Two Cassette Questions

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CV_Wonder
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Two Cassette Questions

Post by CV_Wonder » Mon Sep 21, 2015 12:44 pm

Hello,

I've been searching for answers for these two questions for days and cant seem to find much.

1. Does anyone know of a simple circuit which would drive a cassette tape head up to line level so I could go straight into a mixer?

2. Does anyone know of a supplier of old stock "spindle hubs" for cassette decks? Or even better if there is some part out there that could act as a replacement since apparently these aren't made anymore...

Thank you!

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ubertar
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Post by ubertar » Mon Sep 21, 2015 4:14 pm

I don't know, but it sounds like you've got an interesting project going on!

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Drone
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Post by Drone » Mon Sep 21, 2015 4:38 pm

I'm not sure I understand the question?

Signal isn't written to a cassette as a standard audio signal, there's a bias signal applied.
The previous statement is from a guy who records his own, and other projects for fun. No money is made.

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Post by CV_Wonder » Mon Sep 21, 2015 8:15 pm

ubertar wrote:I don't know, but it sounds like you've got an interesting project going on!
We'll see! If I can get It up and running! It's a Brooklyn based project :) I live here too.

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Post by CV_Wonder » Mon Sep 21, 2015 8:28 pm

Drone wrote:I'm not sure I understand the question?

Signal isn't written to a cassette as a standard audio signal, there's a bias signal applied.
It would make sense that you don't understand the questions since I'm pretty bad with understanding signal levels and even phrasing a question correctly for this sort of thing....:oops:

As far as I know (which is probably wrong!) a "normal" tape head preamp circuit only boosts the signal enough to go into say a stereo receiver which then boosts the signal a great deal more?? I'm trying to find a circuit that will boost the signal to a high enough level to where I can just go straight into a mixer. I'm not sure if that is clearer though...

Or maybe I'm not correct on that? Would for example this circuit do what I'm after?
https://www.quasarelectronics.co.uk/Ite ... eamplifier

Thanks

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Snarl 12/8
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Post by Snarl 12/8 » Tue Sep 22, 2015 6:33 am

Most mixers have "line-ins" somewhere. So that thing outta do ya.

Microphone inputs are even more sensitive, so you could use something with even less gain, if you went that route.
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Drone
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Post by Drone » Tue Sep 22, 2015 6:53 am

Like he says, the signal comng out of the tape deck can go straight to the mixer.
The previous statement is from a guy who records his own, and other projects for fun. No money is made.

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Post by floid » Tue Sep 22, 2015 7:32 am

Are you using a deck, or stealing parts/ mashing parts from a few together? There must be a reason you can't/ don't want to use the existing circuitry. Like the tape violin or a homebrew echo.
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Post by The Scum » Tue Sep 22, 2015 9:50 am

If you've got a naked playback head, try googling for "tape head preamp".

Opamp labs have a few schematics:
http://opamplabs.com/products/opamp-amp ... -tape.html

There's also a section of the National Semi Audio/Radio Handbook with a handful of designs...mostly a single opamp and some passives. They converge on the now obsolete LM1818 IC:
http://www.ti.com/lit/ds/symlink/lm1818.pdf
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CV_Wonder
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Post by CV_Wonder » Tue Sep 22, 2015 2:24 pm

Snarl 12/8 wrote:Most mixers have "line-ins" somewhere. So that thing outta do ya.

Microphone inputs are even more sensitive, so you could use something with even less gain, if you went that route.
Awesome thanks, yea I would love it to just go into a regular 1/4" input without having to use say a Hi-Z Guitar button or anything. So that's mainly what I wanted to make sure of.

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Post by CV_Wonder » Tue Sep 22, 2015 2:29 pm

floid wrote:Are you using a deck, or stealing parts/ mashing parts from a few together? There must be a reason you can't/ don't want to use the existing circuitry. Like the tape violin or a homebrew echo.
Yea the only thing I will need to use is a naked Cassette tape head. I only want to use that with a small preamp circuit to keep things minimal. I'm trying to make a fun little invention that I could sell in small batches to interested parties. I mean, I'm interested in it first and foremost then I can see if others are :)

I would love to have tone control or an interesting filter plus even some distortion option but that would just be way out of my territory. I need everything to just be on one board.

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Post by CV_Wonder » Tue Sep 22, 2015 2:38 pm

The Scum wrote:If you've got a naked playback head, try googling for "tape head preamp".

Opamp labs have a few schematics:
http://opamplabs.com/products/opamp-amp ... -tape.html

There's also a section of the National Semi Audio/Radio Handbook with a handful of designs...mostly a single opamp and some passives. They converge on the now obsolete LM1818 IC:
http://www.ti.com/lit/ds/symlink/lm1818.pdf
Rad thank you! I've looked at quite a few online so far and even gotten permission from one designer to use their adapted Sanyo-type circuit in my project. (Still need to double and triple check with them to make sure I'm being clear).

Edit: Looks like the opamp labs won't work for me since I'm trying to get everything to run off of 9v. The TI chip looks very interesting!


However, I'm still wondering about older designs like the ones you sent. How would it work to include these in a project that could possibly be for sale? I've been trying to read up a lot on circuit design ethics.. Also, how hard would it be to add extra controls to circuits like these, say tone control, volume and then later, and more challenging overdrive? (I know that's an incredibly broad question!)

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