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Messages - iTzALLgoOD

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1
Amplifier Discussion / Re: On/Off Pop Noise Problem
« on: April 28, 2010, 12:20:36 PM »
I like the Standby switch idea. Is it OK to have the power on with the speaker disconnected?  This usually means OT death in a tube amp.

2
Amplifier Discussion / Re: Battery-powered "Busking" amp.
« on: October 19, 2009, 03:01:34 PM »
You can check out the TDA2003. Its a 10 watt chip. My little brother has a little generic practice amp that uses it.  I had to replace the input jack and checked it out while I was in there.  It runs on 12 volts and has provisions for "C" batteries IIRC.

3
Amplifier Discussion / Re: Howler - combo amplifier
« on: October 13, 2009, 12:30:33 PM »
Info on the cabinet?  Did you build it or buy it.  Looks real nice! :tu:

4
Amplifier Discussion / Re: need advice, noob wanna try to build an amp
« on: October 02, 2009, 05:16:39 PM »
Quote
I know that amp is constructed by power and preamp, are you saying that using Fetzer as preamp and combined it with a power amp? how I do that?
and tone control? is that same as adding tonestack to stompboxes when you modified stompboxes?

Yeah you've got the idea.  The output of your stompbox/preamp goes to the input of your power amp.  I know the TDA20XX datasheets have schematics and pcb layouts for functioning power amp circuits.  Not sure about the LM1875.  I don't recall offhand but there is a website that sells LM1875 kits fairly inexpensive.  Try a search for LM1875 kit.

I built the PCB layout for the TDA2030 right from the datasheet.  I just redrew it in PCB Express and etched a board.  Then I set up different preamps on the breadboard until I find what I'm looking for.

Teemuk also has a downloadable PDF book with all the info you'll need in the sticky section.

5
Amplifier Discussion / Re: need advice, noob wanna try to build an amp
« on: October 01, 2009, 03:01:08 PM »
Keep it simple for your first try.  Do you have any experience with electronics i.e. soldering, schematic reading?  A simple preamp and a chipamp should get you started.  What kind of tone control do you need?  It could be as simple as a Fetzer from ROG and a TDA2030 or LM1875 for the power amp.

I've looked at schematics from commercial amps and they usually go above and beyond my ability as a DIY'er.  Good luck on you adventure.  Keep us posted

6
Amplifier Discussion / Re: SSGuitar.com Contest
« on: September 10, 2009, 02:59:55 PM »
Congratulations Armstrom! 

My internet has been out for a little while so I missed out on this one.
There should be one of these contests every few months with a different theme, not necessarily with prizes, but just for fun for some of us to learn a new "trick" or to work with components we wouldn't normally.

7
Schematics and Layouts / Re: Passive Tone Circuit
« on: May 28, 2009, 09:33:18 AM »
Have you downloaded the GM libraries for Eagle?  It is set-up almost perfect for most of the stuff we do here. I'll see if I can find a link.

here ya go.  Click on the link and follow the destructions.

http://gaussmarkov.net/wordpress/tools/software/eagle-cad/

9
Amplifier Discussion / Re: Power amp clipping
« on: May 05, 2009, 09:29:45 AM »
Thanks guys.  I don't mind the low output or the clipping for that matter.  I play guitar 99% of the time.  I bought a cheap Squier bass just for recording and had fun with it.  I figured that it would be a cheap and easy project to make a little practice amp for it.  Everything is ready to go I just have to build a cabinet for it.

10
Amplifier Discussion / Re: Power amp clipping
« on: May 04, 2009, 09:32:37 AM »
Thanks for the help guys.  This is my first attempt at a simple chip amp and my seriously limited knowledge of electronics had me thinking there was a design issue.  I like the MP3 player idea.

11
I just usually use salvaged stuff from old radios.  I don't expect to much from the 386 tone wise so I don't put a lot of effort into the speaker. I have bought a few 50mm speakers and put the circuit in pop cans and they sounded pretty much like the salvaged radio speakers.  I am also not very picky when it comes to tone from these little 0.5 watt amps.

12
Amplifier Discussion / Re: Power amp clipping
« on: April 30, 2009, 09:32:49 AM »
I don't currently have a way to check the actual output. :'( 
Is there any free signal generator software so that I can use my PC's soundcard?  I haven't looked around to much as I only have internet access at work currently.

As far as the TDA chip goes the schematic and PCB are copied directly from the datasheet.

Quote
Clipping in the signal path is not chip failure.

I don't think that the chip is failing.  I don't worry about it in stompboxes but was a little concerned with premature failure of a power amp chip.  I actually kind of want some clipping at 90%-100% of the volume knob.  Just not so early.

I am using this for a bass amp if that makes any difference.  Thanks for any help

13
Amplifier Discussion / Power amp clipping
« on: April 29, 2009, 03:03:35 PM »
I have a functional TDA2030 PCB that I made right from the datasheet but it clips with minimal input.  I am using a 12.5-0-12.5 2 amp transformer and a pair of 4700uf caps in the power supply. Here is the preamp schematic that I am currently using.



I am only using it up to the volume pot with out the extra gain stage on the breadboard.  LTSpice says that I should only have about a 400-600mv output after the BM tonestack but I can readily make the power amp distort. 

Will this lead to premature failure of the power amp chip?? From what I get out of the datasheet I should be able to get closer to 890mv input to get the maximum power output.

14
Amplifier Discussion / Re: Repair or partout?
« on: April 16, 2009, 12:07:53 PM »
Good luck.  let us know it turns out.

15
Amplifier Discussion / Re: Where to get CHEAP guitar speakers??
« on: April 08, 2009, 09:03:19 AM »
Thanks for the ideas.  I'll keep a look out.

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