Been listening to this on the desktop rig for almost an hour. This new Alps pot and cabling wires have brought more transparency and open soundstage. It finally sounds on-par with the A04 I'd say. The heat sink seems to heat up faster and remain a little warmer from applying new thermal paste.
Here's an updated drawing... I guess if you'd want to run an external fan off the factory housing after cutting the case, then you can jumper right off the power LED terminal, go figure...
Here's an updated drawing... I guess if you'd want to run an external fan off the factory housing after cutting the case, then you can jumper right off the power LED terminal, go figure...
Very nice thread 🙂
Are you using lm4562 ? I have done some op amp rolling with my 2 Aiyimas a04 , comparing them side by side. The sound with 4562 is clearly better than ne5532 and the difference between LM4562 and opa1612 is only of different caracter. In my opinion, the lm4562 has better bass punch and the opa1612 has a bigger soundstage. On the Swedish forum Faktiskt.se we have investigated my original ne5532 from Aiyima a04 with measurements and it was not a fake one.
Very subjektive: Maybe the tpa3255 and 3251 chip need different op amps for perfect system matching?, they seems to have slightly different caracters. The 3255 has more bass and 3251 is slightly leaner ( in my opinion ). I found that with Aiyima a04 I prefere the lm4562 . With my tpa3255 , the opa1612 seems a better match.
Are you using lm4562 ? I have done some op amp rolling with my 2 Aiyimas a04 , comparing them side by side. The sound with 4562 is clearly better than ne5532 and the difference between LM4562 and opa1612 is only of different caracter. In my opinion, the lm4562 has better bass punch and the opa1612 has a bigger soundstage. On the Swedish forum Faktiskt.se we have investigated my original ne5532 from Aiyima a04 with measurements and it was not a fake one.
Very subjektive: Maybe the tpa3255 and 3251 chip need different op amps for perfect system matching?, they seems to have slightly different caracters. The 3255 has more bass and 3251 is slightly leaner ( in my opinion ). I found that with Aiyima a04 I prefere the lm4562 . With my tpa3255 , the opa1612 seems a better match.
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Thank you and I can concur. The factory A07, although more powerful, has a slight edge/grit/forward midrange on all my setups. Post #35 to 38 is where I tried the LM4562, running on my main rig (Modified Polk RTA-8TL's). Impressed, I also took it to the shop and ran it on my desktop rig and was equally impressed by the new-found clarity/resolution. I also tried it on the separate shop rig (Custom TMMs)... Excellent sound when the equipment is not running lol. A day or two later, brought back to the house and installed it in my modified Polk 5B garage setup, again was impressed and convinced of the improvement. I had previously auditioned all 4 systems with the un-modded A04, that I came to conclude could actually be an inexpensive permanent solution to all of them. The main rig needing a bit bigger power supply of course.
These 3251/5 amps are hidden gems IMO, and will shake up the market if they already haven't. I started following your 3255 thread because I will build/modify another 3255 and that looks to be the best starting platform/board. All blessings.
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Looks like I'll be receiving a 3255 PFFB board to incorporate soon. Looking forward to comparing myself.
I put in a question to @3eaudio about whether or not the machined heat spreader plate needs to be electrically isolated. Anybody build this and attach directly to alloy housing with or without hum/noise issues after final assembly?
I'm testing a new thermal transfer substrate and would prefer the black-oxide M3 machine screws over nylon if possible, reason for asking....
I'm testing a new thermal transfer substrate and would prefer the black-oxide M3 machine screws over nylon if possible, reason for asking....
Got shop time to work on the XS-3E billet case. Since this one's not getting a volume pot and large dial, I revised the design to eliminate the rear attachment plate. The goal was to allow for only two hidden stainless bolts for assembly. The rear flats are for input/output/power mounts....
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The only improvement I could suggest on this board is making the 12V accessory solder point holes larger diameter. I had to re-do the power LED leads by removing half the strands from supplied 18g wire....
I added thermal compound to entire perimeter so case will distributes heat evenly...
May come back and re-route power button wires...
May come back and re-route power button wires...
For now I glued the XLR connectors in and will get plated alloy XLR housings.
Doing some testing and Interesting that the Aiyima A04 32V 5A SMPS will NOT power this board up.
I tested the el-cheapo 36V 5A SMPS and it powers right up. What I can say is that the alloy case housing is definitely ridding the EMF/RFI from it just a foot away. The amp is DEAD silent unless I remove the billet cover, then I heard some errant noise with ear right to speaker (Testing on B&O C30's)...
Back to the tunes...Cal Tjader on vibes...Wonderful
Doing some testing and Interesting that the Aiyima A04 32V 5A SMPS will NOT power this board up.
I tested the el-cheapo 36V 5A SMPS and it powers right up. What I can say is that the alloy case housing is definitely ridding the EMF/RFI from it just a foot away. The amp is DEAD silent unless I remove the billet cover, then I heard some errant noise with ear right to speaker (Testing on B&O C30's)...
Back to the tunes...Cal Tjader on vibes...Wonderful
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Had a 4 hour listening session today and the case never got more than warm to the touch. I can also report that this 3E board has ZERO thumps/pops on start-up or shut-down.
I found a set of threaded panel XLR connectors, but haven't stumbled upon Neutrik threaded body connectors. Anyone seen these before?
I've thoroughly tested and put the 3E PFFB board through it's paces with the el-cheapo 36V supply and the new Meanwell 48V supply. Already excited about the XRK-3255 PFFB build using this 48V-10A SMPS as it is dead quiet, has ample bass punch at any listening level and most importantly fits my case design.
I'll be compartmentalizing the case with a 1/4" inner alloy plate between the PS and XRK board to negate any possible RF interference...
I'll be compartmentalizing the case with a 1/4" inner alloy plate between the PS and XRK board to negate any possible RF interference...