Hi,
I bought a NAD3130 amp for very cheap after college.
Problem is it pops the speakers when i turn the amp on. The popping occurs on both A, and B in right and left channels.
Also i compared the bass to my brothers JVC hifi and mine seems rather lacking.
Has anyone come across this popping ?
Regards,
Ashley
I bought a NAD3130 amp for very cheap after college.
Problem is it pops the speakers when i turn the amp on. The popping occurs on both A, and B in right and left channels.
Also i compared the bass to my brothers JVC hifi and mine seems rather lacking.
Has anyone come across this popping ?
Regards,
Ashley
Hi Giaime,
I find that all NAD are below the prevailing standard of circuit design at the time of manufacture. Generally, all techs seem to get stuck on these as they are sensitive about things like transistor gain. Even with proper replacement parts. As such, I would avoid them where possible. Since yours works - great. Use it.
I know you can build a better amp. Better sounding too.
Chris
I find that all NAD are below the prevailing standard of circuit design at the time of manufacture. Generally, all techs seem to get stuck on these as they are sensitive about things like transistor gain. Even with proper replacement parts. As such, I would avoid them where possible. Since yours works - great. Use it.
I know you can build a better amp. Better sounding too.
Chris
Hi Ashley,
if you are going to build your first diy amp, then this will
probably not be the best value for money option.
But it will be the best passion for money option.
Nevertheless, I think DIY is a good idea.
No matter how often you will
.
You will have the second 'perfect' amp in mind short after
your first proto is showing basic operation.....
@Chris:
Hm, I love your direct opinion about NAD.
Even if I own two NAD components. I bought them
via eBay, because I needed fast replacement and had no time
to listen in the audio stores....
Well, the CD/MP3/DVD changer is sounding OK, but is
slow. To slow. Much to slow.....
The Receiver sounded poor in the beginning.
My ears were crying: "cross over distorsion... cross over di...."
So I opened that thing (no time to send back and struggle and wait again...) and ..... Really! They had adjusted the idle current of the output stage to .... close to zero.....
Now I am running it around 170mA idle current and it is sounding
alright. I have no idea why they had adjusted it only at 15mA.
The thermal compensation is perfect, the idle current does not change, even when you warm up the heat sink with a hair driyer up
to 100°C.... stable, thermally perfectly stable. Really nice design in this regard! But the adjustment....? Why the hell do adjust it
to 15mA? The heat sink is large enough to allow at least 50mA without any headaches...
And with 50mA it was already sounding like an average amp.
I did not expect much improvement by further increasing of the
idle current. But there was again a respectable benefit.
My adjustment of 170mA is the upper limit with respect to
60°C at the heat sink already without music load. For home music
applications that's OK....
if you are going to build your first diy amp, then this will
probably not be the best value for money option.
But it will be the best passion for money option.
Nevertheless, I think DIY is a good idea.
No matter how often you will
.You will have the second 'perfect' amp in mind short after
your first proto is showing basic operation.....
@Chris:
Hm, I love your direct opinion about NAD.
Even if I own two NAD components. I bought them
via eBay, because I needed fast replacement and had no time
to listen in the audio stores....
Well, the CD/MP3/DVD changer is sounding OK, but is
slow. To slow. Much to slow.....
The Receiver sounded poor in the beginning.
My ears were crying: "cross over distorsion... cross over di...."
So I opened that thing (no time to send back and struggle and wait again...) and ..... Really! They had adjusted the idle current of the output stage to .... close to zero.....
Now I am running it around 170mA idle current and it is sounding
alright. I have no idea why they had adjusted it only at 15mA.
The thermal compensation is perfect, the idle current does not change, even when you warm up the heat sink with a hair driyer up
to 100°C.... stable, thermally perfectly stable. Really nice design in this regard! But the adjustment....? Why the hell do adjust it
to 15mA? The heat sink is large enough to allow at least 50mA without any headaches...
And with 50mA it was already sounding like an average amp.
I did not expect much improvement by further increasing of the
idle current. But there was again a respectable benefit.
My adjustment of 170mA is the upper limit with respect to
60°C at the heat sink already without music load. For home music
applications that's OK....
