Low Cost PCB Group Buy - Page 2 - diyAudio
Go Back   Home > Forums > Commercial Sector > Group Buys

Group Buys Members group buys

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 5th May 2010, 09:40 AM   #11
Luke is offline Luke  New Zealand
diyAudio Member
 
Join Date: Sep 2001
Location: Wellington NZ
Send a message via AIM to Luke
Quote:
Originally Posted by circuitscc View Post
The preferred choice of FETs are 2SK147/2SJ369 or 2SK170/2SJ74 but they are expensive and difficult to get. Fairchild J112/J175 are much cheaper. They are suitable substitues.

I will start the board design and post it soon.
yes but whos design is this, and whats it called?
__________________
If you give a man a fish he will eat for a day. But if you teach a man to fish he will buy an ugly hat. And if you talk about fish to a starving man then you are a consultant. Dilbert
  Reply With Quote
Old 5th May 2010, 11:48 AM   #12
diyAudio Member
 
circuitscc's Avatar
 
Join Date: Sep 2005
I'm making the layout right now. It's half finished.

Please see this pdf file.
Attached Files
File Type: pdf Pre-Amp-FET-1.pdf (30.6 KB, 123 views)
  Reply With Quote
Old 6th May 2010, 06:26 AM   #13
Luke is offline Luke  New Zealand
diyAudio Member
 
Join Date: Sep 2001
Location: Wellington NZ
Send a message via AIM to Luke
why are you avoiding such a simple question?
__________________
If you give a man a fish he will eat for a day. But if you teach a man to fish he will buy an ugly hat. And if you talk about fish to a starving man then you are a consultant. Dilbert
  Reply With Quote
Old 6th May 2010, 06:39 AM   #14
diyAudio Member
 
circuitscc's Avatar
 
Join Date: Sep 2005
The circuit was designed by Mr. Thom Kaman.

This is an all JFET line stage.
  Reply With Quote
Old 11th May 2010, 02:09 PM   #15
diyAudio Member
 
circuitscc's Avatar
 
Join Date: Sep 2005
This line amp can be modified to become a HEADPHONE AMP. The output stage was in increased to 4 pairs while an extra pair of FETs Q6 ad Q8 were connected in parallel to Q5 and Q7 respectively in the VAS stage to provide extra drive.

When it is used as a line amp Q6 /Q8, Q11/Q15 and Q12/Q16 with the associated resistors can be omitted and their locations on the pcb will be left blank.

Regulated +/-15V is provided by LM317, LM337 (not shown the schematic) and associated filter caps, have been integrated to the same circuit board. Each assembled circuit board will form a fully functional and independent channel. It will take 2 identical boards for a stereo setup.

The final circuit and board designed of this all-FET line/headphone amp are presented in the attached pdf files.

Please post your comments.
Attached Files
File Type: pdf Pre-Amp-FET-1-sch.pdf (17.5 KB, 73 views)
File Type: pdf Pre-Amp-FET-1-brd.pdf (34.4 KB, 72 views)
  Reply With Quote
Old 11th May 2010, 06:36 PM   #16
diyAudio Member
 
Join Date: Dec 2008
Hi id like to design a pcb for a tube amp. This might be interesting for many tube beginners.
The schematic was already posted her by a diy member but is very popular in germany. Plese see attachment. Stereo would be fine and the pot should be on the pcb. best regards Thorsten
Attached Images
File Type: gif Schematic PCL Frank signature.GIF (9.5 KB, 290 views)
  Reply With Quote
Old 12th May 2010, 04:35 AM   #17
diyAudio Member
 
circuitscc's Avatar
 
Join Date: Sep 2005
Bengali,

There are locations on the pcb for input and output non-polar caps. If you think they are not necessary, simply replaced them with jumpers. This will become a DC line amp.

circuitscc
  Reply With Quote
Old 12th May 2010, 06:12 AM   #18
diyAudio Member
 
Greg Erskine's Avatar
 
Join Date: Jan 2002
Location: Sydney/Australia
Hi circuitscc,

Very nice work. I can see you have put a lot of effort making symbols and components, they really do look good. I'll have to put a bit more effort into mine to lift my game.

Looking at your transistor symbol, I am wondering if the size is forcing you to space the resistors too far apart. On some of my boards I have been surprised how sparse they end up looking in real life.

I don't know about the actual circuit, I've been spending my time appreciating the excellent drafting.

Have you mastered Eagle 3D yet? If not, send me the PCB file and I'll generate a few pretty pictures.

BTW: On the PCB, the lower right pot has one trace not mitered.

regards
__________________
Greg Erskine
  Reply With Quote
Old 12th May 2010, 06:43 AM   #19
diyAudio Member
 
circuitscc's Avatar
 
Join Date: Sep 2005
As transistor is the only active device in the circuit I make them a bit bigger than average to emphasize its role.

The pot you mentioned was optional. Some music lovers would like to use the volume control of a CD player. It can be replaced with a jumper.

Please tell me your email address so that I can send you the schematic.
  Reply With Quote
Old 12th May 2010, 07:07 AM   #20
diyAudio Member
 
Greg Erskine's Avatar
 
Join Date: Jan 2002
Location: Sydney/Australia
Quote:
Originally Posted by circuitscc View Post
As transistor is the only active device in the circuit I make them a bit bigger than average to emphasize its role.
I see. They look good and fit nicely, but can you see how they have made you space the resistors far apart, though it doesn't really matter on this PCB.

Quote:
The pot you mentioned was optional. Some music lovers would like to use the volume control of a CD player. It can be replaced with a jumper.
See the attachment.

Quote:
Please tell me your email address so that I can send you the schematic.
Email sent.

regards
Attached Images
File Type: gif trace.gif (3.0 KB, 259 views)
__________________
Greg Erskine
  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
Where do I buy C37 lacquer at low cost? chuck55 Full Range 7 20th August 2008 03:35 PM
Group Buy? sharing shiping cost? barackuda Full Range 0 3rd October 2007 07:40 PM
Looking for low-cost PCB vendor Maxhawk Parts 2 19th August 2004 11:24 AM
At cost group buy of Aleph boards harvardian Swap Meet 17 13th March 2003 06:09 PM


New To Site? Need Help?

All times are GMT. The time now is 03:55 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