That you put them on the rear side should in itself have no effect. What I note is the new chokes are large, accordingly rather closely arranged and stray magnetic fields may disturb the neighboring choke(s). Turning every second choke around may have an effect. Before doing that, you may take pieces of iron plate, wrap them in plastic foil for insulation and stick the pieces in-between the chokes as shield from the neighboring choke(s). Does that change heating?
Frequency and magnetic losses have an influence on heating. The frequency is the same but it is difficult to compare magnetic losses for the old and new chokes as you hardly have any documentation for the old chokes.
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Yes I have definitely given myself options.! Until I sort 3116d2 hiss and until 3255 arrives, this will do nicely! I also have a pair of those tiny bluemono boards...8932 Not used those yet
Wander if 3255 will sound much better....and also how will this 7498 sound on 36v?! Gives me ideas!
Been on for 3.5 hours this evening with a mix of music all at fairly high level. Volume pot 100pc for a while. Ambient 18degree room temp, heatsink 25, coils 23, caps 24.
Very pleased. Not sure the aux dc out is working properly. The pot spins and spins and seem set at just under 8v.
This board also has the + - - + mistake.
I did notice when I checked with DMM set to DC to check polarity of outputs, one was .6v and other was .11v. Resistance was also different , in the way you would expect.....higher R on the lower V.
One channel had a much longer cable for testing....could this be the reason?
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Thanks @FauxFrench,
I red in some other threads that power inductors like these can generate more heat than others.
I suspect inductance becomes much lower than expected when temperature rise.
I'll try some shielding structure like you suggest if i can find some iron sheets.
I'll also try to invert 2 coils to pair magnetic sense 2 by 2.
I'm waiting for some shielded 7G17A "style" inductors, it probably will be better and safer.
Just one word about the Red Sanwu TDA749E and Blue TDA7498 with shielded inductors that jimk04 spotted as i get those two.
Both sounds very good but really different to my ears (my wife's too ! She asked me if there was a problem when blue one replaced the red when i was modding the red one).
it can takes some time to change habits !
Blue seem more precise but mids seems far away, more "loudness style", sounds better (i think, compensate a bit the 4inch speakers bass weakness) than red on my little Highland Audio 3201 6Ohms/84db.
Gain is set a bit high though.
Red seem really fuller but bass seems less precise, mids are really nicer to me, works nice on Elipson Prestige 4i (8ohms/91db)
both sounds excellent though, taste questions.
I red in some other threads that power inductors like these can generate more heat than others.
I suspect inductance becomes much lower than expected when temperature rise.
I'll try some shielding structure like you suggest if i can find some iron sheets.
I'll also try to invert 2 coils to pair magnetic sense 2 by 2.
I'm waiting for some shielded 7G17A "style" inductors, it probably will be better and safer.
Just one word about the Red Sanwu TDA749E and Blue TDA7498 with shielded inductors that jimk04 spotted as i get those two.
Both sounds very good but really different to my ears (my wife's too ! She asked me if there was a problem when blue one replaced the red when i was modding the red one).
it can takes some time to change habits !
Blue seem more precise but mids seems far away, more "loudness style", sounds better (i think, compensate a bit the 4inch speakers bass weakness) than red on my little Highland Audio 3201 6Ohms/84db.
Gain is set a bit high though.
Red seem really fuller but bass seems less precise, mids are really nicer to me, works nice on Elipson Prestige 4i (8ohms/91db)
both sounds excellent though, taste questions.
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I only have the red Sanwu TDA7498E board so I cannot compare. I bought it once on offer for just below 14 EUR and I find it an amazing bargain.
Once I find time, I will do A<>B test between my many boards.
I once noticed a very competent Dane's statement that filter chokes operate best at slightly elevated temperatures. I appreciate no more than 40 degrees Celsius.
Really nice speakers you have got!
Once I find time, I will do A<>B test between my many boards.
I once noticed a very competent Dane's statement that filter chokes operate best at slightly elevated temperatures. I appreciate no more than 40 degrees Celsius.
Really nice speakers you have got!
