Converting
the SA-5 or SA-5.1 into a "Junior SA-9"
The
SA-9. Some people consider it the best phono stage ever made. If you own
one, consider yourself lucky. (I have upgrades for that model here.)
If you are looking for one, you probably already know that they are very
hard to find.
I have
developed upgrades for the SA-5 or SA-5.1 that make it essentially
a junior SA-9. If analogue recordings are your sanctuary, and you
despair of ever finding an SA-9, or can't afford one, then get an
SA-5 or SA-5.1 and have me convert it to a standalone phono stage
with that "SA-9 sound."
Here's
how it works: When I designed the SA-9, I used the same technology
that I had used in the earlier SA-5/5.1. Both are triode-based no-feedback
phono stages, and both use the exact same pure-tube power supply technology.
The
reworked SA-5/5.1 sounds uncannily like the SA-9 . . . better, in
fact than a factory-stock SA-9!
This upgrade
is available in two levels:
Basic
and Premium for Moving-Magnet (MM) cartridges, &
Basic
and Premium for Moving-Coil (MC) cartridges.
And as always, there are options, which are described further down the
page. But rest assured, even the Basic conversion will give you a lifetime
of great vinyl reproduction.
Whether you
pick the Basic or Premium, I disconnect the line stage and make the volume
and balance controls inactive, remove the fairly useless high/low gain
phono input jacks which obscure sonic detail, and set you up with a pair
of high-quality MM in jacks, and a pair of Phono Direct Out jacks.
The final result is a magnificent-sounding standalone phono stage,
with a line-level output, ready to be connected to your preamp.
Basic
and Premium MM Versions of the SA-9jr
The
BASIC SA-9jr Upgrade for Moving-magnet Cartridges.
The
phono stage is torn down and rebuilt with modern components,
selected for neutral, dynamic and transparent sound. Bass
clarity, midrange openness and treble sweetness are the
goal here.
In
the phono stage,we replace the all the grid bias, plate
load, and buildout resistors with Caddock Tetrinox film
resistors and Mills Non-inductive wirewound resistors,
and we upgrade all coupling and energy storage caps
to Dynamicaps.
The
power supply for the SA-5.1's audio circuit is is a pure
tube regulator and it sounds very smooth. It has the potential
to sound far livelier, more neutral and more transparent
if the passive parts are upgraded, and some solid-state
parts removed. So I upgrade the tube-based regulator parts
in the audio chassis: the three-tube section on the right
side of the chassis. A "AAA" grade V-type rectifier
tube is installed in place of the original 6CA4 rectifier
tube. (Click here
to read about rectifier tube options.)
In the regulator, we install far better resistors and
film capacitors, and upgrade the aluminum electrolytic
capacitors, using a Black Gate capacitors.
The solid-state constant-current source for the error
amplifier tube is eliminated, removing the final source
of "transistory" colorations.
Price
for Basic MM "SA-9jr" Upgrade: $1,980 (price includes a
pair of high-quality MM In jacks, and a pair of Phono Direct
Out jacks.)
The
PREMIUM SA-9jr Upgrade for Moving-magnet Cartridges.
Not only do you get the bass clarity, midrange openness
and treble sweetness of the Basic, the Premium offers a
quieter background, more three-dimensional imaging and enhanced
musical involvement.
Like
the Basic, the phono stage is rebuilt with better parts
-- the best available, selected for transparency and precise
detailing.
Additional Dynamicap and Black Gate phono stage power supply bypass caps are also used,
and we install ceramic/gold tube sockets throughout
the unit.
The
main focus here is power supply, power supply, power supply.
Not only are the best capacitors and transformers the most
expensive single components in a product, they have the
capability to completely destroy or elevate the sound. WKZ
capacitors, Plitron
transformer, more Dynamicaps and a custom-built power
supply cable made of single Cardas wires all add together
to make a power supply that lets this phono stage strut
its stuff.
We even upgrade the tube's
filament (heater) supply with FRED diodes and Nichicon KZ
power supply bypass caps. Finally,
the rectifier tube socket in then power supply is rewired
to accomodate better-sounding 6BW4 tubes (as well as the
original 6CA4/6V4 types), and a "AAAA"-grade 6BW4
is installed. (Click here
to read about rectifier tube options.)
Price
for Premium MM "SA-9jr" Upgrade: $3,740 (price also includes a
pair of high-quality MM In jacks, and a pair of Phono Direct
Out jacks.)
Basic
and Premium MC Versions of the SA-9jr
The SA-5,
SA-3, SA-5.1 and SA-3.1 were never intended for use with low-output
MC cartridges. (Counterpoint had the SA-2 tube "head amp"
for that purpose.)
The low and high-gain inputs on the SA-5/5.1 were an attempt to offer
some flexibility when dealing with high and low output phono cartridges,
but the phono stage in these preamps is really suitable only with the
higher moving-magnet signal levels of 4.7mV or so. If you've ever attempted
to use one of these preamps with a low-output MC cartridge, you know
that there is really not enough gain, tube noise predominates the background,
and dynamics are not great.
The MC versions of the Basic and Premium conversions
eliminate that restriction by using a pair of transformers to step up
the low output of an MC cartridge to MM level, and by doing so, lets
you listen to vinyl with your best MC cartridge, with pure tube sound.
These
versions are for the person for whom music is a sanctuary.
