electro-music.com   Dedicated to experimental electro-acoustic
and electronic music
 
    Front Page  |  Radio
 |  Media  |  Forum  |  Wiki  |  Links
Forum with support of Syndicator RSS
 FAQFAQ   CalendarCalendar   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   LinksLinks
 RegisterRegister   ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in  Chat RoomChat Room 
 Forum index » DIY Hardware and Software » Circuit Bending
The magnophone up and running!
Post new topic   Reply to topic Moderators: dnny, v-un-v
Page 2 of 2 [40 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Goto page: Previous 1, 2
Author Message
EdisonRex
Site Admin


Joined: Mar 07, 2007
Posts: 4579
Location: London, UK
Audio files: 172

PostPosted: Sun Jun 10, 2007 10:13 am    Post subject: Reply with quote  Mark this post and the followings unread

mosc wrote:
Vcc is usually the term used for the positive supply voltage. The values allowed for Vcc will be in the devices spec sheet. I don't know what the other initials mean.


The "cc" (or "CC") stands for "Collector-Collector". "Vss" would be "Source-Source" and Vdd = "Drain". The term originates from how to supply a transistor. Vee supplies the emitter.

A fair definition of these power supply voltage terms is, perhaps unsurprisingly, in Wikipedia, although you can also find it referred other places if you don't choose to believe Wikipedia. Now that I am reminded, I remember reading this in a Fairchild Semi catalog many years ago.

_________________
Garret: It's so retro.
EGM: What does retro mean to you?
Parker: Like, old and outdated.


Home,My Studio,and another view
Back to top
View user's profile Send private message Visit poster's website
the19thbear



Joined: Apr 19, 2007
Posts: 150
Location: denmark

PostPosted: Thu Jun 28, 2007 3:46 am    Post subject: ok
Subject description: ok
Reply with quote  Mark this post and the followings unread

In my eternal quest for making a cool tape echo, I tried to record music on a harddisk ( with reel to reel tape heads) and it doesnt work... i dont know why, but there is no sound other than some digital bleeps and blops, i cant record anything on the disc.. but does anyone know what kind of magnetic material the binson echorec used??? ( looks like a metal tape. Its solid, on the edge of a solid disc.)
thanks!
Back to top
View user's profile Send private message
blue hell
Site Admin


Joined: Apr 03, 2004
Posts: 24079
Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320

PostPosted: Thu Jun 28, 2007 9:52 am    Post subject: Re: ok
Subject description: ok
Reply with quote  Mark this post and the followings unread

the19thbear wrote:
I tried to record music on a harddisk ( with reel to reel tape heads) and it doesnt work...


It wouldn't surprise me when the magnetic stuff used for a hard disk is "harder" than the stuff used for tape or for floppies, so that more power would be needed to be able to record on it. The fact that you still hear the digital data on playback points into this direction. Floppies would be less troublesome I'd think.

_________________
Jan
also .. could someone please turn down the thermostat a bit.
Posted Image, might have been reduced in size. Click Image to view fullscreen.
Back to top
View user's profile Send private message Visit poster's website
EdisonRex
Site Admin


Joined: Mar 07, 2007
Posts: 4579
Location: London, UK
Audio files: 172

PostPosted: Thu Jun 28, 2007 12:03 pm    Post subject: Re: ok
Subject description: ok
Reply with quote  Mark this post and the followings unread

Blue Hell wrote:
the19thbear wrote:
I tried to record music on a harddisk ( with reel to reel tape heads) and it doesnt work...


It wouldn't surprise me when the magnetic stuff used for a hard disk is "harder" than the stuff used for tape or for floppies, so that more power would be needed to be able to record on it. The fact that you still hear the digital data on playback points into this direction. Floppies would be less troublesome I'd think.


Magnetic tape contacts the record/play head. Disk surfaces are separated from their head. It's not only higher power, it's a very much smaller recording channel.

I think a floppy disk might work, it's a lot closer to magnetic tape than the medium used for hard disks, even old ones.

