Quad 33 (2nd set; ***Updated***)

After the conservative and successful maintainence to my 1st unit, I became more adventurous.

Top view of the 2nd unit

As per the 1st unit, voltage was increased to 16V following Dada Electronics suggestions. I replaced other capacitors in the unit with Wima, ROE,Philips for poly and EC are Panasonic ECA, FC and Rubycon. Poly caps were replaced in the motherboard of the Quad 33 as well, using ROE and Wima.

All value of the new capacitors are as per original except the large Wima used on the tape monitor board (immediate below). Found the 1.5uF MKS-C (replacing a 2.2uF electrolytic capacitor) to be most suitable, resulting in solid and realistic bass reproductions when partner-ed with my 2nd Quad 303 (http://myoldvintagehifi.blogspot.com/2010/12/quad-303-after-recapping-2nd-unit.html) driving the Meridian A500.

Phono and Tape adapters

Another view of the Phono and Tape adapters

Pre-amp adapter boards removed to show mainboard substitutions 

Closer view of the exposed mainboard

One of the pre-amp boards

Back of the pre-amp board with bypass

Phono board

Back of  Phono board with bypass

How do these Quad 33 sound and compare against the original?

Both of the original units were warm but sounding as if they hit a treble ceiling (aka roll-off). Bass was not boomy but neither was it firm. Reproduction of details from the original were acceptable but not superb - reveals much potential. 

After performing maintainence to the 1st Quad 33 unit, it sounds mellow with good reproduction of the background details. The 2nd unit builds upon the1st unit's capabilities with highly improved headroom and much firmer bass when paired with the maintained Quad 303.

The Quad 33 and 303 are well worth preserving as these were well designed with ease of maintain in mind.


Update - 15Nov2012

Bought some ERO KC1849 a while back but did not have the time to install them into my units.

Hence finally had the opportunity to insert four 0.01uF onto the Phono adapter board, replacing the blue Wima(s) of equivalent values.

After ERO replaced the blue Wima

So far so good ...