This
upgrade allows the SA-9jr to completely outperform the factory-stock
SA-9 which used transistors for the MC step-up function. Click
here to read more about
why transformers are your best choice for MC step-up.
Accomodate
low-output moving coil cartridges with your SA-5jr
with Jensen's excellent MC stepup transformers. Dead quiet, transparent
and warm-sounding. These are the same parts used by manufacturers
such as LAMM, Jeff Rowland, ARC and Valve Researh. (Photo of S.
Kushino's SA-5.1 preamp, used with permission.)
There
are two ways your preamp can be modified to use MC stepup transformers:
1. The
Flexible Approach:
The "high gain" phono input becomes a dedicated MC input
and is connected to the stepup transformers. The "low gain"
phono input becomes your MM input. A new switch is mounted on the
back to select between the MC and MM inputs. Handy if you are not
sure which phono cartridge you will be using.
2. The Purist's Approach. Phono cartridge signal levels are
minute, and even the slightest bit of contamination on a switch's
contacts can affect the sound. If you know you will not be using an
MC cartridge, we can hard-wire the transformers directly to the phono
stage.
Please
call to discuss your needs so we can install proper matching for your
cartridge.
The
BASIC SA-9jr Upgrade for Moving-Coil Cartridges.
For the listener
who wants to use MC cartridges.
Just
as in the MM version, the phono stage and power supply regulator
section are rebuilt with modern components as described
above in the MM Basic upgrade.
Price
for Basic MC "SA-9jr" Upgrade: $2,750 (price
includes a pair of high-quality MC In jacks, a second pair
for MM if the "Flexible Approach" is selected,
and a pair of Phono Direct Out jacks. Remove $224 from this
price if you provide your own transformers -- contact us
so we can confirm that they will fit in the chassis.)
The
PREMIUM SA-9jr Upgrade for Moving-Coil Cartridges.
For the listener
who wants the very best possible sound for MC cartridges.
Just
as in the MM version, the phono stage and power supply regulator
section are rebuilt with modern components as described
above in the MM Basic upgrade.
Price
for Premium MC "SA-9jr" Upgrade: $4,500 (price
includes a pair of high-quality MC In jacks, a second pair
for MM if the "Flexible Approach" is selected,
and a pair of Phono Direct Out jacks. Remove $224 from this
price if you provide your own transformers -- contact us
so we can confirm that they will fit in the chassis.)
Other
Cool Options
Since one
of the key points to this conversion to a standalone phono stage is disconnection
of the line stage, there will be two unused tube positions in the SA-5/5.1.
These tubes can be used for one (1) of the following optional functions:
Keep
the Line Stage, Version 1:
If you want to keep the line stage and volume controls connected in
case you need a fallback line stage, no problem -- they only contribute
a slight loss of signal quality by leaving them connected. Just let
us know. Keep the Line Stage, Version 2:
Keep the
line stage operating, but sever the internal connection between the
phono stage and the line stage; then, if you want to run the phono stage
through the SA-5.1's line stage, you connect the new dedicated phono
outs to one of the line inputs with a pair of interconnects that you
provide. No loss of sound quality, no extra charge.
Drive
That Line!
The output
impedance of the SA-9jr's phono stage is pretty high -- about 3,000
ohms. Generally speaking, that's no problem if driving interconnects
no longer than, say, 3 meters (must be shielded), and driving line stages
with input impedances greater than 50k ohms. But if long lines or low-impedances
are expected, then the unused line stage tubes can be converted over
to cathode followers, which will let us drive a hundred feet of line
and line stages down to 5k. $165 for this mod.
A Balancing
Act Another
use for the unused line stage tubes would be to provide balanced outputs
-- pure tube balanced outs. To make room for the XLR's I remove the
serial number I.D. plate and affix it to the chassis bottom. $500
to add balanced outs.
Go West!
Or, the unused line stage tubes could be used for other purposes: For
example, if a fellow had four WE 417A tubes, the line stage could be
employed as part of the phono stage, letting you have a full Western
Electric phono stage (need twice as many 417's as you do 6DJ8's because
the WE is a single-triode, while the 6DJ8 is a dual). $400 (you supply
the four WE417A tubes).
A
Frequently-Asked Question:
Question:
The SA-9 has four phono tubes, while the 9jr has only two -- why?
And does it make a difference?
Answer:
In both the SA-9 and the SA-9jr there are two amplification stages:
one before the riaa network, and one after it. In the SA-9, the
first stage is a single 6DJ8 with both halves wired in parallel,
and the second is also a single 6DJ8 with both halves in parallel
(the 6DJ8 has two triodes in one bottle). The advantage of parallel
operation is theoretically 3dB less noise (presuming both halves
are equally quiet). The disadvantage is if either half goes noisy
or microphonic, the unit needs a new tube. There are four sections,
total, in the SA-9 that can fail that way, per channel, or eight
total tube sections.
In the SA-5/5.1 "SA-9jr" the first
stage of amplification is one-half of the one tube, and the second
gain stage is the second half. This is theoretically 3dB more noisy,
but in reality, the noise disadvantage is far less important than
the fact that you have half as many tube sections that can go noisy.
The fewer tubes, the more reliable. Half the number of tube sections,
twice the reliability.
In addition, we've learned that paralleling
devices (a la the SA-9) usually will not sound as good as using
single devices, like in the SA-5/5.1, or SA-9jr. One more thing:
two phono-grade vintage NOS cost half as much as four!
If I can
be of any further assistance, do not hesitate to contact me.
