Search found 154 matches

by The Peasant
Sun May 24, 2020 8:27 pm
Forum: Music Tech DIY
Topic: ThunderWave ribbon controller
Replies: 5
Views: 108

Re: ThunderWave ribbon controller

Thanks for all of the nice comments, guys!

It really is a blast to play, and the ribbon configuration feels so easy and natural. :drums: :drums:

Hopefully other people will be able to build their own using my instructions. It's definitely worth the effort!

Take care,
Doug
by The Peasant
Sun May 24, 2020 5:07 pm
Forum: Music Tech DIY
Topic: Help! GROUND vs NEGATIVE in circuits.
Replies: 5
Views: 103

Re: Help! GROUND vs NEGATIVE in circuits.

There are two types of power supplies, single ended and double ended. Your first two schematics use single ended types, with a positive voltage source and a ground. The current flows from the positive to ground in these circuits like you are used to. So in these circuits the ground is indeed the neg...
by The Peasant
Sun May 24, 2020 11:49 am
Forum: Music Tech DIY
Topic: ThunderWave ribbon controller
Replies: 5
Views: 108

ThunderWave ribbon controller

I have posted a new project on my website, the ThunderWave percussion ribbon controller: https://youtu.be/AWzXXmBsl2Y Complete project information including build guides and schematic is here: http://www.epeasant.com/projects/thunder/thunder.html Comments, questions, and suggestions all welcome! Tak...
by The Peasant
Wed May 20, 2020 9:17 pm
Forum: Music Tech DIY
Topic: Analog/synth/audio design classes by SynthTech
Replies: 28
Views: 605

Re: Analog/synth/audio design classes by SynthTech

Will there be any limit to the number of students who can sign up?

Take care,
Doug
by The Peasant
Mon Mar 30, 2020 8:41 am
Forum: Music Tech DIY
Topic: lost in a breadboard vortex
Replies: 3
Views: 272

Re: lost in a breadboard vortex

This is what my breadboard looks like these days. Percussion ribbon controller circuit driving a full drum voice using 10 1J24B tubes. The only semiconductors in the audio signal path are two H11F1 in the VCF section.

Anybody else have any cool breadboard pictures to share?

Take care,
Doug
by The Peasant
Tue Mar 17, 2020 11:50 am
Forum: Music Tech DIY
Topic: Inconsistent Transistor Matching Results
Replies: 31
Views: 406

Re: Inconsistent Transistor Matching Results

The majority of the time in synth DIY you can get away with a low quality multimeter, but when you need to do any type of precision measurement such as matching resistors or transistors it won't be good enough. The accuracy specification is the key one here, although higher display counts are also i...
by The Peasant
Mon Mar 16, 2020 8:53 pm
Forum: Music Tech DIY
Topic: Inconsistent Transistor Matching Results
Replies: 31
Views: 406

Re: Inconsistent Transistor Matching Results

Those specifications are actually slightly better, but it's still a cheap low-end meter. Unfortunately you get what you pay for with test equipment and a $25 meter is just not that good. For comparison's sake, the meter that I'm currently using retails for $400. You really should get a decent qualit...
by The Peasant
Mon Mar 16, 2020 7:17 pm
Forum: Music Tech DIY
Topic: Inconsistent Transistor Matching Results
Replies: 31
Views: 406

Re: Inconsistent Transistor Matching Results

What are the specifications of the second meter?

Take care,
Doug
by The Peasant
Mon Mar 16, 2020 4:26 pm
Forum: Music Tech DIY
Topic: Inconsistent Transistor Matching Results
Replies: 31
Views: 406

Re: Inconsistent Transistor Matching Results

You did clean the flux off right? The easiest thing to try would be to swap two closely matched transistors between the two sockets and see how the number changes. That will tell you how closely matched your 100K resistors and the rest of the circuit is. If you do build another one maybe include the...
by The Peasant
Sun Mar 15, 2020 8:46 pm
Forum: Music Tech DIY
Topic: Inconsistent Transistor Matching Results
Replies: 31
Views: 406

Re: Inconsistent Transistor Matching Results

Sounds great, I'm glad that things are working for you now!

Take care,
Doug
by The Peasant
Sun Mar 15, 2020 7:01 pm
Forum: Music Tech DIY
Topic: Inconsistent Transistor Matching Results
Replies: 31
Views: 406

Re: Inconsistent Transistor Matching Results

I completely agree about removing the flux. That stuff is hydroscopic, so it picks up moisture from the air over time and eventually starts acting like a high megohm value resistor. Blowing air on it could change the moisture content and be another cause of drift on such a sensitive circuit. I alway...
by The Peasant
Sun Mar 15, 2020 6:36 pm
Forum: Music Tech DIY
Topic: Inconsistent Transistor Matching Results
Replies: 31
Views: 406

Re: Inconsistent Transistor Matching Results

I just leave one transistor as a reference and compare a bunch of others to it, writing down the mV difference for each one. When I get two transistors with close readings I then compare them directly to each other to confirm the match. I don't do any pre-sorting at all.

Take care,
Doug
by The Peasant
Sun Mar 15, 2020 5:17 pm
Forum: Music Tech DIY
Topic: Inconsistent Transistor Matching Results
Replies: 31
Views: 406

Re: Inconsistent Transistor Matching Results

Our last batch from Mouser were pretty much all within 2mV and we could easily find matches up to 0.1 mV.

