Hieronder een lange lijst met mods voor de 808 gekopieerd van het net:
Hmmm....where to begin...
Well first off, I have so far added 11 modifications to my=
808...
BD extended decay, BD Tune, White Noise Level, Hand Clap=
"offset",
Cowbell tuning (both Oscillators), Snare "snappy" decay time,=
Snare
"snappy" filter and Snare drum tuning (both Oscillators), oh yeah=
and
Ext. Audio input for the Cymbals and Hi hats.
The first two of these mods can be found at music machines, the=
rest
I'll try to cover now.
All of these mods i am building straight in to the 808, no=
external
boxes, but thats up to your preference.
I'm mounting them onto the 2 "black plastic" sides of the 808,=
these
can easily be detached from the 808 for ease of drilling and=
such.
There is enough space to fit 3 "16mm" potentiometers at the top=
of
each of these "sides", however, I've had to use horizontal=
trimmer
pots to fit enough modifications into the 808 itself. I drilled
spaced holes along the
top of the "black plastic" sides and glued trimpots on the inside=
underneath the holes, this may seem clumsy, but it works well=
(and
looks smooth). I basically bent over the trimpots legs, applied
contact adhesive on both the trimpots legs (the points which i=
bent
over) and the inside surface of where i was going to mount them,=
and
stuck em' together
How you interface these controls is up to you, so I'll only cover=
the
modification details.
Before you begin you should have at least a low wattage soldering=
iron (grounded preferably), some "fine" rosin core solder, and
de-soldering braid (or wick). You need to remove resistors,=
trimpots,
and capacitors, so de-soldering wick is essential to remove=
"cleanly
and safely" the solder holding these parts in. A continuance=
meter is
helpful as well for checking circuit traces.
Robin Whittle has also documented the correct procedures for=
opening
up the 808 on music machines under the title "808 disassembly and=
memory stability mod"
Seat belts on?
-----------------------------------------------------------------=
----
Hand Clap "Offset"::
This adds a nice control of the claps, a one knob handclap
synthesizer, you can get sounds anywhere between deep reverb=
claps to
white noise burst (lots of nice setting in between).
looking at the 808 schematics there is a trimpot marked "C.P=
OFFSET".
Inside the 808 this trimpot will be labeled as "TM3". This needs=
to
be
removed and replaced by a 10 k potentiometer, it should seem=
evident
which wires connect to which legs of the pot.
-----------------------------------------------------------------=
----
White Noise level ::
Interesting mod which affect all the 808 sounds which use noise=
as an
element, nice control for snare. Turning down the control also
influences the snare white noise decay.
808 schematics again, there is a trimpot labeled " W.N Level=
130mv
r.m.s". Inside the 808 this trimpot will be labeled "TM4".
Remove this trimpot and replace it with a 22k Pot. I found a 25 k=
works as well.
-----------------------------------------------------------------=
----
Cowbell Tuning "both oscillators" ::
Ahh...the 808 cowbell, Its nice to tune them to
unison or harmonique chords. These tunings will also affect the=
tone
of the Cymbals and Hi hats as both of these a mixed with another=
4
square oscillators as the tone source for these, don't worry=
though,
the Cymbals and Hats still retain there charm after this mod,=
they've
just got a new element to them as well, good thing/bad thing, its=
up
to ya.
808 schematics, there are to trimpots labeled "COWBELL FREQ. 1
1.85ms" and "COWBELL FREQ. 2 1.25ms". Inside the 808 these=
trimpots
will be labeled TM1 and TM2 respectively. These will be on the=
right
hand side of the 808 board. I say this because inside my 808=
there
are an additional 2 trimpot labeled TM1 and TM2 in the 808 close=
to
the tempo knob, I'd assume these have something to do with the=
INT
clock and tempo adjustment, in other words, you probably don't=
want
to phuck with these.
So remove these 2 trimpot (the right ones) and replace them with=
two
"1meg" pots. Originally these two trimpots are only 220k,=
replacing
them with a 1 meg pot allows for a far greater tuning=
range....the
more the resistance the lower the tuning, you could even add a=
larger
pot if you want the pitch going even lower, but this value was=
enough
for me.
-----------------------------------------------------------------=
----
External audio input into the Cymbals and hats ::
This mod involves using a "normally closed" jack to disconnect=
the
original Cymbals and hats tone source (6 square waves formed by
HD14584
IC) and inject your own tonal poison. I found nice results=
pumping
white noise into it and synthesizer oscillators, but really, your=
imagination is the only limit, a radio comes to mind (good for a=
noise source as well). BTW, the way this jack is setup, when=
nothing
is inserted into the jack, the 808 uses its original tone source=
for
the Cymbals and high hats.