Hi ChocoHolic,
I thought I was a little too direct in that I may have offended some people who own them. Glad you weren't.
Now you have been on this forum longer than I have. I am a llittle surprised you haven't built an amplifier. You've no shortage of opinions here either. I write this as I listen to a prototype modified diamond buffer amplifier. Is the bug there? Just curious.
-Chris
I thought I was a little too direct in that I may have offended some people who own them. Glad you weren't.
Now you have been on this forum longer than I have. I am a llittle surprised you haven't built an amplifier. You've no shortage of opinions here either. I write this as I listen to a prototype modified diamond buffer amplifier. Is the bug there? Just curious.
-Chris
@Ashley:
Did you measure the continuous DC-offset at the output?
If it is less than 100mV, you do not need to worry.
Less than 5mV would be nice, but 100mV will not kill the speakers.
Probably the "pop" is resulting from the power up. During power up
the operating points of all nodes are jumping/sloping from zero to their normal steady state values. This is causing the "pop".
To get rid of it you could add a delayed output relay.
You should be able to find several designs for this here in the forum.
@ Chris:
The bug is here. Definitely. Back again, since last winter, when I found this forum.
It is simply the lack of time. I build my last amp 11-12 years back.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=36469&highlight=
And right now I am listening to it. I am using it for my current subwoofer.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=25015&highlight=
And crazy as I am.... right now I am working on two new active subs.
Each one will have a Sadhara Driver from Adire: 12", +/-27mm linear excursion. Size of each cube will be 40cm x 40cm x 35 cm.
The amps will be selfresonant class D, around 800Wrms.
I plan to integrate SMPSs which will give the provison to operate from 120V-277V / AC input voltage and 12V-16V DC car battery as well.
(All my friends are laughing about the 12V topic, because I do not have a car, just a motorbike....)
For DIY I am completely loaded with that two subs......
Heavy collision with time for my friends, work, sports......
But may be after completion of the two subs, I could start some nice
active small satelite speakers with the Dynaudio Esotec drivers of
my current subwoofer ..... ??? !!!!
Cheers Markus
Did you measure the continuous DC-offset at the output?
If it is less than 100mV, you do not need to worry.
Less than 5mV would be nice, but 100mV will not kill the speakers.
Probably the "pop" is resulting from the power up. During power up
the operating points of all nodes are jumping/sloping from zero to their normal steady state values. This is causing the "pop".
To get rid of it you could add a delayed output relay.
You should be able to find several designs for this here in the forum.
@ Chris:
The bug is here. Definitely. Back again, since last winter, when I found this forum.
It is simply the lack of time. I build my last amp 11-12 years back.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=36469&highlight=
And right now I am listening to it. I am using it for my current subwoofer.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=25015&highlight=
And crazy as I am.... right now I am working on two new active subs.
Each one will have a Sadhara Driver from Adire: 12", +/-27mm linear excursion. Size of each cube will be 40cm x 40cm x 35 cm.
The amps will be selfresonant class D, around 800Wrms.
I plan to integrate SMPSs which will give the provison to operate from 120V-277V / AC input voltage and 12V-16V DC car battery as well.
(All my friends are laughing about the 12V topic, because I do not have a car, just a motorbike....)
For DIY I am completely loaded with that two subs......
Heavy collision with time for my friends, work, sports......
But may be after completion of the two subs, I could start some nice
active small satelite speakers with the Dynaudio Esotec drivers of
my current subwoofer ..... ??? !!!!
Cheers Markus
Hi,
Amp is worth more than i thought!
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=3280&item=5760851483&rd=1
Regards,
Ashley
Amp is worth more than i thought!
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=3280&item=5760851483&rd=1
Regards,
Ashley
Hi Ashley,
for me it is hard to believe that this amp does not have a
speaker relay. Are you sure about that? Or is there a relay,
which does not work proper and is always ON ?
If this amp really does not have a speaker relay, then you should
change this only if you want to use it on your own.
For ebay you should let it be unchanged IMHO.
If the amp has a speaker relay, which is not proper working,
then you should try to repair it, no matter if you want to sell it or not.
