Fullrange hiss ?

[mirland]

Hi !

I've just completed (?) my first venture into DIYing a set of speakers. I've used 8" Audio Nirvanas in 18L enclosures made from 19mm mdf lined in the insides with bitumen and damped using some kind of sonically correct speaker wool. Wiring is done using Supra Ply 3.6 and the bassreflex is placed as a slot on the front. These speakers have no real low end but they sound exceptionally clear and welldefined. BUT! As soon as there is no sound they hiss very "loud". This is annoying! Have I done anything wrong ? Or is this a characteristic of the fullrange speaker ?

The rest of the setup: Tripath amp (Audio Digit) and Rega Planet 2000 cd player with Rega Couple interconnect and Supra speaker cables.

Any advice is welcome !

/Mirland

[Stocker]

Speakers are like computers: they do as they are instructed. You are likely hearing noise or some other auditory "junk" from the signal path. Try changing preamplifiers, sources, amplifiers and see what happens. Worst case, change the power circuit (and / or location) in the house.

[Scottmoose]

If you're worried about picking up RFI, grab some ferrite clamps and stick them on all signal and speaker leads. Alternatively, wrap them in aluminium kitchen foil. I kid thee not. It's not as good as a well engineered shield, but it's very cheap, and if RFI is a problem, it's better than nothing until you can change leads or get the clamps.
My money is that it's your amp that's causing the problem; easiest way to find out is to swap it out for one borrowed froma friend if you haven't got another one lurking around the house somewhere.
Best
Scott

[mirland]

I am also comig to the conclusion that it might be the amplifier. I don't know which is worse

/Mirland

[gmilitano]

My guesses would be that the hiss is caused by the source or amp or having AC power cables or power sources near the speaker wire. If the speakers have a BSC, the problem could also be the passive components.

[mirland]

I just got home and tried out a few things:

1. Changed amplifier: First an Onix OA21s - same level of hiss. Then a Naim Nait 1: Same level once again.

2. Changed speakers using my tripath amp: Hiss at a much lower level.

I am really confused. I would like to think it might be the tripath but I don't think so. My setup should be rather well organized BUT I am missing a dedicated ground spur.

Could it be that the speaker is actually too effecient ? That it multiplies the potential hiss from the amplifier/s ?

/Mirland

[Nuuk]

I would like to think it might be the tripath but I don't think so.

Which amp exactly?

[mirland]

I hope this link works:

http://www.autocostruire.com/catalog...f73d47f02e88bb

I have constructed a nice steel casing and am using this psu:

http://www.autocostruire.com/catalog...roducts_id=260

However my version is the 5A.

/Mirland

[Nuuk]

Well there is (was?) a known hiss problem with the Fernice amplifier from Autocostruire but not with the version in that link as far as I know (at least the one I have has no hiss).

But the problem is more likely to be with the amp than the speakers so I would contact the supplier and ask if they can suggest anything. (Or ask on the Class-D forum)

[pinkmouse]

Originally posted by Nuuk
But the problem is more likely to be with the amp than the speakers...

But it could be the source...