Signal Path Components - 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 14th September 2011, 11:24 AM   #1
diyAudio Member
 
Join Date: Sep 2011
Default Signal Path Components

This is going to be a real neewbie question, but would like to learn a little bit here. What is the art, or how do you view a schematic and know which resistors are in the signal path on a circuit board. I am looking on the phono board and preamp board of my Marantz receiver. It is a 2220B and I am pretty much done restoring it but would like to do a little more. Thanks for any help or pointers here.
  Reply With Quote
Old 14th September 2011, 12:24 PM   #2
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
It's not as quite as easy as that.

As your knowledge and experience increases you will begin to understand the operation of the circuit... what each part does and what the effect of changing any value might have.

You need a thorough grounding and background in electronics to do that.

No short cuts to doing that I'm afraid. But don't let that stop you asking questions because it's the only way you learn.
__________________
-------------------------------------------------------
Installing and using LTspice. From beginner to advanced.
  Reply With Quote
Old 14th September 2011, 01:18 PM   #3
diyAudio Member
 
Join Date: Sep 2011
Maybe someone could help me out a little bit on showing me what resistors are in the signal path that are critical if any. Thanks in advance. See the 2 pics below. You can click on the pic and then go and view at any size including full.

Click the image to open in full size.

Click the image to open in full size.
  Reply With Quote
Old 14th September 2011, 02:29 PM   #4
diyAudio Member
 
Join Date: Nov 2008
With the exception of R429, 415, 416 all resistors are part of the signal path, including feedbacks' R411 R423, R427 etc.
What you need to make sure of is that all resistors are metal-film, not carbon-film resistors. This design looks more than 20 years old and there is a good likelyhood that the resistors are carbon based. Metal-films will give you less noise and better temperature stability. E
  Reply With Quote
Old 14th September 2011, 02:56 PM   #5
diyAudio Member
 
Join Date: Sep 2011
Quote:
Originally Posted by mickeymoose View Post
With the exception of R429, 415, 416 all resistors are part of the signal path, including feedbacks' R411 R423, R427 etc.
What you need to make sure of is that all resistors are metal-film, not carbon-film resistors. This design looks more than 20 years old and there is a good likelyhood that the resistors are carbon based. Metal-films will give you less noise and better temperature stability. E
Yes it is probably 30+ years old. Thanks so much for taking the time to look at this for me. I would if possible like to do this in 2 phases, are there certain resistors in the path that would be considered critical that I could do first. There are 29 resistors on the board minus the 3 out of signal path leaves me 26 to do. If I could do critical ones first if that even applies I would like to go that route.
  Reply With Quote
Old 14th September 2011, 06:21 PM   #6
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
The concept of 'signal path' is one that is sometimes used, but almost always incorrectly. A good place to start is that all components are in the 'signal path'. If one does not affect the signal why is it there at all? Once you know enough to decide which ones are important you will know enough to ignore the concept of 'signal path'.
  Reply With Quote
Old 14th September 2011, 06:21 PM   #7
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
For what they cost you may as well just do them all tbh if that's what you want...

I think you will find all the resistors are still perfect, but I can understand the satisfaction of you wanting to do this.

The most critical tend to be the higher value ones and as mm points out, so look at the feedback networks. And C421

Probably easier to say what isn't critical assuming they aren't obviously faulty (they won't be) and thats R421, 419 and R415. Neither is R429 feeding power to the circuit.
__________________
-------------------------------------------------------
Installing and using LTspice. From beginner to advanced.
  Reply With Quote
Old 14th September 2011, 11:19 PM   #8
diyAudio Member
 
Join Date: Sep 2011
Hi and thank you I think I am catching on a little here. Can you tell me which resisters are in the feedback circuit? Thanks! All of the caps were replaced including the 2 tantalums.
  Reply With Quote
Old 15th September 2011, 12:34 AM   #9
diyAudio Member
 
Join Date: Nov 2008
Think about what "feedback" means and what it does (or is supposed to do). E
  Reply With Quote
Old 15th September 2011, 12:49 AM   #10
diyAudio Member
 
Join Date: Sep 2011
My guess,

R411, R412
R423, R424
R427, R428 ???
  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
Hybrid Circlotron Amplifier with only 3 components on the signal path audiodesign Tubes / Valves 199 11th February 2013 08:26 AM
value of capacitors in signal path Oystein Analog Line Level 24 11th February 2010 07:43 AM
Marshall Signal Path Help SaveTheMarshall Instruments and Amps 3 6th May 2007 03:02 PM
Determine the signal path ? lordvader Solid State 12 20th November 2006 09:25 AM
How does this sound for a signal path? Fryguy Digital Source 0 25th May 2004 08:15 PM


New To Site? Need Help?

All times are GMT. The time now is 03:09 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