SpeakerTalk Forum Index SpeakerTalk
This forum has been set up to facilitate discussion of 1970s KEF speakers and drive units. The owner of the Forum has no connection with KEF Audio.
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

KEF C80 Bass issue
Goto page 1, 2, 3  Next
 
Post new topic   Reply to topic    SpeakerTalk Forum Index -> KEF speakers
View previous topic :: View next topic  
Author Message
golanr
Junior Contributor 10+


Joined: 06 Jan 2012
Posts: 17
Location: Chesterfield, MO USA

PostPosted: Fri Jan 06, 2012 11:44 pm    Post subject: KEF C80 Bass issue Reply with quote

Hi everyone,
I have recently purchased a pair of KEF C80 in great shape.
They sound very nice and open but lack in the Bass section.
I am using a Sony CD player and Technics SL-MA1 turntable with Shure M105E cart, Yamaha C-4 Pre Amp, 2 X bridged mono Rotel RB-870BX Power amps (300w each at 8ohm) and good cables between the components and the speakers.

I tried many combinations with wiring (A & B on the speaker back) various distance from the wall, AMPs bridged and non bridged, different Pre Amp (Rotel RC-850) even an ADC sound shaper III...still very dry almost non existing Bass. Also tried with a Yamaha amp, no improvement there as well..

Room size is 11.5x15f and height is 7.2f

I checked the B139 drivers and they work fine, also showing the correct ohm on the tester. I looked at the huge crossover. Caps look in great shape but when comparing to the XO drawing I found on Audiokarma I noticed that one of the two 300uF caps was replaced with 2x600uF in parallel=1200uF which could either indicate at the problem or it may be a change in design by KEF?
I also measured some of the Expotus resistors while on board, the two 47 are showing 24 each, but again, could be because they are still connected to the XO.
I am adding a page where I posted photo of the XO and the XO drawing I have. http://www.audiokarma.org/forums/showthread.php?t=413446

I thought it was my room but I also have pair of KEF 104ab which I used with the same system with excellent Bass....and the 104ab is only a two way speaker with a passive BD139 unit.

I verified polarity in and outside the cabinets, the Drivers are the correct ones for the C80 (T33 SP1210, B160 TS1203 and B139 TS 1212) Interesting that the B160 is made by Eton but has a KEF sticker and correct TS number.

The mid on the other hand is very pronounced, it is virtualy over taking the sound coming out of the C80.

Any idea where I should look at next to try and solve this mystery? anything before I start replacing caps and resitors.

Thank you,
Back to top
View user's profile Send private message
golanr
Junior Contributor 10+


Joined: 06 Jan 2012
Posts: 17
Location: Chesterfield, MO USA

PostPosted: Sat Jan 21, 2012 10:55 pm    Post subject: Reply with quote

15:30 on Saturday,
Finally finished testing all the Caps and Resistors on the XOs. All tested within Normal Parameters. For those interested, I used a FLUKE 87 IV. That was quite a lot of soldering to remove one leg each time I tested... Very Happy

I am still puzzeld by the 2x600uF connected in Parallel instead of one of the 300uF Caps but after seeing few pictures of the same XO (thanks to rx7rotary and others) I am confident that the drawing available on the net is not updated or of a different version.

So seems that this is the nature of the beast and that I either have to live with it and add a Sub if I am looking for more Bass or just get something else. I am leaning toward posting them on Craigslist or ePay and using the money to get someting different, I will appreciate your suggestions in that matter.


Last edited by golanr on Mon Feb 27, 2012 2:15 am; edited 1 time in total
Back to top
View user's profile Send private message
golanr
Junior Contributor 10+


Joined: 06 Jan 2012
Posts: 17
Location: Chesterfield, MO USA

PostPosted: Mon Feb 27, 2012 2:14 am    Post subject: Reply with quote

The C80 mid was too good to give up so I added a 12" Klipsch Sub (Reference series).......Problem solved Very Happy

Last edited by golanr on Tue Feb 28, 2012 5:59 am; edited 1 time in total
Back to top
View user's profile Send private message
Richie
Senior Contributor 100+


Joined: 06 Nov 2010
Posts: 108
Location: Northamptonshire

PostPosted: Mon Feb 27, 2012 11:34 am    Post subject: Reply with quote

So, apart from the issue you had with bass, do you prefer the C80 over the 104 ab's ?
_________________
Still learning ......
Back to top
View user's profile Send private message Send e-mail Visit poster's website
rx7rotary
Intermediate Contributor 50+


Joined: 20 Feb 2012
Posts: 59

PostPosted: Mon Feb 27, 2012 8:37 pm    Post subject: Reply with quote

In my opinion c80 is a much superior speaker, with a very complex xover very well engineered. I have kept c80s, over both calindas and 104's. C80s just produce a lot more sound and details.

only my 50cent...


