Analog tape compression circuit

flexagon · 16th January 2009, 09:20 PM

hi all, been browsing this forum for awhile now, just taken the plunge.
i'm studying electronics at college, for the main reason of getting into audio design, but i'm still a bit of a beginner really.
for my first project i fancy building an analogue tape comp simulator, as i love that natural sounding saturation/compression. i've come across this design http://home3.netcarrier.com/~lxh2/tapesat.html
& have a question about it, it states that 'Any decent quality op-amps can be used'
so was wondering if anyone could enlighten me on this, as i'm not sure whether it means any op-amp or an audio specific one?
cheers

unsolved · 16th January 2009, 10:24 PM

I suppose a ordinary 741 will be good enough and a safe card. Otherwise, maybe NE5534?

//Erik

jman 31 · 16th January 2009, 10:44 PM

This is a very vague application. I have been looking at a DAT 12 track recorder that I was thinking about getting to run my digital recordings through to "warm" them up. I am curious as to where in the scheme of things this would be used? Would you put it between the instrument and the board, or after the total mix in to a final wav file? I guess I just am not getting enough info. I think it would be really cool if it worked and it would save me roughly $650 usd, but me thinks it's to good to be true?

Jman

unsolved · 16th January 2009, 11:02 PM

If you will use it on the final mix, you probably will link the channels (otherwise they will sound different and make a skew stereo image... I think you may have more use of it if you insert it on the channel you are recording. Build one and test, maybe it sounds like crap, maybe it´s perfect on some kind of instrument, you´ll never know. Maybe it gives you a really fat snare... I think you shuld go that way.

Anyway, i prefere the real stuff for tape saturation, so i should use my B62 or B67... :-)

//Erik

jman 31 · 17th January 2009, 12:37 AM

I think I will!

flexagon · 17th January 2009, 10:46 PM

thanks for the replies,
i'll probably be using it between instrument & desk(to soundcard) as i recently transferred some older 8-track recordings onto p.c & was really impressed with how well the bass track sounded. whether it works or not is a different matter of course, but it looks a cheap build to mess about with!
also, if i may, is there a general rule of thumb when choosing resistors for audio, is there a best type, power rating, tolerance e.t.c? i.e. metal film/carbon comp, 0.25w/0.75w...
cheers

jman 31 · 20th January 2009, 11:34 AM

Hey guys, I found this an interesting idea so I am going to try it also. I was wondering about this statement in the instructions:

"1. Power supply is a split supply of +/- 15 volts."

I am assuming that it would be a virtual ground supply, but is that +/- 15 volt supply divided into 7.5 volts, or is it a 30 volt supply divided into 15 volts?

By the way it's stated I would assume that it's the latter, but I would just be guessing. Here is the page again: http://home3.netcarrier.com/~lxh2/tapesat.html

Thanks
Jman

unsolved · 20th January 2009, 11:44 AM

that's right, 30 volts dividet to 2.. It's not critical unless you need +4dB out, if you are using a unbalanced circuit, 0,775 V, and if it's ok for the opamp, you can test the circuit with two 9V batteries..

question about resistors, take what you have. It doesn't matter... 5% will be fine,1/4 W, cheap and easy to find.

jman 31 · 20th January 2009, 11:58 AM

Thanks for the quick response unsolved. I'll let you all know how this works when I get done. I will have to order the 1n34 diodes I think.

flexagon · 30th January 2009, 05:23 PM

quite by accident i stumbled across this site http://doorstopelectronics.googlepages.com/home2
there's a slight mod to the tape comp circuit on there.

hey jman, was wondering if you've built one yet & how it sounds?

16th January 2009, 09:20 PM	#1
flexagon diyAudio Member Join Date: Jan 2009	Analog tape compression circuit hi all, been browsing this forum for awhile now, just taken the plunge. i'm studying electronics at college, for the main reason of getting into audio design, but i'm still a bit of a beginner really. for my first project i fancy building an analogue tape comp simulator, as i love that natural sounding saturation/compression. i've come across this design http://home3.netcarrier.com/~lxh2/tapesat.html & have a question about it, it states that 'Any decent quality op-amps can be used' so was wondering if anyone could enlighten me on this, as i'm not sure whether it means any op-amp or an audio specific one? cheers

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16th January 2009, 10:24 PM	#2
unsolved diyAudio Member Join Date: Jan 2009	I suppose a ordinary 741 will be good enough and a safe card. Otherwise, maybe NE5534? //Erik

16th January 2009, 10:44 PM	#3
jman 31 diyAudio Member Join Date: Oct 2008 Location: Florida	This is a very vague application. I have been looking at a DAT 12 track recorder that I was thinking about getting to run my digital recordings through to "warm" them up. I am curious as to where in the scheme of things this would be used? Would you put it between the instrument and the board, or after the total mix in to a final wav file? I guess I just am not getting enough info. I think it would be really cool if it worked and it would save me roughly $650 usd, but me thinks it's to good to be true? Jman

16th January 2009, 11:02 PM	#4
unsolved diyAudio Member Join Date: Jan 2009	If you will use it on the final mix, you probably will link the channels (otherwise they will sound different and make a skew stereo image... I think you may have more use of it if you insert it on the channel you are recording. Build one and test, maybe it sounds like crap, maybe it´s perfect on some kind of instrument, you´ll never know. Maybe it gives you a really fat snare... I think you shuld go that way. Anyway, i prefere the real stuff for tape saturation, so i should use my B62 or B67... :-) //Erik

17th January 2009, 12:37 AM	#5
jman 31 diyAudio Member Join Date: Oct 2008 Location: Florida	I think I will!

17th January 2009, 10:46 PM	#6
flexagon diyAudio Member Join Date: Jan 2009	thanks for the replies, i'll probably be using it between instrument & desk(to soundcard) as i recently transferred some older 8-track recordings onto p.c & was really impressed with how well the bass track sounded. whether it works or not is a different matter of course, but it looks a cheap build to mess about with! also, if i may, is there a general rule of thumb when choosing resistors for audio, is there a best type, power rating, tolerance e.t.c? i.e. metal film/carbon comp, 0.25w/0.75w... cheers

20th January 2009, 11:34 AM	#7
jman 31 diyAudio Member Join Date: Oct 2008 Location: Florida	Hey guys, I found this an interesting idea so I am going to try it also. I was wondering about this statement in the instructions: "1. Power supply is a split supply of +/- 15 volts." I am assuming that it would be a virtual ground supply, but is that +/- 15 volt supply divided into 7.5 volts, or is it a 30 volt supply divided into 15 volts? By the way it's stated I would assume that it's the latter, but I would just be guessing. Here is the page again: http://home3.netcarrier.com/~lxh2/tapesat.html Thanks Jman

20th January 2009, 11:44 AM	#8
unsolved diyAudio Member Join Date: Jan 2009	that's right, 30 volts dividet to 2.. It's not critical unless you need +4dB out, if you are using a unbalanced circuit, 0,775 V, and if it's ok for the opamp, you can test the circuit with two 9V batteries.. question about resistors, take what you have. It doesn't matter... 5% will be fine,1/4 W, cheap and easy to find.

20th January 2009, 11:58 AM	#9
jman 31 diyAudio Member Join Date: Oct 2008 Location: Florida	Thanks for the quick response unsolved. I'll let you all know how this works when I get done. I will have to order the 1n34 diodes I think.

30th January 2009, 05:23 PM	#10
flexagon diyAudio Member Join Date: Jan 2009	quite by accident i stumbled across this site http://doorstopelectronics.googlepages.com/home2 there's a slight mod to the tape comp circuit on there. hey jman, was wondering if you've built one yet & how it sounds?