5 + 2 (bridge) channel gainclone

[AndrewT]

the power requirements for 5.1 are not the same for all channels. The subwoofer needs the most, followed by the front speakers and finally the rear speakers.

is there a part of the 5.1 specification that defines the maximum peak SPL in the rear channels cf. the front channels?
is the rear defined as -10dB or -6dB or -3dB or some other quieter level?

Similarly is the bass channel defined as capable of higher peak SPL than the front channels?

 

[pra3718]

@AndrewT : 1) Can you solve THUMP problem ? 2) Diode heating problem ? Please find my attached pictures.

Regards.

 

[AndrewT]

the thump at switch on probably requires an input mute and/or an output mute.

 

[gfiandy]

If your amp is still thumping at turn on. I would test your DVD player with another Amp as I suspect it is just creating a big thump and you are not going to get rid of it in the Amp.

2.2uF may work its worth a try.

Can you get hold of an oscilloscope as this is what you really need to tell if the amplifer is oscillating.

I recomend measuring how much current is flowing through the diodes so you can see if it gets better or worse depending on the changes you make.

Regards,
Andrew

 

[pra3718]

If your amp is still thumping at turn on. I would test your DVD player with another Amp as I suspect it is just creating a big thump and you are not going to get rid of it in the Amp.

Prior to make this 6 channels I build mono tda2030 and that was silent on power on. I think, you should see carefully my circuit's ground connection. Is there any fault ? I have used soft thin wire for input signal from RC & RC-Ground to PCB. And accept input signal, I have used hook-up wire everywhere.

Today's modifications.

As per picture attached post # 16. From TOP first two amps are bridge & both amp's gain=33 I wish to increase the gain because this brige is using by subwoofer. If I increase the gain=66 for trial, output becomes unstable but subwoofer sounds very good. I wish to ask what should be maximum gain with stable output. As well as Should I increase the gain for both amps ?

the thump at switch on probably requires an input mute and/or an output mute.

Expert member advised mute relay. (As per picture attached post # 14) I did not find any relay at commercial 6 channel amps. Even I surprised that they use preamp without regulated supply. I did not find any regulated IC on the PCB/Circuit.

 

[ratza]

I did not find any relay at commercial 6 channel amps.

Who stops you to use more relays? Why do you want a single one? Use one DPDT relay per channel (that would be 6 relays).

 

[pra3718]

Powe on thump. With more information it sounds like you are getting a charge pulse from the DVD player on the input coupling capacitor

@gfiandy : I am using 2.2uf 25v electrolytic Cap. Should I use another cap to reduce Power ON clicking ?

 

[star882]

Power on the amplifier after turning on the DVD player.

 

[gfiandy]

No 2.2uF is abot as small as you want to go.

You have changed the description of the sound and different sounds have different causes.

Is it a click?

or

Is it a thump?

I am running out of ideas however you could try a 470R resistor (in fact from 220R to about 1K would do) in series with the 2.2uF this would reduce the inrush into the cap if that is what it is.
470R 2.2uF
i.e input form DVD o-----/\/\/\/\------||----amp

Leave the other resistors in place.

Regards,
Andrew

 

[pra3718]

Is it a thump?

I was..../... am confused what to call it. I am not expert to describe is that thump or click. When I power on All channels speakers move one or two times with sound like .... THAK-THAK..... POOOOOOOOOHHH. (sorry)

Today, I will try for 1k resistor before input cap.

Have you more idea to advise why diode is heating ? You must have build 6 channel with single psu. what was your experience ? I am listening daily one hour this my system I did not find any problem in sound. What is your opinion about diode heating ? Is it normal or fear ?

After one hour listening......

1) Sounding good.
2) Heat sink not over heat ( I can touch )
3) Diode becomes very hot, cannot touch
4) PSU capacitors 4700uf, very cool.
5) All components cool. (accept tda2030)
6) No power switching OFF noise ( how do I shut-down the system : First I OFF the dvd player with remote. Now there is no hum-noise nothing.. Very low noise (Suuuuuuuu) comes if I push my ear very near to speakers. (touch ear to speaker) If I keep myself 3-4 feet away from the speaker, it feels like system is dead. And then I power OFF the switch, again there is NO sound/thumps/clicks ... NO NOTHING.. )

Regards.

 

[gfiandy]

Hi,

Are the diodes to hot to touch with amp on 1hr but not playing?

Just to be clear does the sound happen when you turn teh amps on or when you turne the DVD on?

Regards,
Andrew

 

[pra3718]

@ gfiandy :

Are the diodes to hot to touch with amp on 1hr but not playing?

Yes, it becomes hot with in 5 min.

Just to be clear does the sound happen when you turn teh amps on or when you turne the DVD on?

I have two wall sockets operated by single On/Off switch.

