Hi,
some week ago I bought a small amp equipped with the TPA3123 from Ebay just
to build a small amp for my wife to use with her smartphone/tablet.
The amp is powered through a (DIY) 50VA (25 Volt DC, 8400 uF smoothing caps) power supply and everything is working good, no noise.
The strange problem occurs if I hit repeatedly on the volume pot (or any other components, components side not on the copper side) I can hear a sound ("toc-toc") that is the same as you would hit on a microphone to check if it's on or off !
Someone could point out the reason for that?
Thank you, regards.
Roberto
some week ago I bought a small amp equipped with the TPA3123 from Ebay just
to build a small amp for my wife to use with her smartphone/tablet.
The amp is powered through a (DIY) 50VA (25 Volt DC, 8400 uF smoothing caps) power supply and everything is working good, no noise.
The strange problem occurs if I hit repeatedly on the volume pot (or any other components, components side not on the copper side) I can hear a sound ("toc-toc") that is the same as you would hit on a microphone to check if it's on or off !
Someone could point out the reason for that?
Thank you, regards.
Roberto
I have not had this issue my self, but have read a bit about it. It could be due to a bad capacitor
http://www.millertechinc.com/pdf_files/MTI%20TN095%20Capacitor%20Noise.pdf
http://www.millertechinc.com/pdf_files/MTI%20TN095%20Capacitor%20Noise.pdf
Interesting article.
On the board there are 4 1000 uF caps that I'm going to replace since they are rated at 25V (the board is "fed" up with 23 V), maybe one or more of them is defective.
For 15 Euro I can't expect first quality components !
Thank you, regards.
Roberto
On the board there are 4 1000 uF caps that I'm going to replace since they are rated at 25V (the board is "fed" up with 23 V), maybe one or more of them is defective.
For 15 Euro I can't expect first quality components !
Thank you, regards.
Roberto
TPA3123
Hi Folks,
I got a couple of these amps, not the SURE ones but similar.
I was very pleased with the one I hooked up, lots of tight bass, and very good soundstage. As one of my test discs I tried Filippa Giordano, a self-titled album, her first I think, and for the first time ever I felt connected, so much so it gave me goose-bumps. I don't throw superlatives around, and I don't know the audiophile talk but the sound was magical to me.
However all is not well, because I happened to have a close ear to one speaker when I fired up Mike Oldfield's Tubular Bells 2. It starts with a simple slow piano melody, but every hammer strike had a "fizz" at the end of each note.
I disconnected the TPA3123, lit up my old Adcom, and repeated the beginning of that track. As expected each piano note was bang on, or at least as bang on as a 23 year old Adcom amp can muster. Very nice, but...
Comparing the old Adcom with the TPA3123, back onto Filippa G, the bass was just as deep and tight (big surprise there), plenty of, if you like, "atmosphere"... the parting of the lips sound, and the intake of breath, the cracking of her voice. It was all there just like the TPA 3123, but it didn't seem as, I dunno, involving.
So two things. The Adcom was a fine amp in its day, and for the TPA3123 to perform even remotely as well as an Adcom GFA-535/2 says something for emerging D class and new technology over the intervening years, especially since the TPA3123 is a two-bob chip probably designed for TV's or alarm clocks.
The more urgent thing though is the extra fizz, which I'm sure I didn't pay for when I bought the amp.
I know only enough to put one of these simple modules together and make it work, so the reason for the fizz eludes me. I prodded and poked, put an extra earth wire from the SMPS earth terminal to ground, which did nothing, all of which leaves me peeved because I know I'm on to something with this amp and I would love to fix the problem. I have another identical board on its way by slow-air so I'll eventually swap them over.
Because the board as it stands comes with not a lot of capacitance I added some extra tank capacitance across the 12v input rails to give the amp some oomph on transients, and I haven't as yet tried it without.
Any suggestions anyone? It seems to me that this amp is so good, and yet falls at the first fence..
Cheers, Martin
Hi Folks,
I got a couple of these amps, not the SURE ones but similar.
