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How to get the most out of 105.2?
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andrelly
Intermediate Contributor 25+


Joined: 28 May 2007
Posts: 26

PostPosted: Tue May 29, 2007 3:08 am    Post subject: How to get the most out of 105.2? Reply with quote

Hi, I have been following this forum for some time and finally able to post now. Very Happy
I have been using 105.2 for several months and would like inputs on how to improve 105.2 even further? Rolling Eyes
I have done the following so far:
1. took off castors and put 3 spikes at the bottom of each speaker.
2. replace speaker terminals with gold plated terminals
3. put blue tack at the bottom plate of mid/treble module.
4. replaced wiring from terminal-xover-woofer. Can't do on the mid/treble wiring.
5. put the tweeter/mid module to fire straight ahead and with no tilt (0 degrees).

I also found that the mid/treble module is very prone to vibration, especially from my air-con unit not too far away as well as footfalls. How to remedy this?
Also, replacing the foam in internal chambers with the fibre type would yield improvement?
Also, what x-over parts can be replaced to yield further improvement? I found the treble to be lacking, especially when compared with my Proac Response 1SC.

Associated equipments: SONY DVP-S9000ES, McIntosh c28, McIntosh 2205. QED cables.
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qguy
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Joined: 08 May 2003
Posts: 85

PostPosted: Tue May 29, 2007 6:49 am    Post subject: Re: How to get the most out of 105.2? Reply with quote

Not much high frequency, try the following

1. Remove the screen from the Mid/hi enclosure
2. Toe-in the mid/hi enclosures

Cables.. try silver/silver coated interconnects

I have done 1 and 2 and there is an improvement in clarity and percieved HF energy

Oothers

Replace the capacitors in the crossovers.

andrelly wrote:
Hi, I have been following this forum for some time and finally able to post now. Very Happy
I have been using 105.2 for several months and would like inputs on how to improve 105.2 even further? Rolling Eyes
I have done the following so far:
1. took off castors and put 3 spikes at the bottom of each speaker.
2. replace speaker terminals with gold plated terminals
3. put blue tack at the bottom plate of mid/treble module.
4. replaced wiring from terminal-xover-woofer. Can't do on the mid/treble wiring.
5. put the tweeter/mid module to fire straight ahead and with no tilt (0 degrees).

I also found that the mid/treble module is very prone to vibration, especially from my air-con unit not too far away as well as footfalls. How to remedy this?
Also, replacing the foam in internal chambers with the fibre type would yield improvement?
Also, what x-over parts can be replaced to yield further improvement? I found the treble to be lacking, especially when compared with my Proac Response 1SC.

Associated equipments: SONY DVP-S9000ES, McIntosh c28, McIntosh 2205. QED cables.
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andrelly
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Joined: 28 May 2007
Posts: 26

PostPosted: Tue May 29, 2007 1:22 pm    Post subject: Reply with quote

Screens on the tweeter and mid-range had been taken off. Read on another post regarding fuses on tweeters. Any possible improvement using silver/gold coated fuses? Smile

Caps replacement: what brands are recommended? Solens of 120uF, 80uF etc are just too expensive and too big to fit on the x-over board.
Mad
Cheers...
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qguy
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Posts: 85

PostPosted: Wed May 30, 2007 7:01 am    Post subject: Reply with quote

Not aware that the 105.2 had fuses, you may be referring to the original 105.

andrelly wrote:
Screens on the tweeter and mid-range had been taken off. Read on another post regarding fuses on tweeters. Any possible improvement using silver/gold coated fuses? Smile

Caps replacement: what brands are recommended? Solens of 120uF, 80uF etc are just too expensive and too big to fit on the x-over board.
Mad
Cheers...
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andrelly
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Joined: 28 May 2007
Posts: 26

PostPosted: Thu May 31, 2007 8:29 am    Post subject: Reply with quote

Yes, I think it is a 105.1

Got great inputs from Colin regarding the caps on the x-over.

Come on guys, anybody has tried replacing the foam in the cabs with fibre stuff? Any improvement?

Also, the head unit (mid/treble) vibration is best tamed by damping (sorbothane)? or by mechanical grounding (spike)? or would a small vibrapod fits?

Also another question, at not too high volume (voume at 11 o'clock), the protection circuitry kicks in. What is possibly wrong? I have set the back knob at 200W and OFF position. But no change.
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ColinR
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PostPosted: Sun Jun 03, 2007 11:42 pm    Post subject: Reply with quote

Quote:
Also, the head unit (mid/treble) vibration is best tamed by damping (sorbothane)? or by mechanical grounding (spike)? or would a small vibrapod fits?


Mass loading with a smallish decorative bronze is another option.

Quote:
Also another question, at not too high volume (voume at 11 o'clock), the protection circuitry kicks in. What is possibly wrong? I have set the back knob at 200W and OFF position. But no change


I suspect one party too many with an amplifier clipping has fried your S-STOP transistors.
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andrelly
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Joined: 28 May 2007
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PostPosted: Mon Jun 04, 2007 10:56 am    Post subject: Reply with quote

[quote="ColinR"]
Quote:


Mass loading with a smallish decorative bronze is another option.


