Guys,
I don't know if anybody can answer this "newbie" question: using the TI-EV Board (apparently optimized for a 4 ohm load) on an 8 ohm speaker - does one get more or less high frequency output - in other words: is replacing those 1uF caps useful or not (new coils are already on the way)?
I don't know if anybody can answer this "newbie" question: using the TI-EV Board (apparently optimized for a 4 ohm load) on an 8 ohm speaker - does one get more or less high frequency output - in other words: is replacing those 1uF caps useful or not (new coils are already on the way)?
D
Deleted member 148505
You can download LC Filter designer tool. Using 10uH+1uF only adds around +0.8dB at 20kHz and +3dB at 40kHz, so unless your speaker has an extended frequency tweeter, you won't notice the high frequency difference.
LCFILTER-CALC-TOOL Design tool | TI.com
LCFILTER-CALC-TOOL Design tool | TI.com
D
Deleted member 148505
Hi Pete,
What's the complete part number of the inductor that you've used? my 6.8uH coilcraft has better "highs" compared with the 10uH coilcraft one..
Regards,
Lester
Attachments
I’ll get back to you on that Lester. I have to head off to work. As I remember they may even be 20uH units.
Pete
D
Deleted member 148505
Ok thanks, yes the inductor's linearity is more important than the inductance value itself. I saw some codaca 10uH inductors that have better linearity than their 7uH counterpart.
BTW: I replaced Coilcraft with Würth coils (same value) and the difference is quite noticeable - equally clear but a lot softer.....go figure.
D
Deleted member 148505
Yup not all inductors are created the same, even Coilcraft SER2918 and VER2923 have different performance graphs even though they have the same flat wire coil and similar structure.
What's important is we need to see the published L vs current graph, otherwise we are just doing trial and error.
Lester: they are Wurth 22uH inductors, part # 7444011715220, and the blue caps should be 0.68uF. I changed out the ones that originally came with the 3e amp to those values based on the values listed in the attached article (see "LC filter Design", pg 6) because my speakers are 8ohm (nominal) and not the 4ohm everyone wants to design their LC filters for on most of these 3255 amps (and I’m guessing everyone wanted to copy the specs on original TI 3255 amp board document).
I just wanted to see if changing the LC filter components brought any greater higher frequency depth & sparkle to the amp. The 3e was a really good amp just out of the box but not as audibly rewarding as my My_ref Fremen EVO A build. I was just fooling around with it and after the addition of the 3.3uF bypass caps plus the necessity of the 20000uF power caps, I thought it finally sounded pretty good.
Cheers,
Pete
Listened a bit more - to my ears the Würth (7443631000) are a major upgrade as the "tone" of the amp sounds so much more lifelike (if that makes any sense)...
D
Deleted member 148505
I added the following to my build:
- Ground loop breaker
- PCB for a capacitive switch controlling a 30A relay
- AC filter
Hello,
I received my HanZao TPA3255 from ebay last week and tested it for couple of day and really enjoyed the sound. Today after playing songs for 1 hour I noticed that right chanel speaker sound reduced drastically. I checked the speakers and the magnet was very hot. No issues on the left side speaker. I changed the speakers and tried anagin. Right side speakers started getting hoter so I stopped testing. I am using a Meanwell LSR 350-24 powersuply set at 24 volts to drive the amp. I have 3 more class D amps which are Topping MX3, Allo Volt + and a 6 chanel TPA3116 amp. 6 chanel TPA3116 amp is also having same issues with one chanel. Only common factor is LSR 350-24 SMPS.
I received my HanZao TPA3255 from ebay last week and tested it for couple of day and really enjoyed the sound. Today after playing songs for 1 hour I noticed that right chanel speaker sound reduced drastically. I checked the speakers and the magnet was very hot. No issues on the left side speaker. I changed the speakers and tried anagin. Right side speakers started getting hoter so I stopped testing. I am using a Meanwell LSR 350-24 powersuply set at 24 volts to drive the amp. I have 3 more class D amps which are Topping MX3, Allo Volt + and a 6 chanel TPA3116 amp. 6 chanel TPA3116 amp is also having same issues with one chanel. Only common factor is LSR 350-24 SMPS.
Yes, whichever speaker is connected to right speaker Terminal is overheating. I am connecting the cables directly to the speaker Terminal on the amp as I am yet to buy a case for it.
Just finished testing the amp. Sharing both left and right dc ofset test reading.
Right chanel: -8.40
Left chanel: 0.00
Is there any way I can correct it. I don't want to return this Amp as shippi g cost and import duties are very high in my country.
