So Ive been looking at the Hifimediy T1-M (not the T1) and noticed the estimated power ratings at the bottom of the description which are....
Ouput power (stereo) RMS @4 ohm with supply voltages: 24V - 57W, 21V - 37W, 18V - 31W, 15V - 22W, 12V - 14.5W, 9V - 8W
Are these ratings for each channel or are they the total power output meaning I need to divide them by 2 to get the rating for each channel? Im assuming they are total power so on 24v I would see 28.5w per channel,now I know these are just estimates and there are a lot of variables but Im sure the ratings are not super far off.
Also I see most of their amps are based on the TK2050 chip but I looked at the data sheet for that chip and it doesnt say it can handle a 4ohm load in stereo but it can in BTL. I was just curious as to why it doesnt list 4ohm stereo ratings in the datasheet. I know they use the STA508 in the new batch but that data sheet has nothing about 4ohm stereo either,only 4ohm BTL ratings. I wouldnt think Hifimediy would list their amps as being compatible with 4ohm stereo if they could not handle that load. Every other amp or board I see with that chipset only has stereo ratings down to 6ohm. So what is different about the Hifimediy boards? Why can they handle 4ohm but no other boards with the same chip can? Or can all the TK2050 based chips handle 4ohm stereo with no problem and they just dont list it in the datasheet? I was just curious b/c I was thinking on the T1-M and wanted to make sure my 4ohm speakers would work ok with the board.
One more question about the T1-M board. I see the recommended voltage ratings for this amp/board but what about the amp rating? What is the limit for amperage on this board? What is the recommended amperage if I use a 24v power supply? I will be using 4ohm speakers and I am looking to get the most I can out of this board as far as wattage. Thanks.
Ouput power (stereo) RMS @4 ohm with supply voltages: 24V - 57W, 21V - 37W, 18V - 31W, 15V - 22W, 12V - 14.5W, 9V - 8W
Are these ratings for each channel or are they the total power output meaning I need to divide them by 2 to get the rating for each channel? Im assuming they are total power so on 24v I would see 28.5w per channel,now I know these are just estimates and there are a lot of variables but Im sure the ratings are not super far off.
Also I see most of their amps are based on the TK2050 chip but I looked at the data sheet for that chip and it doesnt say it can handle a 4ohm load in stereo but it can in BTL. I was just curious as to why it doesnt list 4ohm stereo ratings in the datasheet. I know they use the STA508 in the new batch but that data sheet has nothing about 4ohm stereo either,only 4ohm BTL ratings. I wouldnt think Hifimediy would list their amps as being compatible with 4ohm stereo if they could not handle that load. Every other amp or board I see with that chipset only has stereo ratings down to 6ohm. So what is different about the Hifimediy boards? Why can they handle 4ohm but no other boards with the same chip can? Or can all the TK2050 based chips handle 4ohm stereo with no problem and they just dont list it in the datasheet? I was just curious b/c I was thinking on the T1-M and wanted to make sure my 4ohm speakers would work ok with the board.
One more question about the T1-M board. I see the recommended voltage ratings for this amp/board but what about the amp rating? What is the limit for amperage on this board? What is the recommended amperage if I use a 24v power supply? I will be using 4ohm speakers and I am looking to get the most I can out of this board as far as wattage. Thanks.
The Class D Amplifier forum is located here: Class D - diyAudio
Also, according to the datasheet for the ST508: STA508 datasheet, STA508 pdf, 40V 4.5A QUAD POWER HALF BRIDGE - Datasheet4U.com
That's for a bridge amplifier.
The 6.7 ampere load can be run from a 15a 24v SMPS.
HOWEVER, if going without the ST508 output chip, then the TK2050 uses the output ratings here (in the datasheet): TK2050 Datasheet pdf - Stereo 50W Amplifier Chipset - Tripath
TP2050 output chip also looks like a bridge amplifier.
They don't recommend using it with a pair of 4 ohm speakers unless TWO of TP2050 chips are used. Anyway, the limit with one TP2050 output chip, is 45 watts per channel. The 24v would be incorrect if using one TP2050 to drive a pair of 4 ohm speakers. The efficiency falls to about 72%, a problem which will cut the amplifier's capacity, so it can do approximately 35W (each 4 ohm speaker), else explode.
Also, wattage makes heat, not loud--instead, speaker efficiency makes loud. SO, for example, an 87db efficient 4 ohm speaker and a 90db efficient 8 ohm speaker will play about the same loudness; however, a 3db more efficient 8 ohm speaker has done the job on HALF the watts (because, same loud, half the load).
Every time you double the amplifier power you only get 3db more out of the speaker, so of course if you had some 8 ohm speakers with slightly higher efficiency, you could then use that 24v smps (because not killing miniature amplifier with a heavy speaker load). Efficient 8 ohm speaker and the 24v supply, can maximize that amplifier.
On the manufacturer's web page, they state that this particular TK2050 was made for lower power use: Hifimediy T1-M TK2050 9 - 24V The chip manufacturer has not rated that design for use with 4 ohm speakers at all. See the TK2050 datasheet where they say, basically, if you double the load, double the number of output chips. Hifimediy T1-M has a single output chip (not for use with 4 ohm speakers due to breakage). It is designed to use as a pretty sound low power amp, and not for any sort of maximum power prospects.