Looking at the 808 schemz, you should spot an IC labeled=
"HD14584".
All 6 square waves from this IC are mixed together via 120k
resistors. This mixed Audio source then gets sent to capacitors=
"C11"
and "C12". What you will need to do is to cut the trace on the
circuit board leading to these 2 capacitors (you should only need=
1
trace cut leading to both these points). You should solder a wire=
from the "tip" connection of your "normally closed" jack to=
either
"C11" or "C12" (the point from which you have cut the trace=
leading
to!). The "ground" connection of your "audio input" jack should=
be
connected to a ground point inside the 808 (try the ground of the=
direct outputs or the "-" of the battery connection (the black
wire)). There should be one more connection to the "Audio Input"=
jack, which restores the original circuit trace when nothing is
plugged into the jack. You should solder this connection from the=
"Audio input" jack to a suitable point on the other side of the
circuit trace which you have cut, for example, R35, R37, R39,
R46.....etc. etc. etc., basically any point where all these=
resistors
meet.
-----------------------------------------------------------------=
----
The next four modifications are based upon "The Mix" article on
modifying the 606, namely the snare modifications. The 606 snare=
is
quite similar to the 808 snare, though the 808 snare goes a=
little
further circuitry wise. I compared the schematics for the 808=
snare
with that of the 606's, and was able to determine how to adapt=
the
606 snare mods with the 808's.
-----------------------------------------------------------------=
-----
Snare drum tuning (both oscillators)::
The 808 snare, unlike the 606, has two drum tone oscillators. The=
pitch of these are controlled by "R197" and "R198". The "tone"
control in the 808 snare section is actually just a cross fader
between these two drum oscillators.
Check out the Snare Drum Pitch Mod in "part 2" of the 606
modification article (diagram 3).
It involves removing "R112" in the 606 and replacing it with a 1=
meg
pot and a 470 k resistor.
In the 808, you will need to add this modification for each of=
the
two drum oscillators.
Instead of removing "R112" (as done for the 606 snare pitch mod)=
you
will need to remove "R197" and "R198" inside the 808, and replace=
each with a 1 meg pot and 470k resistor, as they show in Diagram=
3.
-----------------------------------------------------------------=
----
Snare drum "Snappy" filter ::
Sweet modification, manual filter control of the white noise in=
the
808 snare, great for deeper snares. Inside the 808, this is set=
by
"R201".
Check out the Snare Noise Filter mod in "part" 2 of the 606
modification article (Diagram 4).
It involves removing a resistor (R153), and replacing it with a=
100k
pot and a 390 ohm resistor.
Adapting this modification for the 808, you will need to remove
"R201" and replace it with a 100k pot and 390 ohm resistor as=
shown
in Diagram 4.
-----------------------------------------------------------------=
----
Snare drum "Snappy" decay control::
Another smooth 808 snare mod. If you have done the "white noise"=
level mod, you will probably notice that it will have an=
influence
over the snare decay as well.
Looking at the Snare decay mod in the 606 mod article (diagram=
5), it
involves removing a capacitor "C35" and replacing it with a 100k=
pot,
5.6k resistor and 2.2uf Capacitor.
Adapting this to the 808 snare, you will need to remove "C51",=
and
replace it with a 100k pot, 5.6k resistor and 2.2uf capacitor as=
is
shown in Diagram 5.
-----------------------------------------------------------------=
----
Well, thats it 4 now. I hope these can help 808 users to expand=
the
sonique pallette of sounds grooving out of the 808, personally i=
love
modifying machines, others are a lil' more grim on the matter,
understandably because there is a risk in damaging the machine=
while
performing mods, static discharge and such, so protect yourself=
and
your machine when performing these here mods. UNPLUG THE UNIT=
FROM
THE WALL!!!!!!!!!!!!!!!!!!
Seeya groovers!
-- Plutonique9,
Plutonique9@symbiocom.com on 01/12/2001
and...
Well.....been a whiles since I've written up a phat mod for the 808, so here
she is;
This is a simple modification to do, yet has a drastic impact over the Bass
Drum's character. Simply put, it adjusts the "depth" of the envelope which
initially sweeps the pitch of the Bass Drum oscillator. It is this envelope
which gives the Bass Drum it's initial "crack". It is also a crutial
modification if you've already perfromed the Bass Drum Tune modification
Robin Whittle describes on Music Machines. This is because as you tune the
808 bass drum up, you are losing the range of this envelope pitch sweep,
this is more evident if you check out the schematics, but it causes the Bass
Drum to lose it's punch as you tune up. So, for harder bass drums, this is
where it's at.
