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Old 13th May 2006, 10:54 PM   #1
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Default Sonic Impact T & Heat

Just got a Sonic Impact T, and I know a lot of people here have one, so I have a couple of initial concerns. After a few hours the top of the case is pretty warm (87db 6ohm bookshelf speakers), hot even. Would it be prudent of me to drill holes in the top of the case for cooling, seeing as it has no heatsink? I'm very nervous about blowing this cheap amp, because it's my second SI T amp in a month, after I blew up the first one! (By switching the walwart polarity to "-"). So I dont have much confidence in the "built-in protection" claimed and I want to be careful with this one!

Also, what's a good power supply to use with this thing? I have some 13v and 15v walwarts. The manual says "12v or 14v" but again, I'm nervous about blowing the amp if I go above 12v. Is that a reasonable concern or can it take 14v as the manual implies, even at long listening sessions?

I hear the amp really comes into its own after burn in, but the neighbours might not like 150 hours non stop of loud blaring music... is burn-in as effective with the speakers not working, or does the amp need a load from the speakers to burn-in effectively?
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Old 13th May 2006, 11:36 PM   #2
cpemma is offline cpemma  United Kingdom
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Are these warts regulated? An unregulated one can go way over the label voltage on light loads, and music is a light load >95% of the time.

If not, you could make up a regulated 12V supply with the 15V wart and an LM7812, plus the datasheet capacitors and maybe a big stiffener cap. Going nearer 14V (with a low-dropout regulator such as the 3A MIC29302BT) will give you a bit more undistorted power, but if you want it loud into inefficient speakers better cooling is a must.

Heat is a result of volume setting rather than supply voltage; higher supply allows higher volume so some restraint is needed.
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Old 14th May 2006, 04:58 AM   #3
Pano is offline Pano  United States
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The new generation of Sonics does not have good cooling. There used to be a generous solder slug under the chip, but not any more. So the poor little fellows get hot. There are ways to correct this, but it sounds like after your bad luck, you don't want to do too much.

As for power, just get a small 2 or 3 amp switch mode power supply. 12 volts. They work very well with the Sonic. You should be able to a "wall-wart" of "line lump" version for a low price.

Best of luck with it!
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Old 14th May 2006, 07:22 AM   #4
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Quote:
Originally posted by cpemma
Are these warts regulated? An unregulated one can go way over the label voltage on light loads, and music is a light load >95% of the time.

If not, you could make up a regulated 12V supply with the 15V wart and an LM7812, plus the datasheet capacitors and maybe a big stiffener cap. Going nearer 14V (with a low-dropout regulator such as the 3A MIC29302BT) will give you a bit more undistorted power, but if you want it loud into inefficient speakers better cooling is a must.

Heat is a result of volume setting rather than supply voltage; higher supply allows higher volume so some restraint is needed.
Sorry, I forgot to mention... I don't have a technical training background. So naturally, I dont know what a "datasheet capacitor" is, or a "stiffener cap", an LM7812, a 3A MIC.... More importantly, I don't know how to tell if my walwart is regulated or not? If it isn't, then what's a good walwart to use with the Sonic Impact, that might be better than the one Sonic Impact sell?

If despite having a good walwart, "better cooling is a must" if I play at louder volumes, then what is "better cooling"? Is drilling holes into the cover as I suggested, sufficient enough to cool these chips, or are people using more radical means to do so?
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Old 14th May 2006, 09:48 AM   #5
Pano is offline Pano  United States
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I don't know what is being sold to power the Sonic, but the Super-T power supply will work and is very nice. From the same company.

For best cooling, you'll have to do some soldering and mechanical work, and you may not want to. But holes in the case will help. Just be sure to remove the top before you drill! Don't want to drill the circuit board.
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Old 14th May 2006, 02:14 PM   #6
cpemma is offline cpemma  United Kingdom
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Quote:
Originally posted by entropy0
.... More importantly, I don't know how to tell if my walwart is regulated or not? If it isn't, then what's a good walwart to use with the Sonic Impact, that might be better than the one Sonic Impact sell?
Most regulated supplies will brag about the fact on the label. One way to check is to measure the output voltage with no or little load, if it's a few volts high it's not regulated.

