While repairing and modding tube equipment for years, Bob
has developed two mods/circuits, one that he incorporates into
all three preamps and the second which is included in the top
two versions.
The first is the "Green Force" power supply which
uses a series of film caps in place of a large group of
electrolytic caps, this is patented. I initially had reservations
about how it would do on the bottom end, after hearing it I can't
believe how much more of a deep and focused bass I have.
The second is the "Auto Bias" tube circuit which does what
its name implies whether your tubes measure at NOS levels,
getting near minimum or anywhere in between. Now to the
differences.
Rhumba 1.2 MSRP $3500.00 usd
#1 - Polystyrene caps in the "Green Force"
#2 - REL PPT Theta output caps
#3 - J/J 12AU7 tubes
#4 - "Auto Bias" circuit NOT included
#5 - Polypropylene caps in "Green Force" regulator circuit
#6 - Rubber feet
#7 - Sound dampening applied inside of top cover and sides
as well as the outside of the "Tube Gondola", more on
that below.
Rhumba 1.2 Extreme MSRP $5500.00 usd
#1 - Upgraded polystyrene and Mundorfs in the "Green Force"
#2 - Mundorf 2015 MCap Supreme EVO Silver, Gold, Oil outputs
#3 - Psvane 12AU7 tubes
#4 - "Auto Bias" circuit IS included
#5 - Upgraded polypropylene caps in "Green Force" regulator
#6 - Four, Edensound "Terracone" footers
#7 - Premium Dynamat applied in same manner as #7 above
A few final thoughts:
#1 - The "Tube Gondola" is accessible via a clear plexiglass
cover on the topcover secured with two thumb screws.
It is a gondola shaped well with raised sides so none of
the innards are visible except the two ceramic sockets
and the axle connecting the front mounted input selector
knob to the actual switch which is toward the rear which
passes through it between the sockets. The Furutech
goldplated IEC with integral fuseholder (both models)
is on the back panel so any adjustments or changes
can be done externally - well thought out and implemented.
#2 - Apparently some of the Rhumba 1.1's were slightly noisy
and this is no longer an issue as circuits were tweaked,
dampening was added as well as strategically placed
gasketing (Terracone feet on the Extreme). With the volume
turned all the way up and tapping anywhere on the case
you hear NOTHING out of the speakers, it is completely
quiet.
#3 - This is a tube preamp so it's going to be at least warm if not
hot right? WRONG, in my 72 f room with my Snap On
infrared thermometer it measures 82 f while my Wadia 15i
measures 80.5 f and my Genesis Digital Lens is 84.3 f
#4 - After spending 2 months with the Extreme I'm completely
satisfied with the added performance and enjoyment that
it has afforded me. Too often in this hobby you spend a lot
to get a little. I spent a lot, got a lot and I'd do it again in a
heartbeat.
Happy listening, Woody