I tried battery power
So I tried the 2X100 with car batteries. The sound is much better than my linear supply. The Sure is now approaching the sound of the Hypex or the bridged 3875 so I am encouraged to try a few more mods such as added supply caps on the board and Oscons for the 5v. I took a chance and even went up to 37.2v with three batteries. Wow! what a spark when I put the last clamp down. No heat problems at all with the little fan running on 6v batteries though, and the amp survived several such spark episodes as I went back and forth between 25 and 37. The heat sink was still cool to the touch even when running an output level that was revealing some rising distortion with 25v supplies. The sound is a little different between 25 and 37v. 37v obviously allows the amps to make way more power which helps when really cranking the listening level but starts to change the frequency response, increasing the lower midrange which makes the highs sound a little weaker. 25v is better balanced but the lesser power is evident. I wish Sure offered one of the 27v Meanwell supplies which could be cranked up to 30v where the sweet spot of the Tripath is. Do these Meanwell supplies work better when using the adjustment to go higher than spec or when taking the 36v down as far as it will go? Hopefully the switching power supplies will sound more like the batteries and better than the linear supply as I wouldn't want to run batteries all of the time.
So I tried the 2X100 with car batteries. The sound is much better than my linear supply. The Sure is now approaching the sound of the Hypex or the bridged 3875 so I am encouraged to try a few more mods such as added supply caps on the board and Oscons for the 5v. I took a chance and even went up to 37.2v with three batteries. Wow! what a spark when I put the last clamp down. No heat problems at all with the little fan running on 6v batteries though, and the amp survived several such spark episodes as I went back and forth between 25 and 37. The heat sink was still cool to the touch even when running an output level that was revealing some rising distortion with 25v supplies. The sound is a little different between 25 and 37v. 37v obviously allows the amps to make way more power which helps when really cranking the listening level but starts to change the frequency response, increasing the lower midrange which makes the highs sound a little weaker. 25v is better balanced but the lesser power is evident. I wish Sure offered one of the 27v Meanwell supplies which could be cranked up to 30v where the sweet spot of the Tripath is. Do these Meanwell supplies work better when using the adjustment to go higher than spec or when taking the 36v down as far as it will go? Hopefully the switching power supplies will sound more like the batteries and better than the linear supply as I wouldn't want to run batteries all of the time.
You can use battery all the time if you use a charger when amp is not in use. A fully charged of twin set of 24 v batteries(4*12V) will last for at least 10 hr(playing at moderate level), voltage drop from 25.2V to about 23.5V
32v supply?
Can your 36v supplies adjust down to 32v? What happens to the performance of a switch mode power supply when you lower the voltage to the limit of the adjustment? Too bad Sure doesn't sell a 27 or 30v supply. It is nice to know that you can run the new style amps that come with fan cooling at 37v and high power into 6ohms without the heat sinks even getting warm.
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Can your 36v supplies adjust down to 32v? What happens to the performance of a switch mode power supply when you lower the voltage to the limit of the adjustment? Too bad Sure doesn't sell a 27 or 30v supply. It is nice to know that you can run the new style amps that come with fan cooling at 37v and high power into 6ohms without the heat sinks even getting warm.
I'm running three Sure 2*100Ws, one on each main speaker (biamped with active crossovers) and one on the subwoofer (dual voice coil). The mains are running at 32 volts and the sub is at 36 volts. All are running on smps bricks from HP and Kodak laser printers (non-adjustable). The 32v bricks make 2.5 amps, the 36v brick makes 3 amps.
I have not tried the mains on the 36v brick and I find it hard to make critical discriminations on a subwoofer. So far I'm very happy with the set up, but I have not done blind comparisons to anything better.
I'm waiting for some Panny FM tank caps from Digikey. I want to finish the mods to the boards before I try swapping power supplies.
Also, I'm not the "golden ear" type. The boards sound good to me. Others may hear artifacts that I don't hear and that's fine. I'm not really searching for the "best" sound. I'm trying different things to see what the effects are; trying to educate myself about how all these things work together.
My actual listening demands are pretty modest. Witness the fact that my home theatre in the TV room is a Sharp 1-bit amp/receiver/dvd player with Wharfedale speakers and an 8" Jamo sub. Decidedly mid-fi.
The Tripath stuff is in the living room where I do my critical music listening and sound system experimenting.
-dr_vega
Don't overinterpret, its just a simulation. The idea is to be flat in the audible region up to 20kHz (provided you are a toddler). Beyond the audible you want the graph to go south in order to quench the switching frequency of the chip.
1dB up is nothing compared to what your speaker will do to the signal. I simuated it to be a resistor, but you know its not.
Bricks
That's right. You are using bricks. I remembered you had mentioned 32 and 36v and assumed they were the Meanwells. The sales man at Sure is pushing me to use the 24v supplies, probably because they had many of the fanless boards come back burnt, but I think I will go ahead and order the big 36v supplies and see how far they turn down. If they will go 10% I should be able to get close to 32v.
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That's right. You are using bricks. I remembered you had mentioned 32 and 36v and assumed they were the Meanwells. The sales man at Sure is pushing me to use the 24v supplies, probably because they had many of the fanless boards come back burnt, but I think I will go ahead and order the big 36v supplies and see how far they turn down. If they will go 10% I should be able to get close to 32v.
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Indeed! It's just a simulation and I am not even sure what my ears are capable of hearing (or not hearing)
I think I will try the simpler output filter and hear for myself once I can get hold of 11uH Carbonyl-E toroidal inductors.
Thanks again!
I bought a 24V Meanwell from Sure and I am currently using it at 29V. On my unit, there is a small white knob thingy that I could change the output voltage and the maximum I can get out of it is 29V. If 29V is enough for you, you could try the 24V Meanwell, especially considering its price.
