ground/mic/operating hum

linee · Post by **linee** » Tue Sep 09, 2008 7:19 am

i've had the 404 for a while now. now i'm getting much deeper into using it (instead of just mucking around learning things), i'm a little bit concerned about the sort of hum i'm getting.

it's pretty obvious on headphones ... tried it on different power points in the house, at different houses altogether and it's always there. if i turn the internal mic on it adds an (even louder) high-pitched hum as well. i'm not using it near any heavy machinery or anything so it's not picking up electrical interference i don't think.

would it be useful if i posted a sample of the hum itself? i don't have any sort of knowledge about electronics really, so maybe the type of hum itself will give away the problem.

thanks!

iG9 · Post by **iG9** » Tue Sep 09, 2008 7:39 pm

If it's really bad you might have fairly dirty power. Try running it off batteries.

HomeMadeInstrumentals · Wed Sep 10, 2008 7:51 am

i get the same hum its annoyin...tho im at least 50% sure its shitty cables running everywhere...to my speakers, from my tt.....i think ur cables will make some differance particularly being rca's which can leak if they aren't fantastic quality. i think.

linee · Post by **linee** » Fri Sep 12, 2008 1:57 am

yeah, rcas can be noisy sometimes, but this hum is there even with just headphones and no other connections...

i've though about running off of batteries - but i got mine 2nd hand and it doesn't seem to work? :cry:

i just need to get the right allen key so i can have a look inside... i presume it's not going to be anything major - i'd assume it's just battery pack -> wire -> power input. so there's hopefully nothing complicated and digital mucking up there. hopefully!

thanks

HomeMadeInstrumentals · Fri Sep 12, 2008 2:08 am

well let me know what u find bro, im intereseted too as my sp seems to be humin away behind my beats too!

iG9 · Post by **iG9** » Fri Sep 12, 2008 3:34 am

It doesn't work off batteries? That sucks man that's one of my favorite 404 charms...

Jim Y · Post by **Jim Y** » Fri Sep 12, 2008 9:23 pm

IIRC...
The battery pack wires have a little plug onto the back connector pcb. I don't think the battery supply has a fuse or anything like one.
I'm not 100% certain, but there could be a switch built into the AC adapter socket that disconnects the battery with the plug in - maybe this switch is faulty?

Taking the top off won't show you anything - it's just a trim.
6 screws I think underneath need to come out.
Open slowly, there's cable between the 2 halves - they unplug and are different so you can't mix them up when you put it back together.

Usually always have batteries in my 404. When it's switched off, there's no drain on them (unlike some things I own that drain the battery if I don't take it out). With the built in mic, it has to be the quickest recorder to set up I own.
After using on AC, I was pleased that when I pulled the AC plug out - it was still on!

Good luck.

Jim

Beanz711 · Post by **Beanz711** » Sat Sep 13, 2008 1:45 am

Have you tried hooking your sp up to a DI box? Some can be expensive but a 40 dollar one works almost as well. This will def solve a lot of your problems. If not, you should go get a new 404.

linee · Post by **linee** » Sat Sep 13, 2008 9:13 am

hey thanks for the the tips jim y... i'll have a look soon and see what happens.

the DI box was something i was thinking about too - i'll see what else i can do first though. maybe even changing the sp404's operating level might help by improving the signal to noise ratio?

the new 404 is definitely out of the question as i got it second-hand - less than half-price a new one here and still in a box etc (even with the factory samples - so it can't have been used very much)... but it's times like this that warranty a new thing has starts to look more and more worth it!

i'll report back... thanks again for the help