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diyAudio Member

Join Date: Feb 2002
I’m sorry Nelson I was being sarcastic there when I said the amps are similar because they both use resistors and semiconductors. It should also be pointed out that the polarity on my schematic is also wrong. Perhaps it’s best to think of it as the bottom (negative side) of an F5.

B.T.W.
You have stated:

Quote:
 Originally Posted by Nelson Pass Consider the two power resistors going from the Source of the CS to the Drain of the primary gain device. The voltage across these resistors and their added resistance sets the DC bias of the current source. Where you tap between them sets the gain. You could easily imagine a string of 0.1 ohm resistors, 10 in series forming 1 ohm but the output to the load is tapped arbitrarily. Then you can adjust to your heart's content either for low distortion or a particular ratio of 2nd to 3rd harmonic.

Would I be right in assuming tapping it closer to Q1 produces more 2nd harmonic and closer to Q2 produces more 3rd harmonic ? (Just guessing here)

I always like to speculate as to your motivation for picking a particular topology. Though I guess if everyone just used the basic diff-pair -> voltage gain -> follower topology it would be a fairly boring world which would sound mostly the same. You have probably forgotten more topologies then I ever understood and most of the ones I have learned about have been from your articles. Would I be correct that you had a dream about riding on the back of a seahorse through a kelp forest triggered by latent memories from childhood camping trips as the motivation for making R1 0.47 Ohms or did you just have a lot of them laying around?

Leve

Last edited by LBHajdu; 18th July 2012 at 10:55 PM.

diyAudio Member

Join Date: Jan 2012
Location: Pennsylvania
Blog Entries: 1
Quote:
 Originally Posted by Zen Mod no xover at all (OK - you can sneak one simple cap and just maybe one resistor in )
Your statement applies only to a wide-band [full range] single driver. An earlier thread recommended [to the novice DIYer] using the Emken loudspeaker which fits this description. Your statement is valuable nonetheless. Now you are giving the DIYer specific and much needed advice. Still, a full range or multi way drivers maybe a boxed loudspeaker. The low DF of the Camp Amplifier may require suggesting an optimal Qts for the loudspeaker. What can/should it be; under, critical or over damped so as to squeeze the best performance there is of the ensemble?

 18th July 2012, 10:50 PM #163 diyAudio Member     Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain whatever as long is easy to drive that means light cone , low power , motor strong enough __________________ my Papa is smarter than your Nelson ! clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa...© by Mighty ZM
The one and only

Join Date: Mar 2001
Quote:
 Originally Posted by LBHajdu Would I be right in assuming tapping it closer to Q1 produces more 2nd harmonic and closer to Q2 produces more 3rd harmonic ? I always like to speculate as to your motivation for picking a particular topology. ...as the motivation for making R1 0.47 Ohms or did you just have a lot of them laying around?
1) I wouldn't assume too much, as it depends on everything. There
generally will be a sweet spot where the 2nd nulls and where the total THD
is lowest, and on either side of that the 2nd comes back.

2) The topology chooses me.

3) I have lots of them, but it's a convenient value.

diyAudio Member

Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
Quote:
 Originally Posted by Nelson Pass ....... 2) The topology chooses me...........

line anticipating entire Chautauqua ..........

__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa...© by Mighty ZM

 19th July 2012, 09:20 AM #166 diyAudio Member   Join Date: Mar 2011 Dear mr. pass and colleague, how to make it less power for headphone? :-D thank you so much denis
 19th July 2012, 11:11 AM #167 diyAudio Editor     Join Date: Dec 2001 Location: San Francisco, USA San José, Costa Rica headphone amp headphone amp!! __________________ "The geek shall inherit the earth" 2016 S.F. Burning Amp Festival To Be Nov. 13 Burning Amp thread here on diyAudio [/B]
 19th July 2012, 11:17 AM #168 diyAudio Member     Join Date: Jan 2003 Location: ancient Batsch , behind Iron Curtain easy just use T0-220 cased mosfets , set current to ~70mA Voila! make R1 // R2 = 3R8 make R3 // R4 = 5R5 or so math is simple in case that you want bigger current , calc Iq as 0V65/ ((R1//R2)+(R3//R4) and maintain same ratio between these two groups IRF510 , IRF610 are good candidates ..... or fancy Toshiba ones __________________ my Papa is smarter than your Nelson ! clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa...© by Mighty ZM Last edited by Zen Mod; 19th July 2012 at 11:35 AM.
diyAudio Member

Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
Quote:
 Originally Posted by Zen Mod difference between 0V55 and 0V65 is bias difference between 478mA and 565mA ..... so , around 16% increase which one will be better to your ears ......... well - those are your ears
Mighty Dumb ZM ;

didn't saw that there are 2 pcs of 0R47 and 0R68

so - current is double ....... say 0V65/((0R47+0R68)/2) = 1A13

so , dissipation is in range of 21W5

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__________________
my Papa is smarter than your Nelson !
clean thread; Cook Book;PSM LS Cook Book;Baby DiyA ;Mighty ZM's Bloggg;Papatreasure;Papa...© by Mighty ZM

Last edited by Zen Mod; 19th July 2012 at 11:38 AM.

diyAudio Member

Join Date: Jan 2012
Location: Pennsylvania
Blog Entries: 1
Quote:
 Originally Posted by buzzforb I think this would be a good intro. THere is a thread with the Tilte EMKEN. Check it out.
Great advice. Zen Mod agrees with you [several threads earlier] to use a full range like the Emken as you suggested to mate with this Camp Amp. I checked the Emken site; but JRKO did not mention the amplifier [I probably missed it] he used to drive his loudpeaker creation. Does anyone else know the nature of JRKO's amp? Is it a voltage or a modulated current source?

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