_________________
Garret: It's so retro.
EGM: What does retro mean to you?
Parker: Like, old and outdated.


Home,My Studio,and another view
Back to top
View user's profile Send private message Visit poster's website
the19thbear



Joined: Apr 19, 2007
Posts: 150
Location: denmark

PostPosted: Fri Jun 29, 2007 2:13 am    Post subject: ok
Subject description: ok
Reply with quote  Mark this post and the followings unread

A floppy disc works fine.. i used an 5. 25 inch. c64 disc..
i dont know about the 3.5 discs.. i guess they would work too, but discs like these and normal tape wear out really fast!
i would like a more robust recording medium..
.. i was told that the binson used an aluminium tape/drum Confused ( this is not the disc itself, but the actual recording material..)


Can you even record on aluminium??sounds way strange to me!
Back to top
View user's profile Send private message
the19thbear



Joined: Apr 19, 2007
Posts: 150
Location: denmark

PostPosted: Fri Jun 29, 2007 4:53 am    Post subject: ok
Subject description: ok
Reply with quote  Mark this post and the followings unread

ok.. so the source was wrong. it is not an aluminium disc! Very Happy
but then, what is it???
Back to top
View user's profile Send private message
blue hell
Site Admin


Joined: Apr 03, 2004
Posts: 24079
Location: The Netherlands, Enschede
Audio files: 278
G2 patch files: 320

PostPosted: Fri Jun 29, 2007 6:15 am    Post subject: Re: ok
Subject description: ok
Reply with quote  Mark this post and the followings unread

the19thbear wrote:
ok.. so the source was wrong. it is not an aluminium disc! Very Happy
but then, what is it???


"No aluminium" makes sense at least Very Happy

_________________
Jan
also .. could someone please turn down the thermostat a bit.
Posted Image, might have been reduced in size. Click Image to view fullscreen.
Back to top
View user's profile Send private message Visit poster's website
Pehr



Joined: Aug 14, 2005
Posts: 1307
Location: Björkvik, Sweden
Audio files: 2

PostPosted: Wed Sep 12, 2012 5:59 am    Post subject: Reply with quote  Mark this post and the followings unread

I have some unused tape heads in the drawer and thinking of making a "floppy echo". Does anyone know of any good enough tape head preamp schematics? for record, erase and playback heads.
_________________
YouTube channel
flickr photostream
http://loxodrom.blogspot.com
http://www.garageband.com/artist/loxodrom
http://soundcloud.com/loxodrom
Back to top
View user's profile Send private message
JingleJoe



Joined: Nov 10, 2011
Posts: 878
Location: Lancashire, England
Audio files: 14

PostPosted: Wed Sep 12, 2012 12:01 pm    Post subject: Reply with quote  Mark this post and the followings unread

Just FYI you need an oscillator too, 40khz or more, to mix with the audio signal. This is standard practice with tape recorders, my limited understanding is that it jiggles the magnetic particles to get a better response.
_________________
As a mad scientist I am ruled by the dictum of science: "I could be wrong about this but lets find out"


Green Dungeon Alchemist Laboratories
Back to top
View user's profile Send private message
Pehr



Joined: Aug 14, 2005
Posts: 1307
Location: Björkvik, Sweden
Audio files: 2

PostPosted: Wed Sep 12, 2012 12:40 pm    Post subject: Reply with quote  Mark this post and the followings unread

ah, yes, the AC-bias!
of course, thanks for reminding.

Isn't it around 120 kHz?

_________________
YouTube channel
flickr photostream
http://loxodrom.blogspot.com
http://www.garageband.com/artist/loxodrom
http://soundcloud.com/loxodrom
Back to top
View user's profile Send private message
JingleJoe



Joined: Nov 10, 2011
Posts: 878
Location: Lancashire, England
Audio files: 14

PostPosted: Wed Sep 12, 2012 12:43 pm    Post subject: Reply with quote  Mark this post and the followings unread

The higher the better! But anything above twice the top end of the audio range (16 to 20khz) should work.
_________________
As a mad scientist I am ruled by the dictum of science: "I could be wrong about this but lets find out"


Green Dungeon Alchemist Laboratories
Back to top
View user's profile Send private message
mosc
Site Admin


Joined: Jan 31, 2003
Posts: 18197
Location: Durham, NC
Audio files: 212
G2 patch files: 60

PostPosted: Sat Sep 22, 2012 9:34 am    Post subject: Reply with quote  Mark this post and the followings unread

JingleJoe wrote:
... it jiggles the magnetic particles to get a better response.


Laughing Let's not get too technical here, Joe.

