OK, then I can tell you why your Bluetooth units cannot find an on-board Bluetooth chip - there is none. The blue light is a "power ON" lamp. I have had the heatsink off and made quite some modifications on the board. I found no Bluetooth chip.
Now to the power supply. Without modifications, this board is intended to be supplied from a transformer with a center-tap. Around 2x22V secondary. The board includes a rectifier bridge and will generate the symmetrical voltages. What have you used as supply (apart from 24V/10A)?
Now to the power supply. Without modifications, this board is intended to be supplied from a transformer with a center-tap. Around 2x22V secondary. The board includes a rectifier bridge and will generate the symmetrical voltages. What have you used as supply (apart from 24V/10A)?
It is probably the 24V version you have tried. The photo shows the 48V version.
This is a single voltage SMPS. It is intended for industrial control systems and may not be useful for audio. As you do not have a symmetrical power supply, the chip under/over-voltage protection has (hopefully) disabled the circuits so they may not have been harmed.
Without a suitable, symmetrical supply voltage there is no hope the amplifier is going to work.
This is a single voltage SMPS. It is intended for industrial control systems and may not be useful for audio. As you do not have a symmetrical power supply, the chip under/over-voltage protection has (hopefully) disabled the circuits so they may not have been harmed.
Without a suitable, symmetrical supply voltage there is no hope the amplifier is going to work.
Hi again, the amplitude (did I use it correctly) from the potentiometer is the same with the input, so I guess my potentiometer is not defective?
The Pre-Amp already arrived but my problem is that I don't have dual 12-15vac, I'm going to finds 2 days from now the transformer that offers both dual 28vac and 12-15vac...
If I don't find it, then I'll have overhaul my current toroidal transformer to meet the requirements...
I was able to buy 12-0-12v transformer for the pre-amp...
An externally hosted image should be here but it was not working when we last tested it.
Here's the pre-amp :
An externally hosted image should be here but it was not working when we last tested it.
at last it is working fine, thanks to you Sir FauxFrench, I almost gave up on this board, for without you I would toss this on the trash
...Anyway, it is now working fine with the pre-amp and I did not bother to check the output or input since it can drive my "600w" 8ohm speakers...
Now this thread can be closed since the amp is working perfectly now, my next step is building this thing up so I could use it
Last question though, my 26-0-26v 6amp transformer heats up around 47C, is it normal after 1 hour use in this amp? If ever, what ampere do you recommend for this chip to maximize it's potential? By the way, it does not heat up anymore compare to before without pre-amp and weak output...
An externally hosted image should be here but it was not working when we last tested it.
I am very happy to hear it works well now. And, I am happy that you had the patience to continue - far too many of my friends gave up on surpass-able problems when we were young. We all have moments where an electronic construction gets seriously annoying. Continuing in that moment is what we learn the most from. And, it feels so good when we finally find a solution.
It is normal that a transformer gets some 10 degrees above room temperature with little loading. Phillipines sounds like a hot place? What you can do is to disconnect the secondary(ies) and see if the temperature remains around 47 degrees. If so, it is the intrinsic core losses. The transformer should not heat up much more from the little loading of the pre-amplifier. The 12Amps you have is far more than needed. You could have done with 0.2-0.5Amps for the pre-amplifier.
More current capacity does not worsen the situation, the transformer only gets bigger and more expensive.
The pre-amplifier you can check for high current consumption by letting it operate and put your finger on the two voltage regulators (U1 and probably U2) near the power input. The voltage regulators should not be unpleasantly hot to touch.
Good luck getting the circuit arranged in a more permanenet way. And, don't use your 600W/8Ohm speakers to their full capacity - you will need your hearing also later ;-))
It is normal that a transformer gets some 10 degrees above room temperature with little loading. Phillipines sounds like a hot place? What you can do is to disconnect the secondary(ies) and see if the temperature remains around 47 degrees. If so, it is the intrinsic core losses. The transformer should not heat up much more from the little loading of the pre-amplifier. The 12Amps you have is far more than needed. You could have done with 0.2-0.5Amps for the pre-amplifier.
