SURE's reply for the polarity and connector issues.
"Thanks for your letter.
I have checked the polarity with our technician and they are indeed opposite.
We feel so sorry for the inconvenience and we will modify this error in our next production.
Regards the size of power connector is 2.5mm*5.5mm. So the 2.1mm*5.5mm connector can not fit into it."
Sent from my iPhone using Tapatalk
"Thanks for your letter.
I have checked the polarity with our technician and they are indeed opposite.
We feel so sorry for the inconvenience and we will modify this error in our next production.
Regards the size of power connector is 2.5mm*5.5mm. So the 2.1mm*5.5mm connector can not fit into it."
Sent from my iPhone using Tapatalk
Thanks! The new board fit perfectly into the little red box. I have a second sample of the Sure 3116 to try this week. I'm hoping it's just as good.
In my SMSL SA-36A Pro TPA3118 amp, I first replaced the 2x 47uF/25V DC decoupling caps (not sure if these are OSCON-type or hybrid-type) with 2x 330uF/25V Panasonic SEPF OSCON caps. This made a significant improvement in sound quality in terms of articulate bass, cleaner treble and warmer midrange. The sound stage became bigger too. After several weeks, I replaced the 8x 470uF/25V Panasonic FM electrolytic caps with 8x 470uF/25V Panasonic M electrolytic caps. My preference would have been to use 4x or 6x 680uF/25V Panasonic FM caps as these have a lower ESR than the 470uF/25V Panasonic FM caps, but they were too tall to comfortably install in such a compact enclosure.
Never the less, the upgrade made a subtle improvement with dynamic transient response and extended bass. Also, the very slight background hiss I heard before with my ear next to the tweeter was further diminished. Overall, I am quite pleased with the parts upgrades, and I've been using this amp as an integrated amp on very warm weather days when I don't want to use my tube amps.
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Thanks! My last two cases came from Ebay. That one in particular was from seller "fan_computer", who is actually in the USA (so fast shipping to me), but still price competitive with the overseas sellers.
I've also built a using case from Context Engineering / San Jose Scientific, as well as one of the Sure branded cases that Parts Express sells. The Sure cases are nice, except they're not a split-body style, so not as convenient to work with (see mine and Lacro's recent posts over on the AudioCircle thread for pics).
As far as the "blacker blacks" comment, don't read too much into that. I spent all my time building the thing, and very little listening to it. I've always noticed a subtle difference in "character" between the 3110 and 3116, though I can't quite put my finger on it. I could quite happily live with either though.
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Keep in mind that the stock Epcos film caps are 3.3uF on the "+" differential inputs. There are two 3.3uF SMD caps (assuming they are ceramic) on the "-" differential inputs. If you are changing the stock film input caps to 2.2uF Mundorf Silver-Oil caps, then ideally, you want to install 2.2uF caps on the "-" inputs to maintain equal impedance on the differential inputs. This was not an issue with modding Tripath Class D amps, but it could be an issue with these Texas Instruments TPA31xx amps.
I should also mention that I installed an Epcos B32921 series 0.047uF/305V metallized film X2 safety cap across the power switch leads on the underside of the amp to eliminate the turn-on pop. The exact part no. is B32921C3473M189. This fit nicely underneath with the proper lead spacing once I trimmed the lead lengths. Sorry I don't have a photo of this installation.
1. for pbtl the values must be the double or the half?
2. how important is it to have the input caps close to the chip?
i would like to try out differential inputs.
but yj didn´t add the holes for C31.
i want to use two identical input caps.
maybe they could be placed outside the board and use the connections of C6 and C7 as inputs with pin-headers?
another thougt is to use caps as big as the original C6 and C32,
connect them to the outputs of C6 and C7,
and use the other end as inputs outside, maybe with two small strips of strip-board...
1. equal
2. I don't know. Source is like 1 meter away, but maybe some kind of filter could be created after the capacitors caused by the 1 to 1.5nH added inductance per 1 mm pcbtrace??? If that isn't added in that 1 meter???
Is this based on actual measurements? I haven't actually measured the capacitance of the two small SMD caps connected to the "-" differential inputs and GND, because I don't want to remove them, measure them, and put them back in place, and I am fine with the stock caps anyway. Seems like it would be best to have both differential inputs for each channel at the same capacitance, which would ideally yield the same impedance.
I still like my highly modded YJ blue/black amp, but I use this strictly as a power amp connected to my tube line stage preamp, while I use the SMSL SA-36A Pro as an integrated amp. I have connected the SMSL SA-36A Pro to the same preamp, and turned the volume pot all the way up, and even though it sounds very good, the modded YJ blue/black amp still sounds more powerful and transparent.
In fact, I still prefer my modded YJ blue/black amp over the stock Sure Electronics TPA3116 amp that I recently received. It's a close race though. The modded YJ amp is a little quieter, has a larger soundstage, sounds a little smoother in the treble and has a more punchy bass. I've mentioned this before that the modded YJ amp has a bit of bloom like a tube amp. Maybe the Sure amp needs more time to burn-in--who knows. I know one thing is certain, and I will install some 330uF/25V Panasonic SEPF OSCONs on the Sure amp as soon as my Mouser order arrives this week. These made a significant improvement on the YJ amp, and I would expect improvements with the Sure amp.
As best as I can measure without actually completely removing them and measuring them stand-alone, they are 3.3uF. They are not film-type SMD caps, but appear to be ceramic-types. I don't know anything about PET film-type SMD caps. I would think that they would be significantly larger than the stock SMD caps, and you would need special reflow tools to apply them so that you don't destroy the metallized PET film. The PPS film-types are what I'm familiar with, and you still need to be careful not to overheat those even though PPS is a higher temperature polymer than PET.
They're from the manufacturer. Ceramics change with the amount of power applied. It's a design feature you might call it... More than one electronics engineer has to learn the hard way. However they might be says 4.7uf or something to compensate already from the factory.
I'm certainly curious if the Sure amp could be modded with just capacitors to equal the heavily modded YJ. Basically whatever you claim is the best is going to be my next version (including mods).
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That makes sense regarding the ceramic caps.
As for the Sure amp vs. the modded YJ blue/black amp, the Sure amp is hands-down a better amp in stock form vs. the YJ amp in stock form. Based on my limited experience using the Panasonic OSCONs in the SMSL and YJ amps, I would expect improvements to the Sure amp as KJA 2013 has reported (and lacro in an indirect way).
Just to throw another wrench into the woodwork, I have four 22uH CoilCraft MSS1583-223MEB SMD inductors on their way to try out. These are a more compact form factor than the CoilCraft 10uH SER2915l-103KL inductors on my modded YJ amp, and since some here insist that 10uH inductors and .668uF caps are the wrong LC filter combination for my 8 ohm nominal impedance Klipsch Forte II speakers, I'll try these.