The goldpoint uses a 23 position switch, the DACT uses a 24 position switch.
Both seem reliable for many years but in my opinion both are too coarse and
do not have enough positions.
For the crazy out there, there is this
http://www.hificollective.co.uk/catalog/glasshouse-ladder-stepped-stereo-charcroft-seiden-p-10088.html
and I do have one of these, also crazy expensive
http://www.tkd-corp.com/products/att/pdf/type-cs-e.pdf
The 48 step khozmo would be great, maybe the newer ones are more reliable.
The 63 step shallco are very VERY nice. Also large.
way back when, Collins radio made 79 step attenuators designed for mixing boards
for radio stations and the like. The most fantastic thing I have ever used. Also large.
Had the best feel of anything else and lived forever. Silver contacts...
The TI pga2320 is a well known and fairly decent chip based thing with a thd of .0003%
but I have never seen a high end preamp use them.
Way back when Levinson had two different solutions both of which evidently people
really liked, and both were expensive. The first one was a 12 bit multiplying dac
(actually 4 of them) where the audio input was the voltage reference. So you can
consider this IC based. The other one was a standard R2R thing that used
datageneral dg501 (now Vishay) cmos switches as the switching elements
all on a Teflon circuit board.
The nelson pass high end preamp does the same R2R attenuator with hand
selected fets used as the switching elements, biased in a way such that they
produce ultra low distortion.
I like my 256 position .25db per step gold crosspoint relay attenuator better
than all the above. (well if I could get the Collins radio things...)
