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Old 8th April 2010, 03:31 AM   #11
kevinkr is offline kevinkr  United States
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Quote:
Originally Posted by infobot View Post
I got nervous being an amateur when I got my K-12G - could've built it myself easily - but got jumpy and instead had S5electronics build and test it before sending it.

Anyhow mine howled too but only with some speakers. Usually hard to drive ones. Amp seems fine. Swapped to easily driven dome / woofer (89-90 dB sensitivity) 2 and 3 ways and all noise totally disappears.

Howl on mine (with some speakers) disappears if volume raised past a certain point - at about 2 to 4 out of 10 on the volume control. Had to turn it up further (4 at most) with harder to drive speakers and all howl goes away.

I'd consider what others say first but just a thought. Amp runs fine, have had it in use for a couple of years, no problems whatsoever.
I think that is a pretty good indication that the amplifier is "conditionally" stable due to improper loop compensation or a design or layout related stability issue. I'm always surprised what people are willing to tolerate.. (hum, buzz, hiss, amps that oscillate at the drop of a hat.)
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Old 8th April 2010, 01:59 PM   #12
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Hi Jeff,

Looks like your going to have to remove your mods one by one until you find which one (or more) has made your K12 unstable. Nobody wants to undo good work unnecessarily so the order in which you remove the mods might be worth some thought.

Could you list all the mods that you have done since buying the amp.

Perhaps some people on the forum might give good reasons why you should de-mod in a particular sequence and perhaps save you some unnecessary work

Brgs Bill
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Old 8th April 2010, 02:50 PM   #13
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If you haven't read this already this might be helpful


S5 Electronics K12G/K12M Amplifier Kit
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Old 8th April 2010, 11:30 PM   #14
infobot is offline infobot  United States
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kevinkr:
people's tolerations: True, good point, and had worried that over many a time in myself.

In my case I feel I just don't know enough to rework it safely myself yet. So I'm pretty limited unless I scrape up the cash and ask someone else to do it safely.

But actually I was wondering if that would turn up in this thread (howl) with the K-12; if it anyone noticed problems driving some speaker loads, even working 'properly' (well, stock for example).

Anyway very clearly I don't know with the K-12; but I meant I'm interested too to see what turns up in this thread, to help address the original poster's problem.

(hope that made sense)
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