This question is in regard to wiring connections for a 300 watt mono amp board with LME49830 driver and 2SK1530/2SJ201 MOSFET s. The board schematic is shown below.
Amp Board Specification:
Status: Class A and B (can be adjusted according to the CPI (A))
Output power: 300W * (4 ohms) <* V = ± 60V
Operating voltage: the recommended voltage driver stage ± 55V / output stage ± 50V
Input Interface: mono signal input
Output Interface: mono speaker output
Power: dual-supply operation, the voltage drive and current power output stage separate power supply voltage level and current level can also be combined power and freedom of choice.
PCB size: 215 x 93.5 mm
Also below is a photo of the terminals present on the amp board. My power supply DC outputs - Vee and +Vcc will be connected to terminals labeled -Vee and +Vcc. What voltage source and of what voltage and current is expected to be connected to terminals labeled -V and +V ? Or do I even need to use the -V and +V terminals?
I can not sort this out from the schematic due to my limited technical knowledge. So looking for help.
The answer for this question may be given in the Amp Board Specifications:
Power: dual-supply operation, the voltage drive and current power output stage separate power supply voltage level and current level can also be combined power and freedom of choice.
I do not understand what this is saying either. It might be a language translation glitch.
Dennis
Amp Board Specification:
Status: Class A and B (can be adjusted according to the CPI (A))
Output power: 300W * (4 ohms) <* V = ± 60V
Operating voltage: the recommended voltage driver stage ± 55V / output stage ± 50V
Input Interface: mono signal input
Output Interface: mono speaker output
Power: dual-supply operation, the voltage drive and current power output stage separate power supply voltage level and current level can also be combined power and freedom of choice.
PCB size: 215 x 93.5 mm
Also below is a photo of the terminals present on the amp board. My power supply DC outputs - Vee and +Vcc will be connected to terminals labeled -Vee and +Vcc. What voltage source and of what voltage and current is expected to be connected to terminals labeled -V and +V ? Or do I even need to use the -V and +V terminals?
I can not sort this out from the schematic due to my limited technical knowledge. So looking for help.
The answer for this question may be given in the Amp Board Specifications:
Power: dual-supply operation, the voltage drive and current power output stage separate power supply voltage level and current level can also be combined power and freedom of choice.
I do not understand what this is saying either. It might be a language translation glitch.
Dennis
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Interestingly, your schematic is not for the amplifier you have described.
Suggest you contact the manufacturer and ask for the correct schematic.
However, IF the manufacturer uses the same notations as on this schematic, I could assume that the V+ and V- is for the input stage, and VCC+/- is for the output stage.
Suggest you contact the manufacturer and ask for the correct schematic.
However, IF the manufacturer uses the same notations as on this schematic, I could assume that the V+ and V- is for the input stage, and VCC+/- is for the output stage.
I did notice right off that printed specs on the CB label the driver chip as a 49810. The actual chip is inscribed as a 49830. It immediately worried me but begin to think that maybe the pc board design and layout for either the 49810 and the 49830 were very similar or the same. I hope it is not a bogus board coming out of China! The company Doukmall seems to have a lot of sales and good feedback on Ebay. They have been somewhat helpful providing a bit of texted info and the schematic posted here.
I found the photo below online showing 2 of these particular boards, PS, and transformer in some form of preliminary wiring configuration. The image is not clear and detailed enough to see exactly which terminals are connected to what wires but It appears that the output and input stages Vcc, Vee and +V -V are connected in parallel to the PS Vcc and Vee outputs. Could this be possibly what is referred to as "can also be combined power and freedom of choice" stated in the amp board sellers specifications?
Dennis
I found the photo below online showing 2 of these particular boards, PS, and transformer in some form of preliminary wiring configuration. The image is not clear and detailed enough to see exactly which terminals are connected to what wires but It appears that the output and input stages Vcc, Vee and +V -V are connected in parallel to the PS Vcc and Vee outputs. Could this be possibly what is referred to as "can also be combined power and freedom of choice" stated in the amp board sellers specifications?
Dennis
An externally hosted image should be here but it was not working when we last tested it.
Last edited:
If we can trust the schematic, you only need to connect the Vcc/Vee (or actually Vdd/Vss on your case) and it will work.
For running the input stage on higher voltage, you connect the V+/- terminals to your PS.
I would recommend using an additional PS to power the input stage, as that will prevent the output stage from interfering with the input stage.
