Improving on LCaudio LowNoise regulator - Page 5

Elso Kwak · 11th January 2005, 10:04 AM

Quote:

Originally posted by ericpeters

There is a possible improvement for you: built in some protection to prevent the supply voltage from exceeding the +/- 22V at the opamp.

If everthing works the way it should this is a fine design, and perform(ed) very well in my system. However a fault in my mains power supply caused temporary 380V instead of 240VAC in the wall socket. As a result the opamp died.

Well Eric, you cannot expect Lars to design in for a 65% to high line voltage. BTW in your country 230V AC is the norm.
If you split up the dual opamp you can use much higher supply voltages as the opamp then is operated single supply.

ericpeters · 11th January 2005, 10:43 AM

Agree, I dont expect that from any designer...but I was answering the question. I would be an improvement but probably make the design unnessecary more expensive.

Yes 230 is the standard but equipment should be suited for 200 - 240V because this is the mains voltage range limits specified by the energy company (if something breaks within those limits they accept no damage responsibility), and with a 15VAC torroid I find the margin to the 22V max quite small.

Come to think of it... It probably wasn't 380V (3 phase) but 2 phases of 230V.

Elso Kwak · 11th January 2005, 11:05 AM

Quote:

Originally posted by ericpeters
Agree, I dont expect that from any designer...but I was answering the question. I would be an improvement but probably make the design unnessecary more expensive.

Two NE5534 instead of one NE5532? Expensive?
Some prices from Farnell:
NE5534N: Euro 1.03 ex VAT
NE5532AD: Euro 0.83 ex VAT

ericpeters · 14th January 2005, 11:53 AM

So I received my new PS yesterday from LC-audio.

I got one thing I do not understand:

I'm using this supply to use a Classe audio phono stage (extension board for their line only pre-amps) as a single phono amp. This works suprisingly good. This is a OP627 based phono amp with onboard capacitor bank (8 pcs of 16V 470uF caps, partly paralell but also in series so they should be able to cope with 32V right?) and some regulation after that, but I cannot read the prints on the regulators / transistors

When I was without power supply I used 2 12V lead batteries, and I had a very small amount of hum in my system, I could not get rid of this totalay and tried all kinds of grounding configurations.

With the LC audio supply fully open I hear also hum, I can lower the voltage and at a certain point the hum dissappears at once. If I lower the voltage more eventually the phono ampl will clip and switch off.

Does anyone have an explenation why at a certain voltage (before regulation) the hum appears/disappears?

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11th January 2005, 10:43 AM	#42
ericpeters diyAudio Member Join Date: Apr 2004 Location: Deep South	Agree, I dont expect that from any designer...but I was answering the question. I would be an improvement but probably make the design unnessecary more expensive. Yes 230 is the standard but equipment should be suited for 200 - 240V because this is the mains voltage range limits specified by the energy company (if something breaks within those limits they accept no damage responsibility), and with a 15VAC torroid I find the margin to the 22V max quite small. Come to think of it... It probably wasn't 380V (3 phase) but 2 phases of 230V.

14th January 2005, 11:53 AM	#44
ericpeters diyAudio Member Join Date: Apr 2004 Location: Deep South	So I received my new PS yesterday from LC-audio. I got one thing I do not understand: I'm using this supply to use a Classe audio phono stage (extension board for their line only pre-amps) as a single phono amp. This works suprisingly good. This is a OP627 based phono amp with onboard capacitor bank (8 pcs of 16V 470uF caps, partly paralell but also in series so they should be able to cope with 32V right?) and some regulation after that, but I cannot read the prints on the regulators / transistors When I was without power supply I used 2 12V lead batteries, and I had a very small amount of hum in my system, I could not get rid of this totalay and tried all kinds of grounding configurations. With the LC audio supply fully open I hear also hum, I can lower the voltage and at a certain point the hum dissappears at once. If I lower the voltage more eventually the phono ampl will clip and switch off. Does anyone have an explenation why at a certain voltage (before regulation) the hum appears/disappears?