I'm interested in building the mosfet citation 12 design, I have some questions for anyone that can answer:
What was the maximum output power level for the HK 12, did it change with the MF 12?
Is it worthwhile paralleling output devices for more power?
Would it be better to bridge channels or biamp for speakers?
thanks,
What was the maximum output power level for the HK 12, did it change with the MF 12?
Is it worthwhile paralleling output devices for more power?
Would it be better to bridge channels or biamp for speakers?
thanks,
Anyone tried changing to fully complementary MOSFET output ?
Wonder if it would be better to go for complementary output , or stick with the original mod of N-channel MOSFET only. Understand that the distortion characterisitcs will be changed.
Also whether the drivers transitors can be ommited if going for complementary MOSFET output. May need to bias the voltage gain stage a bit heavier to drive the gate capacitance?
Wonder if it would be better to go for complementary output , or stick with the original mod of N-channel MOSFET only. Understand that the distortion characterisitcs will be changed.
Also whether the drivers transitors can be ommited if going for complementary MOSFET output. May need to bias the voltage gain stage a bit heavier to drive the gate capacitance?
Building the mosfet citation 12 questions
Im building the PASS Citation 12 mosfet amp, I have a few questions first I notice the schematic in the pdf shows the audio output of the amp strapped with a cap .068 and a resistor 10@1w with the resistor to the output then to the cap with the other lead of the cap going to earth. this is sequence is reversed on the component layout on the diagram for the circuit board ? does this matter???
Im building the PASS Citation 12 mosfet amp, I have a few questions first I notice the schematic in the pdf shows the audio output of the amp strapped with a cap .068 and a resistor 10@1w with the resistor to the output then to the cap with the other lead of the cap going to earth. this is sequence is reversed on the component layout on the diagram for the circuit board ? does this matter???
This nice project keeps popping up!
Here are a few views and comments:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=28402[/URL]
I´ve built both types and there is little or no audible difference so go for complementary which is even simpler. Both models benefit from raising bias, if using original heatsinks better stay below 200 mA/device, with good cooling around 1A/device really makes a difference.
Here are a few views and comments:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=28402[/URL]
I´ve built both types and there is little or no audible difference so go for complementary which is even simpler. Both models benefit from raising bias, if using original heatsinks better stay below 200 mA/device, with good cooling around 1A/device really makes a difference.
response
Thanks, I have all the parts for either circuit, Im just working out the details before I start. I have a service bulletin for the original Citation 12 which has came in handy, I notice the lead colors don't match the Pass mod article, so I want to map all this out first. The diode d3 i think, (don't have it in front of me now) that connects to pins 23 & 24 of the circuit board do ? I see this in the original circuit, Im seeing omitted in the Pass mod.***************************************
Has anyone considered adding an inrush current limiter to this mod ? I use these on all my builds, no more tube flash with tube amps at turn on, and with my SS amps there is absolutley no thump at turn on, and I can beef up the power supply's without the heavy current hit at turn on. ******************************
Thanks, I have all the parts for either circuit, Im just working out the details before I start. I have a service bulletin for the original Citation 12 which has came in handy, I notice the lead colors don't match the Pass mod article, so I want to map all this out first. The diode d3 i think, (don't have it in front of me now) that connects to pins 23 & 24 of the circuit board do ? I see this in the original circuit, Im seeing omitted in the Pass mod.***************************************
Has anyone considered adding an inrush current limiter to this mod ? I use these on all my builds, no more tube flash with tube amps at turn on, and with my SS amps there is absolutley no thump at turn on, and I can beef up the power supply's without the heavy current hit at turn on. ******************************
will do
Ingvar;
I will do, I have a feeling after looking at your boards on the forum I will build a new version of the Citation 12.
Those boards are superb. I am seeing the original Citation as a truly wonderful amp as it is, it's so well built.
I can't tell you how long I have been looking for a 12, I have been saving Nelsons article since the middle 80's in order to build the 12. off the subject I have just finnished totally rebuilding a Marantz 1090 integrated that I picked up at an auction, very rough shape. I actually sandblasted the entire chassis and repainted it. It now looks brand new and also performes as new.
So the Citation will be a labor of love.
Nelson if your out there gotta thank you for all your work, if not for you this wouldn't be possible.
Ingvar;
I will do, I have a feeling after looking at your boards on the forum I will build a new version of the Citation 12.
Those boards are superb. I am seeing the original Citation as a truly wonderful amp as it is, it's so well built.
I can't tell you how long I have been looking for a 12, I have been saving Nelsons article since the middle 80's in order to build the 12. off the subject I have just finnished totally rebuilding a Marantz 1090 integrated that I picked up at an auction, very rough shape. I actually sandblasted the entire chassis and repainted it. It now looks brand new and also performes as new.
So the Citation will be a labor of love.
Nelson if your out there gotta thank you for all your work, if not for you this wouldn't be possible.
Restoration
Yeah i know
Yeah i know
Restoring classic or good old stuff is realy fun, has nothing to do with original cost or media status. In our guestroom there is an old HK 630 reciever, looks as it left factory yesterday, with optional wooden sleeve, a pair of ancient swedish classic speakers, Carlsson OA5 and an AR xb TT ( also a pair of AR 3a´s suffering a bit from not perfectly replaced edge surrounds) and it still is very enjoyable to spend a few hours with this old set, a pile of records and maybe a glass of Caol Ila
Pass citation 12 mod
Hi, I designed and made boards from the schematic in AA. I went with the complimentary version because it made more sense to me. I am including a picture of one channel. With a + and - 55 volt supply I am getting 85 watts into 8 ohms. They sound GREAT. I used these both for a home unit and built a smps to use them in my car. Over ten years, two cars and going into the third. Works flawlessly! The circuit is so simple, it can be breadboarded easily. Thanks to MR. Pass for sharing his knowledge. Regards, Steve
Hi, I designed and made boards from the schematic in AA. I went with the complimentary version because it made more sense to me. I am including a picture of one channel. With a + and - 55 volt supply I am getting 85 watts into 8 ohms. They sound GREAT. I used these both for a home unit and built a smps to use them in my car. Over ten years, two cars and going into the third. Works flawlessly! The circuit is so simple, it can be breadboarded easily. Thanks to MR. Pass for sharing his knowledge. Regards, Steve
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