Test amp

[Kipper4]

PLease suggest a circuit for a small test amp.
1 watt would be plenty i think
I have some 4ohm ,3" full range speakers i can use with it.
I will be using it in conjunction with the quick and dirty test oscillator
to test and probe my failed pedals and connecting them to the breadboard (or stripboards)
thanks
I made the R.G Keen audio probe and it works but i might need some help with that too.

[Kipper4]

I dont quite get this schematic.
The arrows (in black) on the right hand side of the circuit are the audio output right?


http://www.geofex.com/FX_images/q&dosc.pdf

[Jdansti]

Right. R.G. says that the 100mV output best approximates a guitar string when first plucked (paraphrased). The other outputs probably simulate line level and other types of audio signals.

R.G. can probably give you more info.

[Ice-9]

@Kipper4, Can you clarify what you mean by test amp, that schematic is not an amp as such but it is a signal generator for using to inject a signal into a circuit. If it's a small amp you want then this is not what you are looking for.

[Jdansti]

^ Good point!

If you want a small amp for bench testing, I highly recommend the Noisy Cricket.
http://www.beavisaudio.com/projects/NoisyCricket/Noisy_Cricket_Schematic.gif

[tca]

What you want is a simple setup to test you pedals with an audio probe and a clean amp. So you already have the pedals to test, the audio probe and now the amp to build: the PUNCH. 1W clean power that runs at 9V: http://www.diystompboxes.com/smfforum/index.php?topic=99271.0

Cheers.

[Kipper4]

Thanks for reading.
I am clear that schematic is a signal generator. That was a side note from the amp thing.
The amp is to use on the pedal out or with the audio probe for testing and diagnoses.
I'll take a look at the suggested ones right away.

I just built the signal generator.
I'm gonna hook up the 100 out and test it on my amp.
thanks for clearing that up for me.

[Kipper4]

maybe i should have made that post clear.
"It's irrational Jim but its life"
i have a tendancy to shoot from the hip. As i think things they just come out and if everyone else doesnt keep up i wonder why sometimes.
Its a bit like tourettes but mentally.
(no offence to any touretters) I'm just mocking myself.

[Kipper4]

I dont know how i've done it but i've managed to eff up the tone generator.
I'll report back in a bit gonna get my DMM out.

[Kipper4]

Fixed it.
I wasnt paying attention. It's been a long day with the grandkids.
I put 0.1 caps in the place of the 0.01 caps in the schematic.
It works a treat now.
Now to investigat the punch amp some more
it looks like i may have some parts i can substitute to make one, Just got to check the ic pinout and substitiutes
wish me luck.

[Kipper4]

Ok the orders in at Tayda for some LM386's
i'm gonna try and use some of the transistors i have to make a Noisy Cricket amp.
Thanks for the tip.
If anyone has a common transitor type suggestion that will replace the (mpf102) ones in the cricket amp
Post it up please.
I would have made the Punch but i ordered the wrong IC's Grrr.

[Jdansti]

^ I've read that the general purpose 2N5457 JFET might work.  If you have some other JFETs, I'd try them, just watch the pinouts. Otherwise, if you want to use a general purpose NPN, you could find a preamp that uses one and substitute it for the preamp section in the Punch amp or Noisy Cricket.

[Kipper4]

thanks mate i have some j201's and some 5457's too.
Time for bed im affraid i'll check back tommorow
Night Johnboy.

[Jdansti]

Goodnight Jim Bob...  

[jogina111]

try  the RUBY AMP. it has been my test amp ever since I first built it. really takes pedals well..

[chptunes]

I would have made the Punch but i ordered the wrong IC's Grrr.

I much prefer the Punch for a clean amp that auditions pedals well.

-Corey

[bluebunny]

@Rich: if you want a couple of spare MPF102s, PM me a postal address.  BTW, this may have been mentioned before, but take a look at the Murder One and Superfly amps by frequencycentral.  They're completely cool (and quite warm), low-power tube amps.  Recommended.  Markeebee also did a neat little low-voltage tube amp.  Also recommended.  Search the forum for the relevant threads!

[Kipper4]

The Chips came today
So I built my self the Noisy Cricket amp for testing my boards so as i dont ruin a good amp.
The trouble is i really like this one too now. Ultimately i can rebuild it for a few quid so its not as improtant as my Fender pro and German Solid State 80's amp.

I used an old speaker from a reel to reel i have in the loft as the case.
It looks quite good. You be the judge.

I'll test it tommorow as its getting late again.

Heres the pics

https://www.dropbox.com/sh/7ma9n53c5jqdgsr/d-0TvwYXDL

Note the huge 60's 0.47uf cap in the speaker crossover.

I'd like to thank a few people

Mark for the MPF102 trannys. Nice one buddy anything i can do for you, just ask.
Weezer for the music that keeps me up all night.
My mom and my agent.
It's been a blast.
Did i just win an Oscar
lol


Also there some new pics of my board testing box.
Made of abs. Coated in foil tape to try to reduce RF interferance (that didnt work)
Theres a terminal strip to connect the board connections.
The box is wired for true bypass.


I have a small bit of strip board left over from the Cricket project.
I think i'll have a go at millenium bypass later tonight.

Thanks for all the help guys. Its much appreciated.

[Kipper4]

I've just posted a few more pics of the Cricket in my dropbox + an mp3.
1970's Matsumoku Les Paul>Cricket>GLS ES57> Alice Preamp>Cubase SX3>Mp3 conversion. Nil processing.
A very usable sound. Very boxy but, it sure would cut through a mix.

Oh Yer and my new organiser box too. I got it in Poundland.
I showed the wife before we got to the counter. Her response...... "How much is it?"
doh..............

[deadastronaut]

@rich, checkout the 99p stores..(usually old woolworths shops)

they have some great organizer trays, white semi clear plastic....for .......erm......99p.

i bought 6 of them...very handy.