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Basic opamp question [message #334754]

Fri, 18 April 2008 16:39

Version is currently offline

Version
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Registered: September 2005
Location: Berkeley

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I have two beginner questions.

I am trying to build a simple driver/recovery circuit for an Accutronics spring tank. I am following the design on the Accutronics website, found here. (pdf)

My questions are

1. What would be an ideal, commercially available op-amp to replace LM307N and TL071CN?

2. Does TL071CN not require 15+/-? It doesn't seem to show current entering the op-amp on the schem.

Thanks!

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Re: Basic opamp question [message #334775 is a reply to message #334754 ]

Fri, 18 April 2008 18:44

Andy Peters
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Registered: April 2004
Location: Tucson, AZ

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Version wrote on Fri, 18 April 2008 14:39

I have two beginner questions.

I am trying to build a simple driver/recovery circuit for an Accutronics spring tank. I am following the design on the Accutronics website, found here. (pdf)

My questions are

1. What would be an ideal, commercially available op-amp to replace LM307N and TL071CN?

The TL071 is still available, and for this application, it's probably good enough.

The LM307 has been obsolete for over a decade, and in a word, it's not great, and certainly in this application, it can be replaced with pretty much anything, like another TL071.

Quote:

2. Does TL071CN not require 15+/-? It doesn't seem to show current entering the op-amp on the schem.

Yes, I guess they just forgot to draw the power connections on that schematic.

-a

"On the Internet, nobody can hear you mix a band."

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Re: Basic opamp question [message #334844 is a reply to message #334754 ]

Sat, 19 April 2008 00:45

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Thanks!

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Re: Basic opamp question [message #334967 is a reply to message #334754 ]

Sat, 19 April 2008 14:11

Jay Kadis is currently offline

Jay Kadis
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You might want to check out the old PAIA Hot Springs Reverb schematic (http://www.paia.com/ProdArticles/hotspuse.htm) for a clever way of reducing the boinginess of the Accutronics reverb pan, along with good driver and recovery amp circuits. I think I used NE5532 op-amps for it, but it's been so long I can't remember.

-JK

http://ccrma.stanford.edu/~jay/

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Re: Basic opamp question [message #334986 is a reply to message #334967 ]

Sat, 19 April 2008 16:41

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I am after as much boing as possible, to be honest...

It's a "special effect".

I'll check the PAIA schem. Good idea!

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Re: Basic opamp question [message #335095 is a reply to message #334986 ]

Sun, 20 April 2008 06:42

Tomas Danko is currently offline

Tomas Danko
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Version wrote on Sat, 19 April 2008 22:41

I am after as much boing as possible, to be honest...

It's a "special effect".

I'll check the PAIA schem. Good idea!

I've seen some guys making them out of a slinky. Is that boingy enough for you? Smile

Smile

http://www.electronicpeasant.com/projects/springs/springs.ht ml

http://www.plasticpop.se/plasticpop.gif

"T(Z)= (n1+n2*Z^-1+n2*Z^-2)/(1+d1*z^-1+d2*z^-2)" - Mr. Dan Lavry
"Shaw baa laa raaw, sidle' yaa doot in dee splaa" . Mr Shooby Taylor

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Re: Basic opamp question [message #335114 is a reply to message #335095 ]

Sun, 20 April 2008 10:01

Jay Kadis is currently offline

Jay Kadis
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Tomas Danko wrote on Sun, 20 April 2008 04:42

I've seen some guys making them out of a slinky. Is that boingy enough for you? Smile

Smile

I've seen some guys taking an impulse response from a Slinky. Perhaps a boingy plug-in?

-JK

http://ccrma.stanford.edu/~jay/

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Re: Basic opamp question [message #335121 is a reply to message #335114 ]

Sun, 20 April 2008 10:23

Tomas Danko is currently offline

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Jay Kadis wrote on Sun, 20 April 2008 16:01

Tomas Danko wrote on Sun, 20 April 2008 04:42

I've seen some guys making them out of a slinky. Is that boingy enough for you? Smile

Smile

I've seen some guys taking an impulse response from a Slinky. Perhaps a boingy plug-in?

