I did a AB comparison of the power supply noise on a stock APpleTV and on one I did the mods to. I did not use a good linear tho so it could be even better. Remember there is more magic then just the power supply tho.
As an owner of one of these modded Apple TV X units, it is a no brainer for me. 99% of my TV viewing is via streaming, so the argument of "is it as good as blu-ray" is really moot. Most of what I watch isn't available in blu-ray. My modded, souped up OPPO with linear power supply just sits mostly unused, almost ready to pull it completely from the system. Can't remember the last time I went and bought or ordered a Blu-Ray. I needed a solution that improved "Ozark" on Netflix...as well as "The Batman" on HBOMAX.
Initially I upgraded the power cord and also isolated the ethernet thru high quality switch, and physically isolated the unit with vibration control-- all the same as most are doing with digital audio tweaks. Made a little positive difference. Then I did try with just modding the power supply, and although there was some improvement, most of the big improvement came with the whole of the mods. And not just the picture quality, which is easily recognizable difference by anyone, but the audio makes such a big leap. The picture has so much less noise and the colors are so much more saturated and vibrant. You kind of go "whoa" when the Apple menu pops up! Bright, solid, 3D. The audio the first thing you notice is a big soundstage compared to stock.
Anyway, this unit made a profound difference in my system, both on a projection system as well as OLEDs. Again, "no brainer" if like me you watch a lot of streaming and wished the quality was better. Does it depend on the source? Well, sure. But I've yet to find one program that doesn't benefit greatly from stock. I also get that AppleTV will obsolete in a couple of years when the next AppleTV comes out, but that's the nature of the beast. When 8k TVs came out I didn't pull all the 4K OLEDs off the wall...so I'll cross that bridge when I come to it in a year or 2. Meanwhile for the cost of what some of us spend on a power cord....I'll enjoy marked improvements in all programming for a couple of years. Thanks to Xymox for pushing the envelope.
physically isolated the unit with vibration control
isolated the ethernet thru high quality switch
"this unit made a profound difference in my system"
the downside is... oh, that's right, there wasn't one.
Ever bought an upgrade that made you want to go back and listen to every song you'd ever heard and re-see every video and/or show, understanding , maybe for the first time just how much you'd missed. This is that.
Simply using the mods and the associated equipment sent by Xymox is revelatory. Hog heaven.
Hi @marty,While I appreciate this effort, what I really wonder is the improvement possible simply by replacing the existing power supply with a 12V linear supply. There are many good linear supplies available for a few hundred dollars and less. My guess is that this may be the more attractive option (at least it is for me). Pull out the stock digital supply and leave me a female 2.1 mm connection for my own LPS and charge a reasonable fee. But for $2500, as they say on Shark Tank, "I'm out".
Hi @XymoxIts a good first start. But you really need to remove the supply.
ALSO... The + and - are reversed in these pics. This would fry the appleTV and the power supply. You can see the - band on the black cap close to the wire on the left of the pic. The + pin of that cap is connected to the + terminal. You can see the trace on the + side of the cap is labeled - in the pic.
This does offer improvements. But because of the super spiky nature of the CPU you need a really well tuned set of caps run right to the board. Plus I also put tant caps on the appleTV board along with other stuff. But yea, this is where I started.
Thanks for the tip.
i decided to open it up again and removed the SMPS PCB, replaced the wires with MUndorf SG that I had laying around, and used just 1 pc of AN Kaisei 470uF capacitor (SMPS had 330uf).
You were right, both video and audio got even better.
View attachment 92892
I’ll stay with this config for awhile before I try paralleling some more.
Hi @Xymox,There you go !.. NICE choice of parts.. AND WIRE.. There is a tricky balance between the types of caps and values and wire. Remember your creating a impeadance at different frequencies. There is a nasty noise coming from the buck/boost regulators, its got wide spectrum with the worst of it near 20khz but a LOT above it. So think low freq RF. Its steady state and there constantlly. Use some WIMA polys close to the ApplePCB to supply these nasties with juice and quash out the noise from them. Remember this is high frequency, so a small diameter wire with good 20khz-50mhz performance works best. A big ga wire is not best. Then you have the CPU rumble. This rumble is sporadic and SERIOUS. I have dropped 500,000uf hooked right to the PCB and still had measurable rumble. The rumble can be 750mA spiky junk single impulse stuff VS a 100mA background draw. The rumble needs to be dealt with with electrolytics and tant. The rumble has a spectra like 5hz - 100 hz. Its very random. This requires large ga wire. So the wire dia is trick to do both. Overall your wanting to make the lowest impedance possible for these bands. The wire is a balance. Length, dia, spacing all matter at the high freqs.
There is a tricky other component. As you do this and change these values it will effect all the chips of course. the HDMI out chip generates a lot of noise and is sensitive to power supply changes. WEIRD effects can happen at the stupid high freq this chip spits out. Make sure to watch the picture as you make changes because its possible to go bigger in caps and cause pic degradation. Its a weird tricky balance.
Sound gets better with more uF, pic does not, it gets worse after a point.
What you have now tho should be great fun. Add a WIMA poly to that electrolytic. Stack the electrolytics to get better sound.
The impedance at the freqs involved are greatly effected by the wire that goes to the PCB. I spent ALOT of time messing around with caps, spacing, geometry and wire types to nail that whole spectrum. Im sure you can imagine how much time that took opening it up, changing wires, wire lengths, caps doing each one at a time and putting it all back together and measuring..
The wifi gets radiated into the caps and the wires BTW. That was also tricky to get rid of..
You should report what your seeing as improvements. Its all valid for what I do too.
I have to give you some serious credit. I believe you were the first person to discover and mod a AppleTV ? I can't fine anyone else. Your pics were the first back when.. I remember seeing those pics. i saw them back in the day and thought, ooo thats cool. But never did any mods.. BUT.. When it was suggested I mod a AppleTV, I remembered your post and that it was 12V and agreed to give it a whirl.. So I may not have attempted this without your previous work..
i wanted to give you credit for that for sure. You went where no man had gone before.
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