Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Pass Labs This forum is dedicated to Pass Labs discussion.

Amp Camp Amp - ACA
Amp Camp Amp - ACA
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 11th August 2019, 10:22 PM   #7701
Mazeppa is offline Mazeppa  United States
diyAudio Member
 
Mazeppa's Avatar
 
Join Date: Mar 2009
Location: Harrison, Arkansas
Amp Camp Amp - ACA
Quote:
Originally Posted by alextab View Post
..... an actual loss in fidelity? (and interesting to see my grammar plugin wants to change that to infidelity lol).
Har! Post of the day.
__________________
CD transport<Schiit Gungnir Multibit DAC<Iron Pumpkin SE Pre<Aleph J<Tekton Lore Reference
  Reply With Quote
Old 14th August 2019, 06:02 PM   #7702
spiggs is online now spiggs  United States
diyAudio Member
 
Join Date: Dec 2016
Location: Huntington Beach, CA
Default Troubleshooting noise from amp

I am getting noise from the ACA through one channel. Originally I thought it was the pre but have changed everything but the ACA and speakers and still get the noise. Link to thread in analog line level. Note that the noise has gone from left channel to right and back to left as I try to trouble shoot it but for no reason I could figure out. User error in hookup maybe but I did not find anything.

Distortion from preamp

Original posting has a recording attached of the noise. I never notice it when I first turn the amp on, seems to happen after it warms up. I have tried re-flowing solder joints that looked at all questionable. Of course the normal poking to see if moving anything helps. Can't seem to find anything obvious to me but of course this was my first build. Amp is built to v1.6 spec with the exception of .13 uf worth of capacitors on the line in jack to roll off lower freq. It has been in the system for about 6 months and I have noticed the problem just over the last month. Looking for pointers on what to check next, it is driving me a bit nuts 🙁
  Reply With Quote
Old 14th August 2019, 07:00 PM   #7703
Zen Mod is offline Zen Mod  Serbia
Official Court Jester
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
Amp Camp Amp - ACA
pics
__________________
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 15th August 2019, 03:19 AM   #7704
spiggs is online now spiggs  United States
diyAudio Member
 
Join Date: Dec 2016
Location: Huntington Beach, CA
Quote:
Originally Posted by Zen Mod View Post
pics
As requested
Attached Images
File Type: jpg IMG_20190814_195951.jpg (982.2 KB, 279 views)
File Type: jpg IMG_20190814_200009.jpg (987.5 KB, 275 views)
File Type: jpg IMG_20190814_200021.jpg (981.1 KB, 273 views)
File Type: jpg IMG_20190814_200032.jpg (978.4 KB, 258 views)
File Type: jpg IMG_20190814_200424.jpg (961.5 KB, 259 views)
File Type: jpg IMG_20190814_200434.jpg (979.5 KB, 86 views)
  Reply With Quote
Old 15th August 2019, 06:46 AM   #7705
Zen Mod is offline Zen Mod  Serbia
Official Court Jester
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
Amp Camp Amp - ACA
repair soldering of wires on all terminals

if that doesn't help - replace JFets between channels

if trouble moves following JFet , from channel to channel - you found JFet as culprit

if problem stays on same channel as it was , replace mosfets - they're cheap and easy to get everywhere

re-set output node voltage ( some calls it "BIAS") when doing any change , including swapping of JFets
__________________
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 15th August 2019, 08:49 AM   #7706
MEPER is offline MEPER  Denmark
diyAudio Member
 
MEPER's Avatar
 
Join Date: Nov 2017
Location: Copenhagen
You have heard noise from both channels during "testing"?
Have you tried to bypass the caps you have put on input?
This just to start with a "standard" ACA before you modify. The ACA NFB circuit rely on that pre has low impedance. The serial cap at input will influence on that. It may not be the right way to do the "roll of" with this kind of amp design?
If you have a scope it would be helpful to see how the noise looks like......
  Reply With Quote
Old 16th August 2019, 05:40 AM   #7707
spiggs is online now spiggs  United States
diyAudio Member
 
