Guitar Headphone amp with distortion schematics - diyAudio
Go Back   Home > Forums > Amplifiers > Headphone Systems

Headphone Systems Everything to do with Headphones

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 10th December 2008, 06:27 PM   #1
jman 31 is offline jman 31  United States
diyAudio Member
 
jman 31's Avatar
 
Join Date: Oct 2008
Location: Florida
Default Guitar Headphone amp with distortion schematics

Hey guy,
I know I'm probably becoming a bit of a nuisance, but I have gotten really excited about these little amps I'm making and I have designed a schematic to add a distortion channel and was wondering if you could take a look at it and see if any problems jump out at you.

I know the buffer, the main amp and the power supply work because I've built several of them. I am concerned about the distortion path and if the numbers and positioning of the components looks OK.

Here is the schematic that I drew up. I have used other peoples ideas for designing this and I in no way take credit for their ideas.
Attached Images
File Type: png headphone amp with distortion.png (71.8 KB, 501 views)
  Reply With Quote
Old 10th December 2008, 08:06 PM   #2
diyAudio Member
 
Join Date: Jul 2005
Location: North Derbyshire
My first thought is why the buffer at the front? - make R5 1M and connnect the input directly to C3. You can then use the now unused half of the opamp for the second amplifier stage.

But your gains are completely wrong, a gain of only 11 on the input stage, and a gain of 1001 on the second stage, which you're feeding with 0.7V p-p - how do you expect to get 700.7V p-p out of the opamp?.
__________________
Nigel Goodwin
  Reply With Quote
Old 10th December 2008, 09:16 PM   #3
jman 31 is offline jman 31  United States
diyAudio Member
 
jman 31's Avatar
 
Join Date: Oct 2008
Location: Florida
Man, as always thanks for the reply. I did the buffer because the guy that was helping me initially in the chip amp forum said that was the way to go (because of the impedance of the guitar I presume). I am just starting to get a basic idea of what these components do.

I found a site that gave me the calculations for the gain, but how do I determine what is a good starting point. The power supply to the first amp is 4.5v, right? so if I use the .7 volts that the 2 diodes are limiting me to, would I divide the 4.5v by .7v and use the 6.42 that I get from that equation to multiply the gain of 11 by resulting in a gain on the second amp of roughly 71? Or am I completely off base?

Like this?
Attached Images
File Type: png headphone amp with distortion 2.png (69.2 KB, 384 views)
  Reply With Quote
Old 10th December 2008, 09:21 PM   #4
jman 31 is offline jman 31  United States
diyAudio Member
 
jman 31's Avatar
 
Join Date: Oct 2008
Location: Florida
Nope, just got to reading what I wrote there and it doesn't make sense at all. I am using two different values with the 4.5v and the .7v.

I just keep getting myself more and more confused. Please don't give up on me I really would like to learn this basic stuff and I believe that the best way for me is trial and error and asking a lot of questions.

Thanks

EDIT: OK I have been doing some more reading on this an I realize that its a lot more complicated than I gave it credit for. I don't have a clue how to calculate the values for the various components, and the values that I have been using are from others schematics. I am going to keep trudging through this though until I get a working amp!
  Reply With Quote
Old 11th December 2008, 05:12 AM   #5
wxn is offline wxn  Lithuania
diyAudio Member
 
wxn's Avatar
 
Join Date: Sep 2003
Location: Vilnius
Here's a good resource with explanations:
http://www.generalguitargadgets.com/...ion/index.html
I suppose diodes in the feedback path sound a lot nicer, every single commercial distortion pedal I've seen uses this topology.
__________________
Nothing is as simple as it seems
  Reply With Quote
Old 11th December 2008, 11:29 AM   #6
jman 31 is offline jman 31  United States
diyAudio Member
 
jman 31's Avatar
 
Join Date: Oct 2008
Location: Florida
Wow wxn, that was a great help! I don't understand all of it but it clears up a lot! I will study that for a while and then take a stab at it again.
  Reply With Quote
Old 3rd March 2009, 01:49 PM   #7
diyAudio Member
 
Join Date: Jan 2009
Default hmmm

I cant get the distortion circut to change the sound very much ...
  Reply With Quote
Old 3rd March 2009, 02:10 PM   #8
jman 31 is offline jman 31  United States
diyAudio Member
 
jman 31's Avatar
 
Join Date: Oct 2008
Location: Florida
Sorry man, I completely scrapped this design and went to this HERE
  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
Q: headphone amp with variable distortion vladn Headphone Systems 3 17th February 2008 02:16 PM
Headphone distortion x-pro Headphone Systems 6 29th September 2007 12:53 AM
Guitar Distortion davidallancole Instruments and Amps 7 28th July 2006 10:01 PM
Biasing a guitar amp for distortion eeka chu Tubes / Valves 26 19th December 2004 05:44 PM
Preamp for guitar - low distortion Stewen Tubes / Valves 1 26th November 2003 01:21 PM


New To Site? Need Help?

All times are GMT. The time now is 02:21 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