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  #1  
Old 14th November 2019, 10:02 PM
Bonky Bonky is offline
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Default KEL84 Conundrum/advice

The amp is just over a year old. It feeds Living Voice speakers (94dB efficiency). The preamp is a valve Schiit.

Over the last few weeks I think I've noticed a bass boominess. I plugged in a DADA-modified Quad 306 (after a few beers) and thought that it sounded better. I need to repeat the whole op tomorrow night (when my wife is away).

Assuming the same conclusions...what to do?
1. Sell the KEL84
2. Upgrade to the next WD amp (Kevin Scott the owner of LV reckons that valve amps sound better with his speakers).
3. Tube roll the KEL84 - if so - what are the recommendations?
4. Examine the KEL84 for component malfunction...(what...where....how?)

Thanks,
Richard.
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  #2  
Old 14th November 2019, 11:22 PM
Phil Y's Avatar
Phil Y Phil Y is offline
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Default Re: KEL84 Conundrum/advice

Hi Richard,

So are you saying the sound has changed or that you have started to notice something that was there all along?

If something has changed, then obviously you should be able to get it back to where it was. The first question to ask, have you changed anything lately? Moved the speakers, changed some cables, moved the hifi gear around on its supports ?

Suggesting getting rid of the amp is an over reaction, you need to be methodical to get to the bottom of things. I used a KEL84 for about 10 years, they are a great sounding, very musical amp and certainly don't have boomy bass.

Phil.
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  #3  
Old 14th November 2019, 11:34 PM
Bonky Bonky is offline
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Default Re: KEL84 Conundrum/advice

Hi Phil; thanks.

No, nothing changed.

I will be methodical. I'll post impressions later.

Thanks again,

Richard.
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  #4  
Old 15th November 2019, 09:30 AM
bob orbell bob orbell is offline
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Default Re: KEL84 Conundrum/advice

Richard, you may not like to hear this, but I (now 66) began to hear strange things some years ago when playing my music, first was a small distortion to mid frequency's, latter an annoying boom (albeit small) to low frequency's, I tried every thing from new valves, different amps and different speakers, even different components in the pre and power amps, today, the distortion is worse as is the bass boom, but I now know that my hearing is f****d, continues tinnitus, I also know that the sound my system produces is bloody good, every one who hears it says, wow, what I am saying is, it might be your hearing . Bob
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Old 15th November 2019, 09:42 AM
Bonky Bonky is offline
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Default Re: KEL84 Conundrum/advice

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Originally Posted by bob orbell View Post
Richard, you may not like to hear this, but I (now 66) began to hear strange things some years ago when playing my music, first was a small distortion to mid frequency's, latter an annoying boom (albeit small) to low frequency's, I tried every thing from new valves, different amps and different speakers, even different components in the pre and power amps, today, the distortion is worse as is the bass boom, but I now know that my hearing is f****d, continues tinnitus, I also know that the sound my system produces is bloody good, every one who hears it says, wow, what I am saying is, it might be your hearing . Bob
Hi Bob, yes, it's a possibility.

Certainly my 'top end' is far worse!

However, the Quad 306 seemed a little better. More research later this evening - (if my wife goes out !)

Best wishes,

Richard.

Last edited by Bonky; 15th November 2019 at 10:07 AM.
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  #6  
Old 15th November 2019, 09:49 AM
Chris Chris is offline
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Default Re: KEL84 Conundrum/advice

Richard if you prefer Quad 306 then you have the choice to replace the Kel84, or may be a new set of valves, a change of cables, or possible change of caps. I bought some used power cables this week and found the fuse and plugs to be in a need of a clean, the sound improvement was easily noticed. Audio parts degrade and it's a slow process that we do not notice over time. You could easily noticed the different between the Quad 306 and Kel84 so your hearing is not so bad.

Chris.
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  #7  
Old 15th November 2019, 10:33 AM
Bonky Bonky is offline
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Default Re: KEL84 Conundrum/advice

Quote:
Originally Posted by Chris View Post
Richard if you prefer Quad 306 then you have the choice to replace the Kel84, or may be a new set of valves, a change of cables, or possible change of caps. I bought some used power cables this week and found the fuse and plugs to be in a need of a clean, the sound improvement was easily noticed. Audio parts degrade and it's a slow process that we do not notice over time. You could easily noticed the different between the Quad 306 and Kel84 so your hearing is not so bad.

Chris.
Thanks Chris,

Yes, it's the KEL84's components I may wish to explore. Any recommendations for cap or tube replacements would be gratefully received.. I'll clean all leads/contacts later (I think I have some 'dioxit' somewhere).

I can't recall the perceived 'boomings'' when I first used the KEL84.

Rich
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  #8  
Old 15th November 2019, 10:55 AM
Richard Richard is offline
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Default Re: KEL84 Conundrum/advice

Hi Richard, a few thoughts, EL84s tend to last 1-2000 hours when run at their full 12W dissipation as in KEL84. (Remember they will be doing this even at idle regardless of playing music so switch off between sessions.) A year of regular use would seem about right to at least try a new set.

Old valves sound weak and lose top and bottom and a loss of top may cause you to focus elsewhere or feel something is missing. I used to like EI EL84's if you can still find them others may have other suggestions. The ECF80s should last longer but a pair of Mullards may improve the sound.

On the other hand, if you'd not done the comparison before it may simply be that you prefer the 306 and/or it happens to work better with your speakers and room. It certainly has more power and higher electrical damping. Bass problems are usually a room issue though, as you know, most UK rooms will have a resonance around 50Hz. Now you've noticed it you may be able to move the speakers a little or the seating position, as a resonance will cause a different perception of bass as you move around the room. More drastic measures would be speakers with less bass response or a pre such as the matching Quad 34 with a bass step/cut which does actually work. The problem though, ime, tends to be just with a few tracks and if so I live with it as I know what it is.

Move the speakers away from the wall and corners if possible and, if you've not already set them this way, try angling them towards your seating position which helps focus and imaging, and can have the effect of balancing the highs against the bass.

A head cold is also a (non!) favourite problem at this time of year, or fatigue or stress, leave it a few days and it may sound its old self again.
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  #9  
Old 15th November 2019, 12:08 PM
snowman_al snowman_al is offline
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Default Re: KEL84 Conundrum/advice

Depending on what you think has changed, if anything, the KEL84 works well with the Russian 6p14p-ev version of the EL84. (These are the old CCCP Russian valves, not the modern Sovtek family / reproductions.)
It has better bass in every EL84 amplifier I try it in. (NOS Mullards included and the current JJs.) Problem is what you hear as boom I might think is good bass...
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  #10  
Old 15th November 2019, 12:40 PM
Bonky Bonky is offline
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Default Re: KEL84 Conundrum/advice

Thanks for that. EBay: https://www.ebay.co.uk/i/13313468999...waAvF4EALw_wcB

Do these sound Kosher?

Richard.
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