Further notes
I've noticed that now the tripath chip gets VERY hot (I'm not sure exactly how hot, but it's too hot to touch) within about 5 seconds of powering on (I've checked the powersupply, it's delivering a lovely clean 13.4V, well below max for the tripath). This, along with the lack of any amplification, makes me suspect a short, but I can't see anything wrong.....can anyone suggest some test points I could use to see what might be going on?
I've noticed that now the tripath chip gets VERY hot (I'm not sure exactly how hot, but it's too hot to touch) within about 5 seconds of powering on (I've checked the powersupply, it's delivering a lovely clean 13.4V, well below max for the tripath). This, along with the lack of any amplification, makes me suspect a short, but I can't see anything wrong.....can anyone suggest some test points I could use to see what might be going on?
Hi,
I'll try to get that photo posted here sometime in the next hour or two (Eastern Australia is at GMT +11 at the moment, so it's 9PM and thus getting late - forums are a pain as a result). In the meantime, I'll reverse that connection......wouldn't be surprised if that's what's freaking out the chip, since that resistance regulates the input gain, doesn't it? Anyhows, we'll see.
I'll try to get that photo posted here sometime in the next hour or two (Eastern Australia is at GMT +11 at the moment, so it's 9PM and thus getting late - forums are a pain as a result). In the meantime, I'll reverse that connection......wouldn't be surprised if that's what's freaking out the chip, since that resistance regulates the input gain, doesn't it? Anyhows, we'll see.
Here's the photo's - looking closely, it seems that some pins are bridged on the chips output side - but maybe they are V+ and V-? and that there's a lifted pad on an output channel pin (from me trying to remove some excess solder bridging that pin)...but maybe I miscounted. Have a close look please, any help is greatly appreciated.
Attachments
Hi , you are connecting the resistors to the wrong terminals.. Your caps are also connected to the wrong terminals.. R8 connects to CH1 not GND and R14 connects to CH2 not GND. The caps connect to CH1 and CH2, the other end of the caps connect to the centre pin of your new rca's. The ground of the rca's connects to GND..The attached picture just shows where the caps connect to the board. Ignore the arrows..
Attachments
Hi,
Yeah, I did test the amp before playing with it, so I know it DID once work. Unfortunately I started modifying it to add a preamp and volume control, without testing it along the way....I've reversed what I could to get it back to this state. My concern over those pins was more about the general ugliness compared to the other side of the chip, so if anything was to be wrong, I figured it'd be over there. I'll reverse the connections you mentioned (will take ten seconds, just need to swap what's in the screw terminals) and see if it helps.
Yeah, I did test the amp before playing with it, so I know it DID once work. Unfortunately I started modifying it to add a preamp and volume control, without testing it along the way....I've reversed what I could to get it back to this state. My concern over those pins was more about the general ugliness compared to the other side of the chip, so if anything was to be wrong, I figured it'd be over there. I'll reverse the connections you mentioned (will take ten seconds, just need to swap what's in the screw terminals) and see if it helps.
Often cleaning the flux/rosin from the board can make things such as shorts a lot easier to see. Ideally use isopropyl alcohol or methylated spirits for this.
My TA2024 is still sounding excellent btw. One minor complaint is that at times it can sound a bit saturated at the top end, with certain trebles turning into more of a hiss. Also the board is very revealing and any track hiss (white noise) makes it's way through to the speakers. I'm driving it with an unmodified squeezebox 3 as the source.
My TA2024 is still sounding excellent btw. One minor complaint is that at times it can sound a bit saturated at the top end, with certain trebles turning into more of a hiss. Also the board is very revealing and any track hiss (white noise) makes it's way through to the speakers. I'm driving it with an unmodified squeezebox 3 as the source.
No clicks or pops when plugging in power or RCA jacks. Hard to say without a 'scope, but it doesn't seem like anything is making it to the output at all.
No measurable DC offset at input. 10mV at output without speaker connected, 1 - 4mV at output with speaker connected.
Still the same problem. Chip gets very very hot very quickly after applying power.
No measurable DC offset at input. 10mV at output without speaker connected, 1 - 4mV at output with speaker connected.
Still the same problem. Chip gets very very hot very quickly after applying power.
My opinions of this unit...
I've been running one of these for several days now, in place of a modified original Sonic Impact T amp. I've always liked the Sonic Impact's sound, which is wide and deep, with a nice but not overdone high end and decent, though not perfect bass. This unit sounds quite different from that unit. First off, it's bass GRABS you-it's MUCH tighter. This is with only a 1 uf input capacitor across the .3 already there. I also pulled out the other caps and the resistors specified in earlier posts. The high end here at first didn't sound as good-but I now realize that this amp is actually a bit more accurate high end wise. The SI has a slight peak above 10 kHz that's missing with this unit. The stereo image remains as it is with the SI amp-wide and deep.
This unit also lacks the nasty turn on transient that my Sonic Impact has.
This amp (and I have the 1.2 version) is a STEAL at the $15.00 shipped it cost me!! I noticed the now their minimum bid is 15 dollars rather then ten. Still a good deal.
I think the difference between the amplifiers is twofold. First, this unit does not have a volume control, and the Sonic Impact unit still has its stock one (I know-not too good). Also, this unit's gain structure is different-this unit is set up for a voltage gain of -1, where the SI has a gain of 2.2.
I've been running one of these for several days now, in place of a modified original Sonic Impact T amp. I've always liked the Sonic Impact's sound, which is wide and deep, with a nice but not overdone high end and decent, though not perfect bass. This unit sounds quite different from that unit. First off, it's bass GRABS you-it's MUCH tighter. This is with only a 1 uf input capacitor across the .3 already there. I also pulled out the other caps and the resistors specified in earlier posts. The high end here at first didn't sound as good-but I now realize that this amp is actually a bit more accurate high end wise. The SI has a slight peak above 10 kHz that's missing with this unit. The stereo image remains as it is with the SI amp-wide and deep.
This unit also lacks the nasty turn on transient that my Sonic Impact has.
This amp (and I have the 1.2 version) is a STEAL at the $15.00 shipped it cost me!! I noticed the now their minimum bid is 15 dollars rather then ten. Still a good deal.
I think the difference between the amplifiers is twofold. First, this unit does not have a volume control, and the Sonic Impact unit still has its stock one (I know-not too good). Also, this unit's gain structure is different-this unit is set up for a voltage gain of -1, where the SI has a gain of 2.2.
There is now a manual for this-with a schematic!
Here:
http://www.sure-electronics.net/rf,audio/AA-AB012.pdf
Here:
http://www.sure-electronics.net/rf,audio/AA-AB012.pdf
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