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Class D Switching Power Amplifiers and Power D/A conversion

Ebay cheap TDA7498 boards
Ebay cheap TDA7498 boards
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Old 29th March 2018, 08:16 PM   #591
sudreva1 is offline sudreva1
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Quote:
Originally Posted by ICG View Post
Like I said, the TDA7498 does not support 4 Ohm, the high current burns the IC to a crisp, no matter what the seller claims. The limitation is the current and the heat dissipation. That means, if you want to use 4 Ohm speakers, you have to reduce the Voltage by a lot and cannot use the full power either. Buying anotherone of the same amp will not result in a different outcome. Use a 24V or lower voltage power supply.

Or, better, use a different amplifier board like the TPA3116D2, STA508, TAS56xx or IRS2092 (the last two usually need symmetrical power supply though) which actuallc can handle lower impedance loads.

BTW: The position of the potentiometer does not say anything about the output power.
Sorry i am new to this. Do you have know how i can test transformer output power using multi meter ?
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Old 30th March 2018, 11:17 AM   #592
zek is offline zek
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What do you mean by the power of a transformer (power is expressed in watts)?
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Old 30th March 2018, 12:51 PM   #593
ICG is offline ICG  Germany
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Location: I had a Déjà Moo - I've seen that BS before!
Quote:
Originally Posted by sudreva1 View Post
Sorry i am new to this. Do you have know how i can test transformer output power using multi meter ?
Are you talking about a power supply or specifically a transformer? Or how to calculate the power output?

The power output is U * I = P (V*A=W), if your power supply is 24V and delivers 5A, 24*5=120W. If you use the amplifier board at a lower voltage, it does not have that much power like on the maximum voltage anymore, so a smaller power supply will be okay.

For a transformer: I would not suggest to 'test' the output power of a transformer, you'll likely overload it and you get a range of results for the power, short term, long term (or anything inbetween) and that also varies also on how much voltage drop you can accept for a specific use. If you got a transformer, the label says xxx VA, that's the nominal power you can get out of it, VA is Volt Ampere, which practically equals in W (Watt).
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Old 30th March 2018, 09:32 PM   #594
Josv is offline Josv  Netherlands
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In my opinion this version of a tda7498e amp is underrated.
MA-TD02 Module Amplificateur TDA7498E Class D 2x125W - Audiophonics
Compared with the good
TDA7498E 160W+160W digital stereo amplifier board PBTL 220W mono channel 24v-36v | eBay
it sounds brighter with better bass. The soundstage feels a bit "fatter" and more spacious. I really enjoy this amp. It is also built very solid.
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Old 18th April 2018, 06:54 PM   #595
zek is offline zek
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Originally Posted by Josv View Post
....it sounds brighter with better bass. The soundstage feels a bit "fatter" and more spacious. I really enjoy this amp. It is also built very solid.
Is this referring to the first board?
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Old 19th April 2018, 08:35 PM   #597
Josv is offline Josv  Netherlands
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Btw: the speaker connections of this board are swapped: from above + - - + must be: + - + -
I was confused about the difference of the right polarity, more and finer bass and great space.
Found it by accident when connecting speakers.
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Old 2nd May 2018, 12:33 AM   #598
astralboogie is offline astralboogie  Australia
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I have run into a problem recently after using my usb powered dj mixer with my 7498e. I had this setup for around 4 hours and it was working fine but next time I went to use this combination the dj mixer is making a loud humming noise. I'm trying to figure out if I damaged the mixer somehow with my setup or if it was unrelated. Here's how it was setup.

2 x 12v SLA batteries connected in series > dc voltage booster set to 32V > 7498e

My laptop was running off it's own battery and the mixer was powered by the laptop usb port. Does anyone see any problem with this setup? It works fine playing from ipod.
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