Various ways of degrading a signal?

[Brisance]

So I want to build a delay, with a digital delay chip, but I want to emulate the oldschool tape and BBD delays feedback "degradation", what would you guys do? I was thinking of getting some of my really old soviet Ge transistors, and maybe incorporate a sziklai or darlington voltage follower in the feedback path? Anything more clever maybe?

[WhiskeyMadeMeDoIt]

You also need to emulate tape flutter and wow. Look at the clari(not) for ideas on that. It's an enveloped controlled delay that uses the signal level to manipulate the delay. 

[GibsonGM]

Another thing you might try is running thru both a LP and HPF to emulate the limitations of the original media, esp. for tape emulation.  They had a definite bandwidth...  Check out their actual SOUND, see if the highs are missing, and 'copy' that.    Probably some examples on Youtube.   

I had a tape echo, but that was like 30 years ago, so I can't really recall what the tape's limitations were, he he....I know it had a touch of background hiss if you let it roll with no signal.   

Wow/flutter are great ideas....

[WhiskeyMadeMeDoIt]

Also a bit of compression.  Tape compression is almost an effect itself. 

[GibsonGM]

Also a bit of compression.  Tape compression is almost an effect itself. 

+1 

[Mark Hammer]

Tape is a mechanical system as much as an electro-magnetic system.  Because the tape loop is a loop, and not infinite, it is subject to what normally happens with any tape over prolonged use.  It can get crinkled by jams.  The crinkles not only introduce momentary pitch shifts but can also result in the tape being momentarily moved away from the tape head that it needs to be pressed up against to yield signal.  It can lose oxide particles (which is what is used to store the magnetic charge).  It can get demagnetized.

The LFO-based wow and flutter that we try and emulate is more about simulating the transport mechanism, and not the tape itself.  If the capstan is past its prime, you'll get the same wow and flutter with new tape as with old.

That is not to say that emulating the wow and flutter is pointless.  Rather, it is an incomplete depiction of what happens with tape-based delays.  For the sake of realism, it might be optimal to use a LF noise-based modulation of delay-time, than a more predictable LFO.

The same LF noise-based modulation might also be used to introduce very very brief "dropouts" in the feedback or overall delay signal.  That is, very tiny moments where the signal is either blocked, or severely attenuated.

In general, if one want authentic emulation of tape delay, look to the mechanical and physical weak links in that system for a clearer, and more thorough, set of parameters to play with.

[karbomusic]

Various ways of degrading a signal?

You could yell at it and call it names 

[samhay]

As a side note, if you use something like a PT2399 for your digital delay, you will get degradation of the signal when you have multiple repeats, and also when you have a delay time of more than a few hundred ms - it's the nature of how these chips work.

[stm]

I will say this just once:
Tape compression is greatly misunderstood.  It is not what you think it is.  I have never ever seen anybody describe correctly what's going on behind.  Period.

[PBE6]

Got any hints?

[wavley]

Various ways of degrading a signal?

You could yell at it and call it names 

A send and return with one of these plugged in?

Tape is a mechanical system as much as an electro-magnetic system.  Because the tape loop is a loop, and not infinite, it is subject to what normally happens with any tape over prolonged use.  It can get crinkled by jams.  The crinkles not only introduce momentary pitch shifts but can also result in the tape being momentarily moved away from the tape head that it needs to be pressed up against to yield signal.  It can lose oxide particles (which is what is used to store the magnetic charge).  It can get demagnetized.

The LFO-based wow and flutter that we try and emulate is more about simulating the transport mechanism, and not the tape itself.  If the capstan is past its prime, you'll get the same wow and flutter with new tape as with old.

That is not to say that emulating the wow and flutter is pointless.  Rather, it is an incomplete depiction of what happens with tape-based delays.  For the sake of realism, it might be optimal to use a LF noise-based modulation of delay-time, than a more predictable LFO.

The same LF noise-based modulation might also be used to introduce very very brief "dropouts" in the feedback or overall delay signal.  That is, very tiny moments where the signal is either blocked, or severely attenuated.

In general, if one want authentic emulation of tape delay, look to the mechanical and physical weak links in that system for a clearer, and more thorough, set of parameters to play with.

What he said.  Even without crinkles, I've heard very few folks that get the splice right.  Sometimes when I don't get it right I leave it anyway if it's the good kind of not right.