2. amps-preamps
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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
sns
4,060 posts
 

Give it some time. You made a number of changes at one time so there are many variables here. I generally try to make one change at a time. I've never heard this exact issue you speak of with the Cast caps, don't recall tonal balance being an issue.

superchunk OP
23 posts
 

Yes I did them all at the same time, balance between preferring to do one at a time and getting stuff done while I'm in there.

Same values used for everything.

I'll try to basically ignore it and let it play as much as possible over the weekend and report back.

Arions report of similar results helps me relax a bit ;)

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
2,358 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. 

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