Last edited by rx7rotary on Tue Feb 28, 2012 12:30 am; edited 1 time in total
Back to top
View user's profile Send private message
proffski
Über Contributor 1000+


Joined: 22 Aug 2003
Posts: 1296
Location: Tewkesbury UK

PostPosted: Tue Feb 28, 2012 12:22 am    Post subject: Reply with quote

rx7rotary wrote:
In my opinion c80 is a much superior speaker, with a very clomplex xover very well engineered. I have kept c80s, over both calindas and 104's. C80s just produce a lot more sound and details.
only my 50cent...


I have to agree.
Only one opportunity to listen to these in a shop a few years ago, I expected more from the bass but the mid range and all the rest were excellent. One loudspeaker had a very bad cigarette burn on the top, I dread to think as to what nicotene coating was on the drivers.

I also remember a pair of lovely Cantata's in a camera shop in Glucester, tops covered with fag burns and the drivers orange brown with nicotene.
Going for a song, sadly I declined... Crying or Very sad
_________________
I contend that for a nation to try to tax itself into prosperity is like a
man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill
Back to top
View user's profile Send private message Send e-mail
golanr
Junior Contributor 10+


Joined: 06 Jan 2012
Posts: 17
Location: Chesterfield, MO USA

PostPosted: Tue Feb 28, 2012 2:12 am    Post subject: Reply with quote

Yes, 100%. The mid is much more open and works great with the added Bass.
Funny part, my 14 year old daughter was doing some A/B testing with both the 104aB and the C80 and she also commented that the 104aB lack in the "voice part", obviously her words for mid.

I guess there is still hope in the world if a 14 year old who listens to crappy iPod headphones can talk about the differences between two great speakers Very Happy
Back to top
View user's profile Send private message
rx7rotary
Intermediate Contributor 50+


Joined: 20 Feb 2012
Posts: 59

PostPosted: Tue Feb 28, 2012 2:42 am    Post subject: Reply with quote

golanr wrote:
Yes, 100%. The mid is much more open and works great with the added Bass.
Funny part, my 14 year old daughter was doing some A/B testing with both the 104aB and the C80 and she also commented that the 104aB lack in the "voice part", obviously her words for mid.

I guess there is still hope in the world if a 14 year old who listens to crappy iPod headphones can talk about the differences between two great speakers Very Happy


Yes that is correct, on the other hand, if you play a bit of jazz, the t27 is much superrior to the c80s tweeter t33. It has much more controlled highs, in my opinion.

If you ever compare the c80s to a ref type kef speaker such as some of the imfs or kef 105 or any other ones you will find that the mids are so much more blown up on the c80s.

After months of listening to c80s , when switched to imf s or any ref kef speaker, i really missed those mids for a while, but then realised that any other speaker I try, that was somehwat "linear" those mids were not there ...

marko
Back to top
View user's profile Send private message
rx7rotary
Intermediate Contributor 50+


Joined: 20 Feb 2012
Posts: 59

PostPosted: Tue Feb 28, 2012 2:47 am    Post subject: Reply with quote

golanr wrote:
Yes, 100%. The mid is much more open and works great with the added Bass.
Funny part, my 14 year old daughter was doing some A/B testing with both the 104aB and the C80 and she also commented that the 104aB lack in the "voice part", obviously her words for mid.

I guess there is still hope in the world if a 14 year old who listens to crappy iPod headphones can talk about the differences between two great speakers Very Happy


104aB has another beauty to it that I cannot describe, and I love it as much as I loved the Calindas, but they are not a better speaker than the c80.

Infact another thing I wanted to throw in here, is that I have never had issues with the bass with my c80s ... they dont go very low, but I think that the bass is very punchy, well controlled, and setup for a smaller space rather than a very large lounge...

m
Back to top
View user's profile Send private message
golanr
Junior Contributor 10+


Joined: 06 Jan 2012
Posts: 17
Location: Chesterfield, MO USA

PostPosted: Tue Feb 28, 2012 3:31 am    Post subject: Reply with quote

My problem is that I could hear the bass but not feel it. Maybe it's the boxes that are not big enough for the B139, maybe it's my room but it just did not work for me. The addition of the Sub simply made the sound complete for me, especially when listening to classical music.
I use really low volume on the Sub and cut it at 80hz.

