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Duelund cap break in time

I just made some changes to my single ended kt150 amplifier that I was pretty excited about, having had great success with similar mods to my preamp.

Unfortunately, when I set it all back up...it sounded worse. Not terrible, but worse.

It sounds extremely bass heavy. Overwhelming. Less detail, zero "sparkle". Dull.

I run this amp on my wideband driver - 500hz and up so that's extra confusing, it must be super bassy in the 500-1000 region I guess.

Now, I've only got about 6 hours on them so obviously there's a lot of break in needed, but every piece of equipment I've ever had (including cap changes)the initial impression was grainy, a bit harsh and shrill. This is the opposite, it's so smooth it's boring. So that's why I'm sorta baffled and feeling like I messed up, or messed something up in there, it's just far from what I would expect.

Is this level of dullness... reasonable? Happy to hear any thoughts on this, if it's entirely reasonable I'll just settle in and give it hours and try not to focus on it too much.

 

Changes made were:

Kle perfect harmony RCA jacks

Neotech silver gold hook up wire to RCA

Audio Note input coupling caps

Duelund cast pio hybrid coupling caps.

 

Focusing on the duelund because it's the biggest change but...

superchunk
carlsbad2's avatar
carlsbad2
2,036 posts
 

I don't think burnin will create the large changes you are talking about.

There is no such thing as 500-1000Hz bass.  I think what has happened is the amp is not putting out slightly less power so the subs are dominating.  rebalance an see if that fixes it.

If it doesn't, take it back apart, look for a short or open or some sort of miswiring.  we all make errors.

Jerry

superchunk OP
23 posts
 

Yeah 500-1000 is dumb to say I’m just grasping. I did lose the volume on my woofers (it has a mkdbass and woofer in a 3 way open baffle) and that certainly makes it listenable. Had to turn it down by about 50% though which seems pretty nuts...I can’t see why those changes would reduce power like that although it’s a reasonable hypothesis.

I’ll go back in if another 48 hours or so of playtime doesn’t yield what I would expect in improvement.

There’s synergy that can always have unexpected results, but I can’t imagine any of these parts actually making things worse.

 

Appreciate everyone’s thoughts:)

 

It occurs to me...if it was in triode mode it would be a fair bit quieter and a fair bit "softer". The switch is in the correct position for ultralinear but that would be the first place I would look for some sort of wiring damage.

decooney
2,565 posts
 

200hrs - my local tech friend use to say to me this with similar caps and parts changes; "get ready for the roller coaster ride", unquote. 

Then i did the same roller coaster ride four more times on different amps, and it was the same patience waiting game every time.  Best of Luck with patience. 

carlsbad2's avatar
carlsbad2
2,036 posts
 

If you had to turn it down that much, there is something wrong with your amp. Open it back up.

if you can't find any problem with the mods, consider unsoldering the new caps at  one end and look for a shorted cap.  basic RLC meters aren't expensive and you can also confirm the capacitace.

Jerry

superchunk OP
23 posts
 

So I opened it back up and...I had made a very stupid mistake. I'm good at paying lots of attention until I get to the part that seems routine and then I mess that up (this time biasing).

Sounding great now. Well not great great but definitely the direction I wanted to go. Crisper and more detail. I assume that silver wire is gonna take some breaking in as well so it'll be a while before it all settled in but I'm pleased with the direction.

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