My Gaiclone "Pops" :(

[carlmart]

i know it isn't the most audiophile solution, but cheap and it works good. so...

It certainly is far from audiophile to rely on such solutions, as some will probably say it affects audio quality.

There are different house gear that impairs audio or cause a sound of its own (whirr, pops, etc), like any machine hooked on the same AC line: vaccuum cleaner, washer, blender, air-conditioning, computers, motors of any kind).

What you should first do is filter the AC terminals where those motors are, not the amplifier's. VDR and other "slowing down" devices should always be used at refrigerator's and blender's AC sockets.

The best thing to do, if you can afford it, is to re-wire your house using exclusive wires for audio and TV. That's what I did and never had any more problems. A great and effective investment.


Carlos

 

[karma]

i had the same problem. i used a old ups that had no battery so i
paid nothing for it. it has a good line filter in it. now the click's
and pop's are no more

with or without there no change in the sound. not that i can find anyway. if you where to run it on battery's it may change the sound.

im cheap like im going to pay $300 or more for some audio power bar with a line filter in it lol

my fridge is on the same line as my audio so it work's

p.s if you try it use a smart-up's other brand's are cheap

 

[xcortes]

Thanks all for your answers. I ordered an isolation transformer (a good Stancor one) that I'll use with my black cube pre amp. I decided to start with the black cube as it requires much less power (30 VA so I ordered a 35 VA one) and therefore is much cheaper ($20). If it works I might order a large one for the gainclone.

I'll also try the other proposed solutions and let you know of the outcome.

Thanks again,

xavier

 

[qdoc]

Most of 'pop' is from high freqency (high dV / dT) noise spike in the input. The spike makes audible distortion and that sounds 'pop'.
Thus, it can be easily handled by 100-200pf capacitor between positive and negative input or high cut filter of approx. 1kohm and 200pf right at input pin.
Doing something for the power will simply cost you much and do nothing about pop noise.

 

[qdoc]

Another thing was missed to mention.
If both the input source and the amp operate under a circumstance that is filtered or isolated from external power line noise, it also can be a solution - with much more cost.

 

[xcortes]

I'll try the 220 pf cap proposed by Franz G and qdoc. Chep and easy to try. Will get the caps today and let you know tomorrow. I'll get whatever I can get fast and easy to try the effect. If it works should I try other fancier caps?

I will also buy the 1K resistors to try the filter suggested by qdoc. qdoc, could you please explain me a little more about how to "build/connect" the filter?

Which of the two solutions will be best in your opinion?

Again: Thanks all!!,

xavier

 

[qdoc]

I prefer using high cut filter because it cuts noise off befere hand. If my calculation is correct, roll off frequency of 1K and 220pf filter is 723khz and it would not affect audio signals at all. Intead, it would rather contribute to a stable operation by cutting off many different types of RF noises (from switches, florescent lights, modems, 2 way radios....etc.) that can turn into audible noises during the amplification.

input-----------------1KOhm----------input pin of chip
..................|.........................|................................
.......loading resistor...............220pf............................
..................|.........................|................................
...............GND......................GND..............................

 

[qdoc]

Oh, about type of capacitors, I will avoid ceramics. I will select mica caps for the application.

 

[Franz G]

For this type of application, 220 pF between the inputs, you can use ceramics. No problem.

They are not in the signal path.

Franz

 

[qdoc]

The reason why I avoid ceramics is because they have piezo electric properties.
Even if piezo electric noise from ceramics can be nothing significant, I do not see any reason to save less than a dollar and use ceramics when other better options are readily available.

 

[xcortes]

I purchased the capacitors and resistors. I purchased the capacitors in two versions: polyester and ceramic. Probably will try the former first.

If I understand right qdoc's diagram both the resistor and capacitor are connected in parallel between the input and ground. Is yhis right?


Thanks again

 

[qdoc]

No, it was not!
The 1k resistor is between signal input and input pin, and the 220pf capacitor is between the input pin and ground.
Good luck!

 

[xcortes]

The 220pf Capacitor in the input slightly reduces the pops but does not eliminate them.

I also tried the isolation transformer (at the black cube). No success.

I'll try the filter and post my results later.

 

[HDTVman]

Those "pops" are the price you pay for using the toriodal power transformers. That type of transformer has a very wide bandwidth and if your power supply filter doesn't clean up the spike that the transformer passes you get the "pop".

A CLC power supply or regulated power supply will be the best way to take care of that problem. Or just use an old EI core transformer.

Later BZ

 

[Franz G]

Any Filter?

Do you use some kind of filter in front of the torroid? The simplest method is a 100nF Cap, 1,5kV in parallel to the primary.

Franz

 

[qdoc]

If impedence of negative input is not pretty high, bridging 200pf between pos and neg input won't be a solution because of the significant drop off of noise signal at neg input. The difference in pos and neg inputs will be amplified to 'pop' noise (OP amplifier is also called as differential amplifier occasionally.) . Try 1K and 220pf filter and have the result posted.
I do not mean to offend some posters however assumption or un-tested theory won't be any help for xcortes.

 

[qdoc]

I just have reviewed the whole posts again.
If the 'pop' is from the Black Cube, it also must have the input high-cut filter. Isolation transformers or power filters will not do anything.
How do I know? I am the designer and maker of "Zing" MC pre-pre and phono stage amplifiers and experienced the same troubles far more than 10 years ago.
Actually our phono amplifiers use 10 micro henry and 220pf input high cut filters ijnstead of 1k and 220pf.

 

[xcortes]

so my only solution will be a dedicated line?

 

[qdoc]

For the nature of problem basically is a RFI (Radio Frequency Interference), even a dedicated line will not be a permanent fix.
If you can, I recommend minor modification of the Black Cube to put the input filter with 10 micro henry axial lead inductors and 220pf capacitors. I guarantee that would not affect the sound at all.
That will be the cheapest and most reliable fix.

 

[xcortes]

Thanks qdoc. Let me try to summarize what I think I understand.

1. The nature of the problem is RFI.

2. The only way to solve it is via an RFI filter at the signal input of the GC and the BC. The simplest filter is a 10 micro henry inductor and 220pf input high cut filters. The inductor is before the signal input , and the 220pf capacitor is between the input and ground.

And what I don't:

1. If RFI enters via rhe mains why a Power filter designed for RFI won't help?

2. Can I build you proposed filter externaly (for example in the Interconnect)? before messing inside the BC?

Thanks again