elizard said:actually i'll go try the star earths now
also the buzzing is the same at any position of the volume control
Ok.
You can do this very simple test:
With the two cases side by side, connect a short wire (the shortest possible, cut to length) from one star ground to the other (that is, the ground point of the two PSU caps in each channel).
Now turn it on.
Less noise?
Yes!
If they were in the same box, you could get the two channels even closer.
Take a look at the pictures in my "PC Gainclone" thread and you'll see what I mean.
i was debating it, and still may do it .. the main reason however was that i wanted to keep the power and the amps separate
when i get some time, i may however move everything to the public amp box .. maybe even make the thing integrated (although i kinda doubt that, until at least i get another amp goin)
when i get some time, i may however move everything to the public amp box .. maybe even make the thing integrated (although i kinda doubt that, until at least i get another amp goin)
Well, the question is whether the effect cables have is more negative than the effect of having both the PS and the 2 channels with the PS.
I'll say it is, at least with the toroids, since the plitron ones seem to be built very well. I hear no buzzing, slight bit on turn on. It also doesn't get warm at all (well barely!).
It is something I'll definitely try, maybe even tonight
I'll say it is, at least with the toroids, since the plitron ones seem to be built very well. I hear no buzzing, slight bit on turn on. It also doesn't get warm at all (well barely!).
It is something I'll definitely try, maybe even tonight
elizard said:
i speak from practically no knowledge, but i think it should be fine. my gainclone ran fine with the chips in mid-air hanging by the leads. now they are on heatsinks that are about 8cm (3") by 3cm (1") with fins about 5mm (1/4")long and they dont even get warm. (both chips on the same heatsink)
'The road to hell is paved with good intentions'
Matt, the less voltage you are putting into these chips, the less heat they produce and therefore they require less cooling/heatsinking!
It's important when we give advice on these forums, or on our websites to try and be more specific so that beginners don't take what is said here and apply it in a different situation, ie same heatsink with different voltage rails.
I'm not singling you out, we all do it sometimes, but as you know, I am keen to make things as clear as possible for the less knowledgable!
The cooling factor
Guys, or you make some boxes as Peter Daniel does
with thick aluminium, or, if the box is thin, put some heatsinks.
They can be mounted on the bottom of the case.
I bought some heatsinks and am going to intall them.
The problem is when you abbuse the volume (as I did, for testing), mainly with 4 ohm speakers, it creates a "hot-spot" where the chips are mounted (if the case is thin).
What happened was that it was very hot in the place where the chips are mounted in the box, and cold around them.
Then, the chip entered in protection.
It didn't completely cut the volume, it just reduced power until he gets to a certain temperature, and then up again.
The sound went up-down.
That's on the datasheet.
If I remember, thermal protection kicks in at 150ºC.
We were listening at insane levels, with 4 ohm speakers.
At my home I don't have that problem, but for peace of mind, I'm going to put those heatsinks.
Guys, or you make some boxes as Peter Daniel does
with thick aluminium, or, if the box is thin, put some heatsinks.They can be mounted on the bottom of the case.
I bought some heatsinks and am going to intall them.
The problem is when you abbuse the volume (as I did, for testing), mainly with 4 ohm speakers, it creates a "hot-spot" where the chips are mounted (if the case is thin).
What happened was that it was very hot in the place where the chips are mounted in the box, and cold around them.
Then, the chip entered in protection.
It didn't completely cut the volume, it just reduced power until he gets to a certain temperature, and then up again.
The sound went up-down.
That's on the datasheet.
If I remember, thermal protection kicks in at 150ºC.
We were listening at insane levels, with 4 ohm speakers.
At my home I don't have that problem, but for peace of mind, I'm going to put those heatsinks.
elizard said:
Elizard,
Is the blue one really a capacitor? If so, could you let me know what it's doing there? Is it to bypass high frequency noises or voltage spikes? Could you check what's written on it? I have couple of the blue ones removed from broken equipments and am wondering what they are for. What's written on mine is SEM, AA, 472M, Y2, and 250~. I have NO idea what these mean. Thanks.
Yep, it's a cap. It's acting as a snubber to help prolong the life of the switch contacts and hopefully reduce any radiated noise that can induce pops and clicks...JAZZ2250 said:
It's wired across the switch contacts, so plays no part in the operation of the amplifier when the power switch is on.
472 means 4.7nF, the M means 20% tolerance. It's a class Y2 cap rated for continous 250V AC mains duty.
Important safety notice - never connect standard caps across the mains!
Cheers,
Mark
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