Join Date: Dec 2016
Location: Huntington Beach, CA
Thanks for the advice. I'll get soldering and report back what I find. The noise is only in one channel but I'll try bypassing the input caps as well just to check.
  Reply With Quote
Old 16th August 2019, 09:01 AM   #7708
Stanislav is offline Stanislav  Australia
diyAudio Member
 
Join Date: Jan 2003
Location: Southern Barossa
Quote:
Originally Posted by spiggs View Post

Amp is built to v1.6 spec with the exception of .13 uf worth of capacitors on the line in jack to roll off lower freq. It has been in the system for about 6 months and I have noticed the problem just over the last month. Looking for pointers on what to check next, it is driving me a bit nuts 🙁
May I ask why are you rolling off the low freqs?
The cut-off for 0.13uF and 10kOhm is around 120Hz.
Even if you double the Rin the cut-off will be 60Hz
Unless you are using the ACA to drive some MF or HF drivers in an bi-amp setup.
And even then there are better ways to do it.
Just curious...
  Reply With Quote
Old 16th August 2019, 02:01 PM   #7709
spiggs is online now spiggs  United States
diyAudio Member
 
Join Date: Dec 2016
Location: Huntington Beach, CA
Quote:
Originally Posted by Stanislav View Post
May I ask why are you rolling off the low freqs?
The cut-off for 0.13uF and 10kOhm is around 120Hz.
Even if you double the Rin the cut-off will be 60Hz
Unless you are using the ACA to drive some MF or HF drivers in an bi-amp setup.
And even then there are better ways to do it.
Just curious...
I use the ACA to drive a pair of 4" full range drivers and pair that with a subwoofer to handle below 120Hz.
  Reply With Quote
Old 17th August 2019, 03:04 PM   #7710
mraudioguru is offline mraudioguru  United States
diyAudio Member
 
Join Date: Apr 2014
Quote:
Originally Posted by spiggs View Post
I am getting noise from the ACA through one channel. Originally I thought it was the pre but have changed everything but the ACA and speakers and still get the noise. Link to thread in analog line level. Note that the noise has gone from left channel to right and back to left as I try to trouble shoot it but for no reason I could figure out. User error in hookup maybe but I did not find anything.

Distortion from preamp

Original posting has a recording attached of the noise. I never notice it when I first turn the amp on, seems to happen after it warms up. I have tried re-flowing solder joints that looked at all questionable. Of course the normal poking to see if moving anything helps. Can't seem to find anything obvious to me but of course this was my first build. Amp is built to v1.6 spec with the exception of .13 uf worth of capacitors on the line in jack to roll off lower freq. It has been in the system for about 6 months and I have noticed the problem just over the last month. Looking for pointers on what to check next, it is driving me a bit nuts 🙁
I played your sound file and I have the same EXACT noise in the right channel of my amp. It's been there since the beginning, (almost a year now), but I haven't had the time time to fix it...until yesterday.

Mine would only rear it's ugly head once out of every 5 times or so and only on startup for a second or two. Well, it has gotten worse and was time to fix it.

I know this is a very long thread, but 98% of all the problems reported within, were solved by re-flowing solder joints. I was pretty sure that was going to solve my issue and it did! I touched up every solder joint and made sure I had good solid connections.

I also redid a couple of steps, (the build guide was changed during/after it was first completed and a few little changes were made), so mine is now done 100%.

Needless to say, my ACA is now performing perfectly and sounds GREAT. It actually always sounded fine, but now the scratchy, crackly noise is gone!!!
  Reply With Quote

Reply


Amp Camp Amp - ACAHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Amp Camp Amp #1 Nelson Pass diyAudio.com Articles 54 8th May 2018 03:13 AM
Amp Camp! Jason Site Announcements 2 30th June 2012 02:57 PM
Best D camp config for Tweeter amp Zero One Class D 0 24th February 2010 04:57 AM
better the Pass camp? rick57 Tubes / Valves 6 26th March 2005 06:04 AM


New To Site? Need Help?

All times are GMT. The time now is 07:13 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki