Ahoj..Koupil jsem studiové bedny M-Audio BX8 D2 a když je zapnu a to i bez vstupního zdroje tak z beden leze nepříjemný brum.Někde sem četl že ..
Bohužel pro M-Audio jsou zde vlastnosti monitorů, které lze považovat za nezkousnutelné. Tím je neustálý brum, který vydává nízkofrekvenční měnič, což je způsobeno chybou v návrhu plošného spoje zesilovací části právě pro nízkofrekvenční měnič, kde dochází ke krátkému spojení mezi 4 a 6 pinem TDA2052.
Nebo.....
Brum je zde protože nějaký specialista spojil signálovou a napájecí zem. Navíc má každá bedýnka vlastní napájení včetně ochranného vodiče. Takže je tu vytvořena perfektní zemní smyčka která sežere veškerý elektromagnetický smog z okolí a pěkně jej zesílí. Veškerá spotřební elektronika je vyráběna v izolační třídě 2, což zamezuje vzniku zemních smyček. Vyjímkou jsou PC.
Řešení: Kupte si rozdvojku, vymontujte ochranný kolík a zapojte do ní pouze tyto bedýnky.
PS: Pokud Vás to nezabije hned, tak Vás zabije revizák až to uvidí.
Bohužel to se udělal a nefunguje to.
Takže,dá se s tím něco udělat?
Studiové bedny M-Audio BX8 D2, brum
Moderátor: Moderátoři
Nejsem dobrej na Angličtinu ale že je na desce skrat je jasné.
I picked up a pair of BX8a Deluxe speakers on Amazon for a great price. I did some reading online and read about speakers randomly dying after purchase, but the price was just too good and I decided to roll the dice.
Well, 2 months in, my right speaker went bad and never would work properly again. When I would turn it on, the woofer would pop, go full throw, and emit a 60Hz hum. Very bad stuff. I looked at my return / repair options and found I had to return them to M-Audio to get it repaired.
I looked at the M-Audio forums and read quite a bit more about M-Audio speakers failing, and decided I'd take my chances and crack open the speaker to see if I could figure out what was wrong instead of suffering through a potentially long and painful RMA cycle.
3 hours later I had discovered the problem: a short circuit on the main amplifier board, underneath the tweeter's power amplifier chip. The amp is a TDA2052 made by STMicroelectronics. You can look at the datasheet here: [...]
The short was between pins 4 and 6 of this chip, so it was connecting the negative power supply voltage to the audio input pin on both the tweeter and woofer amplifier - very bad! This explains why I could hear 60Hz power line noise on the speaker every time I turned it on.
I was about to start probing each pin on the TDA2052 to see if I could figure out what wire on the circuit board had a problem when I discovered the short between pins 4 and 6. I carefully removed the solder flux and other debris between the two solder pads and plugged the circuit board in, and the problem was gone. You can see a picture of my circuit board and the location of the short here: [...]
As to why the short-circuit suddenly occurred 2 months after purchase - I can only speculate. One possibility is the dreaded "tin whiskers" problem that has been plaguing electronics manufacturers for years. You can read about it here: [...]
Since lot's of people are reporting random failures of these speakers, this is a possibility. There are a couple ways to remedy this, but they all involve tweaking the manufacturing process of the circuit board, and this might not be an option because it would impact the cost and profit margin on these speakers. The other possibility is that the assembly quality control is not good enough on these circuit boards and they are not adequately stress tested / verified before being put into the finished product. Again there is a cost issue and I'm just speculating.
Overall I must say the speakers are an excellent value for the price. The speaker box construction is solid, the speakers are decent, and the electrical design is good enough - simple and effective. I am impressed with this product, and it is unfortunate such a great product is subject to such a high failure rate from what looks like a manufacturing/quality issue and not a design problem. I just hope M-Audio can remedy the issues long term as I'd like to see them continue to develop quality products
I picked up a pair of BX8a Deluxe speakers on Amazon for a great price. I did some reading online and read about speakers randomly dying after purchase, but the price was just too good and I decided to roll the dice.
Well, 2 months in, my right speaker went bad and never would work properly again. When I would turn it on, the woofer would pop, go full throw, and emit a 60Hz hum. Very bad stuff. I looked at my return / repair options and found I had to return them to M-Audio to get it repaired.
I looked at the M-Audio forums and read quite a bit more about M-Audio speakers failing, and decided I'd take my chances and crack open the speaker to see if I could figure out what was wrong instead of suffering through a potentially long and painful RMA cycle.