Decorative bronze on top of head unit? or mass loading inside the head unit? I was thinking of using a thin sheet of sorbothane at the bottom of circular disk that rests on the woofer box.

Update: I just got the caps to replace the 120uF caps in the x-over. However, this Bennic bi-polar 100uF/100V cap is quite small compared to the original Alcap. About 25% of the size. Doesn't look too re-assuring.... Confused
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speakerguru
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PostPosted: Wed Jun 06, 2007 8:17 am    Post subject: Reply with quote

andrelly wrote:
However, this Bennic bi-polar 100uF/100V cap is quite small compared to the original Alcap. About 25% of the size. Doesn't look too re-assuring.... Confused


Beg, steal or borrow a capacitance meter and measure the capacitance and more importantly the loss factor/dissipation factor/series resistance. In certain parts of the circuit any change in series resistance will have a larger effect on the response than the same percentage change in capacitance. High voltage bipolar capacitors tend to have lower losses than standard bipolars.

A high loss factor capacitor may also overheat, dry out or even blow up if used in place of a low loss type. KEF Alcaps used to have "LL" printed on the low voltage low loss types.
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andrelly
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PostPosted: Wed Jun 06, 2007 9:46 am    Post subject: Reply with quote

Aha, speakerguru! Need to ask how do you tell if it is a high voltage or low voltage type? Low loss? Loss factor? Dissipation factor? Series resistance? I have asked my supplier to measure for me. Hopefuly he responds Rolling Eyes

Got a Vibrapod to put at the bottom of mid/treble module. However, too thick such that rod doesn't go deep and hence module is wobbly.

Would a damping sheet be recommended?
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speakerguru
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PostPosted: Wed Jun 06, 2007 10:33 am    Post subject: Reply with quote

Although it goes against the grain to do this Wink , there are some very sound tips and warnings on speaker mods, on this FAQ page :

http://www.bwspeakers.com/index.cfm/fuseaction/local.faq/ObjectID/F5CA2D4B-3D20-11D4-A67F00D0B7473B37

It also has the formula for loss factor and equivalent series resistance, etc.
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andrelly
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PostPosted: Thu Jun 07, 2007 6:12 am    Post subject: Reply with quote

"BENNIC" BI-POLAR ELECTROLYTIC CAPACITORS
B10A & B10R SERIES

1) FIGURE : B10A (AXIAL) B10R (RADIAL)




2) TOL. RANGE : б╛ 20% (M), or б╛ 10% (K), or б╛ 5% (J) @1KHZ
3) LEAKAGE : Max 0.04 CV +3 еьA AFTER CHARGE 5 MINUTES
4) TEMP. RANGE : - 40 имC TO +85 имC
5) SURGE VOLT : 63V-FOR 50WV., 125V FOR 100WV
6) LIFE TEST : FOLLOWS DATAS ARE SATISFIED WHEN RETURN TO 25 имC.
AFTER RATED VOLTAGE APPLIED FOR 1,000 HOURS AT 85 имC :
(a) CAPACITANCE : WITHIN б╛ 20% OF INITIAL VALUE
(b) D.F. : WITHIN 150% OF INITIAL VALUE
(c) LEAKAGE CURRENT : WITHIN INITIAL VALUE
7) MAX. D.F. : Max 10% @ 1KHZ
Cool MARKING : BENNIC
BI - POLAR
xxx MFD xxx WV
9) Sleeve Standard color : Black, Dark blue

This is what I got from the supplier. Does it make any sense?
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speakerguru
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PostPosted: Thu Jun 07, 2007 8:11 am    Post subject: Reply with quote

Yes it makes sense. The dissipation factor (D.F.) is 10% or d=0.1. Using the formula R=d/2piRC it works out at 0.16 Ohms series resistance at 1kHz for your 100uF capacitor. That would count as borderline low loss in my book. Under 0.1 Ohm would be better, but, we don't know what your original Alcap was supposed to be. Do we?
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andrelly
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PostPosted: Fri Jun 08, 2007 6:56 am    Post subject: Reply with quote

I guess that is OK with the Bennic then.
Now I am awaiting the delivery of other parts to complete the caps change-over. I also plan to put dampening sheet inside the mid/treble module so as to make it more inert. Will update on the results.
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proffski
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PostPosted: Fri Jun 08, 2007 8:47 am    Post subject: KEF 105 Reply with quote

Do not spend too much time on this as there will not be enough time to listen to the music!

I posted some KEF newsletter information and test on 105/II to you yesterday.
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andrelly
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Joined: 28 May 2007
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PostPosted: Fri Jun 08, 2007 11:18 am    Post subject: Reply with quote

Agreed! Thanks for the advise and Kef reviews materials, Andy!

I am doing this as a 'might as well do it' thing as I need to replace the busted caps in the x-over. Hence, the quest to bring out the best of 105.2 just for this time, and then to sit back and enjoy.....

Cheers....
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