Also, according to the datasheet for the ST508: STA508 datasheet, STA508 pdf, 40V 4.5A QUAD POWER HALF BRIDGE - Datasheet4U.com
That's for a bridge amplifier.
The 6.7 ampere load can be run from a 15a 24v SMPS.
HOWEVER, if going without the ST508 output chip, then the TK2050 uses the output ratings here (in the datasheet): TK2050 Datasheet pdf - Stereo 50W Amplifier Chipset - Tripath
TP2050 output chip also looks like a bridge amplifier.
They don't recommend using it with a pair of 4 ohm speakers unless TWO of TP2050 chips are used. Anyway, the limit with one TP2050 output chip, is 45 watts per channel. The 24v would be incorrect if using one TP2050 to drive a pair of 4 ohm speakers. The efficiency falls to about 72%, a problem which will cut the amplifier's capacity, so it can do approximately 35W (each 4 ohm speaker), else explode.
Also, wattage makes heat, not loud--instead, speaker efficiency makes loud. SO, for example, an 87db efficient 4 ohm speaker and a 90db efficient 8 ohm speaker will play about the same loudness; however, a 3db more efficient 8 ohm speaker has done the job on HALF the watts (because, same loud, half the load).
Every time you double the amplifier power you only get 3db more out of the speaker, so of course if you had some 8 ohm speakers with slightly higher efficiency, you could then use that 24v smps (because not killing miniature amplifier with a heavy speaker load). Efficient 8 ohm speaker and the 24v supply, can maximize that amplifier.
On the manufacturer's web page, they state that this particular TK2050 was made for lower power use: Hifimediy T1-M TK2050 9 - 24V The chip manufacturer has not rated that design for use with 4 ohm speakers at all. See the TK2050 datasheet where they say, basically, if you double the load, double the number of output chips. Hifimediy T1-M has a single output chip (not for use with 4 ohm speakers due to breakage). It is designed to use as a pretty sound low power amp, and not for any sort of maximum power prospects.
Why would Hifimediy give 4ohm ratings and say it is compatible when it is'nt? They also say you can run it at 24v if it is a steady 24v with no voltage spikes,they recommend a smps. Im not that worried about the voltage,I can get whatever power supply would work best. I am however concerned with the 4ohm load since my speakers are 4ohm,each speaker reads around 4.0-4.1ohm for a final load so having an amp that is stable at 4ohms is important. I know that the imp. load will vary while playing music though. Im just wondering if the T1-M is rated for 4oms but the data sheet says its not then why they list it as compatibe and I wonder if there are a lot of failures with people running 4ohm loads to these boards. They shouldn't be able to say its fine with 4ohm loads if its not and if the boards fail b/c of that then they should be refunded. It seems like people would think poorly of this company if their board fails since right in the description it has ratings for 4ohm stereo. I think I will email them and see what they say about running a 4ohm load. And I will also ask why in the datasheet it is not rated for 4ohm but they say its ok. I was really looking forward to trying out this board and the company one day but until I get some 8ohm speakers I guess it will be on hold.
Oh and sorry if I put this thread in the wrong section,Mods feel free to move it to the correct section.
Oh and sorry if I put this thread in the wrong section,Mods feel free to move it to the correct section.
Ah ha so as long as I keep the voltage lower than 24v it will work with 4ohm? That makes sense but it seems like they should specify that in the description. Not everyone is a pro with this kind of stuff. Including me lol,Im far from it!
I have an old laptop power supply that puts out 19v @ 3.15amps, would that work pretty good for the T1-M? What kind of power could I excpect at 4ohms with that power supply? Thanks for all your help
I have an old laptop power supply that puts out 19v @ 3.15amps, would that work pretty good for the T1-M? What kind of power could I excpect at 4ohms with that power supply? Thanks for all your help
Yes, like most amplifiers, turn down the voltage a bit, if you use a heavy load.
The 19v@3.15a is 19*3.15 = 59va
Multiply by the efficiency of the amp, which is just awful when solo outputs meet 4 ohm speakers; however, it is also Class D, so I guess 72% in that particular case (that the chip manufacturer said not to do). SO, with that power voltage the amp is rated 35 watts per channel. With that amperage you've got 59VA*0.72 =42.4 watts available power. Um? 35+35=70W amplifier running on 42.4W worth of power?
Nope. That power supply doesn't have enough amperage.
What also happens is that 0.72 reversed is 0.28, and for an amplifier that does 70W with 72% efficiency, guess what. . . 70*0.28 = 19.6 Watts will go into your heatsink. OH, see why we didn't want to use 24v so that (57+57= 114)*0.28= 31 watts into the heatsink? Actually the thermal interface area of the chip is not big enough to send that much power into the heatsink, and so the chip emits an olive green colored cloud of smoke with a very peculiar smell that lasts about 3 days (the odor lasts longer than the amp). However, the 19v supply should be alright (if you can get sufficient amperage).
There's one more factor to consider.
