Drip Opto 3 Manual
drip opto ver 3
Instruction and build manual revision 1.0
optical compressor
atom version
copyright 2008 | gregory lomayesva
Attention|disclaimer
This project is presented as artwork, and is solely intended
As such.
Although this board can be assembled and
Built into a functioning optical compressor.
Due to the high voltages and possibilities of
Human error , drip electronics | gregory lomayesva
Hereby assumes no liability for injury/damage/loss
which might unintentionally occur.
This manual is intended for information purposes only.
Proceed at your own risk.
Warnings|caution
It is important to cover a few safety tips and cautions before you
begin.
1. This project has high voltages, at some places on a live
board voltages can be upwards of +300v @ 380 mA.
It is not a terrible amount of current/voltage , and I have been
shocked many times for foolish mistakes such as forgetting the unit
was powered on while servicing it etc.
It’s enough voltage to remind you to never make that mistake
again.
For someone with a heart condition this voltage can be lethal.
2. Once the unit has been powered up , the filtering electrolytic
capacitors (c7a-c7d) will remain with charge in them for
a period after the power has been switched off.
I found that a shock also is still possible for a few moments.
(It seems the NE-2 neon light helps dissipate charge after power
off.)
3. Never ‘lift’ or remove the safety ground (chassis ground from AC
cord).
The board with proper wiring and ground layout will have minimal noise
and hum ,
solving a hum problem by lifting the safety ground is wrong, often il
legal and dangerous to you and others.
4. Work off of an ac plug that is grounded to earth.
5. If the fuse pops on the pcb or a circuit breaker , there IS something
wrong , stop ,re check all connections and review your work.
the fuse will only pop if there is a short or a miswired connection.
6. Do not rush through the project with out reviewing your work
several times . beware of solder bridges .
sloppy work or impatience is dangerous to you and others.
7. Be neat in your connections and wire runs, don’t use more wire then
is needed for each connection.
if you can’t be ‘neat’ , don’t bother with this project.
‘Neatness promotes accuracy’
8. If the electrolytic capacitors are mounted in reverse , they can
explode violently . REMEMBER THIS. CHECK EACH ELECTROLYTIC !.
9. if you do not understand something fully that is not covered
in this manual or are unsure about something. STOP.
and ask a question either in the forum or through email.
you will be helped.
10. This unit is intended as a mono unit , and was not designed
for anything but the ‘rated’ power transformer.
11. The use of a ‘vented’ case IS necessary.
designed by gregory lomayesva | copyright 2008
1. the pcb has been designed around the circuit and not the compo-
nents. Creating the shortest paths to each important connection
2. pcb uses 3 oz copper
3. a new ground plane has been added using the heaviest gauge of
of copper possible .
(ground scheme still follows the original design separating
the reduction/audio/input transformer circuits.)
(also aids in shielding the audio circuit below it)
4. the use OF SPRAGUE ATOMS or equivalent filtering electrolytic
capacitors.
5. use of pcb mount 1 meg potentiometers for stereo adj/lim response
and optionally zero adjust, thus eliminating additional wire runs.
6. pcb is .93”thick
7. pcb is silver plated.
8. tube heaters have dc reference circuit built into board
(Further protecting ac hum from entering the audio circuit)
9. a grid resistor has been added for the 12ax7 in the amp section.
10. an extra 1k resistor has been added to the Pi filter in the
power supply.
11. the diode footprints are now made for fred/hex diodes (to-220)
12. quench arc snubber has been added on board for the power switch
(to control popping noise on power down)
13. 68 pf cap has been added in parallel to r11 to help prevent
occilations.
14. 2nd pad connected to ground has been added for connecting gain
2 and reduction 2 (giving option to omit ‘y’ cable
when connecting potentiometers)
15. ‘x-cap’ has been added to the primary of the transformer
(hf noise filter )
16. resistor footprints are large enough for carbon comp.
17. capacitors foot prints in the amp section are made for
poly-pro caps
18. option to select ground circuit for the output transformer
(into audio gnd or reduction gnd)
19. most trances are 2mm wide on 3 oz copper
(almost 20 times the needed copper)
20. Entirely new design of circuit balancing a compact
Design but ensuring separation between traces.
