Hartke Kilo funny noise

[mrtcat]

I have a Hartke Kilo and I'm really happy with it. My only concern is that when I power it up all is good for a few (10ish) seconds then you hear the usual click and then it makes a kind of pink noise hiss. It's nothing major and isn't that noticeable unless the room is quiet. I've done all the usual troubleshooting basics like trying different power sources, ground lifting, engaging / disengaging all the different buttons and trying various different cabs and cables. I usually run it with a Berg NV412. Is this normal?

[Dood]

The click you are hearing is a relay in the protection circuit that is connecting the amp to the speakers. That is completely normal and yes, it does it after a short time. The hiss you are hearing afterward is general noise created by the valve preamp. This *to an extent* is normal, but if it is really loud there's probably a simple cause. Are you using the overdrive section, boosting treble frequencies, boosting the compressor or using the master volume high and gain control too low? Each or any of these can cause undue hiss in any amplifier.

If you are still getting a huge amount of hiss, then it could be a noisy preamplifier valve.

[mrtcat]

Thanks Dood.
It's not an unbearable amount of hiss and to be fair my old ampeg head (also with valve preamp) was louder. I have input gain set to just below the level where the red light occasionally comes on so now it never comes on. Is that too low? I've seen a post from you elsewhere where you mention you set yours so it comes on frequently. I always thought that was,a bad thing? The master is set to between 12 o'clock and one o'clock with eq pretty much flat and only a small amount of compressor and overdrive. The hiss is always there regardless of compressor and overdrive setting so may well be a preamp valve.
At the end of the day it doesn't worry me as long as it's healthy and I love the way the amp sounds plus it looks awesome :-)

[Dood]

[quote name='mrtcat' timestamp='1385038915' post='2283671']
Thanks Dood.
It's not an unbearable amount of hiss and to be fair my old ampeg head (also with valve preamp) was louder. I have input gain set to just below the level where the red light occasionally comes on so now it never comes on. Is that too low? I've seen a post from you elsewhere where you mention you set yours so it comes on frequently. I always thought that was,a bad thing? The master is set to between 12 o'clock and one o'clock with eq pretty much flat and only a small amount of compressor and overdrive. The hiss is always there regardless of compressor and overdrive setting so may well be a preamp valve.
At the end of the day it doesn't worry me as long as it's healthy and I love the way the amp sounds plus it looks awesome :-)
[/quote]

Hi!

Well, it sounds like you're all set up ok. I wonder if it's a slightly noise valve in the preamp? It's not totally unlikely (and it has to be said no fault of either you or amp) but they can come up a bit noisy unless the valves are premium drive tested ones. I recall having a set of Ampeg preamps and the first thing I did with all of them is replace the valves for quality ones. What a great difference that made too!

I think the amp is healthy, I don't expect that it's a fault and if you can live with it, it won't detract from the amplifier's performance. It could be an interesting thing to try though, popping in some other valves to check it with. Surprisingly, I've had my Kilo for a while and haven't touched the valves at all! lol - Now that IS unlike me Maybe it's just a great amp off bat!

[paul_5]

My amp (not a Kilo) tends to make unwanted noise after I've been playing for about 10 minutes. At first I thought it was the tube, so I took it to a tech, and after a could of hours of me describing the fault (and some fairly extensive oscilloscope work on his part) we came to the conclusion that the amp is fine, I'm just a godawful bassist.

[mrtcat]

Thanks guys, I feel way more comfortable now. I absolutely love the amp and coupled with the Berg NV412 it absolutely rules in all scenarios.I may look into changing valves in the future but as mentioned originally it's not such an issue I'll lose any sleep. Thanks again.