Did you try covering your test jig?

Take care,
Doug
by The Peasant
Sun Mar 15, 2020 4:45 pm
Forum: Music Tech DIY
Topic: Inconsistent Transistor Matching Results
Replies: 31
Views: 406

Re: Inconsistent Transistor Matching Results

Try putting the pcb on a piece of carpet and covering it with a small bowl so that there are no air currents around the transistors at all.

Take care,
Doug
by The Peasant
Sun Mar 15, 2020 3:23 pm
Forum: Music Tech DIY
Topic: Inconsistent Transistor Matching Results
Replies: 31
Views: 406

Re: Inconsistent Transistor Matching Results

Up here in the Great White North, in wintertime the furnace is always cycling on and off. Using the fan method I could always tell from the meter readings when it did, and the drifting never stopped. Using the box completely eliminated this problem. Celtic Peasant, my wife, was recently matching tra...
by The Peasant
Sun Mar 15, 2020 2:47 pm
Forum: Music Tech DIY
Topic: Inconsistent Transistor Matching Results
Replies: 31
Views: 406

Re: Inconsistent Transistor Matching Results

I misspoke initially and realized I am within 100 ohms — not 1k— since I am to the tenth on the ohm meter... Right, that is 0.1% which should be fine. My measurements are just constantly changing. I had the same issue using the fan method but once I started using the plastic box everything began wo...
by The Peasant
Sun Mar 15, 2020 2:34 pm
Forum: Music Tech DIY
Topic: Inconsistent Transistor Matching Results
Replies: 31
Views: 406

Re: Inconsistent Transistor Matching Results

With my build I combined the Ian Fritz circuit with the original Moog circuit, as well as adding switches to select NPN or PNP types. With the Moog circuit I can quickly switch between types so that I can match NPN and PNP transistors to each other. The schematic for this is posted below, as well as...
by The Peasant
Sun Mar 15, 2020 1:24 pm
Forum: Music Tech DIY
Topic: Inconsistent Transistor Matching Results
Replies: 31
Views: 406

Re: Inconsistent Transistor Matching Results

I am not a fan(!) of the fan method for transistor matching, I built my circuit in a small plastic box with tiny holes for the multimeter leads. Inserting the transistors with plastic tweezers and closing the cover of the box, then waiting a couple of minutes for stabilisation works very well and is...
by The Peasant
Wed Feb 12, 2020 1:46 pm
Forum: Music Tech DIY
Topic: Replace 566?
Replies: 5
Views: 299

Re: Replace 566?

Mr. Henry himself used that LM13700 datasheet circuit for a LM566 replacement in his Bass++ project: http://www.birthofasynth.com/Thomas_Henry/Pages/Bass_Plus.html I made a few modifications to the circuit to better suit my needs: http://www.electronicpeasant.com/projects/bassbox/bassbox.html Take c...
by The Peasant
Mon Dec 09, 2019 4:39 pm
Forum: Music Tech DIY
Topic: thinking about tiling my closet for reverb
Replies: 31
Views: 1426

No, I have never recorded with it. It's actually been a very long time since I powered it up, I should get it out and see what I can do. I do remember it being very susceptible to hum pickup.

Take care,
Doug
by The Peasant
Sat Dec 07, 2019 4:36 pm
Forum: Music Tech DIY
Topic: thinking about tiling my closet for reverb
Replies: 31
Views: 1426

Here is how I made transducers for slinkys:

http://www.electronicpeasant.com/projec ... rings.html

Take care,
Doug
by The Peasant
Tue Jul 16, 2019 10:58 pm
Forum: Music Tech DIY
Topic: TS-23 Tube VCO help
Replies: 12
Views: 923

The expected voltage at point A should be 100V when the tune pot is set to 0 ohms, but otherwise it should be changing with the tube oscillation, not a steady DC voltage. Checking here with an oscilloscope would confirm this and would be very helpful for troubleshooting. Measure the actual anode vol...
by The Peasant
Mon Jul 15, 2019 10:08 pm
Forum: Music Tech DIY
Topic: TS-23 Tube VCO help
Replies: 12
Views: 923

Are you using the OP amp CV circuit? The voltage at the CV point before the 10k resistors should be somewhere between about +/- 6 volts and should vary between that depending upon the actual CV input that you have connected and the CV gain setting. Do you have any voltage at point A in the V2 circui...
by The Peasant
Mon Jul 15, 2019 8:23 pm
Forum: Music Tech DIY
Topic: TS-23 Tube VCO help
Replies: 12
Views: 923

Don't worry about the 6BN6 until you get the thyratrons to oscillate, just leave it out for now. Do you have an oscilloscope?

Take care,
Doug
by The Peasant
Mon Jul 15, 2019 11:19 am
Forum: Music Tech DIY
Topic: TS-23 Tube VCO help
Replies: 12
Views: 923

Have you measured the filament voltage at all of the tubes when they are all installed? Do the oscillators function when the 6BN6 is not in it's socket?

5.9V is a little low for the filaments but should be high enough to make them work.

Take care,
Doug

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