I was very pleased with the one I hooked up, lots of tight bass, and very good soundstage. As one of my test discs I tried Filippa Giordano, a self-titled album, her first I think, and for the first time ever I felt connected, so much so it gave me goose-bumps. I don't throw superlatives around, and I don't know the audiophile talk but the sound was magical to me.
However all is not well, because I happened to have a close ear to one speaker when I fired up Mike Oldfield's Tubular Bells 2. It starts with a simple slow piano melody, but every hammer strike had a "fizz" at the end of each note.
I disconnected the TPA3123, lit up my old Adcom, and repeated the beginning of that track. As expected each piano note was bang on, or at least as bang on as a 23 year old Adcom amp can muster. Very nice, but...
Comparing the old Adcom with the TPA3123, back onto Filippa G, the bass was just as deep and tight (big surprise there), plenty of, if you like, "atmosphere"... the parting of the lips sound, and the intake of breath, the cracking of her voice. It was all there just like the TPA 3123, but it didn't seem as, I dunno, involving.
So two things. The Adcom was a fine amp in its day, and for the TPA3123 to perform even remotely as well as an Adcom GFA-535/2 says something for emerging D class and new technology over the intervening years, especially since the TPA3123 is a two-bob chip probably designed for TV's or alarm clocks.
The more urgent thing though is the extra fizz, which I'm sure I didn't pay for when I bought the amp.
I know only enough to put one of these simple modules together and make it work, so the reason for the fizz eludes me. I prodded and poked, put an extra earth wire from the SMPS earth terminal to ground, which did nothing, all of which leaves me peeved because I know I'm on to something with this amp and I would love to fix the problem. I have another identical board on its way by slow-air so I'll eventually swap them over.
Because the board as it stands comes with not a lot of capacitance I added some extra tank capacitance across the 12v input rails to give the amp some oomph on transients, and I haven't as yet tried it without.
Any suggestions anyone? It seems to me that this amp is so good, and yet falls at the first fence..
Cheers, Martin
From lossfound..
[The TPA3123 board is noticeably harsher and hashier in the treble on most speakers than the TA2024 board,]
As an adjunct to my previous post, I wonder if what "lossfound" is referring to is the sound I'm hearing, particularly the word "hashier" which sounds about right, like "fizzy"...
Disappointing if so because this TPA3123 performs so well in other areas.
Dunno then...
Cheers, Martin
[The TPA3123 board is noticeably harsher and hashier in the treble on most speakers than the TA2024 board,]
As an adjunct to my previous post, I wonder if what "lossfound" is referring to is the sound I'm hearing, particularly the word "hashier" which sounds about right, like "fizzy"...
Disappointing if so because this TPA3123 performs so well in other areas.
Dunno then...
Cheers, Martin
Look in tpa3116 thread. I had a fizz on
Piano notes that were forceful and fixed with output snubber circuit before L. 330pF and 10ohm connected to bootstrap to control hash. Sounds fantastic now - fluid vocals and clear piano strikes.
Last edited:
Hash browns
From xrk971
[Look in tpa3116 thread. I had a fizz on
Piano notes that were forceful and fixed with output snubber circuit before L. 330pF and 10ohm connected to bootstrap to control hash. Sounds fantastic now - fluid vocals and clear piano strikes.]
Thank you xrk971 I'll check it out. I'm not entirely familiar with what you propose but I can learn🙂
Cheers, Martin
From xrk971
[Look in tpa3116 thread. I had a fizz on
Piano notes that were forceful and fixed with output snubber circuit before L. 330pF and 10ohm connected to bootstrap to control hash. Sounds fantastic now - fluid vocals and clear piano strikes.]
Thank you xrk971 I'll check it out. I'm not entirely familiar with what you propose but I can learn🙂
Cheers, Martin
Just a few days ago i replaced all of the 4 electrolytics and the "mic sound" disappeared.
Probably one of them was defective.
After almost 5 months of listening to this amp I never noticed any "fizz" or other noise coming from it.
I'm currently using it with 2 100mm car coaxial speakers (4 ohm) but also with my old JBL TLX-2 I didn't listen to any sound disturb.
