Is pre-amp getting killed?


Hi,
   I'm in the market for the Pre-amp and DAC. I had the PS audio Stellar Gain Cell DAC/Pre-amp combo and I sold that to go separates. I thought of buying PS audio Direct Stream DAC and Audio Research REF 6 Pre-amp. I started doing research and spoke to few dealers. Below are the recommendations I got,

1. Bel Canto EX DAC
2. Simaudio 390 Network Player/DAC

3 dealers I spoke recommended to go with Pre-AMP/DAC/Network player combo instead of separate Pre-amp and DAC. Is pre-amp's are getting killed by the combo? 

Any thoughts?

karurravi
I totally disagree that a digital passive preamp with dac is as good as a active preamp. Any professional reviewer .myself owned a
Audio store for a number of years an active preamp has much more capacitance ,discreet power supplies and therefore better dynamics, soundstage size and depth and especially when the spl 
levels get loud the performers stay focused and right there ,not thinned out.  A quality preamp normally is at least $3k and up.
the lneartube Audio is an exception to the rule , I would recommendedthe Latest Mojo Audio power supply for that which 
is much better then then their upgraded $600 unit .  The Lascala 
dac is without question more musical then the ps Audio dac. And similar in price, which I owned their latest and sold this spring.
Therasberry pi is good for the monet, but  cannot come close to anything over $1000.  You get what you pay for . I will say one thing IfiAudio  has been producing excellent products 
try their digital usb cable, and usb-3 purifier, and plug in AC purifiers Fantastic give hem 100 hours nothing in the $100 range 
anywhere gives so much for so little $$. And full money back audition.
I really like my PS Audio GCD and I’m sticking with it.  It’ll be my pre/dac/headphone amp for a long time.
I've yet to hear a combo DAC/Pre that compares to a quality separate DAC/Pre and I've heard a lot of the highly rated ones.