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Topics - EBRAddict

I just picked up a new Hakko solder station and tips from TEquipment. I guess I'll be putting Old Weller for sale soon.
Sorry, jimilee  ;D
It seems so obvious I'm almost ashamed to admit I just learned about this watching YouTube (I think bigclivedotcom)
I saw this today. Their web site is convoluted and they don't stock much to do with pedals, but their pricing is generally pretty good on IC and discretes and free overnight shipping for spending $20 is a great deal.

You can pick up a Raspberry Pi 3 shipped overnight for $35.

This course popped up on a Python programming forum. I don't have 80 hours free in the next 10 weeks, but if I did I'd take the course.

QuoteAbout this course: In this course you will learn about audio signal processing methodologies that are specific for music and of use in real applications. We focus on the spectral processing techniques of relevance for the description and transformation of sounds, developing the basic theoretical and practical knowledge with which to analyze, synthesize, transform and describe audio signals in the context of music applications.

The course is based on open software and content. The demonstrations and programming exercises are done using Python under Ubuntu, and the references and materials for the course come from open online repositories. We are also distributing with open licenses the software and materials developed for the course.

Who is this class for: This course is primary aimed at advanced undergraduate or master students, along with professionals, interested in signal processing, programming and music.
Open Discussion / NLAD
March 20, 2017, 02:24:21 PM

I've been wanting one of these logic analyzers for the last year. This one will capture 8 channels of digital up to 100Mhz and analog up to 50 MS/s, so it should capture analog audio (for debugging, it's not a USB audio interface) with no problem.

Open Discussion / Links to any good SMD capacitor kits?
February 02, 2017, 12:33:11 PM
Anyone have a link to a good SMD 0805 or 1206 capacitor kit on eBay or Aliexpress or Bangood? I'd like to get something in X7R dialectric or better. Most of the eBay kits I saw are Y5R for values > 100pF.

I placed a $8 order on Mouser for $3 of parts last night because I needed a couple values.  :'(
Open Discussion / Not just an ordinary pair of tweezers
January 31, 2017, 02:30:07 PM

I wanted a pair of tweezers which didn't conduct heat (for removing and moving components while hot). Little did I know I was buying SUPPER TWEEZERS. Never again shall I be afraid of magnetism, acids, sloth, premature wear, or sloppy tolerances.
This is a long shot request but there may be a couple in this group who've built one.

I bought a PCB off eBay, the BOM is from a German parts supplier with unhelpful part numbers like "MKS-2 4,7µ".

Wondering if anyone has built one and if you have a BOM?
    Anyone else mess with the STMicro NUCLEO boards? I picked up one of these to program as a button-activated audio test pattern signal generator (12-bit) pulling lookup tables off a MicroSD card. I paid $11 with a recent Mouser order. Some of these boards are supported on the mbed platform (similar to Arduino, but a much smaller community) and also PlatformIO. This thing is an I/O beast and happens to have Arduino Uno shield compatibility.

ARM®32-bit Cortex®-M4 CPU with FPU
Adaptive real-time accelerator (ART Accelerator™) allowing 0-wait state execution from Flash memory
180 MHz max CPU frequency
VDD from 1.7 V to 3.6 V
512 KB Flash
128 KB SRAM System
4 KB SRAM Backup
Timers General Purpose (10)
Timers Advanced-Control (2)
Timers Basic (2)
SPI (4)
I2S (2)
UART (2)
USB OTG Full Speed and High Speed
CAN (2)
SAI (2)
SPDIF-Rx (1)
Quad SPI (1)
Camera Interface
GPIO (50) with external interrupt capability
12-bit ADC (3) with 16 channels
12-bit DAC with 2 channels[/li][/list]

I've been on a DIY PSU kick for a few months now, these Multicomp torroidal transformers seem like a good deal at MCM Electronics (this is a "hobbyist" oriented retail site owned by Farnell, same owner as Newark in USA). Comes with mounting hardware. Usually these are expensive to ship from eBay Chinese sellers.

I picked up a few 50VA for ~$15 each.