Condition # 1 : If I power switch ON, DVDPlayer + 2030amp at a time : Clicking sound = YES. And power switch OFF : Clicking sound = NO

Condition # 2 : If I power switch ON for DVDPlayer and after 10 Sec. power
switch ON for 2030amp (from different wall sockets) : Clicking sound = NO. And Off the DVDPlayer by remote, power switch OFF for 2030amp : Clicking sound = YES

Condition # 3 : If I power switch ON for 2030amp and after 10 Sec. power switch ON for DVDPlayer (from different wall sockets) : Clicking sound = YES. And Off the DVDPlayer by remote & wall socket. power switch OFF for 2030amp : Clicking sound = YES

Condition # 4 : If I don't operate DVDPlayer and Power switch ON for 2030amp : Clicking sound = NO. Power switch OFF : Clicking sound = YES

I got the answer for ( Condition # 3, power switch OFF for 2030amp : Clocking sound = YES ) 4700uf capacitor discharge. Solution : don't know. But yes, 4700uf capacitor discharging at Condition # 1 also. Is that right ?

I have 2.1 multimedia computer speaker brand:iNTEX at my office. I never open it to see what is inside. It has switch ON noise.

All this above stuff, would be easy to advise what exactly happening with me.

@pacificblue, @sangam knows all my attempts. Why they are not in this thread I don't know? I have invest lot-off money in DIY. I could buy a good branded system adding some money. But I am enjoying DIY. Peoples waste lot-off money in hobby. My thought : DIY AUDIO is continuous process and not a target. Now I am at very beginning stage. ( Hope you will not mind this para. is not subject to the thread )

Thank you gfiandy,
Best Regards.

 

[AndrewT]

@ gfiandy :Yes, it becomes hot with in 5 min.

there is something seriously wrong.
The diodes should not become hot even when playing music and certainly not when the system is silent.

 

[gfiandy]

Hi, it really should not be drawing this much current with no audio playing. The only thing I can think of is that it is still unstable and oscillating slightly. Your best bet is to try to find someone who has an oscilloscope then you can see what is going on.

In the mean time measure how much current is being drawn by the system when it is not playing. To make a current measurement you need to put your meter in series with the power cable. The current needs to flow through the meter for it to be able to measure it.

Regards,
Andrew

 

[AndrewT]

insert a 1r0 resistor into each power feed. Measure the voltage drop across each resistor.

 

[pra3718]

@ gfiandy, AndrewT : Good morning,

After very long time to continue this. After several test I could not solve my DIODE heating problem. And yesterday I decided to work again but STEP-BY-STEP. I removed the bridge connection to 4700uf caps, and power on, I found diode hot very soon. This time no load on diode, and decided to replace the diode (it was brand-new)

After replace all four diode (bridge) and connect all wiring properly and listen for 1 hour. I did not find any diode hot problem.

But, I wish to go ahead. Attached picture is my current layout. I wish to make it decent and complete.

1) Right side is output to speaker. Looking for best way to collect all output at single place. ( Heat sink is at right side )

2) Inputs are in the middle, which I have to keep at single place.

3) At the bottom side I made ground star point which is connected to power ground by 1r 0.25 watt resisitor.

Or if you find any other improvement pl. post.

Thank you
Best Regards.

 

[gfiandy]

Hi,

Good to hear you tracked down the fault. I guess the diodes must have been counterfit parts as they should have easly been up to the job.

It is quite difficult to understand your layout as none of the components are shown.

However I think your best bet is probably to connect all the oputput ground returns together where the ground come onto the PCB.

Regards,
Andrew

 

[pra3718]

@ gfiandy : Good morning.

Hope, attached picture would be suitable to guild. First bottom amp is replicate to other 5 amp.

To make completely bug-free, I should remove THUMP/CLICK power on.

1) Can I add Switch for ON/OFF speakers. I will operate manually. I have to handle SIX channels with single switch, Is it possible ?

2) Unfortunately, IC does not have MUTE pin. Manual muting, is that possible ? i.e by On/Off switch at Signal input. I think it is possible for mono amp. I asked to my supplier he has not available 6 channel On/Off switch.

3) I tried On/Off switch to ground supply to speakers WHEN ALL SPEAKERS GROUND CONNECT AT ONE PLACE AND IS NOT CONNECT TO POWER GROUND STILL SPEAKER SOUNDS

If you google for "tda2030 5.1", many commercial amp would be listed. One of those has mute function. How they manage I don't know.

Thank you,
Best Regards.

 

[AndrewT]

3 dpst relays can switch 6poles to ground using just a single contact manual switch.

 

[patnaik_kottakki]

I found attached picture at china site.

Hi sir goodevng. I found this site recently while serching for 5.1 amplifier sch. Regarding to your pic of chinese amp, I found these pcb pics. Check it please.