By the way, if all the parts are original in your boards, you have an excellent amplifier on your hands now...
For running the input stage on higher voltage, you connect the V+/- terminals to your PS.
I would recommend using an additional PS to power the input stage, as that will prevent the output stage from interfering with the input stage.
By the way, if all the parts are original in your boards, you have an excellent amplifier on your hands now...
I see now that the output transistor location on the PC are also mislabeled also. I was hoping these boards would offer quality performance. As you say if the board components are legitimate it should work well. I will keep my fingers crossed. Photo of the actual board below.
To make sure I understand correctly, if I wire only my PS rail outputs to terminals -VCC and +VCC accordingly and ground, not using the +V and -V terminals at all, the board will operate. Though better performance can be achieved connecting the -V and +v in parallel with my same -VCC and +VCC rail outputs . And if I would choose to provide a second PS board and connect -V and +V board terminals to it, even higher quality performance will be attained.
Dennis
To make sure I understand correctly, if I wire only my PS rail outputs to terminals -VCC and +VCC accordingly and ground, not using the +V and -V terminals at all, the board will operate. Though better performance can be achieved connecting the -V and +v in parallel with my same -VCC and +VCC rail outputs . And if I would choose to provide a second PS board and connect -V and +V board terminals to it, even higher quality performance will be attained.
Dennis
An externally hosted image should be here but it was not working when we last tested it.
Last edited:
Andrew is correct that I should not be having these issues with inadequate technical support. Oh well, I guess it is another instance of "live and learn", and try to make the best of it. I did receive more info last night from another DIYer using similar boards. I've posted it here where others might be able to make use of it. I now realize to do this right I will have to consider buying more in the way of transformers and PSUs. Thanks for the suggestions so far.
Dennis
Dennis
An externally hosted image should be here but it was not working when we last tested it.
Your fellow diyer has probably mislabelled the outputs in your circuit.
The input stage needs higher voltages than the output stage.
If your circuit is used as is, you will use a lot of power just to heat the environment, a lot.
Anyways, if you decide to go with higher rail voltages for the input stage, use only a couple more volts for it.
Lets say that 42v+/- (as you have on your circuit now) for the output stage,
and for the input stage +/-45v max...
That way you make the chip still clip before the output stage during the peak demands (you of course try to avoid clipping totally in the first place...).
The chip clips nicer than the mosfets.
And, if you bias this, lets say, only to a moderate 300mA. That 300mA will only make about 45W (in stereo - efficiency) of extra heat, nothing else, no sound quality, just heat.
The input stage needs higher voltages than the output stage.
If your circuit is used as is, you will use a lot of power just to heat the environment, a lot.
Anyways, if you decide to go with higher rail voltages for the input stage, use only a couple more volts for it.
Lets say that 42v+/- (as you have on your circuit now) for the output stage,
and for the input stage +/-45v max...
That way you make the chip still clip before the output stage during the peak demands (you of course try to avoid clipping totally in the first place...).
The chip clips nicer than the mosfets.
And, if you bias this, lets say, only to a moderate 300mA. That 300mA will only make about 45W (in stereo - efficiency) of extra heat, nothing else, no sound quality, just heat.
Last edited:
I am so glad you tech savvy guys are out there willing to help!
So now as I am deciding to spend more money, to double check, is one of my options to power up the 2 amp boards using only the driver stage + Vcc -Vee terminals on the boards not connecting any power to the output stage +V and -V terminals? If this works I can make do with what I have and not buy any additional hardware. Knowing that this configuration will not give optimal performance but at least functional for the time being. I could do the addition of another power supply and transformer at a later date. I have room in my chassis for the additional stuff.
If I want to, or have to purchase the additional transformer and power supply to make these boards work, from the last reply I understand that the other fellows schematic is either miss labeled or he has it wrong showing more voltage going to the output stage then to the driver stage. I have already been looking for an additional transformer and have a line on a used quality toroidal 50/50 500 VAC. Speculating that this transformer after the caps will provide no load + - 70 volts. I would plan to use this as the driver stage voltage supply and my present 500 VAC toroidal showing no load + -59 volt to power the output + V and -V terminals. There will be 10 to 12 volt imbalance between the driver and output supplies. Will this condition also cause an increase in operating temperature with no improvement in performance and only cause a waste of energy and excess heat? Is the ideal situation that the supplies be nearly equal with the higher voltage supply going to the driver?