21. pcb mount sowter transformers
22. Optional grounding through standoffs
23. heater traces moved to bottom of board
24. entire circuit on one side of board (no overlapped traces)
25. grid resistors for 12bh7a
26. Insulated 5.08 screw connectors can be used for all connections
27. Circuit is ‘true’ to the original 1960’s design
28. heater traces on board (no heater wiring)
features
Design notes| history | theory: as also in some camps of thought ac heated tubes ‘sound better’
and is speculated to prolongs tube life.
a dc heated board will be available in the near future.
but by keeping the design AC , readily available power transformers
can be used , eliminating the need for custom jobs.
the design allows the use of a 6.3v 2amp DC power supply.
if wanted simply route the 6.3 dc into the pcb heater pads.
in heavy experimentation with fully regulated high voltage
power supplies and dc regulated heaters ,
this design and early prototypes kept shining though
with almost equivalent specs.
the hv power supply remains a full wave dual diode type
as found on the original unit , but the addition of fred diodes
and use of cde tc series or atom capacitors is a very effective
upgrade.
Although this design does not replace the ver2 opto pcb
it does explore many new concepts and ideas in tube circuity design.
the design layout was made by hand over the course of a year.
the goals were to revolve the circuit around the shortest Connections
Possible ,
often designers rely on component placement first ,
circuit second , with the advent of more advanced pcb design programs and
auto routing Capabilities , it seems that designers are more
Interested in simply connecting a circuit then taking the time to balance
the form and Functionality of it .
there is no ‘rats nest ‘ in this design , it is elegant as it is
functional.
i chose the design based on a flower type interconnection to the
vacuum tubes insuring a greater separation to protect against
interference from adjacent tracks.
great care has been taken in the design of both the amplifier
section and the reduction circuit.
the use of a ground plane has also helped in creating a more
compact design , yet continuing to maintain the original grounding
concept of the original unit :
separation of the audio,reduction,high voltage and input transformer
ground.
thank you for your interest in the new drip opto ver3.
the ver3 is a whole new design and layout based on the
classic ‘la’ compressor/limiter circuit.
this design is true to the schematic of the 1960s compressor
but many new features have been added to the design ,
Including a dc referenced heater circuit , and the use of
Sprague atom or cde tc series filtering capacitors.
the pcb is compatible with most equivalent audio transformers ,
but the use of sowter transformers is recommended for a seamless
build.
a lot of time,testing and prototyping has gone into this board
Assuring you the highest in quality and performance.
under many circumstances, the pcb can stand side by side with most commer-
cial and vintage units and give equal results.
the opto3 pcb uses ac powered heater filaments , but much effort
has gone into routing the heater traces away from critical
Components.
in many tests the ac heater circuit on the opto3 are as quiet as dc
rectified circuits.
your opto’s foundation began as an artistic approach in symmetrical design.
by not compacting the circuit and allowing for great amounts of space
in between traces , cross talk is kept to a minimum.
“Neatness promotes accuracy.”
it was my goal to create a pcb that is compliant to electrical standards
and of a quality rivaling most commercial products.
Compared to other manufacturers of la-style compressors ,
you will be able to use the highest quality components and still come in
under half the price of most retail units .
throughout most of the pcb you will find up to 5mm wide traces on
important connections like the optical cell and the c5 capacitor section
by using 3oz copper ,it equates to a 15 mm wide trace as compared
to commercial pcbs meager usage of 1 oz copper and .5mm wide traces.
please enjoy this latest release from drip electronics.
g.
here is a chart showing side by side comparison of a properly
wired opto3 pcb and other LA style compressors.
(how ever this was not done in a laboratory and should only be
used as an example of the performance possible with this pcb.)
in the frequency response , the opto 3 (light blue) seems to hold it’s
ground in comparison with a brand-x point to point unit.
(the vintage la2 seems to be using the jumper network found on old
units , dipping out from 30hz to 600hz )
as far as noise floor , the opto3 in green seems to do very well.
all machines calibrated to 0 db digital with 1k test tone
vintage la2 was running on filtered ac studio mains.
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