Online Owners Manual for The Cortobass / Sadhana bass - ©2008 Birdsong Guitars, Wimberley Texas
USA
Owner’s Info April,
2008
Note: all specs are subject to change without notice. Everything is a work in
progress, as are we all. Changes will be posted on
the Birdsong Guitars site and every effort will be made to update the paperwork
that accompanies your instrument. If there are any questions feel free to call
us at 512.847.6014. We suggest printing the latest manual and keeping it with
your instrument, as this supercedes all previous material.
BRIDGES & STRINGS
The bridge fitted to your Birdsong bass is made to our specifications
by the Hipshot company of New York. It's their "Style A." Not cast "mystery metal" or bent
steel, it is milled from solid brass
(unless noted otherwise) for
added mass and sustain, and gives you the option of top-loading or stringing
through the body. We STRONGLY recommend you string through-body unless you prefer flatwounds.
I'm weird about the way the windings on flats separate over the sharp bend
coming out of a through-body stringing setup. They may work fine for you &
sound great, but they don't look happy and probably will fatigue there &
break prematurely. Of course, my idea of the lifespan of flatwounds can be
measured in years... I usually ship flats top-loaded for this reason, and don't
recommend flats on the Hy5 bass.
There were a handful of Cortobasses equipped with the
Hipshot "vintage style" bridges in brass.
The bridges on the Hy5s are handmade with modified Hipshot saddles, and these
basses only string "Double Through" the body. This is our design (pat.
pending) and helps improve the feel & voice of the low B. We recommend
"super long" sets of 5-string strings for the Hy5. Some standard
length sets have enough "main string" to get past the nut, and some
don't.
STRINGS USED CURRENTLY:
4-string fretted: Curt Mangan .045 - .105 Nickel Roundwounds, standard
length.
4-string fretless or flatwound requests: D'Addario Chromes ECB82
.050 - .105, standard length.
Tapewound requests:
Fender 9120M .058 - .110 sound great and we through-body string these
(the windings don't separate) or top-load. Great strings. Note: Your nut slots
will have to be widened to fit these. Like plastic or bone, Ebony too can break
if you're not careful.
Hy5s: D'Addario EXL170-5SL Nickel wound .045 - .130 Super Long scale. I
know that seems weird, but trust me.
Standard length 4-string sets strung
through-body wind up with 3/4 of a turn of main E string around the post, but in
100+ instruments we haven't had a problem with that.
Stainless steel roundwound strings don't sound nearly as good
on any of these basses, so they are not
recommended.
We obviously can't warranty the fretboard on our fretless necks if you choose to
use roundwound strings.
Restringing instructions are below in the "tech" section.
BRIDGE SADDLES may occasionally begin to rattle as playing vibration backs
the height adjustment screws ever so slightly back into the saddles. This is a
common occurrence with electric guitar & bass bridges over time. Saddle
adjustment screws on Birdsong instruments are treated to a tiny drop of Loc-Tite
or equivalent if needed during setup. This rattle is a faint metallic buzz
coming from the bridge. To find which saddle screw is vibrating, after picking a
note that causes the vibration, press your finger firmly to each saddle screw.
Repeat until the buzzing goes away when you touch the saddle - you’ve found
it. Take the appropriate allen wrench, back the screw out, coat with a drop of
Loc-Tite or equivalent, and screw it back in until it seats against the bridge
base.
*******
HARDWARE & COMPONENTS:
A WORD ABOUT HARDWARE - Black hardware is more prone to
scratching during your restringing & adjustments over time than chrome or
gold plating. This is the nature of an "anodized" finish. Extra care
should be taken (it is in here during assembly) when you restring or work on
your instrument. And yes, the gold hardware is actually "gold plated" - there is a 3 micron
coating of very high quality gold on the surfaces.
THE GRIPPER STRAP BUTTONS - Your strap buttons are not on "crooked" - look
at how the big piece interacts with the slot on your strap when it's on you
- it should go across the slot (not be in line with it) thereby not
letting it slip off.
NUT
Most Birdsong basses are equipped with a ZERO FRET, which
effectively removes the nut from string height, tension, and tonal issues; now
that its sole
purpose is to set the string spacing at that end of the fretboard, we can use
our favorite material and carve it out of wood. Ebony and/or
Maple are our main choices, though other dense woods such as Purpleheart may be used for their cosmetic
contribution to the instrument. If at some point it comes unglued during a
restring, two small drops of Titebond wood glue or similar will secure it. DO
NOT use super glues - they make future adjustments or repairs very difficult. If
through impact your nut breaks (I hate it when that happens), see the repair
tips below for nut blank measurements or contact us & we'll make you a new
nut, though some final fitting will be needed. In a pinch, being as it's wood
and not under a lot of tension (because of the zero fret), the pieces could be carefully glued back
together.