---------------------------------------------------------------------------
What you will need;
:: 10k "Audio" pot (15mm or smaller if mounting in the 808's side panel).
:: 2.2k resistor
:: Two-conducter insulated wire
:: Standard mod tools (Solder iron, desoldering braid, drill, continuance
meter, ect.)
:: A printed copy of the 808 schematics found at Music Machines;
http://machines.hyperreal.org/manufa.../schematics/BR> ----------------------------------------------------------------------------
- Open up your 808 following the instructions at Music Machines (RW);
http://machines.hyperreal.org/manufa...08.disassembBR> ly.and.memory.stability.mod.txt
-Locate on the board Resistor "R166" (6.8k). Desolder this resistor fom the
board & remove.
*Note- you will have to completley remove the 808 board in order to remove
the resistor from the board. You can cut traces if you'd like to save time,
but it's better to avoid this.
-Where you removed Resistor "R166", replace with your "10k Pot" with a 2.2k
resistor in series.
*Note- The 2.2k resistor limits the Max depth of the envelope sweep.
-Mount the pot where you have space, I've found the side panels are great
for small pots.
----------------------------------------------------------------------------
Thats it folks, easy as pie....but don't go stickin' your hand in the oven
if you don't know how to bake a pie, if ya know what i mean. Always have
patience and extreme care when performing any mod, do it right the first
time.
Seeya
p9
Mp3.com/Plutonique9
and...
I took a brute approach to Modifying the Toms for extended tuning range. I
basically removed the 3 "500ohm" potentiometers currentley used for
Tom/Conga tuning, and replaced them with "2.5k" potentiometers. Now, I don't
think it's possible to track down the "original" style pots used on the 808,
so any generic pots will do. The new pots should have a shaft thin enough so
that the new pots can be mounted to the metal case of the 808(in the holes
left by removing the pots). You'll have to solder 2 wires from the new 2.5k
pots to the points in which the original 500ohm pots were soldered into the
circuit board. (detailed info on this exactly is below)
Now, removing the pots are a real ****, you'll for sure need the following
before attempting the operation;
-40watt soldering iron (or higher)
-Delsoldering tool (for removing the bulk of the solder)
-Delsodering Braid (for removing remaining solder)
Take a look at the 808 schematics (which shows the Toms/Conga schematics)
Check out "VR11" "VR13" & "VR15", these are the tom/conga tune pots.
After you remove the original pots, You'll need to solder points "1" & "2"
(of VR11, VR13 & VR15) to the corresponding legs of your new "2.5k"
potentiometers with some insulated wire.
*Note, make your wire lengths long enough (but not too long) to give you
ample "slack" (between where the pots are mounted to the 808 case and the
circuit board inside the 80.
Now again in regards to "VR11, VR13 & VR15". Check out the points labled
"1". These connect to one side of your "dual-diode" pitch envelopes ("D80
&D81, "D82&D83", "D84& D85". Originaly, these diodes have a 500ohm
connection to ground (provided by the original tune pots). Because you are
increasing the pot values, this meathod can no longer be used.
Instead, solder a 500ohm resistor between "Point 1" of "VR11, VR13 & VR15
(on the cicuit board)" and "ground". This will restore the pitch sweep to
it's original depth.
*If you're extra keen, you could substitute "2.5k" potentiometers instead of
using 500ohm resistors, this would give you a useful depth control for the
pitch sweep effect on the Toms/Conga. I'll eave it up to those curious to
work out the finer details of taking this extra step, but I'd imagine it
would give an interesting touch to the sound of the toms/congas (enabling
more space tom sought of sounds).
After doing this mod, you'll be able to tune each of the toms/congas over
1.5 octaves, nice to finally get some chromatic interaction between the
instruments, Ie. tuning to three congas to a nice chromatic chord.
This mod requires some patience & skill to accomplish, you should be
comfortable in modifications and basic electronics before thinkin' of doing
this to your 808's.
Maybe some people think this will "clash" with the mint cool look of your
808's, well know that i'm more about fuctionality than keepin' my
instruments mint. If you do this well, and add some nice big fat classy knob
for your potentiometers, I'm sure you'll agree it will look "fly".
Enjoy
P9
