What the heck? It's less than lunch!

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#1,065
Not sure best place to post this question - thought I'd try here. Wanted a small, low power amp to drive speakers for testing purposes; a cheap TDA7297 amp board seemed to fill the bill, so I bought a couple from wfyb on Ebay. Initial testing produced around 7% distortion at 1W, 1kHz, which was a bit shocking. Took a hard look at the layout and saw it was pretty bad. I cut and jumpered to isolate input and output sections and managed to get the distortion down to 0.6%, which was still far above the spec limit of 0.1%. I figured maybe I had some counterfeit devices, so bought a couple from Mouser. The new ones looked absolutely identical to the ones received with the board. Nevertheless, I installed one and found the distortion was up to 2%. Anyone have any experience with distortion measurements on this device? I'm wondering if it really makes its claimed spec of 0.1% distortion.
 
#1,066
danschy said:
Not sure best place to post this question - thought I'd try here. Wanted a small, low power amp to drive speakers for testing purposes; a cheap TDA7297 amp board seemed to fill the bill, so I bought a couple from wfyb on Ebay. Initial testing produced around 7% distortion at 1W, 1kHz, which was a bit shocking. Took a hard look at the layout and saw it was pretty bad. I cut and jumpered to isolate input and output sections and managed to get the distortion down to 0.6%, which was still far above the spec limit of 0.1%. I figured maybe I had some counterfeit devices, so bought a couple from Mouser. The new ones looked absolutely identical to the ones received with the board. Nevertheless, I installed one and found the distortion was up to 2%. Anyone have any experience with distortion measurements on this device? I'm wondering if it really makes its claimed spec of 0.1% distortion.
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All the above measurements were single-ended since I didn't want to have to float my measurement system to measure across the load. I decided to just do it, and the distortion dropped to under 0.2%, so I'm happy. Apparently some of the single-ended distortion products cancel out in bridged mode.
 
#1,072
canvas said:
85 cents a piece? That's incredible.
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Yes, incredible. Here is something more in the spirit of diy, and ready to mod from the start:
Free Shipping 2set TDA7297 amplifier board parts dc 12v 2.0 dual audio encoding 2*15w electronic diy kit 2PCS/LOT-in Integrated Circuits from Electronic Components & Supplies on Aliexpress.com | Alibaba Group

I was wondering - if you have 2 of these amps - bridging them is not possible (I read somewhere in this thread), but can one run them as two mono blocks, and will there be any advantage in doing this?
 
#1,073
twocents said:
Yes, incredible. Here is something more in the spirit of diy, and ready to mod from the start:
Free Shipping 2set TDA7297 amplifier board parts dc 12v 2.0 dual audio encoding 2*15w electronic diy kit 2PCS/LOT-in Integrated Circuits from Electronic Components & Supplies on Aliexpress.com | Alibaba Group

I was wondering - if you have 2 of these amps - bridging them is not possible (I read somewhere in this thread), but can one run them as two mono blocks, and will there be any advantage in doing this?
Click to expand...

More current for harder impedance loads.
 
#1,079
All Lunch Money amp fans - check out the Coffee Money amp! 🙂

http://www.diyaudio.com/forums/chip-amps/310816-tda2030-coffee-money-headphone-amp.html#post5150348

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#1,080
LED comes on! But I only get hum coming out of the speakers (I can turn up the volume of the hum). Was trying to follow DestroyerOS ver1 build guide. Does anyone see anything out of place?
Thanks,
Doug
 

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