Thulsa Doom - A low part count bass destroyer

[FUZZZZzzzz]

It's been a while since my last post, but I've wanted to share something with you guys to make up for it .

The Thulsa Doom is very easy to build and sounds 'great' on drum machines / casio keyboards / bass guitars and much more. Let me know what you guys think.

The 10k potmeter was just something I had lying around. Should not make a big difference if you'd use 25 or 50 or 100 k, I guess

layout:


soundsample:
http://www.filedropper.com/thulsadoom

[Buzz]

Cool. Very extreme. I'm gonna have to make one of these.... if I can find a KA567.

[psychedelicfish]

Cool. Very extreme. I'm gonna have to make one of these.... if I can find a KA567.

Don't quote me on this, but I'm pretty sure you can use an NE567 which is far more common.

[markeebee]

Excellent work, thanks.

I found this very special KA567 on eBay. Will it work?

http://pages.ebay.com/link/?nav=item.view&id=251111423041

[Buzz]

Doesn't work for me Mark. *shiver* Did see it when I did an ebay search for the part number. That and mobile phone lanyards and Ford rear vision mirrors.

[Buzz]

Thanks psychodelicfish, will do a search for them instead.

Could you make something similar with a 555 timer? I've got some of them for an Atari Punk I never made.

[FUZZZZzzzz]

I'm sure this will work as well. My online supplier has both and it's always a surprise which one he sends.

Cool. Very extreme. I'm gonna have to make one of these.... if I can find a KA567.

Don't quote me on this, but I'm pretty sure you can use an NE567 which is far more common.

[Buzz]

Sweet, thanks Fuzzz.

Tracking one down now.

[Buzz]

Got some chips on order.

Thought I'd have a go at my first PCB mask while I'm waiting.

Added  pulldown and LED resistors.

Also tied the floating pin on the trimpot to the middle pin. Should I change that?

Anyway, here's my mark 1 design.

You guys reckon it will function?

Definitely doing a mark 2. Gotta put a standoff hole in it somewhere.

[Buzz]

Hey Fuzzzz.

Does this circuit have volume gain above unity?

I mean, with the volume knob turned all the way up, is the effect volume louder than the clean signal?

I'm wondering if I should add a single transistor gain stage after the main circuit.

I can work it out on the breadboard when the chips arrive....

But would be handy to know in advance.

Cheers.

[poppyman]

Hey Fuzzzzzzz!

This project sounds very intersting to me too. I 'm a big fan of bazzfuss/Tim Escobedo's Bronx cheer-ish projects.

I couldn't find the chip anywhere though but could I go with the LM567N instead?

It's labelled "tone decoder" as the KA one on some datasheet found online.

If you know, let us know

[Buzz]

Hi Poppyman.

littlediode_components on ebay ( UK ) has the NE567 in stock. They are a bit expensive, but make the man an offer. He accepted mine.

The LM567N sounds like pretty much the same thing... but I have no idea if it's suitable.

[FUZZZZzzzz]

Once I build a noisebox based on a KA 567 (its floating somewhere on this forum). I made a couple for friends, but noticed one version sounded different. I checked everything but could not find the reason. Then I found out that one had a KA 567 and the rest were LM 567. Maybe you'll get  a sound thats a little bit different, but I dont know. Sorry, those KA 567s are not easy to obtain where you guys live. Should keep that in mind next time I order them and at least try them both.

This project sounds very intersting to me too. I 'm a big fan of bazzfuss/Tim Escobedo's Bronx cheer-ish projects.

I couldn't find the chip anywhere though but could I go with the LM567N instead?

Yes!

Does this circuit have volume gain above unity?

I mean, with the volume knob turned all the way up, is the effect volume louder than the clean signal?

[FUZZZZzzzz]

the trimpot orientation was wrong. changed picture to V1.2!!



soundsample:
http://www.filedropper.com/thulsadoom

[/quote]

[FUZZZZzzzz]

The trimpots 3rd lug is not connected. If I were you I'd check out the best value and put a fixed resistor in there. The trimpot is mainly there to kill the feedback.

Got some chips on order.

Thought I'd have a go at my first PCB mask while I'm waiting.

Added  pulldown and LED resistors.

check the latest layout above. the 3rd lug is not connected on my layout.. I think you should check out which value works best and then use a fixed resistor.

Also tied the floating pin on the trimpot to the middle pin. Should I change that?

Anyway, here's my mark 1 design.

You guys reckon it will function?

Definitely doing a mark 2. Gotta put a standoff hole in it somewhere.

[Buzz]

Hi FUZZZZzzzz....

Have checked ou your bleepboxes page and I love your toys.

I've been extracting the circuits from those audio birthday cards. I've got one that does Thourogoods' bad to the bone in a loop, and another that gives several fart sounds.

Haven't worked out what to do with them yet, but I will.

I bought my eldest child a $4 keyboard when he was about 3. It makes atrocious sounds, with timbre you wish was timber. Can't wait to push that through the tulsa doom.

C'mon Mr Postman, have you got a letter for me?

[FUZZZZzzzz]

easy, make an 8 step fart sequencer.

about my bleepboxes site.. it needs an update, but Im busy making music

Hi FUZZZZzzzz....

Have checked ou your bleepboxes page and I love your toys.

I've been extracting the circuits from those audio birthday cards. I've got one that does Thourogoods' bad to the bone in a loop, and another that gives several fart sounds.

Haven't worked out what to do with them yet, but I will.

I bought my eldest child a $4 keyboard when he was about 3. It makes atrocious sounds, with timbre you wish was timber. Can't wait to push that through the tulsa doom.

C'mon Mr Postman, have you got a letter for me?

[Buzz]

easy, make an 8 step fart sequencer.

Now that you have mentioned it, I am wondering how I've gotten by without one all this time!

C'mon Mr Postman, have you got a letter for me?

btw, that was just an odd way to say I am eagerly awaiting my NE567s  to arrive in the mail.

[FUZZZZzzzz]

I have prototyped a new fuzz with the NE567.. gonna post it here in a couple of days. I might not be the greatest designer ('cough') here (99% of the regular visitors are pure genius!), but I do at least use all my designs myself and they're easy to make for anyone who can hold a solder iron.

so If you've ordered spare 567s you might be in for a double challenge.

C'mon Mr Postman, have you got a letter for me?

[Buzz]

Challenge accepted!