An SMPS does its worst quality power (and worst sound) when run at max. For example, if your computer actually has a 300W demand and you installed a 300W SMPS, I doubt it would even start, but just in case it did, the thing would be sheer dee freakin nuts, and rather hard to use. To avoid this, we derate down to 43%. For example, to run a 300W computer professionally, we'd use a 700W SMPS. That's because 700*0.43=301W. . . so the SMPS doesn't strain. An SMPS that doesn't strain probably doesn't emit dirty power.
Meanwhile, amplifiers. . .
70W amplifier with ~72% efficiency. 19V power source. How many amperes SMPS if derated for 43% load? You know that pain from eating ice cream too fast? Well, maths do that to me, so feel free to double check any of this. Anyway, we need 70W into the speaker and 19.6W into the heatsink (this not 100% efficient), so that is 70+19.6=89.6, round to 90W--your load is 90W. WOW! Very sketchy for such a small chip!! Anyway, what SMPS can push 90W without passing 43% of rated SMPS capacity? 210*0.43=90.3. Okay, 210VA (210W) SMPS then. TO convert the 210VA to amperage, divide off the 19v and you get. . . (drumroll). . . Eleven amperes. Actually a 10a might survive alright. But, 3a is not enough.
When the load is 4.7a, you need an 11a SMPS to run it as cleanly as possible. An 11a SMPS runs at 4.73a when at 43% of maximum capacity. Remember SMPS is a switchmode technology, which basically means that it takes micro-naps, a lot and very quickly; however, if it is not allowed to do that, which happens at 100% load, then it bursts, shuts off or emits dirty power. Anyway, switchmode is supposed to do its switching (micro-naps) about 57% of the time for reliable function.
Ever installed a higher-end video card in a computer and then it just wouldn't work right? Well probably it was compatible with everything Except the SMPS power supply (which emit dirty power when loaded to half or more).
There's some adjustable SMPS on ebay, which might could do the 19vdc@10a spec.
P.S.
What is the voltage rating of the caps on the amplifier board? 35v? Or less? We need to check.
The 19v@3.15a is 19*3.15 = 59va
Multiply by the efficiency of the amp, which is just awful when solo outputs meet 4 ohm speakers; however, it is also Class D, so I guess 72% in that particular case (that the chip manufacturer said not to do). SO, with that power voltage the amp is rated 35 watts per channel. With that amperage you've got 59VA*0.72 =42.4 watts available power. Um? 35+35=70W amplifier running on 42.4W worth of power?
Nope. That power supply doesn't have enough amperage.
What also happens is that 0.72 reversed is 0.28, and for an amplifier that does 70W with 72% efficiency, guess what. . . 70*0.28 = 19.6 Watts will go into your heatsink. OH, see why we didn't want to use 24v so that (57+57= 114)*0.28= 31 watts into the heatsink? Actually the thermal interface area of the chip is not big enough to send that much power into the heatsink, and so the chip emits an olive green colored cloud of smoke with a very peculiar smell that lasts about 3 days (the odor lasts longer than the amp). However, the 19v supply should be alright (if you can get sufficient amperage).
There's one more factor to consider.
An SMPS does its worst quality power (and worst sound) when run at max. For example, if your computer actually has a 300W demand and you installed a 300W SMPS, I doubt it would even start, but just in case it did, the thing would be sheer dee freakin nuts, and rather hard to use. To avoid this, we derate down to 43%. For example, to run a 300W computer professionally, we'd use a 700W SMPS. That's because 700*0.43=301W. . . so the SMPS doesn't strain. An SMPS that doesn't strain probably doesn't emit dirty power.
Meanwhile, amplifiers. . .
70W amplifier with ~72% efficiency. 19V power source. How many amperes SMPS if derated for 43% load? You know that pain from eating ice cream too fast? Well, maths do that to me, so feel free to double check any of this. Anyway, we need 70W into the speaker and 19.6W into the heatsink (this not 100% efficient), so that is 70+19.6=89.6, round to 90W--your load is 90W. WOW! Very sketchy for such a small chip!! Anyway, what SMPS can push 90W without passing 43% of rated SMPS capacity? 210*0.43=90.3. Okay, 210VA (210W) SMPS then. TO convert the 210VA to amperage, divide off the 19v and you get. . . (drumroll). . . Eleven amperes. Actually a 10a might survive alright. But, 3a is not enough.
When the load is 4.7a, you need an 11a SMPS to run it as cleanly as possible. An 11a SMPS runs at 4.73a when at 43% of maximum capacity. Remember SMPS is a switchmode technology, which basically means that it takes micro-naps, a lot and very quickly; however, if it is not allowed to do that, which happens at 100% load, then it bursts, shuts off or emits dirty power. Anyway, switchmode is supposed to do its switching (micro-naps) about 57% of the time for reliable function.
Ever installed a higher-end video card in a computer and then it just wouldn't work right? Well probably it was compatible with everything Except the SMPS power supply (which emit dirty power when loaded to half or more).
There's some adjustable SMPS on ebay, which might could do the 19vdc@10a spec.
P.S.
What is the voltage rating of the caps on the amplifier board? 35v? Or less? We need to check.
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