
Say you need in real life 20W per LS. You need a PS that can deliver say 50W to be safe. That means 25V / 2A will do. On top, lower voltage SMPS can have lower ripple values, and that matters quite a bit more usualy as it is the quailty of the constantness (regularity, think waves)) of the constant voltage they are supposed to deliver... the lower that value, the better usualy. Ok, it is just an indicator as there is far more to quality than that single figure, but a good starting point if you don't have access to an oscilloscope trace
Farther, higher current PS may be better for other reasons, such as low output impedance (ability to deliver quickly more current etc.) and may respond better and quicker. And whereas you can't drive voltage too high as you will wreck your unit, having a high current PS is not a problem as the current that is delivered is what the unit asks for at a given time, whereas max voltage is permanently applied.
Bottom line, IMHO chose a very low ripple regulated SMPS with anything between 24V and 32V and whatever current being at least 5A IF you have current hungry LS (if not, don't bother too much about high A if you already own a unit).
Last but not least, all these quality Audio SMPS cost a fortune and are in fact not all better than a quality Mean Well SMPS, which was admittely designed for different needs. Cresnet's units are indeed dedicated to Audio, but IMHO their price makes little sense for this low cost project.
Therefore, I would go for a quality SMPS from Mean Well & Co with a price that stands in relation to this project. Plus I would add Mark's coming 6A filter, as thas is likely to make nearly ANY non expensive OK quality high current SMPS sound on this little amp probably very close to any top audio SMPS without this filter...
I hope this helps and sorry for the long post again
Claude
Yes, the lower the LS impedance (and that is not a constant but varie with frequency), the more you need current (amperes, A) to drive your LS withe the same power level, whereas high impedance needs more voltage so to speak. The relationship is quite simple, (at each given frequency which has (to simplify a lot as that one is complex in fact and has an imaginary number part, but well...) its own R you have :
P = (U^2)/R = R I^2
Say you want 100W and have a constant R = 1 ohm load (quite low for LS), then the equation tells you that you need 10V and 10A.
Say now you have R= 10 ohm load (a tad high for LS, but depending on frequency some show it), then you need 31.6V and 3.16A. You can see here that you need in this latter case over 3 times more voltage and 3 times less amperes / current.
Now, all this is quite academic as the chip used in this amp has of course limitations and on top I am not sure the tracks and layout quality permits really reliable long term high power output. As of bursts, short term power deliveries, they are taken care by other aspects of the PS, call it short power reserve to address quick power needs.
At the end, as stated in this thread, IMHO it doesn't really matter if you run this unit under 26V or 32V as the real perceived max loudness difference will be small. It is always good to have some A because that's what you may need depending on your speakers (if they are current hungry that is run into low impedances especialy at lower frequencies). But how much power you really need depends on your entire system and needs.
Say you need in real life 20W per LS. You need a PS that can deliver say 50W to be safe. That means 25V / 2A will do. On top, lower voltage SMPS can have lower ripple values, and that matters quite a bit more usualy as it is the quailty of the constantness (regularity, think waves)) of the constant voltage they are supposed to deliver... the lower that value, the better usualy. Ok, it is just an indicator as there is far more to quality than that single figure, but a good starting point if you don't have access to an oscilloscope trace
Farther, higher current PS may be better for other reasons, such as low output impedance (ability to deliver quickly more current etc.) and may respond better and quicker. And whereas you can't drive voltage too high as you will wreck your unit, having a high current PS is not a problem as the current that is delivered is what the unit asks for at a given time, whereas max voltage is permanently applied.
Bottom line, IMHO chose a very low ripple regulated SMPS with anything between 24V and 32V and whatever current being at least 5A IF you have current hungry LS (if not, don't bother too much about high A if you already own a unit).
Last but not least, all these quality Audio SMPS cost a fortune and are in fact not all better than a quality Mean Well SMPS, which was admittely designed for different needs. Cresnet's units are indeed dedicated to Audio, but IMHO their price makes little sense for this low cost project.
Therefore, I would go for a quality SMPS from Mean Well & Co with a price that stands in relation to this project. Plus I would add Mark's coming 6A filter, as thas is likely to make nearly ANY non expensive OK quality high current SMPS sound on this little amp probably very close to any top audio SMPS without this filter...
I hope this helps and sorry for the long post again
Claude
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Daniboun, I know Crenet's product since years, when discussing this PS option for the FO amp. they have indeed good reputation.
But 65E... that's more than the entire unit with the best retained tweaks!
Plus you will find that you need to add shipping and perhaps extra import fees (if you are lucky you don't). Make that a quite a bit more, not mentioning casing and connections (that you will admittely need aswell for a Mean Well, but that can be cheaper as already protected).
Last but not least, once you are ready to spend say 200E in a single Class D Aiyima with all tweaks, then you could start considering other options (unless you are a dedicated Class D fan or need desesperately that form factor and high efficiency).
On the other hand a low ripple Mean Well will cost around 30E and with tweaked PS caps bypasses for less than 3E my bet is most users (that being honest don't run any ultimate speakers obviously) won't notice any difference with an Audio SMPS.
