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Aiyima A07 class D venture

Tangband

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With my A07 i was using a 24v 4amp supply since changed to a 48v 12.5amp being fed by 240v mains (live neutral earth all connected), The A07 does get a lot warmer with the bigger power supply.

Inside it I've upgraded the op-amps to Burson v5i-Ds (same as I used in my DAC-X6) I've also replaced the thermal compound for the amp chip, and changed all of the capacitors, all now 105c rated, the two larger 1000uf 50v caps were changed to some Rubycons although a different profile that keeps a bit more space between the caps and the heatsink, changed all of the other electrolytics, panasonic/rubycon 105c rated.

For the poly caps I thought I'd experiment with some old stock, physically larger ITT 1uf 100v and some old stock philips 250v 1500nf 5% axials.

More of a fun project than anything, What i may still do is put on some different binding posts / RCA connectors, change the 1uf 100v to some WIMA 1uf 250v and also change the 1000uf 50v caps to something higher rated, also considering adding a fan and some vent holes, Volume pot may also be worth looking at but I've not had any problems with mine seems to work well so I've left that alone. How much difference any of this makes well ymmv, I've taken no measurements other than listening and voltages etc via multimeter, Power supply made the most difference but as stated I was using a 24v rather than the usual 32/36v then jumped right up to the 48v.

Note: When I purchased my A07 it is not Aiyima branded, only has "power" and "volume" labels internally though it seems identical. The AUX jack at the back of the unit has left/right reversed but i don't use that, could be fixed though without too much trouble.
A bit off topic, but … when I played with tpa3116 cards one of the best mods where to switch the capacitors to bigger ones - I bought panasonic low esr . This card was also the reason I switched from class A/B amps , because it sounded better.

16CDF084-4269-48BA-98CD-BCDFF5103520.jpeg0C4EB391-DF6C-44F0-AF44-740357BEB18C.jpeg
 
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dr_mick51

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With my A07 i was using a 24v 4amp supply since changed to a 48v 12.5amp being fed by 240v mains (live neutral earth all connected), The A07 does get a lot warmer with the bigger power supply.

Inside it I've upgraded the op-amps to Burson v5i-Ds (same as I used in my DAC-X6) I've also replaced the thermal compound for the amp chip, and changed all of the capacitors, all now 105c rated, the two larger 1000uf 50v caps were changed to some Rubycons although a different profile that keeps a bit more space between the caps and the heatsink, changed all of the other electrolytics, panasonic/rubycon 105c rated.

For the poly caps I thought I'd experiment with some old stock, physically larger ITT 1uf 100v and some old stock philips 250v 1500nf 5% axials.

More of a fun project than anything, What i may still do is put on some different binding posts / RCA connectors, change the 1uf 100v to some WIMA 1uf 250v and also change the 1000uf 50v caps to something higher rated, also considering adding a fan and some vent holes, Volume pot may also be worth looking at but I've not had any problems with mine seems to work well so I've left that alone. How much difference any of this makes well ymmv, I've taken no measurements other than listening and voltages etc via multimeter, Power supply made the most difference but as stated I was using a 24v rather than the usual 32/36v then jumped right up to the 48v.

Note: When I purchased my A07 it is not Aiyima branded, only has "power" and "volume" labels internally though it seems identical. The AUX jack at the back of the unit has left/right reversed but i don't use that, could be fixed though without too much trouble.
Feeding with a higher input voltage allows it to have bigger swings on the output, therefore it allows you have more output power until the current constrains the power output.
But I don't think you use all that power. That's a deafening and very distorted amount of SPL on a regular 89db/Wm speaker
89 >92 >95>98 >101>104 >107 >110dB
1w>2w>4w>8w>16w>32w>64w>128w

Have you tried bypassing your electrolytic capacitors with some C0G/MP0 ceramic capacitors (MLCC)?

On the LC filter you don't have much space to work with. The 1uF and the 0.01uF caps don't have much replacement options with that footprint. Yes, the Wima or some Panasonic ECWDE are good options for the 1uF cap, but for the other little one I don't know.
 

Joe Smith

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What you need is a cleaner power supply with very low ripple and noise.. you can achieve this by using smooth capacitors in parallel to the output(a big Electrolytic one, of 1000uF and two film capacitors, one of 1-2uF and the other 0.1uF)

Q: Anyone know of any "finished" (encased) power supplies (not the bare ones like Drok) that would have these kind of specs/components? I am currently using the Aiyima-branded 32v 5a one for my a04 amp and an older brick that's 24v 5a for the a07. Don't really need more power for my speakers or listening levels but would be nice to get a cleaner power supply in play. I just am not a big fan of the bare-wires units.
 

Holmz

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Feeding with a higher input voltage allows it to have bigger swings on the output, therefore it allows you have more output power until the current constrains the power output.
But I don't think you use all that power. That's a deafening and very distorted amount of SPL on a regular 89db/Wm speaker
89 >92 >95>98 >101>104 >107 >110dB
1w>2w>4w>8w>16w>32w>64w>128w


^That^
And the fact that with non compressed music we have say, 13 dB crest factor, or more or less.

So at a peak SPL of 103dB, we have an RMS SPL of 90dB.
And the peak wattage of 40W and the RMS of about 1W.
 

