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

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, etc.

Salas hotrodded blue DCB1 build
Salas hotrodded blue DCB1 build
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 28th July 2011, 09:22 PM   #1171
InfiniteGain is offline InfiniteGain  United Kingdom
diyAudio Member
 
Join Date: Nov 2005
Location: Greenwich, London, UK
Short and sweet, thanks Salas!
  Reply With Quote
Old 29th July 2011, 01:39 PM   #1172
cersepn is offline cersepn  United States
diyAudio Member
 
Join Date: Feb 2010
Finally wired up everything and took extra careful safety measures when hooking up the power. Seems to have powered up fine

Thank you, Salas and TeaBag for all the hard work you guys have put into the project! Not forgetting the thousands of DIYA members who contributed to this thread!

This is my first project so please forgive me for all my stupid questions.
I tested the V+/V- and the values hover between +9.48 to +9.50 and -9.43 to -9.44. Are the values supposed to hover? I tested them after leaving it on for about 5 minutes. Did i do something wrong and is this perfectly normal?

I'm not sure how to test for dc offset. Is what i'm doing in the picture correct?
Attached Images
File Type: jpg img2800r.jpg (116.7 KB, 347 views)
File Type: jpg img2795e.jpg (105.0 KB, 347 views)
  Reply With Quote
Old 29th July 2011, 01:44 PM   #1173
Tea-Bag is offline Tea-Bag  United States
not politcally affiliated
diyAudio Member
 
Tea-Bag's Avatar
 
Join Date: Feb 2006
Location: Kennebunk
Salas hotrodded blue DCB1 build
Yes, normal voltages in my book. You might be able to get 10v or so with mixing around with LEDs, but the +/- difference is normal. Besides, you bought matched set from Ed, why bother.

-
DC offset meaurements look correct. output to ground voltage. Should be <10mv offset.
If it's way high, then don't hook it up to amp yet.
__________________
Salas Boards 2018#1 On Order | Hot-Rod DCB1 boards and kits In Stock, PM | M2C Boards, PS and transformers Available PM | Sony VFET CSX2 AL boards In Stock

Last edited by Tea-Bag; 29th July 2011 at 01:47 PM.
  Reply With Quote
Old 29th July 2011, 01:45 PM   #1174
akira is offline akira  France
diyAudio Member
 
Join Date: Jan 2002
Location: Paris France
I think you should ground the input (put the input at ground potential) to measure DC offset on the output. Please wait for some more expert comment.
  Reply With Quote
Old 29th July 2011, 01:51 PM   #1175
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Salas hotrodded blue DCB1 build
Quote:
Originally Posted by cersepn View Post
I tested the V+/V- and the values hover between +9.48 to +9.50 and -9.43 to -9.44. Are the values supposed to hover? I tested them after leaving it on for about 5 minutes. Did i do something wrong and is this perfectly normal?

I'm not sure how to test for dc offset. Is what i'm doing in the picture correct?
Its looks like its the DVM's A/D converter to display translation not deciding the 3rd digit if the reading is somewhere in between. Not really a hover.
You put the probes OK for DC offset. How much?
  Reply With Quote
Old 29th July 2011, 02:01 PM   #1176
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Salas hotrodded blue DCB1 build
Quote:
Originally Posted by akira View Post
I think you should ground the input (put the input at ground potential) to measure DC offset on the output. Please wait for some more expert comment.
There is no gain and a differential amp so it won't change much, but in general its correct to ground the input. Here we just do rough initial checks that the circuit isn't wrong though, and if there is some DC in a faulty case we better avoid since there is no capacitor. Not to stress a JFET.
  Reply With Quote
Old 29th July 2011, 02:33 PM   #1177
cersepn is offline cersepn  United States
diyAudio Member
 
Join Date: Feb 2010
Thank you, Tea Bag and Salas! You guys are really awesome.

I set the DMM to 200 mV. Measures 01.6 on L and 00.3 on R. So is it read as 1.6 mV and 0.3 mV? Any other tests i should be doing before hooking it up to the amp? Thanks again!

Last edited by cersepn; 29th July 2011 at 02:36 PM.
  Reply With Quote
Old 29th July 2011, 03:14 PM   #1178
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Salas hotrodded blue DCB1 build
Yep, its mV and really low. See the voltage drops on the black resistors so we know what current the regs run.
  Reply With Quote
Old 29th July 2011, 03:43 PM   #1179
cersepn is offline cersepn  United States
diyAudio Member
 
Join Date: Feb 2010
I get 1.61v and 1.71v. While probing the leads of the resistors, my fingers slipped and some sparks flew. I should have been more careful, I think the resistor leads got burnt. Will it cause any problems?

I re-measured the V out and offset values and they seem fine, no change from before.
Attached Images
File Type: jpg img2802ud.jpg (49.7 KB, 324 views)
  Reply With Quote
Old 29th July 2011, 04:01 PM   #1180
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Salas hotrodded blue DCB1 build
Its just a small battle scar for luck. No consequences. Your currents are near enough, ready to listen.
  Reply With Quote

Reply


Salas hotrodded blue DCB1 buildHide 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
dcb1 buffer with shunt reg. merlin2069er Swap Meet 0 3rd August 2010 05:25 PM
F2 and DCB1 parts selection - please advice! DQ Pass Labs 6 25th November 2009 03:20 PM
Y B Blue - how blue LED improves the CD playback Peter Daniel Digital Source 176 25th September 2003 07:40 AM


New To Site? Need Help?

All times are GMT. The time now is 08:26 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki