Ebay cheap TDA7498 boards

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sudreva1

Member
Joined 2018
ICG said:
You could theoretically go from the sub out to both L + R input of the amp - but that does not help you at all since the TDA7498 is already a bridged IC amplifier. That means you can only use one channel output. Connecting both outputs parallel will destroy the amplifier (and would only give you more power at a lower impedance anyway).

About the power: Well, that's a 4 Ohm subwoofer. The TDA7498 isn't rated for 4 Ohm, it gets too hot, that exceeds the maximum current. You can still use it but you won't get the maximum power out of it (bit below 50W) and you should stay below 22V power supply. To get more power at 4 Ohm you could get a TPA3116 D2 mono amplifier board, these are actually rated for 4 Ohm.
Click to expand...

Previously i tried below board with same connection details as you mentioned. Like, single input to both L&R and 32v input supply and used 6ohms speaker since below board support 4-8 omhs . This board was playing 75% sound for 15 min and it burned after that. Do you have any idea why this is happen ? that's is the reason i bought the new board and don't want to make the same mistake.

Burned Board:
Amazon.com: TDA7498 150w Class D Subwoofer amplifier amp board w/ DC18V to DC32V: Home Audio & Theater

New board:
High Power DC 20V-36V TDA7498 100W+100W Class D Amplifier Board New | eBay
 
S

sailormanbigd

Member
Joined 2014
I have a different question. I am having a clipping problem. I have 3 7498 boards. I am running stock off a 24v 6am cheap power brick. Speakers are nom 8 ohm 2 way bookshelf Zaph audio bargain mini. I have 2 different version of the amp boards but they both clip at same levels, not quite loud enough for “party” mode. I think they played louder before clipping with a 19v supply? I haven’t tried inputting a capacitor bank between power and vcc in but I have caps I could use just trying to keep it small and simple.

So how do I get more spl without clipping? I have tried all the different gain settings and no help. I just need a couple more clicks on source vol to attain LOUD.
 
C

chermann

Member
Joined 2017
sailormanbigd said:
I have a different question. I am having a clipping problem. I have 3 7498 boards. I am running stock off a 24v 6am cheap power brick. Speakers are nom 8 ohm 2 way bookshelf Zaph audio bargain mini. I have 2 different version of the amp boards but they both clip at same levels, not quite loud enough for “party” mode. I think they played louder before clipping with a 19v supply? I haven’t tried inputting a capacitor bank between power and vcc in but I have caps I could use just trying to keep it small and simple.

So how do I get more spl without clipping? I have tried all the different gain settings and no help. I just need a couple more clicks on source vol to attain LOUD.
Click to expand...

"Loud" is normaly not a problem.:D
loud without clipping and/or distortions is a problem :D


your PSu with 24V and 6amp is real nominal enough to get loud, because if the psu is "stable" you should deliver 24V*6A = 144Watts. Maybe your 19V psu idelivers more Ampere and this keeps longer stable = get louder. If possible test your 2 different psu with a dummy load!


yes give the caps a try! mount them as closed as pssoibel to the amp boards. whatch out the polarity.


please link your boards...

chris
 
S

sailormanbigd

Member
Joined 2014
Thanks Cherman. It might be the cheap power brick. I first used it on a Bluetooth version 7498 and it was playing very well then all of a sudden started to clip then the thing flashed on/off, on/off every second and music died. Turned amp off, then back on same flashing. Waited 30 mins now power light remains lit but no sound? I will go back to 19v supply. 24v supply was cheapest available I could find. Also will try cap bank for the last little spl I need thanks.
 
T

Think

Banned
Joined 2017
sailormanbigd said:
I have a different question. I am having a clipping problem. I have 3 7498 boards. I am running stock off a 24v 6am cheap power brick. Speakers are nom 8 ohm 2 way bookshelf Zaph audio bargain mini. I have 2 different version of the amp boards but they both clip at same levels, not quite loud enough for “party” mode. I think they played louder before clipping with a 19v supply? I haven’t tried inputting a capacitor bank between power and vcc in but I have caps I could use just trying to keep it small and simple.

So how do I get more spl without clipping? I have tried all the different gain settings and no help. I just need a couple more clicks on source vol to attain LOUD.
Click to expand...
If your output looks/sounds like it is limited by the power supply, it might be the cable from the supply to the board being to thin or to long. Both give voltage drop. Beter upgrade this weak link instead of adding extra input caps.
 
C

chermann

Member
Joined 2017
sailormanbigd said:
Thanks Cherman. It might be the cheap power brick. I first used it on a Bluetooth version 7498 and it was playing very well then all of a sudden started to clip then the thing flashed on/off, on/off every second and music died. Turned amp off, then back on same flashing. Waited 30 mins now power light remains lit but no sound? I will go back to 19v supply. 24v supply was cheapest available I could find. Also will try cap bank for the last little spl I need thanks.
Click to expand...

