Just acquired some Kef R 107s...

[zaorestes]

As my post count rightly suggests, I know little about electronics or the intricacies of home audio. It happened that my grandparents sold their house and had no space for the Kef Reference Series Model 107s sitting in their garage, a vestige of larger houses and better ears. So three huge boxes and a tote bag filled with wires wound up in the back of my prius, and blocked my rear view mirror for the next eight hours back to souther california. Now these same boxes are stacked off in a corner of my one-bedroom apartment, and I have a range of questions that will help me figure out exactly what to do with them, if knowing members might oblige.


First:
Model 107 Specifications
Frequency Response 20Hz - 20kHz +/- 2dB at 2m on reference axis
Directional Characteristics Within 2dB of response on reference axis up to 15kHz for +/-10° vertically, up to 10kHz for +/-30° horizontally
Maximum Output 112dB spl on programme peaks under typical listening conditions
Enclosure Volumes Low frequency enclosure: 72 litres. MF/HF enclosure: 8.5 litres
Amplifier Requirements Suitable for use with amplifiers capable of providing between 50 and 300W into 4 ohms resistive load.
Nominal Impedance 4 ohms resistive 20Hz-20kHz
Characteristic Sensitivity Level 90dB spl at 1m on reference axis for pink noise input of 2.83 V rms, band limited 50-20kHz (anechoic conditions)
Weight 45 kg (99 lb)
Dimensions 1165 x 330 x 448 mm
45.9" x 13" x 17.6"
Height of Origin of Reference Axis 1020mm (40") above base of cabinet (not including feet).
Angle of Reference = 1.5° from horizontal[/code]


fun, huh? Copied from kef's website which I can't link to on here...

Now I do not own an amplifier, thus cannot determine if these work. At this point I have no reason to assume otherwise, but my present options are limited.
I must test these at some point, is there a particularly cheap amplifier someone could recommend that might drive these?
And assuming somethings wrong, where could I get these fixed? I figure that alone might be seriously expensive, but would be ultimately justified should I sell them.
Now everything I've read indicates that these are absolutely astounding speakers, but I'm a grad strudent wtih a one-bedroom apartment, and even my parents think I would be better served by the money I could get for them. I've been trolling the internet, but I cannot figure out their worth. Assuming they are in working order, what is their general market value? I'll probably try ebay, but I will definitely need some helpful figures.
I'm in Los Angeles, and I know that the ghost of Kef lives on in Britain, but it would be nice to diagnose and fix these without shipping htem off to jolly old england.

Thanks!

 

[mike c]

this one?

how much are you willing to spend on the amp?

do you have a pre-amp or receiver with pre-outs?

 

[WmAx]

To get a suitable amp at low cost, a pro audio amp is likely the best option here, or a used home amp(if you don't buying used) of sufficient performance/capability. They are designed to handle low impedances(which this seems to be) and have high power output. However, you usually have to switch out(every easy to do) the stock fan in pro audio amps for a silent fan(like a Panaflo), or the fan noise may be annoying.

-Chris

 

[zaorestes]

Yeah that's them in that scan.

My budget is just plain small and i'm trying to get an idea of minimal repair/amplifier costs; i dont have any other equipment nor any idea of what range of money i can expect to spend in this process.

 

[TLS Guy]

As my post count rightly suggests, I know little about electronics or the intricacies of home audio. It happened that my grandparents sold their house and had no space for the Kef Reference Series Model 107s sitting in their garage, a vestige of larger houses and better ears. So three huge boxes and a tote bag filled with wires wound up in the back of my prius, and blocked my rear view mirror for the next eight hours back to souther california. Now these same boxes are stacked off in a corner of my one-bedroom apartment, and I have a range of questions that will help me figure out exactly what to do with them, if knowing members might oblige.


First:
Model 107 Specifications
Frequency Response 20Hz - 20kHz +/- 2dB at 2m on reference axis
Directional Characteristics Within 2dB of response on reference axis up to 15kHz for +/-10° vertically, up to 10kHz for +/-30° horizontally
Maximum Output 112dB spl on programme peaks under typical listening conditions
Enclosure Volumes Low frequency enclosure: 72 litres. MF/HF enclosure: 8.5 litres
Amplifier Requirements Suitable for use with amplifiers capable of providing between 50 and 300W into 4 ohms resistive load.
Nominal Impedance 4 ohms resistive 20Hz-20kHz
Characteristic Sensitivity Level 90dB spl at 1m on reference axis for pink noise input of 2.83 V rms, band limited 50-20kHz (anechoic conditions)
Weight 45 kg (99 lb)
Dimensions 1165 x 330 x 448 mm
45.9" x 13" x 17.6"
Height of Origin of Reference Axis 1020mm (40") above base of cabinet (not including feet).
Angle of Reference = 1.5° from horizontal[/code]


fun, huh? Copied from kef's website which I can't link to on here...

