Tape Saturation Pedal Idea

[Barracuda]

So my mate picked up this sony tc-133 tape recorder/player box, and its a bit shoddy but, man.
When you clip this thing it gives a great smooth distortion/saturation which'd be great for a guitar pedal, the only problem is.. I don't understand a lick of it. I wouldn't expect a great deal of people here too either..


https://ibb.co/iid7ka

I've heard transformers can do some great saturation sounds, but I have no idea if that's whats causing it in this case. I'm interested to know whats actually clipping and distorting so nicely, and see if it can be applied in a pedal (even it was over 9v).

Not sure what more information you'd need so, if there's anyone who can decipher this mystery, it would be very educational.

Cheers

[Frank_NH]

Funny you should mention this.  I'm a big Fleetwood Mac fan, and I know Lindsey Buckingham used the guts of a Sony TC-630 tape desk to create the "fuzz" used on the first Buckingham-Nicks era Fleetwood Mac albums (e.g. "Go Your Own Way" from Rumours).  Read about it here...

"For amplifiers I used to use HiWatts, but they all of a sudden somehow became real dirty-sounding. So I got Marshall 100watts, and they seem to have a lot of bite. I use these tape recorder guts for fuzz. When I got out of Fritz and started doing lead, I bought a Sony 630 tape recorder deck for demo tapes. Then I got an Ampeg 4-track and started using the Sony 2-track for slap echo and effects like that with the preamp output of the deck into an amp. It's just an amazing fuzz device. Since then I've taken the guts out of the preamp and put them in a little box, and that's what I use both onstage and in the studio."

http://bla.fleetwoodmac.net/index.php?page=index_v2&id=32

[Heikki]

I don't know much about tape recorders but the amplifier circuit seems fairly simple. Lots of fain going on so it's easy to drive to clipping with guitar. R155 seems to be tone pot and if switches 103, 104 are on the position where drawn, when tone pot turned halfway there's 40dB gain in mid and high frequencies and even more gain at bass. Then theres volume pot and power amp with 50dB gain. What makes it sound great probably has lot to do with the frequency response of the amplifier.

All NPN transistors and single sided power supply, you could easily do a similar pedal that works with 9V.

[Barracuda]

I did not know that about Fleetwood Mac! glad to hear it can be done in hopefully the same or a similar way.

Funny you should say about the mid/high frequencies, because it was probably the pass filter(s) making it such a smooth distortion. I mean I see no clipping diodes, so technically we are talking a fuzzy distortion?

[nonoxxx]

Why don't you take a look at the ep booster it s basically a tape echo minus the echo and the schematic is really simple , I build a pedal for a friend whith a screamer on steroid plus a ep booster clone inside . The Ep after the screamer works like a boost and an exciter (the result is awesome)

[R.G.]

It's fashionable to toss around the word "saturation" for distortion from magnetics based things, but in reality it's quite difficult to get a transformer or other magnetic device to actually saturate in an audio-useful way. I dug into this quite a bit back in the early 2000s.

The electronic - amplifiers, drivers, etc. - on a tape deck, sure. Those are easy enough to overdrive and may produce a likable distortion sound, but it's the electronics, not the magnetics, I think.

[anotherjim]

I'm quite sure it is only the pre-amps clipping making the fuzz.
However, there is also a significant effect due to the low input of impedance of these things.

Made to take a mic', a line input, or head playback, the pre-amps have a "medium" input impedance somewhere from 30k to 50k. This can have a significant effect on the tone of a guitar plugged directly in. Because the guitar pickup is inductive, the effect on tone is a little more complicated than simple filtering, but is heard as a loss of highs or "tone suck". The effect is greater with humbuckers than single coils and lost completely if a buffer of some kind is in between.

Anyway, the impact is to make the distortion smoother. Harmonics generated by the distortion are dominated by harmonics of the note fundamentals, rather than harmonics of the harmonics.

[Barracuda]

I think I'd agree in saying it is the pre-amps doing the job. When I tested it I used one of the mics supplied with it up against my clean amp, into a tiny 1/8th jack input. Is there a way to tell which section would be causing the clipping. (Obviously there is, thats just a polite way of asking if you know which one haha) Just so I can study it a bit.

[anotherjim]

There is a lot of circuit it goes through. To sound like it, I'd expect you would need to copy one channel from beginning to end.

Below switch 102 is the recording path to the Left head. None of that would be needed.
Switches 103 to 105 appear to select tape eq components. Some of that might be needed - I don't know.
By C128 you have the final output amplifier stage followed by everything that routes to the output jacks, the level meters and back to the recording head.