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Old 22nd October 2010, 01:03 PM   #81
Cristi is offline Cristi  Europe
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Location: Dortmund+Shenzhen
The best quality sound have the LME49810 amplifiers, 300W or 500W version.
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www.connexelectronic.com complete assembled amplifier and SMPS
 
Old 25th October 2010, 04:34 AM   #82
hpq is offline hpq  Hong Kong
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Hi Cristi,

What do you think LM4702 amplifier ?
Do you have any recommendation of LM4702 module kit ??

Regards
 
Old 3rd December 2010, 09:24 AM   #83
bjorge is offline bjorge  Norway
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Default I fried my TDA892x Amp V2 (:rectifier - and + markings interchanged)

I was to test one of my TDA892x Amp V2's yesterday, but the only sound it managed to produce was a loud bang ! as one of the large filter caps blew.

I had made a tiny modification to it and was caught by a mistaken rectifier polarity indication on the PCB. It was to be connected to a DC supply and I didn't want the voltage drop of the mounted rectifier. Out came the rectifier, and it was replaced by two little jumpers. So far so good, + to + and - to - and here you go. No output, and I soon realised the psu produced some alarming ticking sounds (current limit). Then blew one of the caps, before I managed to switch power off.

Investigation soon revealed that the rectifier's + marking on the PCB was actually the -.

I assume this amp is fried, will know for sure later today. Just thought I'd share this with you, as I'm possibly not the only one thinking of connecting a DC supply to these amps (and wanting to avoid the energy and power loss of the superflous rectifier).

The good thing was, the psu (also a Connexcelectronic one) survived ;-).
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Last edited by bjorge; 3rd December 2010 at 09:26 AM.
 
Old 3rd December 2010, 09:57 AM   #84
Cristi is offline Cristi  Europe
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Join Date: Dec 2008
Location: Dortmund+Shenzhen
One of the first batches of TDA892x amps has the footprint marking opposite i took that from some old library when i made the board and i discovered at assembly only, i don't remember if only the edge cutting or also the + and - marking, but the bridge was installed correctly. the actual ones are all with correct footprint. send me a mail and tell me what parts do you need to replace.
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Old 10th December 2010, 08:56 AM   #85
bjorge is offline bjorge  Norway
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I have a question about TDA8920SMPS:
- What is maximum peak and continous power will be available when TDA8950 option is chosen (8ohms bridged) ?
- What supply voltage is it running at ?
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Old 10th December 2010, 08:59 AM   #86
bjorge is offline bjorge  Norway
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Now, what about selling a version of the TDA89XX - based amps that do not include a rectifier and large filter caps ?
These components take up more than half the space, and you don't need them when running an SMPS...
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Regards, Bjørge
 
Old 8th January 2011, 11:36 PM   #87
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Join Date: Oct 2009
Hello Cristi
I have problems regarding, multiple amplifiers (TDA8920) powered by one trafo,( I’m in the process of making active loudspeakers). I have previously read that it is necessary to make external synchronization when you have several amplifiers on one trafo.
I have found some documentation in the NXP documents, but I have some problems translating it to something (at least for me) useful.
Will you help me whit a little drawing on these drawings? I have been searching the net for a day, but haven’t found something useful, ( I don’t want to mess up your nicely produced amplifiers, which by the way, works extremely well).

Michael
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File Type: jpg cristi.jpg (84.4 KB, 455 views)
File Type: jpg synchro.jpg (193.3 KB, 445 views)
 
Old 10th January 2011, 01:20 PM   #88
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from page 16 there is some information
http://www.nxp.com/documents/data_sheet/TDA8920B.pdf
 
Old 10th January 2011, 06:27 PM   #89
Cristi is offline Cristi  Europe
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Join Date: Dec 2008
Location: Dortmund+Shenzhen
Default TDA892x Sync

The easiest way to synchronize the carrier switching frequency for multiple ic's used within a system is to use HEF4047 Multivibrator as clock generator. then, it's output can feed several ic's. few notes: the maximum number of the TDA892x ic's which can be feed from an unbuffered generator should not exceed 6 pcs. for more, a simple buffer must be used, or multiple buffers each driving few ic's.
to force the external sync. the actual resistor from osc pin to negative supply !!! must be removed, and a 1K resistor from the multivibrator output to each osc input pin of TDA892x must be used. this will bias the osc pin above 0V and provide sync.

as a side note, in most of the cases, the noise have other causes than the lack of sync, mostly the GND loop which is formed between power supply gnd of each module and Input GND. since the signal source is only one, there should be only one GND connected for all the inputs, and since all of them use a single power supply, the power supply GND will be the other end of the GND loop. an alternative solution is to use balanced input, which the ic already has instead of unbalanced inputs. when using unbalanced, one input (inverted or non-inverted) is fed with input signal and the other one is connected to GND, that's where the the loop can be avoided, by feeding with balanced signal, there will be no looped GND reference for the other input.
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Old 10th January 2011, 06:46 PM   #90
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Default TDA89x0SMPS info

Hi Cristi,

I just ordered one of the TDA8950SMPS units. Could you update the info on the module with the schematic (or send it to me)?

I'm interested in two things,
1) Hookup of the status led indicator
2) Can I tap the power supply for a few milliamps to run a dual op amp as an input pre-amp? (adding in a few voltage regulators of course)

Thanks..

(oh, can you tell me the typical lead time to ship the unit?)
 

 


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