3-stage DC-coupled Ampl

korneluk · 6th April 2009, 01:02 PM

Folks,

Any hints, tips, tricks for designing a 3-stage all DC-coupled amp?

Reference designs, schematics, and sample circuits welcome.

TIA,

leadbelly · 6th April 2009, 02:12 PM

Did you look at the Crystal Palace amp in Morgan Jones' book? He goes over the design in detail.

ray_moth · 7th April 2009, 07:38 AM

I have the strong belief that the key to stable, reliable amd predictable multi-stage DC-coupled tube amps is to use the precision of SS. Regulate, regulate, regulate! If you don't, you run the risk of the amp being adversely affected by mains supply fluctuations, tube ageing and even the weather.

Mutiple DC-coupled stages were not considered seriously a few decades ago, because there was no practical way of making them stable. Nowadays we have access to devices that open the door to success, like high voltage transistors, MOSFETS and zeners. So long as they're treated with due care, they can serve very well in the quest to eliminate capacitors from the signal path yet still utilize tubes for the gain stages.

fg031956 · 7th April 2009, 02:04 PM

1st part

fg031956 · 7th April 2009, 02:04 PM

2nd part

fg031956 · 7th April 2009, 02:04 PM

3rd part

Good luck

korneluk · 7th April 2009, 04:16 PM

Quote:

Originally posted by fg031956
It's in french but ...

Merci beaucoup.

-- josé k.

dshortt9 · 7th April 2009, 05:15 PM

But you can LOOSLEY translate it at google or babelfish.

Hearinspace · 7th April 2009, 09:09 PM

Well, SS regulation isn't the only way, there's always this approach

fg031956 · 8th April 2009, 07:19 PM

Look nice. Not tested.

6th April 2009, 01:02 PM	#1
korneluk diyAudio Member Join Date: Jan 2005 Location: South Florida	3-stage DC-coupled Ampl Folks, Any hints, tips, tricks for designing a 3-stage all DC-coupled amp? Reference designs, schematics, and sample circuits welcome. TIA,

6th April 2009, 02:12 PM	#2
leadbelly diyAudio Member Join Date: Dec 2002 Location: Calgary, Alberta	Did you look at the Crystal Palace amp in Morgan Jones' book? He goes over the design in detail. __________________ Aerodynamics are for people who can't build engines. Enzo Ferrari

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7th April 2009, 07:38 AM	#3
ray_moth diyAudio Moderator Emeritus Join Date: Jan 2004 Location: Jakarta	I have the strong belief that the key to stable, reliable amd predictable multi-stage DC-coupled tube amps is to use the precision of SS. Regulate, regulate, regulate! If you don't, you run the risk of the amp being adversely affected by mains supply fluctuations, tube ageing and even the weather. Mutiple DC-coupled stages were not considered seriously a few decades ago, because there was no practical way of making them stable. Nowadays we have access to devices that open the door to success, like high voltage transistors, MOSFETS and zeners. So long as they're treated with due care, they can serve very well in the quest to eliminate capacitors from the signal path yet still utilize tubes for the gain stages.

7th April 2009, 05:15 PM	#8
dshortt9 diyAudio Member Join Date: Apr 2001 Location: Milwaukee, Wisconsin	But you can LOOSLEY translate it at google or babelfish.

7th April 2009, 09:09 PM	#9
Hearinspace diyAudio Member Join Date: Jun 2008	Well, SS regulation isn't the only way, there's always this approach