Salas hotrodded blue DCB1 build - Page 170 - diyAudio
Go Back   Home > Forums > Source & Line > Analog Line Level

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

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 2nd March 2012, 07:23 AM   #1691
diyAudio Member
 
oneplustwo's Avatar
 
Join Date: Apr 2009
Location: San Francisco
Yes, that's right! Haven't plugged it in yet... but perhaps a good idea before I get much further.
  Reply With Quote
Old 2nd March 2012, 07:26 AM   #1692
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
First all leds should light up. At the regulator +/- outputs to ground, there is an easy probing place reserved for connector if used as solo PSU, see they track near at around 10V ballpark. And DC offset to be under 5mV at each audio output.
  Reply With Quote
Old 2nd March 2012, 07:31 AM   #1693
diyAudio Member
 
oneplustwo's Avatar
 
Join Date: Apr 2009
Location: San Francisco
Ok... if the voltage is off, I know I need to adjust the LEDs. If the offset is off, then what do I do?
  Reply With Quote
Old 2nd March 2012, 07:34 AM   #1694
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
See if all is well first , in case you report not, you will not walk alone.
  Reply With Quote
Old 2nd March 2012, 08:13 AM   #1695
diyAudio Member
 
oneplustwo's Avatar
 
Join Date: Apr 2009
Location: San Francisco
It's late, but I couldn't bear the suspense so I plugged her in.

10.51 and 10.50 volts with DC offset about 1.4 mV on both sides. Seems to be just about right! Those red LEDs are very... red. Reminds me of a fire truck!

I'm a bit torn about whether or not to install a pot. I have a LCDuino that I've built but have yet to case that I was going to use as a stand alone attenuator. But having a pot for the DCB1 as well seems like a good idea just in case. I think I have a couple Alps pots lying around. But I think they're 50K. If I remember correctly, the DCB1 would be better off with 20K-ish?
  Reply With Quote
Old 2nd March 2012, 08:40 AM   #1696
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Correct, up to 20kish is best.
  Reply With Quote
Old 2nd March 2012, 03:58 PM   #1697
diyAudio Member
 
oneplustwo's Avatar
 
Join Date: Apr 2009
Location: San Francisco
Is it normal for the LEDs to not all be the same brightness? I didn't think anything of it since the voltage measurements were fine but wanted to double check.

Also, can the buffer be used as a headphone amp?

(Apologies if these are noobie questions... still continuing to learn!)
  Reply With Quote
Old 2nd March 2012, 04:12 PM   #1698
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Yes its normal bcs of the differences in the unsorted JFETs that are driving them, and for the groups of 3 to generally have more current available shining a bit more than the groups of 5 due to there is more voltage available to their JFETs giving them more IDSS.

No, it has ~270R output impedance, even 600 Ohm headphones would need 60R output impedance for good dynamics, and more current available from bias. Not to mention the lack of gain for the inefficient ones.
  Reply With Quote
Old 5th March 2012, 04:05 PM   #1699
diyAudio Member
 
Join Date: Jan 2007
Will a 30VA, 2x15AC R-Core be able to handle 600mA HotRod?
Got some nice 3.3R Mills from T-B I'd like to use.
Alternatively I can go for 5R (Vishay) resistors and keep Mills for a BiB or something.

I'm going to use Stealth II rectifiers (I have both 600V, 4A and 600V, 8A parts available). I suppose these won't need any heatsinking?
__________________
"You have a hierarchy: a mathematician, a physicist (which is a failed mathematician), and an engineer (which is a failed physicist)." - Andrew Jones

Last edited by TheShaman; 5th March 2012 at 04:10 PM.
  Reply With Quote
Old 5th March 2012, 05:01 PM   #1700
AndrewT is online now AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
30VA 2*15Vac has a maximum continuous AC current of 1Aac
This transformer feeding a capacitor input filter will be able to supply a maximum continuous 500mAdc to each polarity.
At this output it will run hot.

I recommend you take ~250mAdc from each winding as the maximum cool running output.
__________________
regards Andrew T.
  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
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 02:22 PM.


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