Good luck
Markus
for me it is hard to believe that this amp does not have a
speaker relay. Are you sure about that? Or is there a relay,
which does not work proper and is always ON ?
If this amp really does not have a speaker relay, then you should
change this only if you want to use it on your own.
For ebay you should let it be unchanged IMHO.
If the amp has a speaker relay, which is not proper working,
then you should try to repair it, no matter if you want to sell it or not.
Good luck
Markus
Hi Markus,
Time is what we all lack. Takes me a while and sometimes I get interested in something else. Wife is not happy with the basement!
The NAD does not use a speaker relay. Protection consists of a self reseting breaker on the PCB. Many times these need to be replaced. I use fuse holders on the back panel to replace those things. Your idea of using the speaker switch to eliminate pops is good. Most people won't do this. Also, I just worked on an amp with 250mV DC offset. I had to match the diff pair xistors (not NAD). Offsets dropped to about +20mV. Depending on the design, I may accept 100mV DC offset. I doesn't make me to happy though.
-Chris
Time is what we all lack. Takes me a while and sometimes I get interested in something else. Wife is not happy with the basement!
The NAD does not use a speaker relay. Protection consists of a self reseting breaker on the PCB. Many times these need to be replaced. I use fuse holders on the back panel to replace those things. Your idea of using the speaker switch to eliminate pops is good. Most people won't do this. Also, I just worked on an amp with 250mV DC offset. I had to match the diff pair xistors (not NAD). Offsets dropped to about +20mV. Depending on the design, I may accept 100mV DC offset. I doesn't make me to happy though.
-Chris
Doesn't have a relay?
That's a design choice, not a defect. Money is involved.
It doesn't have a remote, or provide draft beer either.
30W is underpowered?
Power is log, 300W only plays twice as loud as 30W.
Put that amp on a pair of Klipsch Cornwalls and try and tell me it doesn't play loud enough.
You don't like it?
Fine, its yours to get rid of.
Find something you like better before you dump it, it may take a bit more effort than you think.
That's a design choice, not a defect. Money is involved.
It doesn't have a remote, or provide draft beer either.
30W is underpowered?
Power is log, 300W only plays twice as loud as 30W.
Put that amp on a pair of Klipsch Cornwalls and try and tell me it doesn't play loud enough.
You don't like it?
Fine, its yours to get rid of.
Find something you like better before you dump it, it may take a bit more effort than you think.
Yes, I also think you can go for some nice speakers.
If you use the speaker selector to avoid the pop, it
should be fine, even for less rugged speakers.
And if that amp sounds fine, then why worry about
its age or low power?
DJK is right. Depending on the speaker, 30W will be
more than loud enough.
And also right, if 30W are not enough, then 50W also will not be
enough. Every doubling of our human loudness perception requires
a full dekade more power.....
If somebody is always running into clipping with his amp, he would
really need step up in large scale to overcome this succesfully.
(Or pick speakers with 100dB@1W)
If you use the speaker selector to avoid the pop, it
should be fine, even for less rugged speakers.
And if that amp sounds fine, then why worry about
its age or low power?
DJK is right. Depending on the speaker, 30W will be
more than loud enough.
And also right, if 30W are not enough, then 50W also will not be
enough. Every doubling of our human loudness perception requires
a full dekade more power.....
If somebody is always running into clipping with his amp, he would
really need step up in large scale to overcome this succesfully.
(Or pick speakers with 100dB@1W)
Of course, output power does not begin to tell the story with an amp. Things like current capability and overload recovery are very important. It's also nice if the heatsinks are big enough so the amp doesn't go boom.
I will say that a poor design can survive in low power because there isn't enough heat and energy to kill the amp. The higher power designs are not so forgiving.
Now I'm a guy that listens softly .... and cranks it sometimes. I find that amps 100 ~ 200W are enough because the headroom is for peaks. Even though the peaks may not show on a smaller amp, they are there.
-Chris
I will say that a poor design can survive in low power because there isn't enough heat and energy to kill the amp. The higher power designs are not so forgiving.
Now I'm a guy that listens softly .... and cranks it sometimes. I find that amps 100 ~ 200W are enough because the headroom is for peaks. Even though the peaks may not show on a smaller amp, they are there.
-Chris
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