More current capacity does not worsen the situation, the transformer only gets bigger and more expensive.
The pre-amplifier you can check for high current consumption by letting it operate and put your finger on the two voltage regulators (U1 and probably U2) near the power input. The voltage regulators should not be unpleasantly hot to touch.
Good luck getting the circuit arranged in a more permanenet way. And, don't use your 600W/8Ohm speakers to their full capacity - you will need your hearing also later ;-))
Last edited:
I am happy as well, even my technician friend gave up on this board and said that TPA3116D2 is better. I'm glad that I have found this forum. I love to learn new things such as this, next project would be the chassis of this amplifier...
Regarding with the transformer, sorry but I am referring with the 26-0-26vac 6amps that I am using in TDA8954, the one that I posted was for the pre-amp testing and later on I will post it in another new thread for converting to DC for my TPA3116D2, hehehe
The ambient temperature during my test was around 28-30C if I'm not mistaken, it is heavily raining that day, the amplifier board no longer heats up, the pre-amp and the 12-0-12vac 12amp has no issue on heating up, just the 26-0-26vac 6amp. I also have 27-0-27vac torodial here but no markings if what ampere does it have, I got it with PMPO 200Wx2 amplifier... Makes me wonder if what ampere should I feed the TDA8954? is the 6amp enough or should I go up? it is said that it can give 2x210w output...
I was able to crank up the volume less than 80% because the speaker is loud in my room not more than 7sqm, it did cancel out the noise from the roof cause by the heavy rain, after that I did lower the volume around 25%. Don't worry much, most of the time the local manufacturer here uses PMPO, it is loud but I doubt that it is really 600w...
Again thank you very much...
Last edited:
Sorry, I mixed up the two transformers.
Some 18 degrees of temperature rise I do not see as a problem. The most important is, there is no obvious flaw like a mounting that causes a current to flow in the mounting structure. See this posting (posting #9):
transformer and heatsink temperature
If you let the transformer run a couple of hours without loading (disconnected from the amplifier), the temperature should be some 5-10 degrees above room temperature. With loading (use of the amplifier), the temperature rise depends on how hard the amplifier is used and accordingly how much current is drawn from the transformer.
I understand you have tested the new amplifier at a good sound level. Then, 18 degrees above room temperature seems reasonable.
On the current rating: 2x26V and 6 Amps leaves a total rated power of 312W.
Rectified, the DC rail-voltages will be close to +/-39V. Rail voltages of 39V will leave a maximum output power (per channel) of 170W in 4 Ohm and 85W in 8 Ohm. Assuming 90% efficiency of the amplifier, 2x170W (4 Ohm) requires some 380W from the power supply. For 8 Ohm speakers, 190W is required from the power supply.
Without taking a reduction of the rail voltages from loading by the amplifier into account, 4 Ohm speakers may (in theory) demand a little more current than available from the transformer (6A/312W). For 8 Ohm speakers, the power supply capacity (312W) is more than adequate.
When loaded (in particular with 4 Ohm speakers), the rectified output voltages from the transformer will reduce. You will no longer have rail voltages of 39V but perhaps 35V. Then, the output power is reduced to 2x136W (4 Ohm). Still assuming 90% efficiency, 302W is required from the power supply. That is within the capacity of the transformer (312W).
In conclusion: with 8 Ohm speakers (what you use) the 2x26V/6A transformer is more than sufficient. Even with 4 Ohm speakers this transformer is sufficient.
On top of these calculations comes the crest-factor of music that results of a considerably lower average loading of the transformer. The transformer is well chosen and you anyway use 8 Ohm speakers.
