Shui Yuan Audio TPA3255 Modification Thread

[mamocel]

Originally Posted by vincepgh

1st of all: my main speakers are floor standing Focal Electra - should I ask someone to insure the cost of these guys for any amp's failure?

2nd: I removed "gold" capacitors and took a picture with original Nichicon caps that I bought on Mouser.

3rd: same for the opamps

4th: seems like TPA3255 IC soldered by hands and not so good. White substance feels like caulk!

Please dont hesitate to guess, which opamps are original

You took 0.47 uF capacitors ... the original ones are 10uF ... You risk losing in the reproduction of the bass...

[vincepgh]

Originally Posted by mamocel

You took 0.47 uF capacitors ... the original ones are 10uF ... You risk losing in the reproduction of the bass...

Cool, you catch the difference! I put .47uF to compare with Chinese caps, not going to install those.

Originally Posted by daniboun

Hi,

Thanks for sharing pictures.
It is obvious that the welds are done manually ... Regarding the thermal paste, it seems a bit messy (I imagine, however, that having disassembled the heatsink must have spread it).

Did you give a try with the new caps finally ?
I suppose if you unsoldered the Nichicon FW from the buffer it is because you had a doubt about their authenticity? And the same goes for the OP amps since you seem to replace them with the same 5532 ...

keep us informed when you have tested the module with the new assembled components to know if there is any better?

Let me explain:
1. White substance is NOT thermal paste. It's kind of caulk to keep TPA IC in place or so.
2. The opamps were NOT original, compare to sourced at Mouser.
3. I'll try to figure out what's wrong with my board and keep results posted.

[Mello4]

Originally Posted by vincepgh

....White substance is NOT thermal paste. It's kind of caulk to keep TPA IC in place or so.....

The White substance looks a little like RTV Silicone

[vincepgh]

Originally Posted by Mello4

The White substance looks a little like RTV Silicone

Right. My point is what's reason to use it? Heatsink uses the screws to hold in place, TPA chip should be soldered etc.
The other picture of the amps boards doesn't have signs of this adhesive.

[Mello4]

Originally Posted by vincepgh

Right. My point is what's reason to use it? Heatsink uses the screws to hold in place, TPA chip should be soldered etc.
The other picture of the amps boards doesn't have signs of this adhesive.

Its common to put this adhesive around SMPS components to keep them from moving around. Often these products are shipped in a container on boat for a few weeks & they get shaken a lot. The Mfr does not want anything coming loose or breaking a solder joint.

See this tear down of a Siglent SDS2000 series oscillocope. There is goop on the SMPS components: EEVblog #1309 – Siglent SDS2000X Plus Scope Teardown+Hack – EEVblog

Also Apple TV circuit board: White glue on circuit board


Siglent SMPS, below....
Sig1.JPG

Sig2.JPG

[daniboun]

That's right, it is also the case for all Pascal UMAC modules :

[irribeo]

and the tpa325x icepowers too, but caps and coils tend to vibrate, some posters here use BluTack on their ampboards

[vincepgh]

Originally Posted by Mello4

Its common to put this adhesive around SMPS components to keep them from moving around. Often these products are shipped in a container on boat for a few weeks & they get shaken a lot. The Mfr does not want anything coming loose or breaking a solder joint.

See this tear down of a Siglent SDS2000 series oscillocope. There is goop on the SMPS components: EEVblog #1309 – Siglent SDS2000X Plus Scope Teardown+Hack – EEVblog

Also Apple TV circuit board: White glue on circuit board


Siglent SMPS, below....
Attachment 928655

Attachment 928656

Originally Posted by daniboun

That's right, it is also the case for all Pascal UMAC modules :

Guys, are you serious?!
all pictures simply show caulk on trough-hole components instead of tiny SMD chip on mine photo. The reason to use the caulk/adhesive/whatever - to fix big chunky part in place and/or additional HV protection. However, I'm not PCB design professional like each other in this discussion, I just have some engineering background.

[Mello4]

Originally Posted by vincepgh

Guys, are you serious?!
all pictures simply show caulk on trough-hole components instead of tiny SMD chip on mine photo. The reason to use the caulk/adhesive/whatever - to fix big chunky part in place and/or additional HV protection. However, I'm not PCB design professional like each other in this discussion, I just have some engineering background.

This silicone was under the bolted down heat sink? Does it wobble, when bolted down on this board?

[bushellj]

There is no silicon on the board I purchased as seen by the photo.

It is quite clear these boards are assembled by hand. They don’t appear to have gone through a solder flow machine. Even the SMD components and the main TPA3255 chip appears to be hand soldered.

So I am guessing there may be a little gang of people assembling these boards and each will do it in their own way.

It appears your board may have the spacer washer also “glued” in place with the silicon. Maybe this was to ensure the heat sink didn’t short out the SMD components under it. There does appear to be quite a lot of solder on some components. Probably just a quick fix !!

So for we have 9 pages of comments and some other non-relevant stuff on this thread but very little about Sound Quality and Upgrades !!

Still waiting for my order for upgrade components from Mouser to arrive - They ship everything from the US so it takes time !! Also some of the Electrolytic’s I ordered were out of stock so still not going to be able to upgrade as I intended until these parts arrive.
.