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more bass needed from my reference 105 II
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paclfamily
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PostPosted: Fri Sep 12, 2008 10:01 am    Post subject: more bass needed from my reference 105 II Reply with quote

hi.
can someone advise on what i can do to my 105 speakers to increase the bass output. i can only generally listen to them at lowish volumes.
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ColinR
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PostPosted: Fri Sep 12, 2008 1:40 pm    Post subject: Reply with quote

Depending upon the serial number and crossover varient it might be worthwhile replacing the four 120uF or two 450uF capacitors in the bass section which put a "hump" in the bass units' response just above resonance to flatten the overall response of the unit.

Failing that get a Quad 44 to put in a little bass lift or a ~12 band octave or third octave equalizer.
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paclfamily
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PostPosted: Fri Sep 12, 2008 8:06 pm    Post subject: more bass needed for my reference 105 II Reply with quote

thanks for the info. what value do you recommend i replace them with.
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ColinR
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PostPosted: Sat Sep 13, 2008 11:14 am    Post subject: Reply with quote

Confused
Quote:
Depending upon the serial number and crossover varient it might be worthwhile replacing the four 120uF or two 450uF


Replace with whatever value was there originally.

Ref 105-2s are not "bass shy" when working properly; although if you do turn them down low it's just the B110B that produces the goods, the B300B and T52 tend to "kick in" together wihen you give them a few more mA Smile .
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qguy
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PostPosted: Fri Oct 24, 2008 12:52 am    Post subject: Re: more bass needed from my reference 105 II Reply with quote

what happens when you increase the volume ?

paclfamily wrote:
hi.
can someone advise on what i can do to my 105 speakers to increase the bass output. i can only generally listen to them at lowish volumes.
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T.O. Chef
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PostPosted: Fri May 01, 2009 11:50 pm    Post subject: Bass shy 105 II's Reply with quote

Don't know if the original post person is still interested in this question, but I can say unequivocally that replacing those 120uF cap's on the input can alleviate the tendency of the 105 II to shut off it's bass output at low volumes. Unfortunately 150V electrolytic cap's are simply not available, but 100V Bennic's by Solen seem to work quite well.
Over time? We'll have to see, but the sonic result is well worth the trial.
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speakerguru
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PostPosted: Tue May 05, 2009 7:23 am    Post subject: Re: Bass shy 105 II's Reply with quote

T.O. Chef wrote:
....shut off it's bass output at low volumes.

It's human ears which lose bass sensitivity at low volumes not the speakers. Check out the Fletcher-Munson curves in any book on acoustics.
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T.O. Chef
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PostPosted: Tue May 05, 2009 7:53 pm    Post subject: Reply with quote

What am I "hearing" I wonder? And yes ... my ears are old.
If I percieve a bass boost by replacing the 480uF cap's (that actually read just over 530uF when they came out BTW), with new but different elctrolytic cap's that are bang on 480uF would you suggest Speakerguru that the difference is due to something other than that value variance?
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speakerguru
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PostPosted: Tue May 05, 2009 8:03 pm    Post subject: Reply with quote

T.O. Chef wrote:
What am I "hearing" I wonder? And yes ... my ears are old.
If I percieve a bass boost by replacing the 480uF cap's (that actually read just over 530uF when they came out BTW), with new but different elctrolytic cap's that are bang on 480uF would you suggest Speakerguru that the difference is due to something other than that value variance?

Without measuring the capacitance and loss factor of the old and new capacitors I wouldn't even dream of trying to guess.
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Javaman
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PostPosted: Tue Sep 22, 2009 1:30 am    Post subject: kEF Bass response Reply with quote

There may indeed be a problem with your caps. I listen to my 105.2's in my loft in the early morning, so most of my listening is at low volumes, and the bass is adequate and well-defined. I just replaced the caps on one of my crossovers, and couldn't find 150 V 120 uf, so I got 100 V 125 uf which worked fine. Also, I wasn't able to get 1% tolerance like KEF used, so I used 5% - again, no problem.
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François
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PostPosted: Sat Oct 17, 2009 11:06 am    Post subject: Reply with quote

What about removing these caps ? What is their use exactly ? Limit low end ? Avoid dry current from the amp ?

Also, I note that the first version had 150v caps, but the second had 50V caps... Doesn't this means 50V should be enough ?


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T.O. Chef
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PostPosted: Sat Oct 17, 2009 3:22 pm    Post subject: Reply with quote

http://www.hifiloudspeakers.info/speakertalk/viewtopic.php?t=1000

Have a look here, I think you'll find some of your answers.
Is the 50V cap rating shown a typo perhaps? Bet it is.
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ColinR
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PostPosted: Sat Oct 17, 2009 3:57 pm    Post subject: Reply with quote

Quote:
Is the 50V cap rating shown a typo perhaps? Bet it is.


Let's see the 1st schematic I did all by myself and the 2nd I copied verbatim from one of my KEF blueprints Cool .

I don't think KEF allowed "typos" out of the drawing office Shocked .
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Lee in Montreal
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PostPosted: Sat Oct 17, 2009 4:09 pm    Post subject: Reply with quote

ColinR wrote:
Quote:
Is the 50V cap rating shown a typo perhaps? Bet it is.


Let's see the 1st schematic I did all by myself and the 2nd I copied verbatim from one of my KEF blueprints Cool


Hmmm... from 150v to 50v, it seems the logical explanation might be as simple as a typo. Shit happens Wink Nonetheless I am still curious to figure out the other dfferences in bass-mid circuits between Mk1 and Mk2 circuits.

I have been looking on the internet for a software that could make a frequencies model by simply entering LCR values. With no luck. This would help understand and visualize the differences. Of course, no software can take in account the impedance variations that are specific to each brand of drivers.

Anyone knows where to find a crossover modelizer?
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Last edited by Lee in Montreal on Sat Oct 17, 2009 6:27 pm; edited 1 time in total
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ColinR
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PostPosted: Sat Oct 17, 2009 4:17 pm    Post subject: Reply with quote

Again you've missed the point, the difference between the two crossovers is the change between T52 SP1049 and SP1072 and associated target function calculation.

The small difference in the bass unit's capacitors is spurious compared to the changes in mid/treble sections and 600uF 50V capacitors can be found in Ref. 103-2 and Carlton III crossovers..
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