J Corder/Bottlehead-Modded Technics RS-1500US With Charles King-Modded Analog Engineering Tape Preamp - The Ultimate Analog Combination

This is a state-of-the-art custom J-Corder Technics RS 1500 2 and 4 track reel-to-reel tape deck named “The
Blues” plus a Charles King-modified Analog Engineering vacuum tube IEC/NAB tape
preamp. Both are in good working order and have no issues. Both were recently
gone through by an experienced technician and given a clean bill of health. The
tubes in the Analog Engineering tape preamp have all been tested and all tubes
test strong with plenty of life left on them.

The J-Corder Technics RS 1500 does have some cosmetic issues, however these are mostly on the side panels. I have tried
to show these cosmetic defects in the pictures, however there may be a few
others the camera did not pick up. 
Hence the 6/10 rating. The easiest way to overcome this would be to
either prime and paint the sides or source new ones from J-Corder or one of the
other aftermarket RTR specialists. There is also a compromised corner on the
bottom left side of the pre-amp’s faceplate as you can see in the pictures.
This happened during shipping at one point and, like the blemishes on the deck,
has no effect whatsoever on the sound. 
One word of warning -you will need a preamp or integrated amp that has a
decent amount of gain as the levels coming out of the preamp are on the low
side.

The J-Corder-modified deck originally
cost $7500.00 and the Analog Engineering tape tube preamp retails for $2495.00
before the modifications. So it would cost you about $10,000.00 to get these
two pieces of gear in new condition today.

Included in the asking price are the original shipping container from J-Corder, the
original Technics soft plastic dust cover, the two Darklab/Revox hub adapters
pictured in the photos plus the original J-Corder custom blue Technics reels
also shown in the pictures. You will want to source some spacers for playback
as the metal reels have slightly warped over time and may rub against the deck.
A better idea would be to source plastic reels for actual playback and keep the
metal ones for display. Plastic sounds a lot better – especially plastic reels
that do no require a hub adapter – just fewer pieces to impart their own noise.

Please note that the RS 1500 has both the tape counters and LED meters removed from
the circuit.  There are no record
heads in this highly-modded unit.  If you are in the market for a
great playback tape deck, this is the one. I will not separate these two units
so please do not ask.

Buyer
pays Paypal fees and is responsible for covering ALL real-life shipping costs.
I am constantly amazed by buyers who think that 75lbs of gear split between
three boxes shipped with insurance across the country costs only $25. It
doesn’t.  Plan for something in the
vicinity of $150.

Here is some general information about
both units taken from the listing by the original owner:

 

J-Corder-modded
Technics RS 1500 2 and 4 track tape deck:

Our quest for the Holy Grail began with
the purchase of a rebuilt Technics RS-1500US reel-to-reel tape machine
(manufactured between 1978 to 1986 and retailing then in the neighborhood of
$1600), from Jeff Jacobs at J-corder.com. Jeff, for those who don't know him,
is a preeminent Technics reel-to-reel technician with over 35 years of
experience as both a dealer and authorized technician for a number of audio
manufacturers. While I paid a lot more for my Technics machine than if buying
off eBay, I had the piece of mind that Jeff had completely stripped down, serviced
(including replacement with upgraded brake pads), recalibrated and then bench
tested my deck to ensure it met manufacturer specs. Furthermore, Jeff inspects
and tests the tape heads; if they measure less than 70% of tip depth, he
replaces them. For those searching for the ultimate, sexy looking reel-to-reel
tape machine, Jeff also customizes the Technics reel-to-reel machines and gives
them unique names like The Blues, The Natural, The Pearl, Jade or Black Crown Jewel.
Running anywhere from $4000 to $8000 (or more), these tape machines are
unmatched works of art. Owners can customize their decks even further by adding
some color matched Dark Labs NAB hubs and/or J-corder or Dark Labs customized
reels to their machines.

 

Step
Two: Hot Rodding the Deck

After Jeff worked his magic on my deck,
the J-corder Technics deck went to Dan at Bottlehead Electronics to eke out
that last couple of percent of performance from my deck. These performance
upgrades included hot rodding the Technics for use with outboard electronics
and use of an after market IEC plug, disconnecting the tape counter and level meters
and upgrading the tape path.

