I have just made an update to my basement system. I have installed the Quad FM 4 ans Quad 34 premp last week. In addition since the album was made the has the Quad 909 power amp in place of a Quad 405-2. A Quad 405-2 still powers the two isobaric coupled cavity subs.
The system consists of an APC UPS behind the TV, a Sony Bravia TV, Direct TV DVR, Sony DVD player, an automatic HDMI switch that switches automatically between the DVY and DVD player, Quad FM 4 , Quad 34 preamp, Thorens TD 125 II turntable, SME series 3 arm and Shure V14 xmr cartridge, Quad 909 and 405-II pwer amps, my Raymond E Cooke memorial speakers and my isobarik coupled cavity subs.
This is a link to the album.
Here are the highlights.
While doing the instal I took some pictures of one of the speakers out of the entertainment center.
The speakers use the now half century old KEF B 139 bass units. This is one of my favorite drivers of all time. There really is no good substitute even now. They provide deep bass with low coloration. Although rated at 27 watts, this is a way underrated spec. I have pushed these drivers hard in a number of installations and never had one fail.
I would love to update this unit with modern voice coil manufacturing techniques and magnet materials.
The unit is the ideal shape, as you can keep a narrow cabinet. A couple of updated units could easily allow for the design of a full range active speaker and reproduce the LFE signal.
The midrange is the famous Dynaudio D76 mid range dome.
The tweeter is a Hi-Vi Research mylar ribbon type unit.
Crossover point are 400 Hz and 4 kHz. The crossover is complex and totally impedance compensated to provide an essentially flat 6 ohm load.
The impedance compensation leans heavily on Raymond Cooke's work that was used so successfully in the BBC LSA 1 monitors.
The previous Quad FM3 and Quad 33 preamp.
The newly mounted Quad FM4 and Quad 34 preamp. The Quad 909 power amp is also visible.
The two isobarik coupled cavity subs. Te furniture between the two contains the active crossover and the Quad 405-2 power amp. (100 watts per channel). The two subs are driven mono. Crossover is third order at 70 Hz and fifth order at 90 Hz. The main speakers are operated full range and roll off first order around 53 Hz and fall away fourth order at 35 Hz. They basically have good and useful output to the mid thirties though. So not much output is required from the subs in fill in duty.
I have really come to enjoy this system. It has been a lot of work to really make this system an excellent one. 3db would droll over the way it reproduces vinyl LPs. The ported enclosure is over damped by intention, the subs fill in and have a low Q of 0.5 by design. The bass is very tight with no overhang. F3 for the system is 27 Hz. So it reaches to 30 Hz effectively.
Voices are very crisp and the stereo image very stable well outside the speakers.
The day I did the installation of the equipment it was 25 below and on those days I draw up the log Wilkening fireplace.
This system performs very well in this space which is large and highly ambient. Also the speaker locations by reason of interior design are problematic. However the the system has been tweaked and voiced and sounds really nice in that space. The tonal balance is very close indeed to the big studio system upstairs with the addition of ambiance, which on much program material is an advantage. The system fills the space with ease.
I have put together
an album on how to panel mount Quad head units from the Peter Walker era at Quad. He developed this simple and elegant system right from the start in the late forties.
It is an example of what a great designer he was. All his circuits and engineering have this elegant simplicity about them. This alum will give members a good insight as to how Peter thought problems through and reduced them to the simplest essentials.