Turned amp off, then back on same flashing. Waited 30 mins now power light remains lit but no sound?

is your 24V PSu dead...and when did this psu recover?

remains lit but no sound? --> i guess the overheat protection is set your amp silent. try with cooling fan for testing...not a final solution but...

chris
 
C

chermann

Member
Joined 2017
Think said:
If your output looks/sounds like it is limited by the power supply, it might be the cable from the supply to the board being to thin or to long. Both give voltage drop. Beter upgrade this weak link instead of adding extra input caps.
Click to expand...


yes... also a possiblity to check ! the additionally caps if available are not bad to use. near the boards is recommended!


Do you have a DMM to give us some measurements.:)

chris

ps: look at Ebay cheap TDA7498 boards
 
ICG

ICG

Disabled Account
Joined 2007
sudreva1 said:
Previously i tried below board with same connection details as you mentioned. Like, single input to both L&R and 32v input supply and used 6ohms speaker since below board support 4-8 omhs . This board was playing 75% sound for 15 min and it burned after that. Do you have any idea why this is happen ? that's is the reason i bought the new board and don't want to make the same mistake.
Click to expand...

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.
 
T

Think

Banned
Joined 2017
ICG said:
Like I said, the TDA7498 does not support 4 Ohm, ..........
Click to expand...
But with the 6 Ω speakers he is using, he should be ok. Bad luck then, better not run amps on the limit.

www.st.com/resource/en/datasheet/tda7498.pdf
Features
• 100 W + 100 W output power at THD = 10%
with RL = 6 Ω and VCC = 36 V
• 80 W + 80 W output power at THD = 10%
with RL = 8 Ω and VCC = 34 V

// 7498E should do 4 Ω http://www.st.com/resource/en/datasheet/tda7498e.pdf
Features 160-W + 160-W output power at THD = 10% with RL = 4 Ω and VCC = 36 V
and 3 Ω in PBTL: 1 x 220 W output power mono parallel BTL at THD = 10% with RL = 3 Ω and VCC = 36 V
 
Last edited:
S

sudreva1

Member
Joined 2018
ICG said:
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.
Click to expand...

Sorry i am new to this. Do you have know how i can test transformer output power using multi meter ?
 
ICG

ICG

Disabled Account
Joined 2007
sudreva1 said:
Sorry i am new to this. Do you have know how i can test transformer output power using multi meter ?
Click to expand...

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).
 
A

astralboogie

Member
Joined 2018
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.
 
T

t-minik

Member
Joined 2006
Hi Guys

I uses a red sanwu TDA7498E board as my main amp since a year .
I just added 1uf MKT on each input and sorted the 2 diodes as described above :
Ebay cheap TDA7498 boards

to day i received some 22uH inductors Bourns 2305-RC
https://www.google.com/url?sa=t&rct...0_series.pdf&usg=AOvVaw1H7iFvk5EEIm8Hn9m3k5zj

after doing the mod it seems to works pretty good but after an hour or two playing music i can see new inductors are hoter than the old one.
I can touch them without problem but it feels Hot!

does the fact that i soldered under the board (ground side) can be the reason ?

As you can see i soldered them all in the same direction (blue side of core) should i solder the by pair (blue side by side) ?

Best regards
 

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J

jimk04

Member
Joined 2018
Paid Member
Hey guys. I took delivery of this last week.

Promotions TDA7498 high-power digital amplifier board (100W 100 W) Finished amplifier board
Online Shop Promotions TDA7498 high-power digital amplifier board (100W +100 W) Finished amplifier board | Aliexpress Mobile

And I have to say it sounds lovely. And the thing is as cool as a cucumber now, having been on for an hour at a reasonable level....into 8ohm speakers.

Best China class d I bought so far. No hiss at all. I recently made some full range with Faital 3fe22.....known to be bright at the top. With my Denon Avr they were not great. With this.....mega! Now to see if using the Denon as pre amp into the board still sounds as good.

Oh and running on a 24v Meanwell CLG 100 watt smps
 
Y

Yatsushiro

Member
Joined 2016
jimk04 said:
Hey guys. I took delivery of this last week.

Promotions TDA7498 high-power digital amplifier board (100W 100 W) Finished amplifier board
Online Shop Promotions TDA7498 high-power digital amplifier board (100W +100 W) Finished amplifier board | Aliexpress Mobile

And I have to say it sounds lovely. And the thing is as cool as a cucumber now, having been on for an hour at a reasonable level....into 8ohm speakers.

Best China class d I bought so far. No hiss at all. I recently made some full range with Faital 3fe22.....known to be bright at the top. With my Denon Avr they were not great. With this.....mega! Now to see if using the Denon as pre amp into the board still sounds as good.

Oh and running on a 24v Meanwell CLG 100 watt smps
Click to expand...

Blimey, you're spreading yourself a but thin?

A TPA3255EVM on order, a 3e 3255 just arrived and a 7498...

That's the thing about these relatively cheap Class D boards; not too much outlay to experiment in the hope of finding a good amtch for the rest of your system.

I struggle to choose (and find myself swapping in and out) between my 'best' TPA3116, TPA3250EVM, TPA3251 3E, TDA7498E and an Icepower 50ASX2...
 
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