I still have the 104aB connected and I change to them with a simple press of a button on the Pre-amp. Indeed there are some genre that sound better so I can enjoy the best of both worlds Very Happy
Back to top
View user's profile Send private message
Richie
Senior Contributor 100+


Joined: 06 Nov 2010
Posts: 108
Location: Northamptonshire

PostPosted: Tue Feb 28, 2012 8:25 am    Post subject: Reply with quote

Well maybe the 104ab's don't excel at anything but they are a great all rounder, very musical.
Having said that I have just acquired a Linn Klout which has astonishing bass control, separation and articulation so I was looking for a better speaker and thinking the C80 having an active bass rather than the passive in the 104 ab's would be just the ticket ..... now I'm not so sure.

With regard to subs, and I'm no expert here but most folk who have added them say they have great depth and feel but also add a sort of woolliness, maybe good for AV but no so good for HiFi ?
_________________
Still learning ......
Back to top
View user's profile Send private message Send e-mail Visit poster's website
proffski
Über Contributor 1000+


Joined: 22 Aug 2003
Posts: 1296
Location: Tewkesbury UK

PostPosted: Tue Feb 28, 2012 8:57 am    Post subject: Reply with quote

My old 104ab's thrived on big American power amplifiers like Amcron, Adcom, and Phase Linear. I did not play them any louder but the cotrol in the bass and general feeling of ease on transients was just amazing!
_________________
I contend that for a nation to try to tax itself into prosperity is like a
man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill
Back to top
View user's profile Send private message Send e-mail
Richie
Senior Contributor 100+


Joined: 06 Nov 2010
Posts: 108
Location: Northamptonshire

PostPosted: Tue Feb 28, 2012 9:29 am    Post subject: Reply with quote

What's your current amp / speaker combination Proffi ?
_________________
Still learning ......
Back to top
View user's profile Send private message Send e-mail Visit poster's website
proffski
Über Contributor 1000+


Joined: 22 Aug 2003
Posts: 1296
Location: Tewkesbury UK

PostPosted: Tue Feb 28, 2012 2:53 pm    Post subject: Reply with quote

Richie wrote:
What's your current amp / speaker combination Proffi ?


I have for the time being gone over to the Dark Side... Shocked
Denon 1910 AV amplifier and Richter 88 speakers front and rear.(Speakers Home Made).
Side channels are Wharfedale Diamonds 10.1
Centre Tannoy Sensys DCC
Subwoofers two B&K Gemini IIs

The list of the KEF and IMF stuff I used to own is long and extended, I still own a few which are on almost permanent loan to the extended family... list will follow!
_________________
I contend that for a nation to try to tax itself into prosperity is like a
man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill
Back to top
View user's profile Send private message Send e-mail
proffski
Über Contributor 1000+


Joined: 22 Aug 2003
Posts: 1296
Location: Tewkesbury UK

PostPosted: Tue Feb 28, 2012 10:53 pm    Post subject: Reply with quote

Apologies to the management for being off topic.

As promised...

Ok, if my memory is not playing tricks, list of stuff I have owned and sold and some of which is still in the family somewhere.
KEF Concerto , IMF TLS50, Amcron DC300 & DC150, the DC150 is still in family.

KEF Coda, this till recently were my computer loudspeakers driven by original Naim Nait.
Both now in sem- retirement somewhere in Cheltenham.

KEF Reference Series 4 and 3, somewhere in Scotland… with Krell DC100.

Two pairs of KEF 104ab, one pair sold one still in family.

Phase Linear 400 amplifier MKI, kept popping all those O/P transistors at random, sold.

The last version of the Cambridge P60 amplifier, sold to a friend in Amesbury and driving 1st pair of 104abs to this day!

Radford HD250 amplifier, that too is in Cheltenham somewhere.
There was also either a Radford Z50 or Z100, probably Z50 power amplifier.
Memory is playing tricks again, but one of the Radford units was hooting at some RF frequency, it may have been the HD250. When I stopped the oscillation it did not sound as good, go figure!

IMF Super Compact, yup, in Cheltenham somewhere…

I cannot remember the pre-amps, one was German I think.
Of course there were many KEF base DIY projects as well.

Allowing for mental lapses that is the “ex” list from 1968 to the present day.
_________________
I contend that for a nation to try to tax itself into prosperity is like a
man standing in a bucket and trying to lift himself up by the handle.
-Winston Churchill
Back to top
View user's profile Send private message Send e-mail
Display posts from previous:   
Post new topic   Reply to topic    SpeakerTalk Forum Index -> KEF speakers All times are GMT + 1 Hour
Goto page 1, 2, 3  Next
Page 1 of 3

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group