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Hello,
I soldered out those Bourns 2305 inductors as they cause realy to much heat, I was nervous about that...
I received today my "Sagami like" 7G17A from Ali, as the PCB isn't designed for it, is it safe to solder some wire between pin and solder pad ?
I was thinking of using some multi braided wires (AWG 16 / 1.5mm²) to fix them.
Hope that wont generate moise ...
best regards
I soldered out those Bourns 2305 inductors as they cause realy to much heat, I was nervous about that...
I received today my "Sagami like" 7G17A from Ali, as the PCB isn't designed for it, is it safe to solder some wire between pin and solder pad ?
I was thinking of using some multi braided wires (AWG 16 / 1.5mm²) to fix them.
Hope that wont generate moise ...
best regards
I have the same chokes, also from Ali.
Mounting them with wires is "safe" to the extent that you only add a little bit of extra inductance with the wires and increase the radiated noise a little. Given that most class D amplifiers use semi open or even fully open chokes, I wouln't worry about the noise radiation before proven to be a problem. I often use "external" output filters in the sense that I add a better output filter on a separate board and connect this filter to the amplifier board pads with short and rather thick wires. It seems to work fine.
For mechanical fixation I use thermo-glue sticks, at least in part.
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Yep you're right, i soldered it with pieces of 2.5mm2 speaker wire, just had to enlage Pcb holes à bit.
Seem to works really nice and no more excessive heat!
As there was not so much différences with bourns open chokes, i can say I'm impressed by these new 7g17a chokes... sound seem cleaner, it feels more airy , basses and trebles are cleaner and more defined and background darkened a bit.
I just have to listen to it now, it seems more clinical, probably better at thd etc etc, but sometime little imperfection can be pleasant to ears.
Edit // I forgot, thanks a lot FauxFrench for your replies.
Best regards
Seem to works really nice and no more excessive heat!
As there was not so much différences with bourns open chokes, i can say I'm impressed by these new 7g17a chokes... sound seem cleaner, it feels more airy , basses and trebles are cleaner and more defined and background darkened a bit.
I just have to listen to it now, it seems more clinical, probably better at thd etc etc, but sometime little imperfection can be pleasant to ears.
Edit // I forgot, thanks a lot FauxFrench for your replies.
Best regards
Rigged up the 7498 through my Denon AVR. It has some keen turn on 'SNAP' now. Pity....I thought the AVRs turn on delay would pass through to the preouts .
And I think the AVR has robbed is of some SQ....despite being able to EQ a bit. I think it sounds better totally direct. Which I guess is expected but it doesn't help my implementation!
And I think the AVR has robbed is of some SQ....despite being able to EQ a bit. I think it sounds better totally direct. Which I guess is expected but it doesn't help my implementation!
An AVR is a very complex unit. The signals are routed through a plurality of stages. Each stage add distortion. Denon is high-end but cannot fully compensate for the need to include exorbitant features expected by those buying such a rather expensive unit. I guess my Denon AVR 3208 had some 2000 components inside, with JRC2184 OP-AMPs in most amplifier stages.
I guess you mainly chose an AVR for your home-cinema. When 007 once more saves the honor of England, the sound quality and level is fully sufficient in front of the huge screen.
One thing I have noticed is that the really expensive and reputedly stereo amplifiers follow the concept “as little as possible at a quality as high as possible”. A high quality power amplifier with top class components. No Japanese “features”. A pre-amplifier with few high quality stages including a source selector and a volume control. No tone regulation, no filters, no record player preamps, no video features – only the minimum but in highest quality. Less stages -> less distortion. Money are spend on a top class source.
From what I understand, you are a bit disappointed that your 15Kg Denon hasn’t got the sound clarity of you 200gr TDA7498 amplifier.
Use your Denon for what it is designed for. When 007 has put Blofeld behind bars (or what is worse) and you just want to listen to good music, switch the TDA7498 input to a good music source through a small switch-box/volume control and let the Denon have its beauty-sleep.
The turn-on ‘snap’ is trivial and can be overcome by proper timing of the power-up of the TDA7498 relative to the the power up of the pre-amp (Denon). If your TDA7498 is active and you turn on the Denon, a ‘snap’ cannot be avoided when the bias levels in the pre-amp settles.