The use of the high frequency bias oscillator was discovered by accident, just like the cosmic background radiation, at Bell Labs, by Dr. Dean Wooldridge, but nobody in Bell Labs used the term Dr. because it wasn't considered cool.

Here is an excerpt of an interview with Wooldridge:

    “The other requirement was superposed high
    frequency on the recording. You have to, at the same
    time as you are putting in your growing magnetic
    fields, to put down the sound record you have to
    superpose a high frequency bias on it. The physics
    involved there is just a little more abstruse than you
    might imagine . But...it does two things: first of all, it
    greatly reduces the amount of noise that comes
    through, and in the second place, it greatly improves
    the quality. Now, I discovered that process.

    “The way I discovered it was entirely by accident.
    I had rigged up some electronic test rig so that I could
    make various kinds of changes in my electrical
    recording techniques on some tape that I was dealing
    with. And, since my electronic wiring wasn't very good
    and I hadn't shielded some of my wires, quite by
    accident some of the output of a 20,000 cycle
    oscillator that I had going over in one corner leaked
    onto the wires that were going into the recording unit,
    and accidentally put some high frequency on it, and I
    discovered that I was getting some amazingly low
    noise and high-quality recording. I had to run it down
    and this looked like a very exciting invention


That was taken from this AES paper written by Jay McKnight AC Bias at Bell Telephone Laboratories, 1936...1939, a great short read with some fine pics too.

Full interview with Dean Wooldridge is here: http://www.aip.org/history/ohilist/4981.html but I can't quote from it because of the anal restrictions posted on that American Institute of Physics web page.

Anyway, Jingle Joe's explaination seems to be at least as good as Wooldridge's. Very Happy

_________________
--Howard
my music and other stuff
Back to top
View user's profile Send private message Send e-mail Visit poster's website AIM Address
JingleJoe



Joined: Nov 10, 2011
Posts: 878
Location: Lancashire, England
Audio files: 14

PostPosted: Sun Sep 23, 2012 1:53 am    Post subject: Reply with quote  Mark this post and the followings unread

Very interesting to read, magnetic tape machines are going to be one of my next endeavours. I've read all about them but not built one yet, all theory no practice Rolling Eyes
So while you are here mosc, let me probe your vast knowledge; I was going to ask, what are the internal resistances of the read/write heads on the average cassette tape recorder like? If they are just an electro-magnet; an inductor with a core, then it could be very very low resistance depending on the industance. Does this mean series resistance would be required to prevent them overloading? if so, what sort of current should they be limited to?
I can foresee other problems too if they are very low resistance.

_________________
As a mad scientist I am ruled by the dictum of science: "I could be wrong about this but lets find out"


Green Dungeon Alchemist Laboratories
Back to top
View user's profile Send private message
mosc
Site Admin


Joined: Jan 31, 2003
Posts: 18197
Location: Durham, NC
Audio files: 212
G2 patch files: 60

PostPosted: Sun Sep 23, 2012 5:41 pm    Post subject: Reply with quote  Mark this post and the followings unread

My knowledge is not all that vast. Shocked

Unfortunately, I don't know too much about tape recorder electronics. Suggest you look up some tape recorder schematics and see what others have done.

I am more interested in forgetting about tape recorders. Wink

_________________
--Howard
my music and other stuff
Back to top
View user's profile Send private message Send e-mail Visit poster's website AIM Address
JingleJoe



Joined: Nov 10, 2011
Posts: 878
Location: Lancashire, England
Audio files: 14

PostPosted: Mon Sep 24, 2012 4:01 am    Post subject: Reply with quote  Mark this post and the followings unread

Hahaha I assumed all you oldschoool chaps grew up with them and subsequently knew all about them. Laughing I've looked up tape recorders before but I don't remember too much about them, I suppose I may have had difficulty finding them, the search continues!
_________________
As a mad scientist I am ruled by the dictum of science: "I could be wrong about this but lets find out"


Green Dungeon Alchemist Laboratories
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic Moderators: dnny, v-un-v
Page 2 of 2 [40 Posts]
View unread posts
View new posts in the last week
Goto page: Previous 1, 2
Mark the topic unread :: View previous topic :: View next topic
 Forum index » DIY Hardware and Software » Circuit Bending
Jump to:  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


Forum with support of Syndicator RSS
Powered by phpBB © 2001, 2005 phpBB Group
Copyright © 2003 through 2009 by electro-music.com - Conditions Of Use