Regards,
Roberto
Probably one of them was defective.
After almost 5 months of listening to this amp I never noticed any "fizz" or other noise coming from it.
I'm currently using it with 2 100mm car coaxial speakers (4 ohm) but also with my old JBL TLX-2 I didn't listen to any sound disturb.
Regards,
Roberto
Thanks Roberto,
Changing out those caps as you suggest will be easier for me at my current knowledge level than cooking up a snubber addition as suggested by lossfound, however I appreciate everyone's input no matter the difficulty or ease presented.
I've ordered some hopefully better caps than the ones the TPA3123 is presently fitted with, rated at 35v. I though the 25v might be a tad too low, not that I know anything much. They're Nichicon 1000uf/35v. Might have better luck with Nichicon than no-name caps, or as you say, finding a dud the culprit...
Anyway, when they arrive on slow boat from China, I'll whack em in...
I don't know how responsible those 4 caps are for power reserve, so as stated in a previous post I strapped a fairly big cap (2200uf/63v, a size I have a few of) across the voltage rails, in the hope of a bit of oomph on transients, and indeed the amp will still run for a couple of seconds after switching off. Don't know if this would cause problems elsewhere, but I've come across reference to this dodge several times, and it seems to be kosher...
Cheers, Martin
Changing out those caps as you suggest will be easier for me at my current knowledge level than cooking up a snubber addition as suggested by lossfound, however I appreciate everyone's input no matter the difficulty or ease presented.
I've ordered some hopefully better caps than the ones the TPA3123 is presently fitted with, rated at 35v. I though the 25v might be a tad too low, not that I know anything much. They're Nichicon 1000uf/35v. Might have better luck with Nichicon than no-name caps, or as you say, finding a dud the culprit...
Anyway, when they arrive on slow boat from China, I'll whack em in...
I don't know how responsible those 4 caps are for power reserve, so as stated in a previous post I strapped a fairly big cap (2200uf/63v, a size I have a few of) across the voltage rails, in the hope of a bit of oomph on transients, and indeed the amp will still run for a couple of seconds after switching off. Don't know if this would cause problems elsewhere, but I've come across reference to this dodge several times, and it seems to be kosher...
Cheers, Martin
Sorry, meant to give credit to xrk971 for the snubber suggestion. Lossfound gave a credible name to the fizzy sound I was hearing...
Cheers, Martin
Cheers, Martin
Look at how C11 and R11 are connected to the output pin before the inductor. This is the so-called "bootstrap snubber" and is an optional circuit on the TPA3116D2. Many boards made use the standard circuit which doesn't have this, but the TI EVM board has it. I have used both ways and it make a big difference with hash or fizz sound on hard percussion like piano or sibilance from certain female singers. It is not a standard implementation on the 3123 but I don't think it can hurt.
Here is how I implemented it on the back of my board by scraping off varnish to expose ground pads and used existing bootstrap cap pins poking through:
I used 330pF 100v ceramics from AVX and 1/4 watt 10 ohm metal film resistors.
Here is how I implemented it on the back of my board by scraping off varnish to expose ground pads and used existing bootstrap cap pins poking through:
I used 330pF 100v ceramics from AVX and 1/4 watt 10 ohm metal film resistors.
Thanks xrk971,
Sorry for the late reply, only 2 years late, but life sometimes gets in the way and I'd all but forgotten about this thread.
What you suggest looks doable for me so now I'm back on board so to say I'll give this a shot. The second 3123 board I alluded to earlier sits in my gubbins draw along with others, all waiting for me to get around to fixing up, but the 3123 really did sound pretty good and so deserves another crack.
Cheers Martin
Sorry for the late reply, only 2 years late, but life sometimes gets in the way and I'd all but forgotten about this thread.
What you suggest looks doable for me so now I'm back on board so to say I'll give this a shot. The second 3123 board I alluded to earlier sits in my gubbins draw along with others, all waiting for me to get around to fixing up, but the 3123 really did sound pretty good and so deserves another crack.
Cheers Martin
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