KVR Audio

khanyz · Post by **khanyz** » Sun Sep 04, 2011 4:59 am

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

.

@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?

xtp · Post by **xtp** » Sun Sep 04, 2011 7:19 am

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.

Dean Aka Nekro · Post by **Dean Aka Nekro** » Tue Sep 06, 2011 11:08 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

khanyz · Post by **khanyz** » Wed Sep 07, 2011 5:29 am

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

.

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

khanyz · Post by **khanyz** » Tue Sep 13, 2011 4:14 pm

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.

Uncle E · Post by **Uncle E** » Tue Sep 13, 2011 8:01 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.

khanyz · Post by **khanyz** » Wed Sep 14, 2011 3:49 am

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.

xtp · Post by **xtp** » Sun Sep 25, 2011 6:42 pm

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.

Hink · Post by **Hink** » Sun Sep 25, 2011 6:51 pm

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

khanyz · Post by **khanyz** » Sun Sep 25, 2011 7:14 pm

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

pj geerlings · Post by **pj geerlings** » Thu Feb 16, 2012 12:25 am

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

Hink · Post by **Hink** » Thu Feb 16, 2012 1:04 am

Hi pj, good to see you

pj geerlings · Post by **pj geerlings** » Thu Feb 16, 2012 1:09 am

Hink wrote:Hi pj, good to see you

Nice little forum ya got here, Hink

Hink · Post by **Hink** » Thu Feb 16, 2012 2:39 am

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

khanyz · Post by **khanyz** » Thu Feb 16, 2012 8:15 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

OpAmps for DIY Bass & Guitar Pedals