2000w Digital Starsound Class D

[VICK]

Howzit all ! Need some help on this Amp. strange output when gain level and all other adjustments is turned off. It's sound's like distortion
and frequency and other small interference humming sounds.So irritating to the ear ! Barely on for 30 seconds and the output drivers get extremely hot. When measuring on speaker output I get 16volt.Dont think thats normal. Anyway any news were i should check The HIP4080 IS OK.
Regard
Vick

 

[VICK]

OK after closer inspection. There should be no output
because of the input line taken to ground.Then when switched on 16 volts on the output and speaker movement(DC) when switched on !
When input is applied then I get the above problem and sound.
Build's up heat quickly.Changed the HIP4080 , the 2 comparators (LM393) , op amp (LM833) and the Flip-flop(cd4013).Still no joy

regards

 

[Perry Babin]

The amp will have DC on the output if you use chassis ground for the reference. How much DC do you have measuring across the speaker terminals?

Is there a DC offset adjustment pot? Many of the 4080 amps have them.

Using chassis ground for the reference, what is the DC voltage on pins 1-10 of the 4080?

Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:

 

[VICK]

Hello and thank you for answering Perry .Yes chassis ground was my reference when I measured the speaker output to 16volts each! The 4080 1-10 pin voltage before adjusting the original(the way it was handed to me before , It's been worked on by someone else) DC offset adjustment pot Here is the voltage:
pin1 - 23.26
pin2 - 11.99
pin3 - 0
pin4 - 0
pin5 - 8.82
pin6 - 6.3
pin7 - 4.5
pin8 - 5.1
pin9 - 5.1
pin10 - 41.2

Now with the DC offset adjustment pot set so that there is NO effect on the speaker. I get from ground reference to the speaker out 22v and on other 21v and 4080 pin voltage:
pin1 - 33.34
pin2 - 11.98
pin3 - 0
pin4 - 0
pin5 - 6.11
pin6 - 6.45
pin7 - 6.54
pin8 - 5.24
pin9 - 5.24
pin10 - 33.88

Testing the amp after the offset adjustment.It barely play's
then it go into protection.
regards

 

[Perry Babin]

To adjust the offset properly, you measure the DC voltage with one probe on a positive speaker terminal and the other probe on the negative speaker terminal (no audio). Adjust to 0.000 or as close as you can get.

When it goes into protect does it draw excessive current?

Does it go into protect if you drive signal into it but don't connect speakers to it?

 

[VICK]

OK since I set the offset it is giving a total other problem.
Now with signal level set to max i hear slight distortion and
very low sound.Turning the LPF pod increase volume a bit then suddenly put's it in protection.Need to do some fresh measurements
again.

 

[VICK]

After looking again I realized that it's the protection led that's connected to a transistor which is connected to the the second leg of the flip flop trough a diode and resistor that goes on.

 

[Perry Babin]

Does it shut down if you drive signal into it with no speakers connected to the amp?

Do you have an oscilloscope?

 

[VICK]

Thank you for the help Perry ! The flip flop is the wrong part number !! Put back the original one ahaaaaaaaaa it's working !! So the problem was either lm833 or the lm393n
regards

 

[VICK]

Hello Perry help please problem with this amp again.
OK fresh start here goes:

DC offset 0volt taken from the the output.
apply 12 volt with no speaker only input and set all adjustments on minimum.Power led on adjust the gain full Still o.k adjust lpf and in kicks the protection circuit.Same goes with a speaker.

Set all adjustments full(max) with speaker and no signal then it stays on.Insert signal input back and on goes the protection circuit.

Pin on the HIP4080

1- 33.1volt (this seems to be the problem)
2- 11.9v
3- 0
4- 0
5- 5.9
6- 6.3
7- 6.5
8- 5.1
9- 5.1
10- 33.1


11- 27
12- 21.7
13- 5.6
14- 0
15- 11.9
16- 11.9
17- 0
18- 5.6
19- 21.7
20- 27

Please help
regards

 

[Perry Babin]

I don't see any problem with these numbers.

You could have a broken potentiometer. If you connect a speaker to the amp, do you hear any noise when touching (pushing on, rotating) the controls or moving the switches?

 

[VICK]

Glad to see your reply.I,m new to D class so some noob Questions Well according the data sheet(hip4080) it states that pin 1 (BHB) has a internal circuitry that clamps the bootstrap supply to approximately 12.8volt.Now pin 1 and pin 10 is getting power from the 12volt supply and get 33 volt out on the bootstrap diode is that normal? So I disconnect the bootstrap diode and then I get normal 12v out on diode and 21volt on the pin(So this is were the 33volt comes from).Where is the clamping to 12.8v ?
Part of my problem is that I never had the privilege to take the measurement of the pinouts on a decent working D class amp.
All the amps that I got so far is in a bad shape this starsound amp
looks like my best shot at the moment.
Why would you think that the switches is faulty?