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-   -   Help!! Irritating sound of my GainKlone (http://www.diyaudio.com/forums/chip-amps/16025-help-irritating-sound-my-gainklone.html)

overmind 4th June 2003 10:13 AM

Help!! Irritating sound of my GainKlone
 
2 Attachment(s)
I had my Gainklone mono blocks up and swinging. Refer to my last post.
http://www.diyaudio.com/forums/showt...threadid=15425

Although, sound produced by it is ok; no hiss, no hum, quiet and with good bass, I do find it very irritating, not at ease at all, I just simply cannot immerse into the music.

After having the amps up and running for two weeks, I decided to change the value of resistor (in red) from 49.9kohm to 30.1kohm, Thus the gain increases from 13.6 to 22. After that, the sound is still very irritating, I would say no improvement at all.

I have also added two pairs of Rifa X2+WimaFKP1 cap before and after the rectifier, and it still sounded very inrriating.

What else can I do to improve this particular aspect of the amps? Can anyone share their experience with me? Would change to the inverting configuration improve the situation?

Thanks
SW Yeo

overmind 4th June 2003 10:14 AM

2 Attachment(s)
The power supply

overmind 4th June 2003 10:16 AM

2 Attachment(s)
Picture of the make shift power supply, without the RifaX2+WimaFKP caps.

ALW 4th June 2003 10:24 AM

With a PSU like that
 
You'll have ripple measuring volts I would think.

Try some adequate reservoir capacitance for starters

Andy.

Cradle22 4th June 2003 10:32 AM

Hi!

You can try omitting the ERO MKP (the input cap) from the circuit (but measure DC offset prior to connecting speakers... probably anything up to 100 mV will be OK).

Or try substituting that input cap with a better one (I also sometimes use those ERO, but never as an input cap so far).

Also the cap from pin 1 to 4 is probably not necessary, try omitting it as well (but always carefully try out if the amp remains stable).

Also, what speakers do you use?

Bye,

Arndt

Cradle22 4th June 2003 10:34 AM

Re: With a PSU like that
 
Quote:

Originally posted by ALW
You'll have ripple measuring volts I would think.

Try some adequate reservoir capacitance for starters

Andy.

That should not be necessary if you follow the GainClone discussions.

2 * 1000 uF directly at the pins of the IC should be sufficient, and some small caps directly at the supply should also suffice for stabilizing the voltage through the supplies cables...


Bye,

Arndt

mhennessy 4th June 2003 10:41 AM

overmind,

From the picture, the PSU cables look too long, and too thin...

The feedback resistor seems too high at 631K - try reducing it to 220K or even 120K (and changing the 49.9K so that the ratio of them is the same to maintain the gain)

Consider trying two seperate bridges, and locate them nearer to the amps. And try a pair of torroidal transformers - I found this made a big difference.

Try removing all the small PSU decoupling caps, leaving just the 1000uF's on the chip itself. You can alway put them back in.

Have you seen my WWW? Also check Nuuk's pages. Both of us have built inverting GainClones - have you considered trying an inverting version?

Cheers,

Mark ;)

GNAKED 4th June 2003 10:42 AM

It proposes to exchange power cables for the better. Gainclone is sensitive on used conductors.

overmind 4th June 2003 03:28 PM

Re: Re: With a PSU like that
 
I have tried adding two Nichicon KG 15000uF 63V and found that it made the sound more tense, the bass is also tighter. The difference was not big, but still do not like it. I had them removed.

Yeo

Quote:

Originally posted by ALW
You'll have ripple measuring volts I would think.

Try some adequate reservoir capacitance for starters

Andy.


Quote:

Originally posted by Cradle22


That should not be necessary if you follow the GainClone discussions.

2 * 1000 uF directly at the pins of the IC should be sufficient, and some small caps directly at the supply should also suffice for stabilizing the voltage through the supplies cables...


Bye,

Arndt


carlosfm 4th June 2003 03:38 PM

Overmind,
What's the VA rating of that transformer?
It seams small to me.
Yes, 1000uf is good for a Gainclone, but you're supposed to have a good transformer.
Or else you'll have voltage variations that do no good for sound.
I didn't try the non-inverted configuration (and I'm not thinking in trying), so I can't say if that's the cause.
My Gainclone (inverted) sounds fantastic.:nod:


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