Messages

1

Open Discussion / Re: NOD - New Oscilloscope Day

« on: November 10, 2018, 09:51:31 AM »

nice scope, i'm pretty sure i used that model or similar in university. fft mode can be really interesting! try looking at a signal before and after a distortion to see all the additional harmonics that are added.

2

Open Discussion / Re: For the vintage computer enthusiasts: vid of booting a PDP-11 from tape drive

« on: September 10, 2018, 05:37:50 PM »

that's a pretty crazy machine. how do you actually write programs for it? manual input with individual bit entry register by register? i guess there is some machine language code that you have to follow?

3

Build Reports / Re: 1776 Effects Multiplex with Mod board

« on: September 10, 2018, 05:19:21 PM »

ya well done on that vader, multiplex is one of my favorite circuits too. great build.

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Build Reports / Re: Busy Summer Build Bonanza

« on: September 10, 2018, 05:17:19 PM »

your builds are always cool chris, always good stuff

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Open Discussion / Re: Boost pedal with 11 vactrols

« on: June 10, 2018, 10:08:01 AM »

It maybe related to the presets/dipswitches the chase bliss stuff has.

It's this, I do believe. I think he uses vactrols in conjunction with switching (somehow). Dude is on a mission to get selenium into landfills in 50 years, haha. 

my guess is that he uses the DIP switches to set different bias points and uses that to control the resistance of the vactrol. basically using the vactrols as voltage-controlled resistors. pretty clever! i think this was used in early synths as a way to implement preset voices without digital controls.

6

Open Discussion / Re: Christman present for myself .....NOD!!

« on: December 22, 2017, 06:40:05 PM »

sweet, being able to see FFT's might be very cool, i highly recommend playing around with that. if you compare the input of a circuit against the output, you can see what kind of harmonics are generated.

7

Open Discussion / Re: Christman present for myself .....NOD!!

« on: December 21, 2017, 05:59:22 PM »

simple signal generators will work for almost all audio applications, especially hobbyist stuff. they are useful for calibrating but don't forget you still have to try it with a real instrument after 

cool scope! does it do XY mode? does it do fft mode/spectrum mode?

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Build Reports / Re: Total Recall - anyone else have this issue?

« on: December 17, 2017, 11:34:31 AM »

buy a new 2.1mm connector, cut the 2.5mm connector off and install the smaller one. just make sure you double check the polarity.

9

Open Discussion / Re: Germanium transistors spotting the oddest place: an old calculator

« on: December 04, 2017, 04:39:37 PM »

the "Millionaire" mechanical calculator video in the same series is pretty cool too.

10

Open Discussion / Re: Advice on JCM800 clone

« on: November 04, 2017, 08:04:58 PM »

seems kind of weird that the tube heater wiring isn't twisted.

Correction: it's kind of out of view against the rear panel. up for debate.

11

Open Discussion / Re: Advise for a simple DIY hi-fi amp

« on: July 15, 2017, 08:16:33 AM »

i would go with a IC based amp like the one posted above for build simplicity. the TDA729 chip is also popular for diy. i think there are a few different chips in the TDA series, that one seems to be the most popular.

i have never built one myself but you can buy kits for these types of project from china quite cheaply on ebay or what have you.

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Open Discussion / Re: Good read if you want to understand JFETs

« on: June 22, 2017, 05:40:24 PM »

good find

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Open Discussion / Re: Any auto wah use an ADSR?

« on: May 26, 2017, 06:14:29 PM »

good question, there are none that i know of but keep in mind that a plucked string's envelope will look a lot like a typical ADSR envelope. a simpler attack/decay control setup (which are more common) may be all you need for most guitar applications since you can sorta fake the extra controls with picking and a threshold/intensity control. the primary reason a synth needs an ADSR envelope is because synth oscillators are either on/off with no other control over the volume.

14

Open Discussion / Re: Automatic center punch

« on: May 08, 2017, 06:37:10 PM »

ya mine does the same thing, ive had it for years and i cant remember where i got it anymore. it has a pretty nice machined brass (i think) handle but i do have to open it up and mess around with the spring a bit.

15

General Questions / Re: Total recall dc jack size and grounding question

« on: May 06, 2017, 01:35:58 PM »

no the ehx is a 2.1mm connector, same as boss-style connector

yes, you should use an insulated jack.