41 Hz Amp 6?

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#141
Hi Nuuk,

I am loving my AMP3 with the SMPS you sold me.

Around the same time i also added a BHC 10,000uf off board and tweaked the input caps to maplin LCR polys from maplin.

Each had it own effect and all positive, combined they make it a much nice sounds amp, stunning sound stage . I really am very happy with it, i had gone back to my Gainclone since i found the initial AMP3 missing somthing but now with inproved PSU setup i prefer it.

I also find it very good watching DVDs with since they produce such a 3d soundstage.

How are the AMp 6's compare to the AMP3?

Anyway thanks and keep up the good work

Phil
 
#142
Hi Phil, what you say shows how important it is to play around until you either get an improvement, or realise that what you had before is better.

To be honest, I prefer the sound of the AMP-6 to the AMP-3. I found the AMP-3 slightly tiring to listen to but the AMP-6 is more like the other 2020 amps! :att'n:
 
#143
Amp6 is rated at 2x25w with 4ohm load, at 80% efficiency (given a 14.6vdc power and 10% distortion), so thats 60w required power / 14.6 and you get 4amperes. At 8ohms load, output is rated at 2x13w at 90% efficiency, so thats 28.6 watts / 13.5V so thats around 2.11 amperes. Hope this helps.
 
#146
Getting there

OK, I have now managed to get sound out of my AMP6! The only problem is that it is not really the type of sound I want. It sounds like it is AC from the power supply. It sounds like a very loud hummming sounds on a low frequency, I am able to hear music too, but the humming noise is the most prevalent noise.
I have two amps and they both have the same characteristic.

Also, when tapping on the LM1084 I can hear it in the speker. It works like a microphone, is there a short somewhere? How do I find it?
 
#148
Saso said:
Have you connected the GND signal on the PCB (where the transformer is connected)? I forgot to do it and found large amounts of noise in the music. Then I connected it to GND on the IEC socket and all was well.
Click to expand...

Saso, you're the man! It now works!

2 of my amps now works properly but one is a little funny. The red lamp comes on on startup and stays on, the green lamp goes on and off depending on the mute switch being closed or not.

All amps play music irrespective if the mute switch is closed or not.
 
#150
Humming sound?

After connecting the AMP6 to ground the very loud hum went away. However a little noise remained, I traced it down to the signal (input) cables (I use Van Den Hul "The Bay C5"). I have cut the cables in half and soldered one end to the curcuit board, so there are no terminals.

The hum that was produced from the amp was lessened after grounding the shield of of the cable to J8.

However, still a little hum remain yet, should I not connect the shield ground to something else than J8?

Interestingly enough the Amp is dead silent when not plugged into the PC source, as soon as I plug it in the humming begin.
 
#151
Re: Humming sound?

Ninfendo said:
Interestingly enough the Amp is dead silent when not plugged into the PC source, as soon as I plug it in the humming begin.
Click to expand...

Probabaly a ground loop. Happens to me sometimes with the PC as well. Or it could be the PC itself! They are not known to be the quietest sources unless you tweak them.
 
#152
Re: Re: Humming sound?

panomaniac said:


Probabaly a ground loop. Happens to me sometimes with the PC as well. Or it could be the PC itself! They are not known to be the quietest sources unless you tweak them.
Click to expand...


Since this seems to be a problem with the input cable shield, doesn't the PSU affect the input negatively if they are both connected to the same ground? When I connect the PC to my old Arcam amplifier there is no humming.
 
#153
There is likely to be current flowing thru the cable shield.

What other ground points are there? Is there a ground connection thru the PSU or some other place?

Try a signal source that has no ground, e.g. a CD player or radio. Do you get hum then?

Tracing down hum and buzz can be very difficult. After decades of doing it on the job, I've gotten a good feel for it - but it can still be tricky. Look for more than one path to ground and try to eliminate anything more than you need. That's a start. WIth these little low voltage amps you can usually let the ground return be back thru you other equipment, the preamp, PC, whatever. If none of the other gear has ground, then ground the amp.

Now you know why pro gear has a ground lift switch! So many different situations to deal with.
 
#154
panomaniac said:
There is likely to be current flowing thru the cable shield.

What other ground points are there? Is there a ground connection thru the PSU or some other place?

Try a signal source that has no ground, e.g. a CD player or radio. Do you get hum then?

Tracing down hum and buzz can be very difficult. After decades of doing it on the job, I've gotten a good feel for it - but it can still be tricky. Look for more than one path to ground and try to eliminate anything more than you need. That's a start. WIth these little low voltage amps you can usually let the ground return be back thru you other equipment, the preamp, PC, whatever. If none of the other gear has ground, then ground the amp.

Now you know why pro gear has a ground lift switch! So many different situations to deal with.
Click to expand...


Thanks for the advice. I will solder a shielded cable to the signal shield and try connecting it to various places, I.e. Circuitry board, star ground, and heatsink. Perhaps it might be worth connecting it to the PC too. I will see if any of these will improve things.

I will also definitely try another source as well, will start with the IPod.
 
#155
Ninfendo said:



Thanks for the advice. I will solder a shielded cable to the signal shield and try connecting it to various places, I.e. Circuitry board, star ground, and heatsink. Perhaps it might be worth connecting it to the PC too. I will see if any of these will improve things.

I will also definitely try another source as well, will start with the IPod.
Click to expand...

OK, my 6 channel AMP6 amplifier is almost done. I managed to solve the problem with the humming over the weekend. All I had to do was connect the shield of the signal cable to the GND of the power cable. So I now have 6 cables soldered to the ground point, one for each of the PCBs, and one for every two signal cables, I will put up some images when the little beast is finished.
 
#156
ok so i read all post on the amp6 and nobody have the problem that I have with my amp6

ok so I chek all the diode and there on the right side

i connect a 15va transformer 2 ampere and the fuse blow imediately

so i decided to go take a speed test and conected it anyway whitout fuse to take a read

and woaw the rectifier is very hot not the regulator strange

i got 16 volt on reading

and 16 amprere wow so i disconnect all and test the transformer and it give 16 ampere and spark to wow so what did I make wrong

can anyone help a noob thanks
 
#157
Jonastus, there must be a short circuit in your rectifier circuit. Check the soldering, copper traces etc. My AMP6 takes around 50mA idle. I guess you have either swapped the rectifier or made short circuit around the large filtering capacitor, before the regulator.
 
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