Now I do not own an amplifier, thus cannot determine if these work. At this point I have no reason to assume otherwise, but my present options are limited.
I must test these at some point, is there a particularly cheap amplifier someone could recommend that might drive these?
And assuming somethings wrong, where could I get these fixed? I figure that alone might be seriously expensive, but would be ultimately justified should I sell them.
Now everything I've read indicates that these are absolutely astounding speakers, but I'm a grad strudent wtih a one-bedroom apartment, and even my parents think I would be better served by the money I could get for them. I've been trolling the internet, but I cannot figure out their worth. Assuming they are in working order, what is their general market value? I'll probably try ebay, but I will definitely need some helpful figures.
I'm in Los Angeles, and I know that the ghost of Kef lives on in Britain, but it would be nice to diagnose and fix these without shipping htem off to jolly old england.

Thanks!

You have an exotic speaker, that was one of the best in its day. I hope you picked up the active equalizer with the speakers. The speakers are quite useless without it.

The bass system on these is exotic. It is an equalized coupled cavity system. It requires are very hefty amp to drive it. The active equalizer has to be inserted in the tape monitor loop of the preamp. I know of no receiver that would drive these.

Now the woofer in these speakers have foam surrounds, which have been very prone to rot out. Unless the surrounds have been replaced on these speakers the surrounds are very likely rotted out. These surrounds can be replaced.

You have inherited a famous and historically important set of speakers. They will need to be checked by someone very experienced. They are quite unlike anything you will be familiar with.

It is important that the woofers be inspected before powering up so the voice coils are not damaged. The woofers are inside the bass enclosures.

KEF have a lot more than a ghost presence and I'm sure will give you advice. They are still located in Tovil, a suburb of Maidstone, the county town of Kent. It is located on the River Medway.

 

[mike c]

how about the Harman Kardon stereo receivers ... those are stable to 4 ohms and should cost around 300+USD (after discount)

http://www.harmankardon.com/product_detail.aspx?Region=USA&Country=US&Language=ENG&cat=REC&prod=HK 3490&sType=C

 

[zaorestes]

excellent advice, i've nailed down a few good leads in my local area, as KEF recommends contacting local retailers regarding issues of repair and such. I'm sure if I call around I'll get some help out of sheer curiosity. Maybe I'll post some pics at some point... some noble speakers.
And that reciever would fit the bill nicely. seems beefy enough

 

[WmAx]

It really is best to use outboard amplification, considering this is a rather low sensitivity speaker based on stereophile measurements(approx. 86 dB/1w/1M), and that apparently you need to insert a special EQ box between the pre-amp signal and amplifier input. Modern receivers pretty much are void of this ability(to place a signal processor between the internal pre-amp and internal amp stages). So.. 4 ohms.. low sensitivity.. signal processing box required... a receiver as the amplifier does not make much sense considering these factors. The receiver recommend 'might' have ability to insert the processor... but it seems unlikely. Be sure to check to see if such feature is present.

-Chris

 

[mike c]

It really is best to use outboard amplification, considering this is a rather low sensitivity speaker based on stereophile measurements(approx. 86 dB/1w/1M), and that apparently you need to insert a special EQ box between the pre-amp signal and amplifier input. Modern receivers pretty much are void of this ability(to place a signal processor between the internal pre-amp and internal amp stages). So.. 4 ohms.. low sensitivity.. signal processing box required... a receiver as the amplifier does not make much sense considering these factors. The receiver recommend 'might' have ability to insert the processor... but it seems unlikely. Be sure to check to see if such feature is present.

-Chris

the HK stereo receiver i suggested has a pre-out and main-in connection where you can insert an EQ box.

it's also rated as 120wpc at 8 ohms and 150wpc at 4 ohms.

 

[dayking79]

Any news on your 107's yet? What have you done with them? I only ask because i'm going through a total refurb/rebuild on my recently aquired 107's.

 

[highfigh]

You don't want to use a "cheap" amp with these. You won't like it, the speakers won't like it. If you find a reasonable receiver, make sure it has pre-amp output and save your money for a used pro power amp, to get into a decent power range. They aren't terribly sensitive and if you like it loud, don't try with low power.

If the foam surrounds are falling apart, which they probably are, don't play them. Call "Orange County Speaker Repair" and if you copy/paste the name in quotes to google, it'll be at the top of the page. after you click on Search.

If you like punk rock, these aren't the speakers for you however, they do work very nicely for a wide range of music.