The SI supply costs about the going rate for that size (US$20), but does it suit Antigua's mains voltage? I think a minimum would be its 12V 2A rating though a bit more current would be better IMO - say 3-4A.
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Old 14th May 2006, 09:30 PM   #7
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> Most regulated supplies will brag about the fact on the label. One way to check is to
> measure the output voltage with no or little load, if it's a few volts high it's not
> regulated.

...uh... how do I do that, exactly? The probe of my digital multimeter is not going to fit into the female plug at the end....

> The SI supply costs about the going rate for that size (US$20), but does it suit Antigua's > mains voltage?

Antigua?? Oh, that. No, I was too lazy to scroll down the list, I'm in NA on 120v.

>I think a minimum would be its 12V 2A rating though a bit more current would be better
>IMO - say 3-4A.

The SI power supply is apparently a 14v 2a walwart. Is there not a risk of frying the amp if you go above 2a? Say, even 5a?


Quote:
Originally posted by cpemma


Most regulated supplies will brag about the fact on the label. One way to check is to measure the output voltage with no or little load, if it's a few volts high it's not regulated.

The SI supply costs about the going rate for that size (US$20), but does it suit Antigua's mains voltage? I think a minimum would be its 12V 2A rating though a bit more current would be better IMO - say 3-4A.
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Old 14th May 2006, 10:19 PM   #8
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No, the amount of amperes the PSU can deliver is not 'too much'.
If the amp draws a certain current, the PSU has to deliver and if it can not it will result in weak bass, distortion etc. In short the more amperes the better (within limits of course; my 12V 2A switched PSU is plenty for my T-AMP) it acts as your power reserve so to speak. Not so for voltage, this must be strictly within safe operating range which is quite narrow on the T-Amps.
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Old 15th May 2006, 01:09 AM   #9
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If you think its necessary, sure, I'll do some work on designing a cooling system. I decided after reading all these mods people made, I'm going to set about fitting my SI T into another box, with decent RCA plugs and speaker outs. I was thinking of using a small heatsink for a computer chip that I have in my parts box, for the chip in the SI. I'm sure that would work well, but.... how to adhere it to the chip? If I hot glue it, the glue renders the heat sink useless. If I try to drill holes in the PCB, there goes the PCB! I have a small computer chip fan that can fit in the case, but.... now we're getting complicated, and I have worry not only about how to connect it, but what effect the fan drawing power from the 12v supply will have on the sonics that require good clean power from that same supply.

As a matter of fact, I also worry about the effect on sonics from simply cooling the chip. I know from experience that the cooler a part runs the worse it sounds. I'm still not sure if simply putting the board in a larger case would take care of the "potential" problem, without introducing heat sinks and tiny fans...



Quote:
Originally posted by panomaniac
I don't know what is being sold to power the Sonic, but the Super-T power supply will work and is very nice. From the same company.

For best cooling, you'll have to do some soldering and mechanical work, and you may not want to. But holes in the case will help. Just be sure to remove the top before you drill! Don't want to drill the circuit board.
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Old 15th May 2006, 01:09 AM   #10
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Quote:
Originally posted by DocLorren
No, the amount of amperes the PSU can deliver is not 'too much'.
If the amp draws a certain current, the PSU has to deliver and if it can not it will result in weak bass, distortion etc. In short the more amperes the better (within limits of course; my 12V 2A switched PSU is plenty for my T-AMP) it acts as your power reserve so to speak. Not so for voltage, this must be strictly within safe operating range which is quite narrow on the T-Amps.
That's what I thought, thanks. I'm starting to look at the idea of using a computer power supply, since I have a couple of those hanging around. They seem like they may be ideal, as they use 12v. But I also read that they can introduce noise, so I dont know if a computer PS unit will sound better than a 12v 2a walwart.

It might not hurt to try, but that's the bigger mystery. How do I connect the PC power supply so that the SI amp can use it? I've seen someone use a PC power supply with a Charlize, and the photo showed a lot of funky connections, but no info on how to do it....
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