I have Harman-Kardon, Nakamichi, Marantz and Denon amplifiers at home. I use none of them anymore. Only my home-mades. With an upgraded DACMagic and an upgraded Music Fidelity headphone amplifier serving as volume control, I also have better SQ and much more fun.
I guess you mainly chose an AVR for your home-cinema. When 007 once more saves the honor of England, the sound quality and level is fully sufficient in front of the huge screen.
One thing I have noticed is that the really expensive and reputedly stereo amplifiers follow the concept “as little as possible at a quality as high as possible”. A high quality power amplifier with top class components. No Japanese “features”. A pre-amplifier with few high quality stages including a source selector and a volume control. No tone regulation, no filters, no record player preamps, no video features – only the minimum but in highest quality. Less stages -> less distortion. Money are spend on a top class source.
From what I understand, you are a bit disappointed that your 15Kg Denon hasn’t got the sound clarity of you 200gr TDA7498 amplifier.
Use your Denon for what it is designed for. When 007 has put Blofeld behind bars (or what is worse) and you just want to listen to good music, switch the TDA7498 input to a good music source through a small switch-box/volume control and let the Denon have its beauty-sleep.
The turn-on ‘snap’ is trivial and can be overcome by proper timing of the power-up of the TDA7498 relative to the the power up of the pre-amp (Denon). If your TDA7498 is active and you turn on the Denon, a ‘snap’ cannot be avoided when the bias levels in the pre-amp settles.
I have Harman-Kardon, Nakamichi, Marantz and Denon amplifiers at home. I use none of them anymore. Only my home-mades. With an upgraded DACMagic and an upgraded Music Fidelity headphone amplifier serving as volume control, I also have better SQ and much more fun.
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Perfect summation my friend. You got that nail right on the head! I guess I am LISTENING to music more critically now and I'm hearing the shortcomings of my AVR2105 for stereo music. Sounds great for James Bond though!
Now I try to implement and integrate a separate stereo system without adding too many more boxes and wires,.....the wife won't like that!
Is that the Cambridge Audio Dacmagic? Just looked up and read about the dacmagic plus. I have looked in on the dac forum here but is seems very in-depth to me!
My problem will be separating sources from AV amp and stereo class d.....2channel and 5.1 requirements
Now I try to implement and integrate a separate stereo system without adding too many more boxes and wires,.....the wife won't like that!
Is that the Cambridge Audio Dacmagic? Just looked up and read about the dacmagic plus. I have looked in on the dac forum here but is seems very in-depth to me!
My problem will be separating sources from AV amp and stereo class d.....2channel and 5.1 requirements
Can you specify the exact models of your amplifiers, just for comparison.
Thanks in advance.
It is a Cambridge Audio DACMagic, 1st version, with the JRC5532 replaced by LM4562.
The Denon boards use JRC4580 OP-AMPs. Not JRC2184 as postulated before. "2184" is a FET-driver, it must be a sign of age of my brain.
Can't you keep the TDA7498 amplifier connected permanently to the left and right front speakers with a line-out from the Denon, when you watch films, and switch the TDA7498 input to another source when you want to use it for music?
I took a photo of the top- and rear-side of one of the boards from my Denon AVR 3208. This is one of probably 7 boards, not all with the same density of components. It leaves you with an idea about how difficult it is to modify such a construction. And, why routing of the music signal is quite complex and doesn't leave top-sound.
Attachments
This is embarrassing. I said I didn't use them anymore. I could find only two. A HK980 and a Denon PMA510. The two other are "somewhere" in the mess. A dated Nakamichi receiver with some 2x70W and a rather dated Marantz with 2x40W, as I recall. Perhaps I should look for them one day?
I can suggest you something like that in the version with a volume potentiometer.
Dual NE5532 OP AMP HIFI Preamplifier Preamp Board Signal Amplification Base on Music fax A1 circuit-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
The advantage of this particular preamp is that it can be operated from a single DC voltage and the OP-AMPS (NE5532, quite good) are mounted in sockets and can easily be upgraded if you feel like it. None of the modules I know of have an input selector on-board. Probably because it is very individual how many sources a customer uses. Anyway, such an input selector is easy to connect at the input of the preamp.