Some Cortobasses (especially from inventory) are equipped with necks that have a
standard nut & no zero fret. The nut is made from Ebony and the above
re-gluing info applies; however if it gets broken it's best to cut a new one.
We'll be happy to supply you with an Ebony blank for your local luthier.
NECK
Our necks are extremely strong. Instruments are set up with no relief and left
to settle in for a few days. This generally results in minimal relief, as they
just don't generally move much. Due to climatic changes from here to wherever
you may be, some movement is to be expected over time as the instrument adjusts
to its new climate. This is true in any new instrument. Any competent shop can do the
slight adjustments that may be necessary. If you tackle it, remember "righty
tighty" (for less relief) and "lefty loosey" (for more
relief). Don't turn more than 1/4 turn without letting it settle in again for a
few hours. More info below in the "notes for repairs"
section. As a short scale bass has less tension, which results in a larger
string vibration, more relief will be needed for very aggressive players used to
a longer scale higher-tension instrument... or you Michael Anthony types.
JACK
The input jack loosening up is another common occasional problem on all electric
instruments. Jacks are fitted with toothed washers and securely tightened on all
Birdsong instruments but over time with use they may loosen. Don’t just
tighten the nut - sometimes it has loosened to where this will cause the jack to
spin inside the cavity. The jack is attached to two small wires that, if spun
around enough, will break loose from the other components. To fix a loose jack,
carefully unscrew the jack plate, so you can hold the jack with your fingers or
small needle-nosed pliers as you tighten the nut with the appropriate sized
socket. (All Birdsong guitars and basses are equipped with Switchcraft jacks and
use a ½” socket.)
The Switchcraft jack is much sturdier and heavily built than typical (imported)
factory jacks. However this is a high wear component, and may loosen internally
over time. If the jack isn’t holding the plug securely or is cutting out,
carefully remove the jack plate and bend the lug coming off of the jack in
towards the hole slightly. Replace and try it; this takes care of it sometimes.
If not, replacement is a standard Switchcraft ¼” input jack, AllParts number
EP 0055. If it wears out under warranty, we’ll be happy to ship you one
with easy instructions on how to replace the part.
Of course if you have a long threaded jack fitted to your instrument (no visible
nut where you plug in), you'll need AllParts number EP0151. Same offer applies.
PICKUPS
The pickups in the Cortobass have been chosen by the designer after years of
experimentation. If he ever finds a better sounding pickup in this
application, he'll update the specs and equip the bass accordingly.
A few pickups have been used: The neck pickup on most basses has been a Lace
"gold sensor"; the CortoFusions have a specially chosen humbucker used, mounted and wired
so completely
differently than it was designed for that brand & model names are
irrelevant. Contact us for details. The Hy5s have an EMG HZ in the neck. As for
bridge pickups:
The EMG Select SEHB humbucker, a humble but fantastic sounding pickup by
a company that wouldn't give us the time of day... (pre-2006)
The custom-designed Birdsong "Punchbucker", a
further refinement of that tone. The company that made them for us decided our
orders were too small to bother with and stopped the supply. And you thought
this was easy? This is why most companies just build P-basses and be done with
it. Sigh. (2006)
The high-output Lace we put in some single pickup basses needing a growly
aggressive thing since it doesn't play well with others...
and a milder Lace with a great tone we've used as standard equipment since early
2007. In the bridge of the Hy5 is a Kent Armstrong... again, different from the
neck as the pickups in each position are selected by tone, not brand or model
consistency.
A word about the pot taper - the main goal was to get the absolute best tone
from each pickup position. To do this, the pickups were chosen for their tone.
These chosen pickups are of different strength and sometimes even from different
manufacturer. Their ideal pots are of different value too. This results in some
loss of blendability and a bump in the taper about half to three quarters of the
way towards full volume when turning the pot. This happens to some extent anyway
in passive systems, as one pickup wants to dominate over the other. Why our
basses sound so good in the main (neck, bridge, combined) settings all the way
up is why this issue is present. A blend pot would smooth the balance but
degrade the tone, as you'd be putting two very different pickups through one
value pot... and I've never (20+ years) heard a blend pot in a
passive bass sound as good "in the middle" (both on full) as one with
separate volumes. The tone of our instruments built the company. This is a known
quirk and I consider it relatively minor and well worth what you give for what
you get, tone-wise. As always, I'm here to talk with you if you disagree.
VARITONE
Some Birdsongs have a 6-position varitone in place of a standard tone knob.
The varitone is a series of tone filters designed to change the tone of
the bass with each setting of the switch. There are five settings and one bypass
setting which allows the stock, unaltered tone of the pickups to pass through.
Some varitone settings may be more effective than others depending on your
personal amplifier settings. Please note: this is not a circuit designed to
emulate the tones of other basses; it is here as an alternative to a tone
control with a single capacitor, most of which are not voiced to do anything but
turn your tone to meatmush.