A minute of Googling should yield a 10% off code. Shipping is $8.
Open Discussion / Large aluminum enclosure source?
July 19, 2016, 06:27:49 PM
I'm trying to find an inexpensive aluminum enclosure approx 6" x 8" by 4" tall (152x203x102 in mm) without sloped sides.

I've used a 16ga steel Bud Industries NEMA enclsoure. The size and shape are right but steel is not my favorite thing to work with. I get tired of picking slivers out of my hands and cutting small square holes is a pain.

I've also used a Hammond 1550H but I'd really prefer a square box for stacking not a slope-sided XXXL pedal enclosure.

Any ideas?
I have a PCB I built from a poorly-designed regulator circuit in a textbook. I need to cut a trace and wire in the negative rail power to an op amp socket. Is there an elegant way to do this or should I just hardwire it to a new DIP socket and double-stack them?

Also, phear my leet MS Paint skills.
Open Discussion / Verical sale code
May 16, 2016, 03:03:41 PM
Verical is having a sale through May 18, 10% off with code MaySave10.

Most of their stuff is sold in bulk but I picked up 16 LT1054 for $1.86 ea including tax & shipping. For me Mouser would be closer to $3 each with shipping.

The sale code is entered on the last order screen, there's a link above the "place order" button. I had to ask for help to find it  :-[.
Open Discussion / NBPSD (??)
May 11, 2016, 06:00:34 PM
Finally finished up some work on my bench and work area, added 11" depth, some heavy duty wall shelving... then I started working on the overhead lights. The previous owner's electrical handyman skills were lacking so I rewired that section of the garage entirely and added a new 20A circuit separate from the lights and fan and door openers.

To christen my new workspace I bought a bench power supply. +/- 24V 2A plus a dedicated 5V supply.

Open Discussion / Semiconductor quality
April 04, 2016, 03:19:50 PM
Is there any difference in brand reputation aka "quality" between the big manufacturers? TI, ON Semiconductor, Fairchild, NXP, JRC/NJM, Central Semiconductor, Diodes Incorporated, etc.

I was shopping on Mouser and came across some transistors from an Indian semiconductor company selling for cheap, I passed on buying them and went with a big name brand instead. It occurred to me it's probably all commodity grade crap and I should just pick the cheapest from a reliable vendor.
Saw these on eBay while looking for something else:

It's like a Beavis Box for Arduino geeks but attaches to the power rails of a breadboard. Was thinking some other features would make it nice for stompbox use:

Power filtering & polarity protection
In/out 1/4 PCB mount jacks with coupling caps & audio probe
User selection of 18V/9V/-9V/-18V for either power rail & and jumper connectors for each
Bypass-able input +/- 20dB gain, variable
True bypass switch audio channel
Power on-off with LED indicator
Test points out the wazoo
Bypass-able output A100k volume pot
Variable 0V to VCC DC out for quick and dirty biasing

To keep it small it would probably need to go SMD

Open Discussion / NAD
March 24, 2016, 04:23:24 PM
Picked up this Quilter Micro Pro head yesterday and finally had a chance to play with it.

So far so good. I'm still dialing it in with the guitars but there's a depth of good sounds available and it feels like a real amp head. I've bought and returned a few modeling amps in the same price range because they sounded like toys.
Edit: I should have had another cup of coffee before asking this. The AC impedance is 12k parallel with 12k + some impedance from the bypass cap. Roughly half of 12k.

I found a schematic for the JHS Morning Glory (Marshall Bluesbreaker based OD) online but this part of the schematic is a head scratcher. It's a JFET common source gain stage but as drawn there is no reason for any current to pass through the circled part short of a lightning strike. The bypass/AC path has a greater impedance than the DC path.

I'm *guessing* that one of two things has happened. Either the DC JFET source  resistor had to be reduced to properly bias the JFET and the bypass resistor wasn't changed to match, or whoever traced the board messed up on the values. Not that it matters, I would re-bias the JFET anyway but I'm curious about the intended ratio of resistance between the DC path and the bypass path.


What is the purpose of film capacitor C9 (circled in red) on the Pastyface power input? I understand what everything else does (mostly), and C9 isn't part of the basic inverter layout in the data sheet. I searched but didn't see anything.