Typically you use a rotary double deck type with as many input terminals as you have sources, and one (double) output terminal.
Nice KA3020. I recall from my childhood, Kenwood amplifiers made and designed in the US with a similar look, 2x70W, that did cost around a month salary. This was a reason why I entered DIY.
Dual NE5532 OP AMP HIFI Preamplifier Preamp Board Signal Amplification Base on Music fax A1 circuit-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
The advantage of this particular preamp is that it can be operated from a single DC voltage and the OP-AMPS (NE5532, quite good) are mounted in sockets and can easily be upgraded if you feel like it. None of the modules I know of have an input selector on-board. Probably because it is very individual how many sources a customer uses. Anyway, such an input selector is easy to connect at the input of the preamp.
Typically you use a rotary double deck type with as many input terminals as you have sources, and one (double) output terminal.
Nice KA3020. I recall from my childhood, Kenwood amplifiers made and designed in the US with a similar look, 2x70W, that did cost around a month salary. This was a reason why I entered DIY.
Hi guys, could you suggest me a nice TDA7498 board. Recently I tried a blue board like the Ayima one from amazon but it was defective & I didnt like that the heatsink was glued improperly, so I was hoping to get one that has the heatsink mounted on the board using screws or such. I ran the one I tried at 32V and the caps & the heatsink were running warm along with the inductors too.
The one requiring least amount of mods would be nice, but a better built one is preferable. Any experience with the ones I shortlisted?
1. It's a black board, might be hard to trouble shoot when trying to follow traces & the heat sink is probably glued/held in place.
CIRMECH Digital Amplifier Audio Board TDA7498 Power Audio Amp 2.0 Class D Amplifiers Stereo HIFI amplifier DC12 36V 2*100W-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
2. It's the red one with Chinese lettering on the board.
Lusya TDA7498 Digital Power Amplifier Board 100W+100W Dual channel Stereo Audio Amplifier Class D for speaker DC 15 34V B3 007-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
3. It looks like a smaller sized board, haven't checked too careful for more details
TDA7498 2 Channel 2X100W Digital Stereo Power Amplifier Board Module DC 8 32V-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
4. This one has a big electrolytic cap on it.
SCLS 100W + 100W Amplifier TDA7498 Class D Amp Subwoofer Assembled Board Module DIY-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
5. This one has big size inductors on it
New pattern TDA7498 amplifier board 1.0 channel 200w class D Subwoofer Home bass amplifier DIY-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
And last but not the least the TDA7498E board. This one is twice the price of the red board & has more power but there was a feedback somewhere with photos of the chip burnt up. But maybe it lacked thermal paste
oh well...
https://www.aliexpress.com/item/CIR...86f2-4334-b687-f0df045fb145&priceBeautifyAB=0
The one requiring least amount of mods would be nice, but a better built one is preferable. Any experience with the ones I shortlisted?
1. It's a black board, might be hard to trouble shoot when trying to follow traces & the heat sink is probably glued/held in place.
CIRMECH Digital Amplifier Audio Board TDA7498 Power Audio Amp 2.0 Class D Amplifiers Stereo HIFI amplifier DC12 36V 2*100W-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
2. It's the red one with Chinese lettering on the board.
Lusya TDA7498 Digital Power Amplifier Board 100W+100W Dual channel Stereo Audio Amplifier Class D for speaker DC 15 34V B3 007-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
3. It looks like a smaller sized board, haven't checked too careful for more details
TDA7498 2 Channel 2X100W Digital Stereo Power Amplifier Board Module DC 8 32V-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
4. This one has a big electrolytic cap on it.
SCLS 100W + 100W Amplifier TDA7498 Class D Amp Subwoofer Assembled Board Module DIY-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
5. This one has big size inductors on it
New pattern TDA7498 amplifier board 1.0 channel 200w class D Subwoofer Home bass amplifier DIY-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
And last but not the least the TDA7498E board. This one is twice the price of the red board & has more power but there was a feedback somewhere with photos of the chip burnt up. But maybe it lacked thermal paste
oh well...https://www.aliexpress.com/item/CIR...86f2-4334-b687-f0df045fb145&priceBeautifyAB=0
I have a 7498E board very similar to the last board you show. I am very happy with it. But, keep in mind that taking it to the limits with low impedance speakers is a risk because the chip is very small and the leads to the chip housing are tiny (but for power leads two are used in parallel). It is a chip where thermal coupling to the heatsink is delicate. For normal home use, fine. For PA use, less suited.
