diyAudio

diyAudio (http://www.diyaudio.com/forums/)
-   Class D (http://www.diyaudio.com/forums/class-d/)
-   -   pop up noise on Arjen's Mk2 t2020 (http://www.diyaudio.com/forums/class-d/229087-pop-up-noise-arjens-mk2-t2020.html)

msj965 31st January 2013 08:16 PM

pop up noise on Arjen's Mk2 t2020
 
Hello:)

Just wanna ask this problem. Since I bought a t amp s from Arjens a long time ago, I just got a chance to assemble it by my own.but the out come is not good. If you turn the power on you can hear this pop up noise from the speakers.I don't wanna ruin my bookshelf speakers. Is there any solution for this? I know how to solder,understand diagrams and make a circuit connection.

Thanks and more power,
ps: t-amps MKII 2020, I dont know if Arjens still selling this on ebay.

nigelwright7557 31st January 2013 08:23 PM

You could build a soft start circuit which has a relay to the speaker.
You hold off the relay activating for a few seconds to let the amp settle.

Saturnus 31st January 2013 08:43 PM

Yes. The solution is simple. Change the "audiograde" input caps to class D appropriate caps. For example, 1uF Wima or Epcos MKP/MKT cap.

Large high voltage caps with large antenna area and high parasitic inductance have no place in the input of a class D amp.

nigelwright7557 31st January 2013 08:51 PM

I had a similar problem with an IRs2092 class d amp.
It clicked, made a loud crack and sometimes sounded like a siren !

Turned out the 2092 doesn't like large smoothing capacitors.
They make the power supply come up slowly and go down slowly.
I found the simplest fix was to add an 8 pin PIC with analogue to digital converter to monitor the power supply and hold off the 2092's reset if the voltage was out of range.

tamphist 2nd February 2013 07:42 PM

Quote:

Originally Posted by msj965 (Post 3350616)
Hello:)
If you turn the power on you can hear this pop up noise from the speakers.I don't wanna ruin my bookshelf speakers. Is there any solution for this?

Adjust bias voltage to 0mV (using those blue potentiometers).
You can use these same instructions for Arjens TA2020:
6moons audio reviews: Trends Audio TA-10


from trends ta 10 manual:
"4.1 Offset the DC bias voltage of the speaker terminals
There are two blue adjustable potentiometers (Rt) for offsetting the DC bias voltage between the positive (+ve) and negative (-ve) terminals of each channel. Offset this DC bias voltage can enhance the purity of the sound and minimize the “pop" sound when power on and off. The DC bias has been pre-set in factory. But after run-in for a period, it would be slightly changed that the fine-tuning is needed."

msj965 3rd February 2013 05:10 AM

Hi:)
 
Quote:

Originally Posted by tamphist (Post 3353293)
Adjust bias voltage to 0mV (using those blue potentiometers).
You can use these same instructions for Arjens TA2020:
6moons audio reviews: Trends Audio TA-10


from trends ta 10 manual:
"4.1 Offset the DC bias voltage of the speaker terminals
There are two blue adjustable potentiometers (Rt) for offsetting the DC bias voltage between the positive (+ve) and negative (-ve) terminals of each channel. Offset this DC bias voltage can enhance the purity of the sound and minimize the “pop" sound when power on and off. The DC bias has been pre-set in factory. But after run-in for a period, it would be slightly changed that the fine-tuning is needed."

Got yah, But this MkII pcb board doesn't have an Offset bias adjustment. Ill try to check the voltage output and let you know what is the outcome.

tamphist 3rd February 2013 12:31 PM

Quote:

Originally Posted by msj965 (Post 3353796)
Got yah, But this MkII pcb board doesn't have an Offset bias adjustment. Ill try to check the voltage output and let you know what is the outcome.

Found instructions for adding those trim pots
http://www.diyaudio.com/forums/class...ml#post1888645

But I would rather buy new board with speaker protections relays
and bias adjustment pots. http://www.ebay.com/itm/170955692451


All times are GMT. The time now is 12:51 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio


Content Relevant URLs by vBSEO 3.3.2