Every machine that comes into Dan's
shop undergoes a rigorous inspection and replacement (if necessary) of any worn
tape path and alignment of components in the tape path for straight and consistent
tape travel over the heads and a flat, well centered tape pack on the reels.
The Bottlehead tape path modifications also reduce friction on the tape surface
and scrape flutter and make the tape sit a little closer to the heads when
running in fast forward and rewind. "The end result" according to
Dan, "is a machine that handles tape extremely well and sounds cleaner, with
better low level resolution and snap and begins to approach the sound quality
of a pro machine."

But prior to carrying out any of the
above modification, Dan adjusts the deck's brake tension. According to Dan, the
one common problem he's encountered "is setting the correct brake tension,
regardless of how new the stock felt brake pads look." After experimenting
with different brake lining materials, Dan found a material that meets the
tension specifications in both directions. All the decks that come into his
shop have their brake pads retrofitted with this material. Dan also mentioned that,
"it's remarkable how much better a RS-1500US works with the proper brake
tension. The tension rollers never pop up at stop and the reels stop very
quickly at runout. With the tape kept in good tension the pack seems to come
out better when you stop and start a lot too."

The next order of business is aligning
the ever so critical tape path. First, a careful visual alignment using some
established reference points is a starting point for static alignment; the bulk
of the alignment adjustment is made with shims. Then once the visual alignment
is complete, the travel of the tape over the rollers, guides and heads and the
tape pack position is noted. Dan has found that if the tape path alignment is
done with enough care some sources of friction in the tape path can be removed
and some guide surfaces can be replaced with lower friction materials resulting
in subtle improvement in dynamics.In addition, Dan disconnects the tape counter
because the belts create speed instabilities that degrade the sound. As Dan
says, "You can tell how much the counter influences the smoothness of the
reversing idler if you've ever heard the dreaded screech of the cheesy tape
counter belts and pulleys when you rewind. The tape counter is not that
accurate anyway."

Last but not least, Dan hot rodded my
machine for direct head output and use with the Analog Engineering Charles King
modified IEC/NAB vacuum tube preamp.

Analog
Engineering Charles King-modified vacuum tube IEC/NAB tape preamp:

Preamp
Circuit:

The phono preamp uses three triodes per
channel: one half of two 6N1P-EB type tubes for gain, and one half of a 12BH7
for cathode follower output. The 6N1P is a current production Russian tube; its
high performance specs and sound quality have made it a favorite alternative to
pricey NOS valves.

The RIAA equalization is split; the
first EQ constant is implemented between the two 6N1P gain stages, and the
second EQ constant between the second gain stage and the cathode follower. The cathode
follower is direct coupled, with an output impedance of roughly 500 ohms, so
the circuit can easily drive long interconnects.

Constant Current Sources (CCS) are used
for loads on all the tubes, and LEDs are used within the CCS for cathode bias.
The LEDs are selected for their low noise, dynamic impedance, and RF stability
in the circuit.

If you’re not an engineer, don’t worry
if this all sounds complicated. The simple result of the circuit is rich,
smooth, detailed analog sound in all its glory.

Layout
and Lead Dress:

Since layout and lead dress are vital
in analog circuits, a great deal of attention was given to the placement of key
components. No detail has been spared. Signal leads are kept very short, to
minimize both magnetic loop area and capacitance to other wiring. On the signal
return loop, ground connections all return to a low impedance ground plane.

Grid stopper resistors are used on each
vacuum tube grid, to damp any resonance associated with grid capacitance and
lead inductance.

High current heater wiring is elevated
from the circuit board on heavy gauge shielded twisted pair wire.

Experienced craftsmen assemble each
preamp by hand with loving pride. We treat every unit as if it were going to be
hooked up to our own system.

Power
Supply:

The power supply has been designed to
minimize noise and exhibit extreme stability. It all starts with a
high-performance torroidal power transformer. The 6V heater circuit powers the
6N1P tubes, and is exceptionally quiet. The circuit is rectified with Schottky diodes,
and feeds a choke input filter for an extra degree of common mode noise
rejection. Capacitive bypasses around each heater eliminate any remnants of VHF
hash.

The 12V heater circuit is rectified
with Schottky diodes, and employs an RC (Resistor-Capacitor) filter. The 12V
heaters are bypassed in the same manner as the 6V heaters.

The high voltage is rectified with SiC
Schottky diodes, and is well-filtered with a three-stage RC network. This
filter supplies two shunt regulators, providing dual mono regulated power for
the preamp.

What does all this tech talk mean to
you, the listener? An inky, blacker-than-black background, from which music
leaps out with astonishing clarity.