OpAmps for DIY Bass & Guitar Pedals

...and how to do so...
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khanyz
KVRAF
1556 posts since 16 Jul, 2004 from Deepest Yorkshire

Post Sat Sep 03, 2011 8:59 pm

^ OOh, my first sticky. I feel like a teenager again :oops: .

@jonnyG - I've ordered some Rail to Rail OpAmps to try. I've never used them before, so are there any special considerations I need to make with them?
I miss MindPrint. My TRIO needs a big brother.

xtp
KVRian
841 posts since 4 Jun, 2006 from The West Coast of New Zealand

Post Sat Sep 03, 2011 11:19 pm

Uncle E wrote:
xtp wrote:AD797
If it helps at all, the Mad Professor Mighty Red Distortion uses it and sounds fantastic.
To be honest they are a bit out of my price range. My current project needs 11 opamps, in my country they are $15.00 per opamp.
Last edited by xtp on Sun Sep 25, 2011 10:29 am, edited 1 time in total.

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Dean Aka Nekro
KVRAF
6179 posts since 4 Oct, 2007 from Escaped At Last

Post Tue Sep 06, 2011 3:08 pm

This has not got that much to do with Op-Amps but they will come into play if anyone is into the magazine/builds but its mainly for the overall amount of links to useful stuff:

http://www.audioxpress.com/

I do not know how good it is as i have not ever bought a copy, It seems to be a US publication so no wonder it ain't in my local newsagents though :)

Hope its of use to all DIYer's here

Dean

Edit: I mean check this out, Loads of PDFs all about VoiceCoil/LoudSpeaker/Headphones: http://voicecoilmagazine.com/articles_addenda.html

Its like finding my uncle's pr0n collection when i was 13 all over again but more useful :oops: :lol:

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khanyz
KVRAF
1556 posts since 16 Jul, 2004 from Deepest Yorkshire

Post Tue Sep 06, 2011 9:29 pm

Thanks Dean. And the samples are steadily streaming in. Some are SOIC but I've got a couple of adapters to use with them. Seems like a bit of a fiddly soldering job but I've got a big magnifying glass and I'll have a shot to steady my hand :wink: .

Also, I've got a book called Electronics Projects for Musicians. It's got some good basics to start with a short, but nice intro to electronics. It goes through ICs/OpAmps and includes a too brief bit about substituting parts. One little caveat though, it is a little old so there are better components out there that you can use. For example, it mentions Carbon Composite resistors. Whilst these are, very subjectively, "more musical" they add noise like a starlet in a horror movie, particularly for small signal stuff. IMO, try them and then go with Metal Film for precision or even Carbon Film for a little drift.

Cheers,
Nigel
I miss MindPrint. My TRIO needs a big brother.

User avatar
khanyz
KVRAF
1556 posts since 16 Jul, 2004 from Deepest Yorkshire

Post Tue Sep 13, 2011 8:14 am

Anybody know anything about OnSemi ( www.onsemi.com ) ? The seem to be an offshoot of Motorola's Semiconductor business. They do the NE5532/5534s and some others which TI also do, but there is a price difference. Any difference in quality? They also charge for samples.
I miss MindPrint. My TRIO needs a big brother.

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Uncle E
KVRAF
10941 posts since 22 Nov, 2000 from Southern California

Post Tue Sep 13, 2011 12:01 pm

OnSemi is high-end stuff. They've taken over for Motorola in supplying the 2N3055 that is so crucial for great Neve 1073 emulations.

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khanyz
KVRAF
1556 posts since 16 Jul, 2004 from Deepest Yorkshire

Post Tue Sep 13, 2011 7:49 pm

Uncle E wrote:OnSemi is high-end stuff. They've taken over for Motorola in supplying the 2N3055 that is so crucial for great Neve 1073 emulations.
Thanks, I'll check them out. Unfortunately they seem to have discontinued the LM308, which is good for RAT mods.
I miss MindPrint. My TRIO needs a big brother.

xtp
KVRian
841 posts since 4 Jun, 2006 from The West Coast of New Zealand

Post Sun Sep 25, 2011 10:42 am

I may have mentioned this before but since I have been using it all last week to put an number of circuits together I thought I'd mention it here, Kicad is a very useful free spice/cad program.