Synrgy87

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Just got some parts in and changed the volume pot with an ALPS 50k Logarithmic, if you do anything to the A07, I totally recommend doing that, gives a much nicer gradient to the volume control from the old generic "B50K" linear pot, If you do this you may need to drill out the front panel hole to fit the ALPS shaft is a little more girthy than the original, you'll also need a new knob, the replacement is D shaped. and wider as stated. Drilling is easy as it'll pretty much self center and it's relatively soft Aluminium/Aloominum

Still have the binding posts on the way to change out, maybe throw some pics up of the insides.
 

dr_mick51

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Just got some parts in and changed the volume pot with an ALPS 50k Logarithmic, if you do anything to the A07, I totally recommend doing that, gives a much nicer gradient to the volume control from the old generic "B50K" linear pot, If you do this you may need to drill out the front panel hole to fit the ALPS shaft is a little more girthy than the original, you'll also need a new knob, the replacement is D shaped. and wider as stated. Drilling is easy as it'll pretty much self center and it's relatively soft Aluminium/Aloominum

Still have the binding posts on the way to change out, maybe throw some pics up of the insides.

Definitely looking forward to see pictures of your mods. I can share mine as well.
 

andrewjohn007

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Any suggestions. I do have a lead with same barrel jack connector already on from one my linear power supplies. The cable is pretty robust but after opening it up The gauge is very thin. I’m thinking like 22 gauge or thinner. Amazon has some pig tail leads 16awg with the dc barrel jack connected. I’m thinking it’s 5.5mm x 2.1. I’m thinking this should be suffice.
Check out Tensility's 5.5/2.5 DC barrel jack with 16 AWG. (The A07, A04 and A3001 do not use a 5.5/2.1.)


I split the zip wire, sheathed it and twisted it. This is an A3001 and an LRS-200-36 enclosed in a Hammond case.

index.php
 
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dr_mick51

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As promised. These are some pictures of my modded Aiyima A04:
OPA1656 on adapter with multiple supply bypasses.
ELNA Silmic II Coupling capacitors
3000uF Nichicon UBY Power supply capacitors
EPCOS output filter capacitors(the stock ones looked not right. In fact I believe most of the parts used on these amplifier are not original/genuine)
Multiple EPCOS and Murata MLCC bypass capacitors used on each electrolytic capacitor.
 

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JeffGB

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I have an a07 as well and was reading the TI data sheet. They seem to be of the opinion that for up to 51v operation the big capacitors should be rated at 80 to 100 volts...​

10.2.1.2.2 PVDD Capacitor Recommendation​

The PVDD decoupling capacitors must be placed as close to the device pins a possible to insure short trace length and low a low inductance path. Likewise the ground path for these capacitors must provide a good reference and should be substantial. This will keep voltage ringing on PVDD to a minimum.

The voltage of the decoupling capacitors should be selected in accordance with good design practices. Temperature, ripple current, and voltage overshoot must be considered. This fact is particularly true in the selection of the 1μF that is placed on the power supply to each full-bridge. It must withstand the voltage overshoot of the PWM switching, the heat generated by the amplifier during high power output, and the ripple current created by high power output. A minimum voltage rating of 100 V is required for use with a 51-V power supply.

The large capacitors used in conjunction with each full-bridge, are referred to as the PVDD Capacitors. These capacitors should be selected for proper voltage margin and adequate capacitance to support the power requirements. In practice, with a well designed system power supply, 1000 μF, 80 V supports most applications. The PVDD capacitors should be low ESR type because they are used in a circuit associated with high-speed switching.
 

Talisman

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Again. Have you measured how much power you use during your listening sessions?. People who listen at 80db need less than a watt per channel. I, during my listening sessions need 50mA per channel. That's 20mW per channel. Now add some headroom for dynamic range x 10. That means 2w maximum per channel.
I really welcome people to do their own measurements and realize they don't need as much power as they believe.
Again , it's about clean power not raw power.
How boring these discussions about power, although we will still be bored by these useless digressions on "if people knew how much power they use ...."
I believe that if people knew that it was enough to want to listen to a high dynamic track at a louder and more satisfying volume (and I hope I can do it with my amplifier, not everyone listens to background jazz while sipping wine) then they will find that the requests of the dynamic peaks can be HEAVY, and I have no desire to buy an amplifier that cuts the peaks, I want to be able to hear my music in full dynamics, even at high volumes and even with insensitive speakers.
please just get bored with the story that 5watts is more than enough for everyone and everything in any situation. if you think so, buy 10watt amplifiers and live happy.

ps Amir has two 1000 watt monoblocks, explain to him that they are useless and he just wasted money
 

SIY

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"Bypassing" caps can cause all sorts of unexpected and unwanted effects. Putting aside the utter uselessness of cap replacement in general (beyond keeping you off the streets and out of trouble), you're setting up a potential resonant circuit, not what you want.
 
OP
G

Gaspar74

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Mounted my Aiyima Board in an old Chassis had lying around. Its the Cambridge Audio A3255 now. This is just a test run of it. Im using the same volume pot form the Aiyima and have the board mounted removed from its black case. I soldered 16 gauge wire from the speaker terminals off the Aiyima to the original speaker posts on the Amp. Used an RCA extender and hoy glued the RCa to the chassis.
 

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Holmz

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How boring these discussions about power, although we will still be bored by these useless digressions on "if people knew how much power they use ...."
I believe that if people knew that it was enough to want to listen to a high dynamic track at a louder and more satisfying volume (and I hope I can do it with my amplifier, not everyone listens to background jazz while sipping wine) then they will find that the requests of the dynamic peaks can be HEAVY, and I have no desire to buy an amplifier that cuts the peaks, I want to be able to hear my music in full dynamics, even at high volumes and even with insensitive speakers.
please just get bored with the story that 5watts is more than enough for everyone and everything in any situation. if you think so, buy 10watt amplifiers and live happy.

ps Amir has two 1000 watt monoblocks, explain to him that they are useless and he just wasted money

But in my example, I mentioned 5W RMS for a center channel. So on 13 dB crest factor that is 20x peaks, which is 100W. 16 dB crest factor is 200W.
So the talk about thermal loading doing minutes of testing at 100W are a bit more like subwoofer use than like music or movie use.
 
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