Some 18 degrees of temperature rise I do not see as a problem. The most important is, there is no obvious flaw like a mounting that causes a current to flow in the mounting structure. See this posting (posting #9):
transformer and heatsink temperature
If you let the transformer run a couple of hours without loading (disconnected from the amplifier), the temperature should be some 5-10 degrees above room temperature. With loading (use of the amplifier), the temperature rise depends on how hard the amplifier is used and accordingly how much current is drawn from the transformer.
I understand you have tested the new amplifier at a good sound level. Then, 18 degrees above room temperature seems reasonable.
On the current rating: 2x26V and 6 Amps leaves a total rated power of 312W.
Rectified, the DC rail-voltages will be close to +/-39V. Rail voltages of 39V will leave a maximum output power (per channel) of 170W in 4 Ohm and 85W in 8 Ohm. Assuming 90% efficiency of the amplifier, 2x170W (4 Ohm) requires some 380W from the power supply. For 8 Ohm speakers, 190W is required from the power supply.
Without taking a reduction of the rail voltages from loading by the amplifier into account, 4 Ohm speakers may (in theory) demand a little more current than available from the transformer (6A/312W). For 8 Ohm speakers, the power supply capacity (312W) is more than adequate.
When loaded (in particular with 4 Ohm speakers), the rectified output voltages from the transformer will reduce. You will no longer have rail voltages of 39V but perhaps 35V. Then, the output power is reduced to 2x136W (4 Ohm). Still assuming 90% efficiency, 302W is required from the power supply. That is within the capacity of the transformer (312W).
In conclusion: with 8 Ohm speakers (what you use) the 2x26V/6A transformer is more than sufficient. Even with 4 Ohm speakers this transformer is sufficient.
On top of these calculations comes the crest-factor of music that results of a considerably lower average loading of the transformer. The transformer is well chosen and you anyway use 8 Ohm speakers.
Last edited:
Nah, I was the one that has a confusing post, mixing things up... Sorry for that.
Yes, I have already browse that link after posting, and I conclude that my transformer is somewhat normal, and also you been lurking in the forum everywhere, hehehe
it's my first time running a unit without case so I got curious regarding the transformer. The music I play requires a lot of power, I know that because when I use the 12v 25a LED PSU on Car Amplifier, the amplifier protects itself when I play the certain music loud enough, but playing normal songs there is no problem at all, on sample is the Kanye Ookay remix if your interested too...
Thanks for your computation, my mind is has difficulty figuring it out after my first read, had to read again to make it clear, hehehe
The Amplifier has 2x210w@4Ohms potential, if ever I replace the transformer to reach that potential, is 24-0-24v 12a would be sufficient or I'll stick with my current transformer because an upgrade isn't worth it given that I'll be using it as a portable sound system that will be played as karaoke/home theater amplifier during Sundays...
For reference :
https://www.nxp.com/docs/en/data-sheet/TDA8954.pdf
To get 2x210W (in 4 Ohm) you will need a 500W regulated power supply with +/-42.5V output voltage. With a non-regulated power supply, an amplifier can never be used to its theoretical maximum because the rail voltages will necessarily lower with increase in output power while the idle mode voltage has to stay below the maximum supply voltage.
Even with 2x210W, you would hardly notice the difference. With 2x210W the cooling of the chip becomes critical and difficult. Not worth the costs and time.
The 2x210W is stated to impress customers, not to be used for much in practice.
Even with 2x210W, you would hardly notice the difference. With 2x210W the cooling of the chip becomes critical and difficult. Not worth the costs and time.
The 2x210W is stated to impress customers, not to be used for much in practice.
Last edited:
Hi
Please dont think you get 2x 210 W out of this amp (...its 10% thd = boom box)
: short exam:if you get out 210W per channel you might have 90% effincency, look at the datasheet figure 23.......so that means you have still 2x21W loss = heat?!!!!
do you know a class A amp? then dont think that 20W per channel heat disappation is nice ...with this kind of heatsink what is mounted !......
temp shut dowm of the amp is a matter of time...sorry...belive Fauxfrench
Last edited:
Thanks for the response...