Well, the plug-in sure takes a lot less space. But I don't think it's going to be as random in the boingy qualities. hehe

I once saw a guy that just mounted it from ceiling to floor in a corner, though. Sounded very spaced out.

http://www.plasticpop.se/plasticpop.gif

"T(Z)= (n1+n2*Z^-1+n2*Z^-2)/(1+d1*z^-1+d2*z^-2)" - Mr. Dan Lavry
"Shaw baa laa raaw, sidle' yaa doot in dee splaa" . Mr Shooby Taylor

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Re: Basic opamp question [message #335209 is a reply to message #335121 ]

Sun, 20 April 2008 19:42

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yeah, a zube tube. a slinky. a cheap echo mic.

http://www.beyondplay.com/LARGE/T452.JPG

noisy and fun. Actually, I think I already have IRs in Altiverb for the echo mic and the zube tube.

But as Tomas states, there is a special magic in electromechanical devices.

Floor to ceiling? That's nuts!

http://www.zubetube.com/images/boy.jpg

This picture kind of demonstrates how I feel about real springs.

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Re: Basic opamp question [message #335396 is a reply to message #334775 ]

Mon, 21 April 2008 16:36

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Andy Peters wrote on Fri, 18 April 2008 16:44

Version wrote on Fri, 18 April 2008 14:39

I have two beginner questions.

I am trying to build a simple driver/recovery circuit for an Accutronics spring tank. I am following the design on the Accutronics website, found here. (pdf)

My questions are

1. What would be an ideal, commercially available op-amp to replace LM307N and TL071CN?

The TL071 is still available, and for this application, it's probably good enough.

The LM307 has been obsolete for over a decade, and in a word, it's not great, and certainly in this application, it can be replaced with pretty much anything, like another TL071.

Quote:

2. Does TL071CN not require 15+/-? It doesn't seem to show current entering the op-amp on the schem.

Yes, I guess they just forgot to draw the power connections on that schematic.

-a

Back on topic, I have a 15 VDC regulted power supply here, but it delivers 1.5 amps. Is that too much for this circuit?

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Re: Basic opamp question [message #335402 is a reply to message #335396 ]

Mon, 21 April 2008 16:50

Jay Kadis is currently offline

Jay Kadis
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Version wrote on Mon, 21 April 2008 14:36

Back on topic, I have a 15 VDC regulted power supply here, but it delivers 1.5 amps. Is that too much for this circuit?

You'll need a supply with both positive and negative 15 volt outputs. Too high a current rating will not do any damage to the circuit, as it will only draw as much current as it needs, but the size, weight and cost of an over-sized supply may pose a problem.

I use the Power-One HAD15-0.4-A linear PS for a lot of op-amp audio projects. It gives 400 mA on each of the outputs, which is more than enough for most circuits.

-JK

http://ccrma.stanford.edu/~jay/

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Re: Basic opamp question [message #335405 is a reply to message #335402 ]

Mon, 21 April 2008 17:01

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The Condor PSU I have has both +/- poles. I think it's probably very similar (at least in form factor) to the Power One PSU you speak of.

Here it is.

My only complaint is that it's too tall to pack into a 1U box. I guess I could connect it externally, which wouldn't be a bad idea, considering the magnetic field and its possible RF interference with the transducers on the spring pan.

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Re: Basic opamp question [message #335508 is a reply to message #334754 ]

Tue, 22 April 2008 03:59

Dave Hecht is currently offline

Dave Hecht
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Registered: February 2005

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The supply you linked to is single sided. If that is the supply you have, you'll need a second supply for +/-15v, or just get a bipolar supply (it'll be easier to rack up). I'd go with external psu, just hook up with a 4 pin XLR should be fine.

Dave Hecht

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Re: Basic opamp question [message #335608 is a reply to message #334754 ]

Tue, 22 April 2008 11:40

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Thanks everyone for the advice.

Next up is the filter network!

I'm such a hack, but this is all very fascinating and educational.

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Re: Basic opamp question [message #337230 is a reply to message #334754 ]

Mon, 28 April 2008 04:54

Brian Kehew
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Registered: January 2005
Location: North Hollywood

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You are doing the right things - asking and TRYing yourself. You will learn a lot and be comfortable with your own gear. Very cool.

I started out knowing nothing about electronics or circuits over 20 years ago, and now I can PRETEND to know very well!

Relax and float downstream...

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Re: Basic opamp question [message #337472 is a reply to message #334754 ]

Mon, 28 April 2008 19:59

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Thanks for the encouragement BK.

It is more fun this way. Sometimes it's a trade off, though, because when I run into trouble, like hum or noise...it's kind of hard to ask questions, without being too sure about what I'm doing.

At the end of the day, though, it's all very entertaining and educational.

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