chipmusic.org is an online community in respect and relation to chip music, art and its parallels.
You are not logged in. Please login or register.
I was using my A1200 as a midi trigger sampler and noticed a annoying hum. Wondered if it was common on my other machines.
Found the A600 a lot cleaner and the A500 to be the best.
Is this common?
(used amigas a lot and haven't noticed it before).
Both the A1200 and A600 have been recapped in the last decade the A500 is running as stock and has never been recapped.
Bit of a test image post of a spectrum graph from Cubase, when to post the image on my VPS but it died..
This is from a reddit thread I post the same query in. Not sure if reddit will allow me to link the image hence the test.
I was using A1200 in 1994-1998 and i don't remember anything like that, if you google you can find similar questions, it can be anything, bad grounding (sometimes some electrical sockets in same room are badly grounded, so do you need to plug computer, monitors or hifi system, recording device to same socket or use galvanic isolation), it can be also bad cables (A1200 can be more sensitive than A500/600). This is maybe also reason i don't have A1200 again, nostalgia factor from 90's is still strong but i am really not computer collector and from musical side is it only a sample player, so UAE is for me enough. C64 is a different thing because it have real synth chip. 
Last edited by martin_demsky (May 24, 2021 1:52 pm)
Thanks, All computers were running off the same power strip and going into the same interface.
They are at different heights (A1200 is closer to supplies), I will do some basic trouble shooting and swap the power supplies and audio cables.
Cheers for the tip on galvanic isolation, I will also look into this. My room is kinda chaotic with gear so interference or ground issues are possible.
Funny thing is, I got back into the Amiga ages ago when I was looking for a chromatic sampler and all the VSTs I could find were just sample players.. remembering it was so simple on the Amiga I bought the 1200 with a 500.. Now I am kind of a computer collector..
The C64 is great fun along with the Atari but the Amiga 500 was my childhood machine and nostalgia is strong.
I don't know what is chromatic sampler, it is kinda tunning more to guitar than normal keyboard? I have had custom sampler called Ramikola, it was from my friend Tronik, which was in my land probably Amiga HW leader, it was capable of sample up to 56 kHz in mono, so i sampled a lot from out local radios, probably most house music, because i don't have had in that time my own synths. According to that hum issue, also check if you have in room cable tv with internet socked (twin) near electric plug, this can also be reason of more hum. Of course most people use wifi now, but there is still rooms with internet socked right next to electric plug.
Last edited by martin_demsky (May 25, 2021 7:12 pm)
Chromatic sampler just means it can play back a sound a different pitches. All the VSTs I found were just one shot play backs rather than playing one sound over a keyboard range.
There is one ethernet cabled running to the room but on the other side (my machines are all WiFi). I have a vague plan of testing now. I also got a hint on my reddit thread which suggests the op-amps are driven from the 12v lines so even more reason to swap around the power supplies.
Rough plan is
Turn off monitor
Swap audio cables (again)
Swap power supplies
Move the 1200
Try a galvanic isolator
Hoping to get some time over the weekend to try all this.
Thanks for the suggestions