I cannot give you detailed comparisons to other alternatives as I haven't tried, but I can certainly say that I have been happy with it especially in comparison to my old brick SMPS rated at 12V, 3A.
Inductor value can drop 50% with rising current
I just noticed something important in the data sheets of the Bourns/J.W Miller inductors I was about to order. For low loss cores, the inductance can change by 50% as the current increases toward to full rating! So, the 22uH inductors that Sure has installed may actually provide only 11uH in use which makes the stock filter much flatter through 20k than the printed value would indicate.
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http://www.bourns.com/data/global/pdfs/bourns_jwmiller_magnetics.pdf#search="2100"
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Have a look at page 23.3
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I just noticed something important in the data sheets of the Bourns/J.W Miller inductors I was about to order. For low loss cores, the inductance can change by 50% as the current increases toward to full rating! So, the 22uH inductors that Sure has installed may actually provide only 11uH in use which makes the stock filter much flatter through 20k than the printed value would indicate.
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http://www.bourns.com/data/global/pdfs/bourns_jwmiller_magnetics.pdf#search="2100"
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Have a look at page 23.3
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Coil removal
Place a small screw driver under one side of the coil by the solder. Use the soldering iron tip to pry up, along with the screw driver to lift one side. With one side up, the second side can be pushed off the pad easily with the iron tip
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Place a small screw driver under one side of the coil by the solder. Use the soldering iron tip to pry up, along with the screw driver to lift one side. With one side up, the second side can be pushed off the pad easily with the iron tip
Meanwell 27V DC 13A 351W
I got my Meanwell 27V DC 13A 351W from Sure Electronics about two months ago. The Meanwell 27V will go up to 32V with the pot adj. I'm running two 2*100W boards at 30V - still testing. Just installed them in a case two days ago).
Great Thread - Thanks guys for all the information and making me aware of
this great little board.
I got my Meanwell 27V DC 13A 351W from Sure Electronics about two months ago. The Meanwell 27V will go up to 32V with the pot adj. I'm running two 2*100W boards at 30V - still testing. Just installed them in a case two days ago).
Great Thread - Thanks guys for all the information and making me aware of
this great little board.
A question about the power supply. I have a trafo (2x18 VAC) and something similar to this: http://bit.ly/aRyBL
In goes 18 AC and out comes 28 DC. However normally I can connect the [-][GND][+] to the PCB of my amp with 3 wires. In this case I can only connect the [GND] and [+] ? Is this correct?
In goes 18 AC and out comes 28 DC. However normally I can connect the [-][GND][+] to the PCB of my amp with 3 wires. In this case I can only connect the [GND] and [+] ? Is this correct?
The mute does not turn the amp on and off, it "disconnects" the speakers while the amp is on. It's most common use is to keep the speakers disconnected until after the thump when you first turn on the amp.
Because the standby current is so low in digital amps, it costs almost nothing to leave them on all the time. Then they will start playing when a signal arrives.
-dr_vega
IMHO all upgrades you want to do are worth doing, just for what you learn. As to improving the sound, I doubt if it will make an audible difference. They are part of the feedback loop and not directly in the path of that. And smt caps tend to be very fast. I doubt if you could improve them much, perhaps going to Oscons. You might want to upgrade resistors R15, R22, R28, and R33. They also bleed off the feedback loop.
But the real gains in the feedback come from replacing resistors R13, R17, R25, and R31. They are directly in the feedback signal path and should be matched to your power supply voltage (see my previous posts).
Anyone else want to weigh in on replacing surface mount caps. Can you improve them?
-dr_vega
I fried it
I inadvertently interrupted the connections to some tank caps before the board and reconnected them again while the amp was under voltage.
There was a smacking sound of something blowing.
Now I measure some 2 Ohms across VCC and GND, it draws a lot of current when I try to run it and the power led doesn't come on. I tried and disconnected all the tank caps I have onboard - they are not to blame.
When I hook the whole amp up to my lab power supply both tp2050 get hot, but apparently nothing else.
I can check that the LM317 is OK, b/c I can run that separately as I interrupted the traces on the PCB as audio1st has taught us (http://www.diyaudio.com/forums/showpost.php?p=1860518&postcount=170). When I interrupt the jumper to Vcc and apply the voltage only to Vin of the LM317, the power led does shine.
However, in this configuration (no voltage on Vcc, voltage on Vin) the right channel TP2050 gets hot, left doesn't.
Any hope?
I inadvertently interrupted the connections to some tank caps before the board and reconnected them again while the amp was under voltage.
There was a smacking sound of something blowing.
Now I measure some 2 Ohms across VCC and GND, it draws a lot of current when I try to run it and the power led doesn't come on. I tried and disconnected all the tank caps I have onboard - they are not to blame.
When I hook the whole amp up to my lab power supply both tp2050 get hot, but apparently nothing else.
I can check that the LM317 is OK, b/c I can run that separately as I interrupted the traces on the PCB as audio1st has taught us (http://www.diyaudio.com/forums/showpost.php?p=1860518&postcount=170). When I interrupt the jumper to Vcc and apply the voltage only to Vin of the LM317, the power led does shine.
However, in this configuration (no voltage on Vcc, voltage on Vin) the right channel TP2050 gets hot, left doesn't.
Any hope?
I fried it too! I heard a hissing noise while playing which I did not hear before so resoldered some points. I removed some surplus solder (in the wrong way I am affraid with a small screwdriver). I also removed the RCA connectors because I was affraid they could function as antenna. Then I started it up and heard a high peeping noise. One test speaker is no longer with us. RIP.
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