I want to know what would be the most efficient PSU for my application, I wouldn't like that 2x21w of Heat...
So my 26-0-26vac 6a is sufficient or can I upgrade it? Cooling system would not be much of a problem, it can be worked out...
By the way, what RMS would I get from the output? I guess that 210w was the power consumption?
Planning to use this on dual 600w pmpo speaker box...
I want to know what would be the most efficient PSU for my application, I wouldn't like that 2x21w of Heat...
So my 26-0-26vac 6a is sufficient or can I upgrade it? Cooling system would not be much of a problem, it can be worked out...
By the way, what RMS would I get from the output? I guess that 210w was the power consumption?
Planning to use this on dual 600w pmpo speaker box...
Only when playing sine waves @10% THD; with heavily compressed music this will be max. 1/4 or even 1/8@ 1% THD.Hi
Please dont think you get 2x 210 W out of this amp (...its 10% thd = boom box)
if you get out 210W per channel you might have 90% effincency, look at the datasheet figure 23.......so that means you have still 2x21W loss = heat?!!!!
....
sorry but i mentioned the 2x21W heat for the amp...not the psu
your trafo is a way enough, especially for your room ( i remember 7 qm)
Yes, that is my calculation of my room
I know, that the 2x21w heat would be at the heatsink of the amplifier, that problem is, the heat sink is around 5sqcm I guess, so it would burn up.
I found out that my current Transformer is only producing 26vac 3a per channel, so it is 78W per channel right?
I'll repeat my question in paraphrase form
What would be the most efficient transformer that would at least bring out the value for money in regards with my TDA8954 Amplifier?
Would it be worth the upgrade of the transformer or that upgrade would not be noticeable given that my current transformer is 26-0-26vac 3a/rail...
Thanks!
hi fidgety
as FF wrote...you need a 500W PSU and i guess its a lot of money to get this. Trafo with 2 output windings, filter caps (CRC) is about 132 euro transf - caps = 3 x 10000 µ each rail = 6 x 11 euros..........200 euros sum.
SFB0500-230-24 | Ringkerntransformator, 500VA, Primar 230Vac / Sekundar 2 x 24Vac mit Anzapfung, 10,4A | Nuvotem Talema
Vishay 2222 056 58103 Elektrolyt-Kondensator SnapIn 10 mm 10000 mF 63 V 20 % (O x H) 35 mm x 50 mm 1 St.
i do not think this is a good idea to spend this kind of money.
cheap transfomer
Ringkerntransformator 1 x 230 V 2 x 24 225 VA 4688 mA TC-RKT225/2X24 TRU COMPONENTS
my proposal is tho keep this amp as it is and build a complete housing around (class D = stell housing), so you can get more experienced with building....if you build the PSU part of your amp in a seperat housing you can change easily the psu in the future.
i am not an expert for psu. you ask about efficient trafo. read the power supply thread.
if you want to push you could plan to cool with a silent fan for cooling the amps heatsink.
chris
The amount of EI transformer here is somewhat the same for the price of the board, so an upgrade is okay for me as long as it is worth it. around 30$ more or less...
The housing cost much more here, double than the transformer and board, but the ordinary thin steel housing is much cheaper.
As agreed, I will stick with my current transformer for the meantime
Thanks!
The amount of EI transformer here is somewhat the same for the price of the board, so an upgrade is okay for me as long as it is worth it. around 30$ more or less...
The housing cost much more here, double than the transformer and board, but the ordinary thin steel housing is much cheaper. :)
As agreed, I will stick with my current transformer for the meantime
Thanks!
i bought a second hand old not function amp (home cinema = enough room inside...20 euro) and use the case...the front plate is at the beginning strange but you can change later to a fine wooden plate with your ideas...
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.