English Amiga Board


Go Back   English Amiga Board > Support > support.Hardware > Hardware mods

 
 
Thread Tools
Old 21 March 2010, 23:19   #1
8bitbubsy
Registered User
 
8bitbubsy's Avatar
 
Join Date: Sep 2009
Location: Norway
Posts: 1,711
Doing mods to the Amiga sound output

Hey ho (let's go)...
One day I was changing the capacitors on an A1200 motherboard I had lying, then I accidentally broke a resistor near the very end of the sound output circuit. I tried to boot the Amiga for shits and giggles-- the left sound channel was all dead.. Then I did something sick just to save her: I desoldered the right resistor too, then I shorted both of them (individually of course). Now the sound worked, but to my surprise it was way louder than normal.
Now it was more like it should be. As pre-amplified as it can be without distortion or clipping. I like this because I run the sound through line-in on my sound card. The louder the better, so I can enjoy sounds from my Amiga without turning the volume up a bit more than usual.

Thus I wondered, can't we just replace those resistors with some of a lower value, so the sound will be a bit louder? Or even short them if this is acceptable after all? The names of these two resistors are R324 and R334 (A1200). They are to find around the two output RCAs. Let me know if this is dangerous to the circuit or something like that...

And here's another pondering:
The sound output is hard-panned... 100% to the left, 100% to the right... This is like a semi-stereo (fake stereo), but it annoys me to death. Can one with some electronic components make the "panning" less hard-panned? Not much, but just a tad bit. I know this is not likely to be easy or simple at all, but who knows.. I'm not the electricity genius.
I use headphones all the time and I have no money for a mixer board to pan the sound. And AHI eats up too much CPU...

Thanks for reading my wall of text.

Last edited by 8bitbubsy; 21 March 2010 at 23:27.
8bitbubsy is offline  
Old 22 March 2010, 06:21   #2
rkauer
I hate potatos and shirts
 
rkauer's Avatar
 
Join Date: Oct 2007
Location: Sao Leopoldo / Brazil
Age: 58
Posts: 3,482
Send a message via MSN to rkauer Send a message via Yahoo to rkauer
Dangerous for the circuit, yes.

Put back the resistors or even ones with a small lower values to keep the operational amplifier back to safe conditions.
rkauer is offline  
Old 22 March 2010, 07:41   #3
Loedown
Precious & fragile things
 
Join Date: Feb 2009
Location: Victoria, Australia
Posts: 1,946
Quote:
Originally Posted by 8bitbubsy View Post
Hey ho (let's go)...
One day I was changing the capacitors on an A1200 motherboard I had lying, then I accidentally broke a resistor near the very end of the sound output circuit. I tried to boot the Amiga for shits and giggles-- the left sound channel was all dead.. Then I did something sick just to save her: I desoldered the right resistor too, then I shorted both of them (individually of course). Now the sound worked, but to my surprise it was way louder than normal.
Now it was more like it should be. As pre-amplified as it can be without distortion or clipping. I like this because I run the sound through line-in on my sound card. The louder the better, so I can enjoy sounds from my Amiga without turning the volume up a bit more than usual.

Thus I wondered, can't we just replace those resistors with some of a lower value, so the sound will be a bit louder? Or even short them if this is acceptable after all? The names of these two resistors are R324 and R334 (A1200). They are to find around the two output RCAs. Let me know if this is dangerous to the circuit or something like that...

And here's another pondering:
The sound output is hard-panned... 100% to the left, 100% to the right... This is like a semi-stereo (fake stereo), but it annoys me to death. Can one with some electronic components make the "panning" less hard-panned? Not much, but just a tad bit. I know this is not likely to be easy or simple at all, but who knows.. I'm not the electricity genius.
I use headphones all the time and I have no money for a mixer board to pan the sound. And AHI eats up too much CPU...

Thanks for reading my wall of text.
Run a couple of resistors to each channel input from the other will allow some signal to go from L - R and R - L, do it before the first op amp to allow the filter to remain effective. Op amps were never my specialty, someone with better knowledge may be able to give you better values. At a guess, try 47K, then slowly go down through 22k, 10k etc until you find something that works to your liking, or use a pot (50k linear, dual gang)
Loedown is offline  
 


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Similar Threads
Thread Thread Starter Forum Replies Last Post
AHI or Sound Blaster Output Support for OctaMED SS? XDelusion support.Apps 4 08 September 2011 19:21
Is there a way to output all 4 sound channels of an amiga to separate outs? Kola New to Emulation or Amiga scene 6 19 September 2010 15:20
Winuae 1.3.4.0 - savestate kills sound output PiCiJi support.WinUAE 6 15 January 2007 18:23
Sound output bug Minuous support.WinUAE 7 08 November 2006 12:23
Q: recording 4-channels sound output and "Playback Rate" jbl007 support.WinUAE 0 07 June 2005 18:23

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


All times are GMT +2. The time now is 14:12.

Top

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Page generated in 0.06697 seconds with 13 queries