According to the designer of this particular varitone, Dan
Torres of Torres Engineering, it is normal for a varitone to make an audible
“pop” as you switch through the settings at first. (Note: more recent
ones don't seem to do this - perhaps a spec change in the switch was made?) This is caused by a
discharge of voltage stored in the capacitors. It is recommended that you run
the varitone through all of the notches once or twice before you turn the amp on
& begin playing. And be nice with it; it's not a wah pedal. Don't powershift it like a friggin'
Trans Am, ok? It's a camera lens filter, not a hammer.
From the first setting (bypass), the next few will cut the high frequencies at
increasingly lower points resulting in funky midrangey tones. The last two are
very deep sounding; with some sonic tweaking on your amp these could provide
interesting main tones, huge sounding with distortion or great for reggae or dub
clean. The varitone can also be modified by those with electronics experience, a
handful of capacitors and a soldering iron. This may, however, void the warranty
on certain electronic components. Please contact Birdsong Guitars for any
schematics or assistance.
Explore the tones and try them in a variety of pickup blends and amplifier
settings. I like & use them all, especially during recording sessions.
There's nothing like having more colors on the palette to paint with. Some
tonal colors are more visible than others depending on your amp setup, EQ, room,
ears, fingers, style, volume, etc. There IS a difference between all the
settings.
CONTROLS
The Lace neck pickup is connected to a 250K pot, the bridge position
humbucker to a 500K.
These volumes work independently and the pickups may be blended to taste. Note
that in passive circuits, it is difficult to gain smooth blend tapers and the
blending variations work much better when the pickups are both backed
off very slightly from full volume. CortoFusion pot specs are different; please
contact for details. Hy5s use 2 500K pots.
ANTI-SHOCK CIRCUIT
The grounding wire from under the bridge (which on electric guitars
minimizes electronic hum when your hands are on the strings) may be equipped with a
.001 capacitor and a 100K-250K resistor in parallel that under certain
conditions may minimize electric shock. It is not a sure-fire prevention and no
guarantees are expressed or implied, but it is the least we can do to try. If the
Universe decides you need a good zap, however, there isn’t a capacitor around
that’ll spare you. So it is no substitute for checking the ground on your
equipment and generally being nice.
FINISH
The finish we use is a special oil blend. Records are kept on every instrument
built and any adjustments to the blend; please contact for assistance to
questions.
An oil finish will age and show wear. Preventive steps are the key - wash your
hands before playing, wipe the instrument down with a soft cloth after. With a
hand rubbed oil finish you have traded away a thick plastic sound-deadening permanent
lamination
of your instrument for a more natural finish that feels better in the hands,
allows for better tone, and gives a more organic and natural look to the wood.
The oil finish protects against moisture, but hard knocks and scrapes will show,
and the finish will take on the patina of something that is being used
regularly.
This, to us, is even more beautiful; you are in a
relationship with this instrument, it is NOT an appliance. You will both age,
you will both scar. Wear spots may be lightly sanded and boiled linseed oil mixed with clear poly should be applied per instructions on the
can. Light grime can be taken off the neck with a gentle rubbing of #0000 or
finer steel wool. We blend some poly into our oil, but your guitar will still
not stay looking new without some action of prevention or maintenance on your
part. We feel it is more important that the wood be respected, and made to
neither look nor feel like plastic.
And please know we humbly thank you for allowing us the privilege of building
your instrument. If we can ever be of assistance in any way, contact us; we
encourage you to keep in touch with us and keep us posted on yourselves and your
musical journey.
Scott Beckwith
Jamie Hornbuckle
Birdsong Guitars
PO Box 1745
Wimberley, TX 78676
512.847.6014
www.birdsongguitars.com
©2008
Bass Tech Notes For Future Repairs / Modifications:
Pots are standard CTS, 250K audio for the neck & 500K audio for the
bridge. Fusions have a custom made 1meg pot. Instruments ordered with metal set screw-type knobs have solid shaft
pots, instruments ordered with wood knobs generally have split-shaft pots.
Exceptions happen.
Two truss rods have been used:
Heavy duty single-action adjustable with 5mm allen wrench
2-way rod adjustable with 4mm allen wrench
I know it's confusing, it's confusing as #@$& here too. If there's no zero
fret, it's a 4mm double-acting rod; most others and all HYy5s have a 5mm heavy
duty single action rod.
The Varitone is based on a kit from Torres Engineering.
A Cortobass is star grounded, meaning all grounds go to a central point.
The circuit between the bridge ground wire and the star grounding point is an anti-shock
circuit consisting of a .001 capacitor and a resistor of 100 - 250K wired in
series.
Cortobass cavities have always been shielded, first with paint &
foil, then paint & copper. After serial number C-009 and all other models
are completely copper
shielded with soldered joints.
