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Old 26th February 2006, 12:10 AM   #1
kmtang is offline kmtang  Canada
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Default Clone Marantz 7C power supply

My friends around me all have their Marantz 7C line amp. Most of the using tube regulated power supply. I just tried something special using choke input passive filter for the power supply.


250Vac CT Power Tran - 6X5GT rectifier - 4H 120mA choke - 68uF capacitor - 20H 120mA choke - 47uF blackgate capacitor (12AU7 buffer) - 3.3K resistor - 47uF blackgate capacitor (2 x 12AX7).

With this power supply circuit, the amp sound very lively, bright and excellent dynamic.

I ran the Duncan's PS software and it seems the circuit is not quite stable. I will try to replace the 4H choke with 20H one.

I like this passive filter because the noise level is significant lower and with very fine resolution.


Your comments are most welcome.


Johnny
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Old 12th June 2007, 01:00 PM   #2
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When people talk about 4H choke, it mean 4mH inductor ????
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Old 12th June 2007, 01:31 PM   #3
SY is offline SY  United States
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Cascaded chokes like that are an engraved invitation for instability. PSUD's results may go a long way to explain the "lively" and "bright" colorations you observed. Some carefully applied snubbing or damping resistances could go a long way toward getting your supply rails to look more like DC under dynamic conditions.

Of course, if you like those colorations, you'll be unhappy with the sonic results of power supply stabilization.
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Old 12th June 2007, 03:24 PM   #4
kevinkr is offline kevinkr  United States
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Quote:
Originally posted by arold19
When people talk about 4H choke, it mean 4mH inductor ????

No, it means 4H (henry) inductor.
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Old 13th June 2007, 12:53 PM   #5
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if this is right, where can I get a 10H choke ???
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Old 13th June 2007, 02:03 PM   #6
chrish is offline chrish  Australia
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I Just ordered a Hammond 193H 5H, 200mA one from these guys yesterday for $26...

http://www.tubesandmore.com/

Hammond 193J, 10H, 200mA, 800VDC, $41.95 though...

Allied has a 6H for $15 (open style)

http://www.alliedelec.com/Search/Pro...6F3380519BE17F
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Old 27th June 2007, 06:58 AM   #7
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Default Re: Clone Marantz 7C power supply

Quote:
Originally posted by kmtang
I ran the Duncan's PS software and it seems the circuit is not quite stable. I will try to replace the 4H choke with 20H one.
My question is how you define instability? Is that the so called resonance that appear at your RLC circuit (due to poles at right hand side or at the origin)?
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