You'll have to check whether the negative output terminal is connected to PE or not. If it is, connecting them in series will become very tricky, if not impossible without impacting safety.
And you know that a supply voltage of just 38 Vdc will decrease the maximum output power considerably, i.e. to about 60 %?
Best regards!
And you know that a supply voltage of just 38 Vdc will decrease the maximum output power considerably, i.e. to about 60 %?
Best regards!
Hi
have seen you are from France
Do you know where can I buy 48V MeanWell 48V/7A in France
for about 44 EUR?
Is it symmetrical + / - 48 V out put voltage to use fpr power amplifier
Personally I would pick up a second hand (or new) Mean Well 48volt or 36volt SMPS Power Supply off eBay. A 200W or 320/350W one would probably be more than adequate. I actually run all my TPA325x Amplifiers from a Mean Well LRS-200-24 (24 volt) model but turn the voltage up to 30 Volts. For most domestic situations you are only going to be using a few 10's of Watts !!
Audiophonics, one of the best European Audio shop )
MEAN WELL LRS-350-48 Module d'Alimentation a Decoupage SMPS 48V 7.3A 350W - Audiophonics
Other alternative : you can make your DIY Linear 48V PSU for about the same price ) What I did.
For those using the AIYIMA, I've isolated the pull-down for the RESET pin.
If you are encountering the pop sound when turning on, you should be able to up the 105 capacitor value beside the 510k resistor to further delay the start-up of the power amp.
According to the datasheet, it should be at least 250ms delay before the pin goes high. From what I calculated, the pin is at 1.3V at 250ms which is above 0.8V for a low level.
Ideally, swapping the 105 for 1.8uF would put it at 0.8V at 250ms.
I'm still trying to figure out how to eliminate the turn off pop. My thought is using an NPN transistor to pull RESET to ground, upon flicking the switch. If anyone has an idea, do share it.
Oh btw, this TPA3255 amp sounds amazing after swapping to OPA1622. Can't wait to swap the other parts
If you are encountering the pop sound when turning on, you should be able to up the 105 capacitor value beside the 510k resistor to further delay the start-up of the power amp.
According to the datasheet, it should be at least 250ms delay before the pin goes high. From what I calculated, the pin is at 1.3V at 250ms which is above 0.8V for a low level.
Ideally, swapping the 105 for 1.8uF would put it at 0.8V at 250ms.
I'm still trying to figure out how to eliminate the turn off pop. My thought is using an NPN transistor to pull RESET to ground, upon flicking the switch. If anyone has an idea, do share it.
Oh btw, this TPA3255 amp sounds amazing after swapping to OPA1622. Can't wait to swap the other parts
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So you can compare, AIYIMA TPA3251 with Anti Pop VS AIYIMA TPA3255 wihout Antipop :
AIYIMA TPA3251 with AntiPop
I just started modding the AIYIMA 3255 for a friend. In my test setup I noticed quite high hiss level. Anymods to fix that or reduce gain? It came with only 50V caps so a link to a cheap ebay auction with low esr 63V caps would be appreciated! I went through ebay last night but all I could find was either too big or very expensive.
The front switch also creates a loud pop when used, isn't that the mute function? At this point I would not the recommend this amp. My 3e Audio is flawless in comparison and based on that experience and the recommendation on this forum I bought this amp. Any help to fix this mess of an amp would be appreciated!
The front switch also creates a loud pop when used, isn't that the mute function? At this point I would not the recommend this amp. My 3e Audio is flawless in comparison and based on that experience and the recommendation on this forum I bought this amp. Any help to fix this mess of an amp would be appreciated!
lwj5, what is the voltage rating I should look for that RESET pin cap? With the psu and the Aiyima 3255 its much less pop just turning the psu on/off than using the switch.
@impulse60, the source is the DVDD pin, which on the datasheet is from 3-3.6V (3.3V typical). I would use the absolute max or 4.3V for buying the cap, so anything above that will do.
The graph is here: Graphing Calculator
You can play around with V, R and C. Currently, V=3-3.6V, R=510k and C=1uF
RESET should be <0.8V (y-axis) for at least 250ms (x-axis)
The graph is here: Graphing Calculator
You can play around with V, R and C. Currently, V=3-3.6V, R=510k and C=1uF
RESET should be <0.8V (y-axis) for at least 250ms (x-axis)
Hi lwj5.
The part you highlight doesn't appear to have any marking on any of the amps I have seen but is almost certainly the Anti Pop circuitry and only present on the TPA3251 version (Aiyima A04) of the board - It is completely absent on the TPA3255 version (Aiyima A07). You will also note that the main switch on the TPA3251 version is double pole and one of the poles appears to connect with this chip !!
Interesting that it doesn't appear to be the same chip used in the Texas documentation ??? A real pity that they excluded this for the sake of a few $$$ in the TPA3255 version.
Anyone that has the TPA3255 version it is far easier just to control the power by turning the Power Supply on and off - No "Pops" whatsoever !!! Playing with surface mount components is just a pain !!
I also get a very low level hiss from the speakers when there is no signal which I find quite strange for a digital amplifier !!?? It is so low that it cannot be heard at normal listening distances - even with the speaker next to my monitor.
The quality of the sound is exceptional, especially once you have upgraded the Op-Amps to OPA1656 (OPA1622 are much the same) and I have no complaints.
I run mine at about 30Volts from a Mean Well LRS-200-24 which gives me all the power I need for normal domestic use. The main Power Supply Caps seem to be better than most of the other electrolytic caps used in this model so probably the last ones I would want to change.
Yes this version of the Amplifier does not have "Anti Pop". The circuitry included in the TPA3251 version is completely missing in this version !!?? Chinese saving a few $$$
Hi James, I hope you re doing well ?
So finally, which is your favorite one TPA3251 or 55 ?
Did you notice a Power (RMS) difference between both amps ?
Seems inappropriate to blame an entire race of people for your own poor purchasing habits 😉
There's always the TI reference board for $149 if you want a properly designed board with good quality parts. Seems a bargain for 600W+ of well performing audio amplifier.
I think you misunderstood what James wanted to express. This guy is really kind and cool
A few people prefer the AIYIMA Tpa3251over the Ti evm board and the 3E Audio. I am among these people. Take a look at the Tpa 3251 thread so you Can understand why �� I own almost all TPA32XX boards including the very best 360 Customs...
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Hi Opc. I have lots of low cost TPA based boards all made in China by various suppliers and on this thread we have been “Evaluating” which ones are worth considering. Yes there is always the TI evaluation boards - I used to work for TI !!
The point I was making that for the sake of probably a fraction of a dollar cost, on the TPA3255 Amplifier they have omitted the Anti Pop circuit where it is present on the almost identical TPA3251 amplifier board which is clearly designed by the same person or company (or possibly a good clone).
Thanks for that lwj5! Skipping the mute function was clearly going too far since we pay for as switch that is useless.
I just found a symmetrical 26V powersupply.
Would it be possible to use positive and negativ without GND to get 52V? Or will this burn the supply?
I must change voltage sense for beeing more to 24V each rail for a total of 48V.
Would it be possible to use positive and negativ without GND to get 52V? Or will this burn the supply?
I must change voltage sense for beeing more to 24V each rail for a total of 48V.