And my bet is that the same Mean Well with Mark's filter to come (perhaps 15E?) will completely outperform any Audio SMPS per definition re current quality delivery and reliability. In fact, it may come close to any high quality $$$$ PS, regardless if SMPS or CRCR linear and the project you are considering as it will be of some use in a Pass amp. It is something I am even looking into myself for a real high end amp - but then I like to build things and SMPS is out of my scope - let's see if I can beat it, another story though.
What is true though is that most Class D amps seem to benefit clearly from regulated SMPS (per definition and due to their PSSR) and that a low ripple "hard" (quick, low impedance) PS is key. The positive of a mainstream SMPS from a reputated company is that it is low cost and can be easily replaced when it will fail (and being SMPS it will fail sooner than later). Crenet's is a valuable exception to most Audio SMPS providers in that he sems to provide good support and he uses easy to replace parts.
Claude
But 65E... that's more than the entire unit with the best retained tweaks!
Plus you will find that you need to add shipping and perhaps extra import fees (if you are lucky you don't). Make that a quite a bit more, not mentioning casing and connections (that you will admittely need aswell for a Mean Well, but that can be cheaper as already protected).
Last but not least, once you are ready to spend say 200E in a single Class D Aiyima with all tweaks, then you could start considering other options (unless you are a dedicated Class D fan or need desesperately that form factor and high efficiency).
On the other hand a low ripple Mean Well will cost around 30E and with tweaked PS caps bypasses for less than 3E my bet is most users (that being honest don't run any ultimate speakers obviously) won't notice any difference with an Audio SMPS.
And my bet is that the same Mean Well with Mark's filter to come (perhaps 15E?) will completely outperform any Audio SMPS per definition re current quality delivery and reliability. In fact, it may come close to any high quality $$$$ PS, regardless if SMPS or CRCR linear and the project you are considering as it will be of some use in a Pass amp. It is something I am even looking into myself for a real high end amp - but then I like to build things and SMPS is out of my scope - let's see if I can beat it, another story though.
What is true though is that most Class D amps seem to benefit clearly from regulated SMPS (per definition and due to their PSSR) and that a low ripple "hard" (quick, low impedance) PS is key. The positive of a mainstream SMPS from a reputated company is that it is low cost and can be easily replaced when it will fail (and being SMPS it will fail sooner than later). Crenet's is a valuable exception to most Audio SMPS providers in that he sems to provide good support and he uses easy to replace parts.
Claude
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That makes sense Claude )
from a budget point of view, I'm OK your arguments hold up)
I agree 100% this has been discussed with Cdsgames. You should take a look at the next Allo TPA3255 by the way (special SMPS Psu + Air Core inductors). Seems really surprising :
THD+N 5W , 1Khz 0.00014
THD+N 100W 20-20Khz 0.0097
THD+N 10W 20-20Khz 0.0091
SNR : about 117DB
from a budget point of view, I'm OK your arguments hold up)
I agree 100% this has been discussed with Cdsgames. You should take a look at the next Allo TPA3255 by the way (special SMPS Psu + Air Core inductors). Seems really surprising :
THD+N 5W , 1Khz 0.00014
THD+N 100W 20-20Khz 0.0097
THD+N 10W 20-20Khz 0.0091
SNR : about 117DB
Last but not least, I don't know about that SMPS of yours, but is it regulated?
Whereas some Class A or AB amp seem to benefit from unregulated PS, this little amp is likely to benefit from a regulated PS.
If considering powering a single Aiyima, the Mean Well LRS-200-24 would be my choice. Voltage can be adjusted to anything between 21.6V and 28.9V, which is more than enough in terms of voltage. It is regulated and low ripple with reputable advertised max 150mVp-p, and anyway if more quality is needed then there will be Mark's filter. Oh, and it has 8.8A permanent current ability, more than is needed to fry the Aiyima. And can deliver more on impulses, should you need it.
Cost 25E and would be my choice.
Should you want to go biamping with 2 amps, then take the same in the 350 line instead of the 200 line. That's what we did for Gilles. Cost 40E or so. Why going bi-amping? Because if your loudspeaker permit it, given the very low unit cost and footprint, it turns out that you are sonicaly better off running 2 amps for say (tweaked) an extra 55E than you are likely to be tweaking output coils or power supplies for far more money in fact. Oh, plus you could then go active Xover and open an entirely new world.
Just my 2p's of course
Claude
Whereas some Class A or AB amp seem to benefit from unregulated PS, this little amp is likely to benefit from a regulated PS.
If considering powering a single Aiyima, the Mean Well LRS-200-24 would be my choice. Voltage can be adjusted to anything between 21.6V and 28.9V, which is more than enough in terms of voltage. It is regulated and low ripple with reputable advertised max 150mVp-p, and anyway if more quality is needed then there will be Mark's filter. Oh, and it has 8.8A permanent current ability, more than is needed to fry the Aiyima. And can deliver more on impulses, should you need it
.Cost 25E and would be my choice.
Should you want to go biamping with 2 amps, then take the same in the 350 line instead of the 200 line. That's what we did for Gilles. Cost 40E or so. Why going bi-amping? Because if your loudspeaker permit it, given the very low unit cost and footprint, it turns out that you are sonicaly better off running 2 amps for say (tweaked) an extra 55E than you are likely to be tweaking output coils or power supplies for far more money in fact. Oh, plus you could then go active Xover and open an entirely new world.
Just my 2p's of course
Claude