Hi guys, could you suggest me a nice TDA7498 board. Recently I tried a blue board like the Ayima one from amazon but it was defective & I didnt like that the heatsink was glued improperly, so I was hoping to get one that has the heatsink mounted on the board using screws or such. I ran the one I tried at 32V and the caps & the heatsink were running warm along with the inductors too.
The one requiring least amount of mods would be nice, but a better built one is preferable. Any experience with the ones I shortlisted?
1. It's a black board, might be hard to trouble shoot when trying to follow traces & the heat sink is probably glued/held in place.
CIRMECH Digital Amplifier Audio Board TDA7498 Power Audio Amp 2.0 Class D Amplifiers Stereo HIFI amplifier DC12 36V 2*100W-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
2. It's the red one with Chinese lettering on the board.
Lusya TDA7498 Digital Power Amplifier Board 100W+100W Dual channel Stereo Audio Amplifier Class D for speaker DC 15 34V B3 007-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
3. It looks like a smaller sized board, haven't checked too careful for more details
TDA7498 2 Channel 2X100W Digital Stereo Power Amplifier Board Module DC 8 32V-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
4. This one has a big electrolytic cap on it.
SCLS 100W + 100W Amplifier TDA7498 Class D Amp Subwoofer Assembled Board Module DIY-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
5. This one has big size inductors on it
New pattern TDA7498 amplifier board 1.0 channel 200w class D Subwoofer Home bass amplifier DIY-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
And last but not the least the TDA7498E board. This one is twice the price of the red board & has more power but there was a feedback somewhere with photos of the chip burnt up. But maybe it lacked thermal paste
https://www.aliexpress.com/item/CIR...86f2-4334-b687-f0df045fb145&priceBeautifyAB=0
I'd happily recommend this one (ignore that it says Aiyima, it's actually made by Feixiang). Of the 4 7498/7498E boards I have, this works best with my source (RPi, Allo DAC) and speakers (Q Acoustics 2050i)
https://www.aliexpress.com/item/Aiyima-TDA7498E-160W-2-High-Output-Power-Digital-Amplifier-Board-Dual-Channels-Audio-Stereo-Amplifiers/32837865639.html?spm=2114.search0104.3.223.7360529a9fTwBQ&ws_ab_test=searchweb0_0,searchweb201602_3_10065_10068_204_10843_318_319_10892_10059_10884_10887_10696_100031_320_10084_10083_10103_452_10618_10304_10307_10820_532_10821_10302,searchweb201603_60,ppcSwitch_0&algo_expid=632e9f57-1232-4079-a432-e752028845e2-36&algo_pvid=632e9f57-1232-4079-a432-e752028845e2&transAbTest=ae803_4&priceBeautifyAB=0
I recently got this one
Promotions TDA7498 high-power digital amplifier board (100W 100 W) Finished amplifier board
Promotions TDA7498 high power digital amplifier board (100W +100 W) Finished amplifier board-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
Very pleased and is fine as is. No mods required for a decent overall sound.
Runs very cool on 24v. Has negligible noise from the 3.5mm stereo Jack from my Samsung S9. Noisier from my pc soundcard
Promotions TDA7498 high-power digital amplifier board (100W 100 W) Finished amplifier board
Promotions TDA7498 high power digital amplifier board (100W +100 W) Finished amplifier board-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
Very pleased and is fine as is. No mods required for a decent overall sound.
Runs very cool on 24v. Has negligible noise from the 3.5mm stereo Jack from my Samsung S9. Noisier from my pc soundcard
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