3 hours later I had discovered the problem: a short circuit on the main amplifier board, underneath the tweeter's power amplifier chip. The amp is a TDA2052 made by STMicroelectronics. You can look at the datasheet here: [...]
The short was between pins 4 and 6 of this chip, so it was connecting the negative power supply voltage to the audio input pin on both the tweeter and woofer amplifier - very bad! This explains why I could hear 60Hz power line noise on the speaker every time I turned it on.
I was about to start probing each pin on the TDA2052 to see if I could figure out what wire on the circuit board had a problem when I discovered the short between pins 4 and 6. I carefully removed the solder flux and other debris between the two solder pads and plugged the circuit board in, and the problem was gone. You can see a picture of my circuit board and the location of the short here: [...]
As to why the short-circuit suddenly occurred 2 months after purchase - I can only speculate. One possibility is the dreaded "tin whiskers" problem that has been plaguing electronics manufacturers for years. You can read about it here: [...]
Since lot's of people are reporting random failures of these speakers, this is a possibility. There are a couple ways to remedy this, but they all involve tweaking the manufacturing process of the circuit board, and this might not be an option because it would impact the cost and profit margin on these speakers. The other possibility is that the assembly quality control is not good enough on these circuit boards and they are not adequately stress tested / verified before being put into the finished product. Again there is a cost issue and I'm just speculating.
Overall I must say the speakers are an excellent value for the price. The speaker box construction is solid, the speakers are decent, and the electrical design is good enough - simple and effective. I am impressed with this product, and it is unfortunate such a great product is subject to such a high failure rate from what looks like a manufacturing/quality issue and not a design problem. I just hope M-Audio can remedy the issues long term as I'd like to see them continue to develop quality products
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Generalsound
- Příspěvky: 324
- Registrován: 20 lis 2009, 01:00
- Bydliště: Doma, kde asi?
- Kontaktovat uživatele:
Pokud to vrčí i bez čehokoli připojenýho do vstupu a obě bedny, bude to opravdu nějaká konstrukční chyba. Už jsem se s tim setkal vícekrát a i u mnohem dražších zařízení. Na to odpojení ochrannýho vodiče opravdu ani nemůže mít vliv. Jak by se asi smyčka vytvořila, když tam neni nic připojenýho. Spojení 4 a 6 TDA 2052 to asi těžko - pokud by to přežil ten IC, tak reprák určitě ne. To zas někdo chytrej psal bludy. Nesmíš taky všemu na netu věřit. Pokud s tím chceš pomoct, tak SZ
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Generalsound
- Příspěvky: 324
- Registrován: 20 lis 2009, 01:00
- Bydliště: Doma, kde asi?
- Kontaktovat uživatele:
Tak jsi mě předběhl. To co popisuje, je uplně jiná závada. Tam ze zesilovače šlo plný kladný napájení, což se projevuje i brumem, ale hlavně značným přetížením repráku. To asi nebude tvuj případ. Při zapnutí zůstane reprák v klidu, a jen slabě hučí, nebo se vychýlí membrána na doraz, jak popisuje ten borec?
Zapnu bedny do sítě ,vytáhnu z nich kabely od mixáku,zapnu bedny a z beden jde slabé hučení..ono v hudbě slyšet není ale při tichu a pauzách je to slyšet a dost.Generalsound píše:Tak jsi mě předběhl. To co popisuje, je uplně jiná závada. Tam ze zesilovače šlo plný kladný napájení, což se projevuje i brumem, ale hlavně značný vm přetížením repráku. To asi nebude tvuj případ. Při zapnutí zůstane reprák v klidu, a jen slabě hučí, nebo se vychýlí membrána na doraz, jak popisuje ten borec?
Kde se šíří takové nebezpečné a dementní rady ? A proč se tím řídíš ??Rosta píše: ... Řešení: Kupte si rozdvojku, vymontujte ochranný kolík a zapojte do ní pouze tyto bedýnky.
PS: Pokud Vás to nezabije hned, tak Vás zabije revizák až to uvidí
Ano, dá. Nechat změřit a posoudit odborníkem, najít optimální řešení problému a aplikovat v praxi.Rosta píše:... Takže,dá se s tím něco udělat?
Pozn. : ujo Google fakt není odborník, který by měl něco posuzovat a doporučovat.