The pickups on the Cortobass & Sadhana are set as follows:
Neck pickup is flush with the fretboard edges.
Bridge pickup is roughly 2mm lower into the body on the bass side, 3mm on the
treble side (EMG SEHB - marked Select in silver letters) or set flat somewhere
around there (Punchbucker - plain black face) and the Lace humbuckers (marked
LACE in gold or embossed) are level, at that height or
slightly lower.
The jack is a standard mono Switchcraft ¼”.
The nut is Ebony, Maple, Purpleheart or other dense wood, grain running
side to side.
Dimensions for cutting a rough blank are as follows: 39mm W x 8mm H x 8mm. We
like mm; they're easy to work with. I want to build your bass, not do math
homework. When we make them, we size the blank, fit the blank to the nut
slot, mark the top of the fretboard on the nut with a sharp pencil, mark the
string spacing, carefully slot it on a band or scroll saw, down to the top of
the fretboard on the playing side, angling the slots back with the headstock
pitch so the strings angle properly and don't buzz in the nut. Clean up the
slots, remove excess material, edges & corners on top & shape the nut.
Sand & buff with steel wool. Install with 2 drops of Titebond wood glue or
equivalent - NOT super glue! If I have to explain why, please let someone else
work on this bass.
Instruments from 2006-7 and the occasional "CortoBasic" may be equipped with a traditional (non zero fret) nut
arrangement. These are cut like our fretless neck nuts - out of Ebony (black)
generally, same technique as above but the string slots are not cut to
be level with the fretboard, obviously. They are cut for suitable string height
over the frets like slotting a normal nut.
It is a good idea to check the gear screw on the back of the Hipshot Ultralight
tuners occasionally. If one over time comes loose and is lost, it is a phillips
head, 6/32 x 1/4" screw. Feel free to contact us for assistance, or Hipshot
directly at 1.800.262.5630.
Instruments are strobed on a Petersen VS-series, intonated to the attack
of the note (plucked with medium force), not the decay of the note. There is a
difference, and this works for me, so that's how I do it.
Action is generally set in the 2 to 3 mm range @ the 24th fret, from the
top of the fret to the underside of the string. Shorter scale basses have less
tension and appreciate slightly higher string height than longer scale, higher
tension instruments. Higher string height in general sounds better too, so raise
'em up and dig in, hoss! Players with a light touch can lower their strings
further.
A nut on an instrument with a zero fret functions differently than a
standard one - all scale accuracy & tension is borne by the zero fret. I cut
the nut slots wide for a looser feel - bend a string at the first few frets and
this will become self-explanatory. You don’t have to fight the nut.
Strings are nickel roundwound .045 - .105 (4s) or .045 - .130 (5s);
fretless
basses come with flat or tapewound strings unless roundwounds are requested by
the client. Please read your warranty sheet. More on string selection is up in
the first section.
To restring - cut string & remove. Feed new string through the back,
pulling it up snugly into the ferrule. For the E, trim about 2" off the end. Insert the end into the hole in the center of the tuning
machine shaft. Yes, fully down into it. Then near the top, bend it around the
edge & wind neatly under tension the rest of the string. It should look like
7 neat winds going all the way down the shaft, with 3/4 wrap of the full size
part of the E string. It should not look like a spool of yarn the cat got
a hold of. "Wind it all the way down the shaft." This
will get you the maximum benefit from the tension of the tilt-back headstock,
seat the strings properly in the nut & over the zero fret, and thereby give
the best tone & performance.
A = same process only use the full length of the string. Should result in
approx. 7 neat, tight winds around the shaft.
D = same process only use the full length of the string. Should result in
approx. 8 neat, tight winds around the shaft.
G = same process only use the full length of the string. Should result in
approx. 8 neat, tight winds around the shaft.
Tune to pitch, grab & stretch them a bit. Retune. Go play.
CortoClassic or other owners of our basses with Gotoh tuners should cut
about 4" off the E and 2" off the rest; the Gotoh posts are shaped
slightly differently and this gives the best wind. You still want to wind the
string neatly all the way down the shaft for proper seating in the nut and down
pressure on the zero fret.
Hy5 players using the recommended super-long strings (those generally used on
35" + scale 5-strings, such as the D'Addario EXL 170-5SL set) should trim a
couple of inches off the B and use the rest full length, winding neatly down the
post for optimum pressure on the zero fret.
The Cortobass & Sadhana should fit into any rectangular “universal” electric guitar
case and most guitar gig bags (though some can be a tight fit).
The finish consists of two poly & oil blends - contact for
specifics. We do not use filler on any of our bodies, so variations in grain
texture are normal & natural... we see these as character and not
“flaws”. It is part of working with natural materials.
Recommended source for parts: AllParts, Houston, TX USA 1-800-327-8942
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