Spectrum Computing

Hello again folks.

Fixed my 48K , issue 4a bout 2 weeks ago and really having a blast going through the database of software.

now im messing with sound demos

But i still have 1 nagging problem - i can barely hear the speaker / sound

its so quite I have to put my ear to the machine to hear the key click when i press a key

what i did 2 weeks ago to get sound - I replaced tr7- didnt fix it - then i replaced D9 , that got me sound

I replaced tr7 with a new one from retrolium and i checked the transistor had the right number on it before swapping

speaker gives me 38 ohms

is there something else that might cause low volume ?

im 50+ years old , the dollar is collapsing , the world is going insane and im spending hours loading up old software from the 80's - I have it so bad that I am enjoying sitting there , loading up all the software the old way ........ the long way ........ listening to the sound of the data being fed into the machine ........ first signs of loosing it id say - no wimpy SD card cheating for me !!!!!

could the little speaker be damaged ?

cheers people

Check the two IN4148 diodes that form part of the speaker circuit - these would drag the output voltage down if they are failing.

That's diode D13 (1N4148).

Speakers unless the cone is damaged, either work normally or are completely broken.

Mark

Thanks for that lads - Ill swap out the other diode so

Whats the story with these new membranes - I take it they are OK to open the machine and put it back together a few times and the membranes
wont start cracking

As I was fixing the machine a few weeks ago the original membrane kept cracking with the 2 ribbons getting shorter and shorter until they would not reach - That shouldnt happen with the new one

replaced d13 with a new one - no change

tested the d13 when i took it out and it appears to be ok

loaded up hyper active for the music and its playing ok but volume is very low

I dont know folks but im real happy with the little machine and i rekon its good enough


i remember from back then that the sound was never too loud to begin with - maybe its working perfectly for all i know

ill have a look for some video of the zx sound ...... maybe it is fine


Thanks again people

Load up Booty, then play it for 20 minutes. You'll be glad of a quiet speaker There are times I'd like to add a volume control.

The speaker should be plenty loud enough in a quiet room to be be able to hear the keyboard clicks clearly, and the beeps be easily audible a few metres away.

Adrian45 wrote: ↑Tue Mar 05, 2024 7:37 pm loaded up hyper active for the music and its playing ok but volume is very low

Don't use Hyper Active as a measurement of the sound output.

That game uses some tricks to create the sound, so it's less loud than a regular beep. On the other hand, it is a very nice tune.

Try a game like Manic Miner or make your own beeps to check how loud it can be.