krell kas power suppy hum

minh_827 · 16th September 2005, 05:15 AM

My krell kas mono-block power suppy has a noticible hum when it is on stanby. I've read somewhere that it is the power supply filter caps that has gone bad. Is the filter caps the main big caps in the power supply and is it fairly easy to change? I don't want to send the amp back to krell cause it would costs a lot and it would be more fun to do it myself. Does anyone have a simillar experience they can share with me or can help me with this problem?
Thanks Minh

Jozua · 16th September 2005, 06:37 AM

Hi

My experience has been that at peak power periods- especially round about suppertime my Krell amp transformers tend to hum. Also when somebody close to me is doing some welding in his backyard. The best is possibly to switch off during these periods.

Jozua

amplifierguru · 16th September 2005, 06:55 AM

Sounds like poor design under the guise of 'audiophile' to me!

Cheers,
Greg

CBS240 · 16th September 2005, 07:04 AM

I guess poor design includes pi$$ poor PSRR.

amplifierguru · 16th September 2005, 07:14 AM

Hi CBS240,

Yes indeed that's exactly what it sounds like!

But hey, they're getting something special ... I'm sure they know what they're doing?

Cheers,
Greg

minh_827 · 16th September 2005, 07:49 AM

amplifierguru, cbs
What are u guys talking about and how is it going to help me.

amplifierguru · 16th September 2005, 08:00 AM

Sorry Minh,

A couple of armchaire critics I guess, playing old favourites! Maybe a good power filter is in order.

Or ask (pester) Krell about it!

Cheers,
Greg

minh_827 · 16th September 2005, 08:11 AM

Jozua,
My power supply is seperated from the amplification part. So when the amp is off the power suppy is still on.

peranders · 16th September 2005, 08:27 AM

All transformers hum more or less, by nature but some may hum more. Toroid transformers may also be very sensitive againt DC on the mains and "DC" is simply unsymmetrical waveform coming from hairdryers, microwave ovens and other "non-resistive" loads.

Jozua · 16th September 2005, 08:38 AM

Hi

I would love to have those Krells- I used to drool over that model in the magazines.

I have the KSA100 and KSA200s. So far I like the KSA100 best.

Personally I would suggest that you send those specialized amps to Krell or their agents for an overall service- also they are quite "old" by modern standards and possibly in need of service. The design of those models are also quite complex and I would not suggest that a novice fiddle inside them.

My gut feeling is that it possibly is a dry soldering joint in the power supply. Years ago my KSA 100 transformer sounded as if there was loose wire inside- all it took was a resolder of the mains wire on the inside of the connecting IEE connector plug.

Regards

Jozua

16th September 2005, 05:15 AM	#1
minh_827 diyAudio Member Join Date: Apr 2005 Location: san jose california	krell kas power suppy hum My krell kas mono-block power suppy has a noticible hum when it is on stanby. I've read somewhere that it is the power supply filter caps that has gone bad. Is the filter caps the main big caps in the power supply and is it fairly easy to change? I don't want to send the amp back to krell cause it would costs a lot and it would be more fun to do it myself. Does anyone have a simillar experience they can share with me or can help me with this problem? Thanks Minh

16th September 2005, 07:04 AM	#4
CBS240 diyAudio Member Join Date: Aug 2005 Location: K-town	I guess poor design includes pi$$ poor PSRR. __________________ All the trouble I've ever been in started out as fun......

16th September 2005, 08:27 AM	#9
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	All transformers hum more or less, by nature but some may hum more. Toroid transformers may also be very sensitive againt DC on the mains and "DC" is simply unsymmetrical waveform coming from hairdryers, microwave ovens and other "non-resistive" loads. __________________ /Per-Anders (my first name) or P-A as my friends call me

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16th September 2005, 06:37 AM	#2
Jozua diyAudio Member Join Date: Aug 2003 Location: Cape Town	Hi My experience has been that at peak power periods- especially round about suppertime my Krell amp transformers tend to hum. Also when somebody close to me is doing some welding in his backyard. The best is possibly to switch off during these periods. Jozua

16th September 2005, 06:55 AM	#3
amplifierguru Account Disabled Join Date: Aug 2004 Location: Earth	Sounds like poor design under the guise of 'audiophile' to me! Cheers, Greg

16th September 2005, 07:14 AM	#5
amplifierguru Account Disabled Join Date: Aug 2004 Location: Earth	Hi CBS240, Yes indeed that's exactly what it sounds like! But hey, they're getting something special ... I'm sure they know what they're doing? Cheers, Greg

16th September 2005, 07:49 AM	#6
minh_827 diyAudio Member Join Date: Apr 2005 Location: san jose california	amplifierguru, cbs What are u guys talking about and how is it going to help me.

16th September 2005, 08:00 AM	#7
amplifierguru Account Disabled Join Date: Aug 2004 Location: Earth	Sorry Minh, A couple of armchaire critics I guess, playing old favourites! Maybe a good power filter is in order. Or ask (pester) Krell about it! Cheers, Greg

16th September 2005, 08:38 AM	#10
Jozua diyAudio Member Join Date: Aug 2003 Location: Cape Town	Hi I would love to have those Krells- I used to drool over that model in the magazines. I have the KSA100 and KSA200s. So far I like the KSA100 best. Personally I would suggest that you send those specialized amps to Krell or their agents for an overall service- also they are quite "old" by modern standards and possibly in need of service. The design of those models are also quite complex and I would not suggest that a novice fiddle inside them. My gut feeling is that it possibly is a dry soldering joint in the power supply. Years ago my KSA 100 transformer sounded as if there was loose wire inside- all it took was a resolder of the mains wire on the inside of the connecting IEE connector plug. Regards Jozua

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