Dennis
So now as I am deciding to spend more money, to double check, is one of my options to power up the 2 amp boards using only the driver stage + Vcc -Vee terminals on the boards not connecting any power to the output stage +V and -V terminals? If this works I can make do with what I have and not buy any additional hardware. Knowing that this configuration will not give optimal performance but at least functional for the time being. I could do the addition of another power supply and transformer at a later date. I have room in my chassis for the additional stuff.
If I want to, or have to purchase the additional transformer and power supply to make these boards work, from the last reply I understand that the other fellows schematic is either miss labeled or he has it wrong showing more voltage going to the output stage then to the driver stage. I have already been looking for an additional transformer and have a line on a used quality toroidal 50/50 500 VAC. Speculating that this transformer after the caps will provide no load + - 70 volts. I would plan to use this as the driver stage voltage supply and my present 500 VAC toroidal showing no load + -59 volt to power the output + V and -V terminals. There will be 10 to 12 volt imbalance between the driver and output supplies. Will this condition also cause an increase in operating temperature with no improvement in performance and only cause a waste of energy and excess heat? Is the ideal situation that the supplies be nearly equal with the higher voltage supply going to the driver?
Dennis
I am slowly making progress on my amp project. I have *obtained *a second transformer, assembled *a second dual power supply board and now have DC voltage sources of + - 49 and + - 51 volts and have applied power to one of the 49830 boards. *It seems to be functioning at idle. *There is warmth from the transistors present in the heat sinks, and all seems stable. *But connecting an input and speaker provides no audible sound output. *Only dead silence. *From what limited schematic and technical info I have on this board, it appears that that an AC voltage supply is needed for the speaker protection circuit. *Where does this voltage supply need to be connected on the board? *I can not see an obvious connection point after examining the board. *I am thinking lack of voltage to the protection circuit is the reason there is no sound output.
*I hope that all of this stuff assembled into one chassis will give quiet quality performance. *With EMF interaction and ground loops not causing an annoying amount of background noise. *If the amp proves to be noisy I will attempt to put together separate mono block units out of what I have been working with so far. Attached are a few more photos of what I've put together so far.
*I hope that all of this stuff assembled into one chassis will give quiet quality performance. *With EMF interaction and ground loops not causing an annoying amount of background noise. *If the amp proves to be noisy I will attempt to put together separate mono block units out of what I have been working with so far. Attached are a few more photos of what I've put together so far.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Still no luck with any sound output. Dead silence. I am posting a sketch of my latest wiring scheme . Also a pic of the bottom side wiring of one of my 2 PS boards. Please look over the PS wiring to see if it is acceptable. I used a Texas Instrument power supply design intended for use with their LME49830 chip amp as a guide. The PSs' are producing the rail voltages shown on my sketch. I have not connected my second LME49830 amp board to any power yet. For fear of causing additional damage if it has occurred to the one I've powered up. I have compared diodes, resistances and made sure the chip amp and transistors are not shorted as best I could. At this point there seems to be no variation in the board that has been powered up and the one that hasn't. I am hoping no board damage has occurred as I have struggled. I am a persistent cuss!
From what little tech information I am still faced with, I did read where MOSFETS need a small level of AC voltage in addition to the DC rail voltage to function correctly. Is this correct and where does this additional AC voltage need to be applied? I saw on a similar LME49810 board with the same MOSFET design, connection terminals being almost the same, except for the terminal labeled GRD1 on my board (also referred to as GRD_A on the schematic shown earlier in this thread), was labeled as AC. So as you see on my sketch I have 18 AC volts connected to my board terminal labeled GRD1. The board does power up and seems stable with some heat being generated in the heat sink. Or am I way wrong here and this additional AC voltage is needed for the speaker protection circuit? Or something else?
My latest pics should load a lot quicker this time.
Dennis
From what little tech information I am still faced with, I did read where MOSFETS need a small level of AC voltage in addition to the DC rail voltage to function correctly. Is this correct and where does this additional AC voltage need to be applied? I saw on a similar LME49810 board with the same MOSFET design, connection terminals being almost the same, except for the terminal labeled GRD1 on my board (also referred to as GRD_A on the schematic shown earlier in this thread), was labeled as AC. So as you see on my sketch I have 18 AC volts connected to my board terminal labeled GRD1. The board does power up and seems stable with some heat being generated in the heat sink. Or am I way wrong here and this additional AC voltage is needed for the speaker protection circuit? Or something else?
My latest pics should load a lot quicker this time.
Dennis
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.