Amp Camp Amp - ACA - Page 17 - diyAudio
Go Back   Home > Forums > Amplifiers > Pass Labs

Pass Labs This forum is dedicated to Pass Labs discussion.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 18th July 2012, 10:34 PM   #161
LBHajdu is offline LBHajdu  United States
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 View Post
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.
  Reply With Quote
Old 18th July 2012, 10:37 PM   #162
diyAudio Member
 
Join Date: Jan 2012
Location: Pennsylvania
Blog Entries: 1
Quote:
Originally Posted by Zen Mod View Post
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?
  Reply With Quote
Old 18th July 2012, 10:50 PM   #163
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
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
  Reply With Quote
Old 19th July 2012, 12:34 AM   #164
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
Quote:
Originally Posted by LBHajdu View Post
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.

  Reply With Quote
Old 19th July 2012, 09:07 AM   #165
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
Quote:
Originally Posted by Nelson Pass View Post
.......

2) The topology chooses me...........
Baaad Papa , baaad !

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
  Reply With Quote
Old 19th July 2012, 09:20 AM   #166
jambul is online now jambul  Belgium
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
  Reply With Quote
Old 19th July 2012, 11:11 AM   #167
Variac is offline Variac  United States
diyAudio Editor
 
Variac's Avatar
 
Join Date: Dec 2001
Location: San Francisco, USA
headphone amp headphone amp!!
  Reply With Quote
Old 19th July 2012, 11:17 AM   #168
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
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.
  Reply With Quote
Old 19th July 2012, 11:25 AM   #169
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
Quote:
Originally Posted by Zen Mod View Post
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

Attached Images
File Type: jpg Mr-Bean-as-Pippi-Longstocki.jpg (55.4 KB, 1027 views)
__________________
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.
  Reply With Quote
Old 19th July 2012, 05:52 PM   #170
diyAudio Member
 
Join Date: Jan 2012
Location: Pennsylvania
Blog Entries: 1
Quote:
Originally Posted by buzzforb View Post
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?
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Amp Camp Amp #1 Nelson Pass diyAudio.com Articles 35 12th September 2014 02:49 AM
Amp Camp! Jason Site Announcements 2 30th June 2012 03:57 PM
Best D camp config for Tweeter amp Zero One Class D 0 24th February 2010 05:57 AM
better the Pass camp? rick57 Tubes / Valves 6 26th March 2005 07:04 AM


New To Site? Need Help?

All times are GMT. The time now is 08:53 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2