My Quad 33/303 have already benefited enormously from the upgrades David Pritchard at Net Audio (www.net-audio.co.uk) has supplied - I was thus very keen to try the new Quad 33 PSU he has recently made available - reading his website it seems that they are all designed to work together to produce an ultra low-noise regulated power supply with all the attendant benefits this brings to SQ.
Removing the existing PSU and fitting the new unit (including minor component mods to my tape adapter board) took less than an hour and the 33 powered up with no problems on first switch on.
I left things 4 hours or so to warm up - I was immediately aware of a big increase in the soundstage and a more dynamic and musical sound - a bit forward but not overly so. There was a clarity and control not present before as well as revealling previously "hidden" detail - especially obvious on my "test record" dark side of the moon. The previous lightness in bass I'd noticed since putting in the Type 24 crossovers was now gone (but this of course could be due to the X-overs just burning in) and the overall tonal balance is now (for my tastes) spot on. Really impressed
This IMHO is a very worthwhile and cost-effective upgrade to the 33 (£69). I'm not sure if David recommends an "upgrade path" with his 33 mods (do you need to have all the other goodies before getting the best out of the new PSU for example?) but I'm sure an email would bring the answer (sales@net-audio.co.uk).
For the record I have no conflict of interest with Net Audio or David Pritchard but can recommend his 33/303 upgrades unreservedly and this latest one especially.
Attached photos show new PSU and sequence of removing original and fitting upgrade.
Steve