Complete novice alert! *don't read if easily annoyed by stupid questions*

[GooseyGander]

Not done much what with real life getting in the way but I'm intending to build it as I have drawn it so that I can troubleshoot it slightly more easily. Well, that's the theory.

An externally hosted image should be here but it was not working when we last tested it.

I've mounted the chips onto the heatsink and joined this to a piece of perspex which has the holes for the two large caps drilled into it. Then the rectifier is fixed to the end 'leg' that doubles as another heatsink.

 

[Mooly]

Can't see an image and a look at the URL gives this:

 

[GooseyGander]

Bugger!
Is this better?...

An externally hosted image should be here but it was not working when we last tested it.

 

[Mooly]

Nope

Just attach them in the proper way. That way they are here forever:

How to attach images to your posts.

 

[GooseyGander]

Ha! I never saw that option before, sorry.

 

[Mooly]

Ah so a new construction technique now...

 

[GooseyGander]

Yep. I can follow this easier than before and better see what goes where. I'm trying to make this as similar to my diagram as possible.

 

[Mooly]

OK, that sound's like a plan. Now why not perhaps just concentrate on getting one channel completed first. Take it one step at a time.

 

[GooseyGander]

Okay yes, good idea, thanks.

 

[Mooly]

OK, and remember to use the bulb tester and to check the DC conditions before thinking about connecting a speaker.

 

[GooseyGander]

Hi again. I'm getting on with it, but want to check I'm wiring up the potentiometer properly. I've done as in this diagram...

 

[Mooly]

That is OK electrically although you are DC coupled as shown... which will work but which will cause the DC offset to be larger than it need and also to vary with the setting of the volume control.

But it will work... so lets just get audio from it all first.

 

[GooseyGander]

Okay I've wired up just the left channel. When I turn it on (using DBT of course) the bulb stays lit and I get a buzzing through the speaker. I notice that I have continuity for both the positive and the ground through the speaker terminals. Obviously this isn't right.

 

[aparatusonitus]

Your wiring diagram in post #91 is confusing and/or wrong because you displayed the left potentiometer as a front image while you displayed the right potentiometer as a rear image. The wiring diagram would be ok if the left potentiometer is displayed as well as the right (from rear). Please, do not connect speakers at this stage...
how to wire a stereo potentiometer - Google Search

 

[Mooly]

Okay I've wired up just the left channel. When I turn it on (using DBT of course) the bulb stays lit and I get a buzzing through the speaker. I notice that I have continuity for both the positive and the ground through the speaker terminals. Obviously this isn't right.

Is it a very loud buzzing?

If you disconnect the speaker does the bulb go out or dim?

If the bulb does go dim then what DC voltage do you see between the speaker terminals?

(you will measure continuity all over the place as you will be reading through the internals of the chip. If there were a short across the speaker output then you wouldn't get the buzz)

 

[Mark Whitney]

You should solder the resistors directly to pin 10 and use interconnect wiring between the pot and resistors.

 

[GooseyGander]

Hello all. Mooly: I will try that in a bit. Mark and aparatusonitus, I have amalgamated your comments into this diagram, is it correct?

 

[aparatusonitus]

No, it's not correct...hint: audio out (left and right) are output from the potentiometer to amplifier input resistors, not an input from amplifier output to potentiometer. See image below...

 

[GooseyGander]

So the audio output should be going to the speakers?

 

[aparatusonitus]

...a picture is worth more than 1000 words...