Salas hotrodded blue DCB1 build - 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 11th August 2010, 10:27 AM   #1
diyAudio Member
 
Join Date: Jan 2006
Location: Las Vegas
Default Salas hotrodded blue DCB1 build

Ok, been stuffing the boards with parts I have available. If we are looking at the board horizontally on top right IRFP240 it looks as if there is an insertion hole missing for one end of the 470r resistor.

Also, the BOM states that there are 4 sk170 matched, where on the board do they go?
  Reply With Quote
Old 11th August 2010, 11:30 AM   #2
diyAudio Member
 
Join Date: Jan 2010
Quote:
Originally Posted by wendell c View Post
Ok, been stuffing the boards with parts I have available. If we are looking at the board horizontally on top right IRFP240 it looks as if there is an insertion hole missing for one end of the 470r resistor.

Also, the BOM states that there are 4 sk170 matched, where on the board do they go?
Concerning that 470R resistor, the pad is there. However, it is positioned on its end instead of mounting flat against the board. This was done as a compromise for the board layout.

The matched 2SK170's are in a row near the muting relay marked 4x 2SK170BL. You will want to keep the the matched FET's together with one set on each side. They are arranged so one set will have the flat side pointing to one side and the other set reversed from that. I believe that if you have a set of FET's where one has a slightly higher Ids than the other (eg. 7.7 & 7.8 Ids) then you place the higher Ids (7.8) in the middle of that row. The signal FET (7.7) is on the end of the row.

Last edited by Macronaut; 11th August 2010 at 11:35 AM.
  Reply With Quote
Old 11th August 2010, 12:46 PM   #3
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
Originally Posted by Macronaut View Post
I believe that if you have a set of FET's where one has a slightly higher Ids than the other (eg. 7.7 & 7.8 Ids) then you place the higher Ids (7.8) in the middle of that row. The signal FET (7.7) is on the end of the row.
there was an earlier poster who claimed that he got better sound by running the amplifying FET at a bias above it's Idss.

I disagreed then and still do now.
A jFET follower will tolerate some higher current running during signal induced high Vgs, read Curl. But there is a big downside to using a high bias at above Idss and then applying the signal induced Vgs sending current even higher.

I would much rather run the bias at 95% of Idss rather than set bias to 105% of Idss
What the B1, as proposed by Pass, does is run the FET follower at very near but not above 100% Idss.
__________________
regards Andrew T.

Last edited by AndrewT; 11th August 2010 at 01:02 PM.
  Reply With Quote
Old 11th August 2010, 12:58 PM   #4
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Quote:
Originally Posted by wendell c View Post
Also, the BOM states that there are 4 sk170 matched, where on the board do they go?
Middle ones are to be the (very slightly) lower IDSS ones between matched pairs. Example.

Please make all assembly questions to the building thread so we keep them together in a known place.

P.S. The new board & its circuit we talk about for people bumping here to understand, are in the pictures below:
Attached Images
File Type: jpg img_3170.jpg (207.0 KB, 11182 views)
File Type: gif BluePartsSide.gif (53.4 KB, 10482 views)
File Type: gif CCTblue.gif (28.7 KB, 10761 views)
  Reply With Quote
Old 11th August 2010, 01:11 PM   #5
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Default Salas hotrodded blue DCB1 build

Hi Builders,
place your solutions and problems here.
__________________
regards Andrew T.
  Reply With Quote
Old 11th August 2010, 01:55 PM   #6
diyAudio Member
 
Join Date: Jul 2006
Default Thank You

Quote:
Originally Posted by AndrewT View Post
Hi Builders,
place your solutions and problems here.
  Reply With Quote
Old 11th August 2010, 02:10 PM   #7
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
OK, I moved the relevant posts here, although they went to the top because they auto arrange in chronological order. Is it OK?

What was that you wanted to know ppcb?
  Reply With Quote
Old 11th August 2010, 02:11 PM   #8
diyAudio Member
 
dvb projekt's Avatar
 
Join Date: Feb 2009
Location: Willich, Germany
Blog Entries: 38
Send a message via Skype™ to dvb projekt
Started a GB for the new Mundorf HighEnd M-LYTIC AG psu caps
__________________
Reference TDA1541A DAC project PCBs / Tube-I-zator PCB / SSHV-Shunt PCB
Stock status in my Blog
  Reply With Quote
Old 11th August 2010, 02:25 PM   #9
diyAudio Member
 
Join Date: Jul 2006
Default Blue DCB1 BOM

Here is my BOM please advise.
Attached Files
File Type: zip BLUE DCB1 BOM.zip (10.3 KB, 768 views)
  Reply With Quote
Old 11th August 2010, 02:29 PM   #10
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
To understand, your question is about opinions in parts quality decisions? If yes, the members will surely have comments.

*Here I upload the general BOM guide too so it can be found in this thread as well.
Attached Files
File Type: pdf Blue DCB1 v1.0.4.pdf (42.5 KB, 2467 views)
  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 06:47 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