You are able to make/draw your own custom library/components. I use it mainly as a cad tool rather than a spice simulation tool as I breadboard everything before I build.

The latest build has improved considerably in usability.

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Hink
Rad Grandad
28710 posts since 6 Sep, 2003 from Downeast Maine

Post Sun Sep 25, 2011 10:51 am

probably not what you guys are looking for but this place I found when I bought the YJs http://www.tubesandmore.com/ has some opamps
Albert Einstein may have been a genius but his brother Frank was a monster

User avatar
khanyz
KVRAF
1556 posts since 16 Jul, 2004 from Deepest Yorkshire

Post Sun Sep 25, 2011 11:14 am

There's a couple on there that I haven't seen before.

Also, slight OT but, I've found that plastic companies send out samples of PCB supports (self-adhesive). It's a good way to get different heights to find the best fit. You can then buy only the ones you'll use.

Cheers,
Nigel
I miss MindPrint. My TRIO needs a big brother.

pj geerlings
KVRian
909 posts since 1 Dec, 2003 from tejas

Post Wed Feb 15, 2012 4:25 pm

I bought a few of these - but since they are surface mount I still haven't tried them out :(

Texas Instruments / Burr Brown
OPA1641 / OPA1642 / OPA1644

FEATURES DESCRIPTION
• SUPERIOR SOUND QUALITY
• TRUE JFET INPUT OP AMP WITH LOW INPUT BIAS CURRENT
• LOW NOISE: 5.1nV/√Hz at 1kHz
• ULTRALOW DISTORTION: 0.00005% at 1kHz
• HIGH SLEW RATE: 20V/ms
• UNITY GAIN STABLE
• NO PHASE REVERSAL
• LOW QUIESCENT CURRENT: 1.8mA per channel.
• RAIL-TO-RAIL OUTPUT
• WIDE SUPPLY RANGE: ±2.25V to ±18V
• SINGLE, DUAL, AND QUAD VERSIONS AVAILABLE

They do look pretty darn cool

They are $4.90 each so I want to practice my surface mount soldering skills before tacking them down to the DIP-8 adapters that I (also) bought

peace y'all
pj

User avatar
Hink
Rad Grandad
28710 posts since 6 Sep, 2003 from Downeast Maine

Post Wed Feb 15, 2012 5:04 pm

Hi pj, good to see you :)
Albert Einstein may have been a genius but his brother Frank was a monster

pj geerlings
KVRian
909 posts since 1 Dec, 2003 from tejas

Post Wed Feb 15, 2012 5:09 pm

Hink wrote:Hi pj, good to see you :)
Nice little forum ya got here, Hink ;)

User avatar
Hink
Rad Grandad
28710 posts since 6 Sep, 2003 from Downeast Maine

Post Wed Feb 15, 2012 6:39 pm

pj geerlings wrote:
Hink wrote:Hi pj, good to see you :)
Nice little forum ya got here, Hink ;)
thanks, I think it's going well...I thank Ben for having faith in me :)
Albert Einstein may have been a genius but his brother Frank was a monster

User avatar
khanyz
KVRAF
1556 posts since 16 Jul, 2004 from Deepest Yorkshire

Post Thu Feb 16, 2012 12:15 am

pj geerlings wrote:Texas Instruments / Burr Brown
OPA1641 / OPA1642 / OPA1644
These look nice, I'll give them a try. I could have already, but I've gone through so many that I've really lost track. I really need to write notes on them rather than having good/bad piles. :?

Anyway, BTW: Nearly finished designing my first pedal. It's called "HiMo LoJo" and is a dual band distortion pedal with a pre-stage boost/overdrive. It uses very simple filter circuits for the band split. They are variable, though not independently, but have a mid split switch to produce a bigger gap between the high/low cutoff frequencies. This produces a rather primative mid-scoop but it works nicely.

I settled on OP27GPZ's for the boost/overdrive stage and AD797's for the distortion. It's not quite off the breadboard yet, so that may still change.

Cheers,
Nigel
I miss MindPrint. My TRIO needs a big brother.

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