above are two NPS100 amplifiers that have received complete upgrading
including hardwire monoblock conversion and Plitron toroidal transformers.
Property of Jeff Parks. These upgrades reveal the authority, clarity
and seemingly limitless dynamics that the Natural Progression Stereo
amplifiers are capable of delivering.
[upgraded NPS100] is silent as all get-out. The top end is sweet yet
extended, which means that I can turn it up without ear-bleed,
at levels that had my Bryston 60-watter sounding harsh.
The overload characteristics are something special. The bass now sounds
like it just happens, instead of being pushed out of speaker drivers
(the transmission line speakers help). The bass feels limitless and
natural, without the artificial lock-step feel of typical high current
solid state. Voices and acoustic instruments are wonderful. Strings
decay in a continuous stream. There is more `there' there, more dimensionality.
more about Tom Schuman's upgraded NPS100 on the
Improved Input RCA Connectors
Option: Upgraded Speaker Terminals
Option: Upgrade to Plitron Transformer
Option: Hardwire Monoblock Conversion
Circuit Board Damping
are three separate levels of upgrades possible with the NPS100. They
consist of circuit topology changes and use a class of parts we could
never use in production because the normal multiplier used in manufacturing
is much higher than I use in my Custom Shop, which means that the cost
of a new amplifier using these parts would have been astronomical.
is the place to start. This basic upgrade is incredible. It changes
the character of the sound altgether by eliminating several sources
of electronic coloration. As the designer of this amplifier I am intimately
familiar with how it operates, so I can do far, far more to it than
simply upgrade the components I make several changes to the circuitry
itself. First, I completely redesigned the way the predriver circuit
is balanced, which makes it far sweeter-sounding; second, I eliminate
the DC servo altogether (servos never sound good: they are always a
huge source of "hashy" coloration).
it has not already been done, your NPS amplifier also receives the
factory's simple MKII conversion where several solid-state parts are
removed from the tube circuit. For this step, I install new plate
and cathode loads using Mills resistors. (Even if your amplifier already
had the MKII mod done, I pull out the resistors that were installed
at the factory and put in the new ones, which sound far more neutral
and dynamic.) I replace the bias source and predriver transistors
with Zetex Super E-line transistors, which sound warm and smooth;
and I rebias the predriver and driver stages for sweeter sound. Finally,
I upgrade the coupling capacitors to TRT Dynamicaps
, which are far more dimensional and liquid than the dry-sounding
TRT caps originally used.
for NPS100 "Basic" Upgrade: $1200
getting the Basic, for even better sound, this would be your next step.
It's a cost-effective upgrade that gets added on top of the Basic upgrade
which provides weightier bass, a deeper soundstage and quieter background
with less "fuzz" around the musical notes.
With this upgrade I build in a completely new power supply for the output
stages driver and predriver sections, isolating them from the
output stage power supply and eliminating modulation effects. Nichicon
Great Supply capacitors are used for the local, onboard rail decoupling
caps, and for the main rail caps which provide the energy used to drive
This modification results is significantly tighter, deeper and more
powerful bass. Some chassis modification is required, but it's invisible.
The rectifiers are upgraded to FRED (Fast Recovery) diodes for incredible
intertransient silence and smoothness.
(Note: this is an improved version of the Counterpoint factory's
1996 "full-mod" upgrade designed by consultant Bruce Wenger
for the NPS200 and NPS400.)
for NPS100 Premium Upgrade 2: $1920
Includes the Basic and the Turn
your NPS100 into the sweetest little amp you've ever heard. This
upgrade is for serious audiophiles and music lovers only. If sound
quality is your topmost requirement, then get this upgrade after you
get the Basic and Premium upgrades. This ultimate upgrade transforms
the amp into a sonic masterpiece. A lot of expensive parts are involved,
but the results are worth it.
The purity of the tubes high-voltage power supply is dramatically
improved by upgrading the rectifier to a specially-selected 6BW4, and
by upgrading all the aluminum electrolytic capacitors used in the the
tubes plate and cathode supplies to Black Gates exceptional
powdered graphite non-polarized caps.
More of the signal-carrying components are upgraded, including replacing
the tube input resistors with Caddock Tetrinox parts, and replacing
the amplifier's output (emitter) resistors with Mills non-inductive
wirewound resistors. Then I remove the old RCA jacks and speaker terminals
and mount Sound Connections' excellent CM1F-OFC direct gold plating
over oxygen-free copper RCA jacks and BP-HEX/OFC speaker terminals.
Finally, the internal power supply and speaker wiring is re-done with
Van den Hul "The Wind" Hybrid 2 wire.
This upgrade lowers background noise, increases stage depth and width,
sweetens the sound, tightens the bass and "liquifies" the
midrange and treble. (The wiring upgrade and choice of connectors
were suggested by Bruce Wenger in 1996 for the NPS200 and NPS400.)
for NPS100 Gold Upgrade: $3700
I am making
available some additional modifications for the NPS100 that either greatly
improve the unit's sonics, or make it more "user friendly" in
certain situations. Please note that these options have been priced with
the assumption that they will be installed concurrently with the Basic
upgrade, in other words, while the amplifier is already being worked on.
As stand-alone modifications, these options will cost a bit more. If you
wish to have any of these installed separately, please contact me to discuss
1. Improved Input RCA Connectors
old RCA jacks are removed and Cardas GRFA RCA jacks are installed in the
Option 1. Add $120 to upgrade the input RCA jacks.
(Not available separately, requires either the Basic, Premium, or GOLD upgrades.)
2. Improved Speaker Terminals
replace the original speaker terminals with Cardas CCGR posts. Some chassis
for Option 2. Add $300 to upgrade the speaker terminals.
(Not available separately, requires either the Basic, Premium, or GOLD upgrades.)
3. Upgraded Transformer
power transformer in the NPS100 can be upgraded to an extremely nice toroid.
Counterpoint built their own transformers, which made sense from a business
perspective, but as a designer I always wished we could use Plitron
toroidal transformers. I don't know how they do it, but Plitron toroids
sound great. No one else comes close. All other transformers make theNPS100
sound sluggish and thick; a Plitron brings the sound to life: delicate
and vibrant with a dead-quiet background. These transformers are custom-built
to my specifications. Allow 10 weeks for these transformers to be built.
to Upgrade to Plitron Transformer: $760
4. Hardwire Monobloc Conversion
you have two NPS100 amplifiers, we can convert them into powerful, yet
sweet and detailed, 260W mono amps. Very worthwhile having done: mono
amplifiers image perfectly and have zero crosstalk or interchannel interference.
A very ballsy upgrade.
for Monobloc Conversion: Add $180 to convert to mono with upgraded RCA input jack.
(Not available separately, requires either the Basic, Premium, or GOLD upgrades)
5. Circuit Board Damping.
boards are light and stiff -- they are resonant as heck, which causes
smearing of the sound. Your audio will be substantially improved when
we apply thick wool felt damping pads between the circuit boards and the
chassis to damp all resonances. This results in MUCH tighter imaging and
spatial resolution, MUCH greater retrieval of low-level details, a surprising
reduction in edginess, and a greater weight to the tone, which makes everything
sound fuller and more "real." Click here for pricing. (Not available separately, requires either the Basic, Premium, or GOLD upgrades.)
If I can
be of any further assistance, do not hesitate to contact me.
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