Since cathode follower is of lower impedance than plate, should
there be a 10K in line with the lower impedance coupling cap?
Still not sure how "impedance" of followers works, since its
obvious they can pull up a lot harder than pull down...
there be a 10K in line with the lower impedance coupling cap?
Still not sure how "impedance" of followers works, since its
obvious they can pull up a lot harder than pull down...
You have to love the web. Whenever you think you have a great idea, someone has already thought of it, plus come up with a better solution!
Cheers,
Chris
Cheers,
Chris
Ken:
2N6449? You found a decent source for these yet? All I could find was American Microsemi listing them as $16.51 and as an obsolete part. (Looks like Moto made them once) No fun burning those things out. How about using a cheap low volt JFET with a HV Mosfet tracking cascode above it, it's gate driven from the JFET source (zener volt shift, etc.).
The concertina splitter needs equal impedances on the plate and cathode sides to get equal drive voltages out. It does have a problem with capacitance loading, causing unequal slew rates.
Ya know, the cathode true complementary current mirror scheme (the SET from P-P thing) and a center tapped plate load inductor might make the ultimate spitter too. Equal slew rates and current drives. Maybe could replace the CT plate inductor with some P-channel voltage controlled Mosfet differential mirrors.
Don
2N6449? You found a decent source for these yet? All I could find was American Microsemi listing them as $16.51 and as an obsolete part. (Looks like Moto made them once) No fun burning those things out. How about using a cheap low volt JFET with a HV Mosfet tracking cascode above it, it's gate driven from the JFET source (zener volt shift, etc.).
The concertina splitter needs equal impedances on the plate and cathode sides to get equal drive voltages out. It does have a problem with capacitance loading, causing unequal slew rates.
Ya know, the cathode true complementary current mirror scheme (the SET from P-P thing) and a center tapped plate load inductor might make the ultimate spitter too. Equal slew rates and current drives. Maybe could replace the CT plate inductor with some P-channel voltage controlled Mosfet differential mirrors.
Don
InterFET, and just down the street from me it would appear.
I may have to pay them a visit. http://www.interfet.com/
Quote from sidebar at the site.
3/18/2007 12:00:00 AM
InterFET's Celebrates 25 Years!
25 years have come and gone since we opened our doors in 1982, a business spun off from Texas Instruments when they elected to exit the small signal discrete market. The JFET market still thrives, albeit certainly smaller than it once was, and we are thriving in it.
We continue to manufacture virtually all of our products and packages for many of the same customers we have supported, and have supported us, for a lot of those 25 years. At the same time, we continue to enter new markets, and support new customers with custom, selected, as well as standard products.
UnQuote
So I guess that means somebody still makes em?
Anyways, this is the websight I found the spec sheet for it.
And if you get desparate, an augmented follower, any lame
parts will do. But simple goes out the window.
I may have to pay them a visit. http://www.interfet.com/
Quote from sidebar at the site.
3/18/2007 12:00:00 AM
InterFET's Celebrates 25 Years!
25 years have come and gone since we opened our doors in 1982, a business spun off from Texas Instruments when they elected to exit the small signal discrete market. The JFET market still thrives, albeit certainly smaller than it once was, and we are thriving in it.
We continue to manufacture virtually all of our products and packages for many of the same customers we have supported, and have supported us, for a lot of those 25 years. At the same time, we continue to enter new markets, and support new customers with custom, selected, as well as standard products.
UnQuote
So I guess that means somebody still makes em?
Anyways, this is the websight I found the spec sheet for it.
And if you get desparate, an augmented follower, any lame
parts will do. But simple goes out the window.
I haven't had any time to experiment since the first post, but my somewhat misguided brain has cooked up several more ideas. Next chance I get, I am going to test the pentode based LTP that I mentioned back in post #21.
I am still looking for a design that is simple (no adjustments with a very high first time success rate) and low cost, that delivers the sound that I am looking for. I haven't found it yet, but I have about 15 more ideas to test. By the way my reference standard amp is a 300B P-P that I built about 6 years ago, lofty goals.
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