diytube Poseidon Driver Installation instructions

DIY Tube Poseidon Mk 3 Board - TubeZone Assembled -Instructions Page 1
TubeZone Assembled Version
© 20063 TubeZone.net Inc and Shannon Parks
Re roduction in whole or art without ex ress written ermission rohibited.

DIY Tube Poseidon Mk 3 Board - TubeZone Assembled -Instructions Page 2
READ ME FIRST!
This is a modified version of the usual disclaimer/warning that comes with most transmitting
equipment and parts.
Since similar conditions exist in all tube audio amplifiers we believe it be appropriate here.
Please note prior to beginning construction that there are high(over 400 volts DC and AC
voltages present in the equipment you are about to work on, and in the right situation these
voltages could injure or kill you if you contact them. Normally the worst you can encounter is a
nasty shock, however you must remember at all times this possibility of a injurious situation.
Follow the same precautions you would with any electrical appliance,including not working
with plugged in equipment (including soldering irons with bare feet on a wet floor, use only
insulated probes & tools when working on live high voltage, and if you are working with one
hand taking measurements or working in live equipment, keep the other hand off the chassis
or other grounded conductive item. Always use the proper size fuse or circuit breaker in the
equipment installed when operating amplifiers or any other electronic gear.
In a work situation you would be required to use eye protection when working with tools,
soldering, or testing equipment and we strongly recommend you do so also, and remind you that
when you fail to use safety glasses or follow recommendations regarding safety or simply do not
practice common sense about safe procedures, you do so completely at your own risk.
Failing or defective components in high voltage tube equipment, particularly elderly equipment,
when failing may arc, spark,smoke, spit, sputter, get hot enough to burn flesh, catch on fire,
rupture or shatter sending shards of possibly hot glass, metal, or plastic at your face or body
and may spew possibly hot and injurious goo or fluid, or cause normally harmless pieces of
metal to become electrically charged at dangerous voltages.
If you have no previous experience repairing high voltage equipment, you must have a
professional repair person to install this modification for you , or obtain competent
third party help and and obtain basic knowledge of electronic components, soldering, safety and
construction techniques prior to proceeding.
Disclaimer
Under no circumstances does diytube or Tubezone.net Inc assume liability or responsibility for
injury or damages sustained in the assembly, test or operation of this kit or for damages to any
other equipment connected to it. As this is a partial kit, proper assembly is buyer's responsibility.
diytube reserves the right to make design changes or improvements without the obligation to
revise prior versions. All specifications are subject to change without notice.
. WARNING: Lethal voltages (greater than 400VDC are present in this project.
. Use a Variac or isolation transformer while working on and testing the unit.
. Use a rubber mat to stand on while working on and testing the unit.
. Keep one hand in your back pocket if probing voltages with a DMM.
. Wrap a small piece of electrical tape around the test lead probe shaft to expose
just the tip.
. Do not connect or disconnect wires to the board when unit is powered or plugged in.
. Lethal voltages exist in the capacitors even after unit is powered down, so wait
at least one hour to after unplugging to allow charge to dissipate.
Warranty and returns
UNINSTALLED and unmodified boards (meaning in identical condition as received from
Tubezone.net Inc may be returned within 30 days for refund or credit, so you have that amount
of time to consider your options and decide whether installing this kit is within your capability.
Once installed, at my option, within 6 months of purchase, I will either supply repair parts to you
to replace any defective components, or repair the board to replace defective components.
Repairs due to mis-wiring or other user errors will be billed @ $50/hour. Defective tubes must be
returned to be replaced. Any return postage or shipping is on customer's account.

DIY Tube Poseidon Mk 3 Board - TubeZone Assembled -Instructions Page 3
Parts list for TubeZone assembled version of diytube
Poseidon Mark III driver PCB
Voltages and wattages are minimums.
QTY Reference Part
2 R1, R4 1K, 1/4W
1 R2 470K 1/4W
1 R3 100 hm 1/4W
1 R5 2.7K 1/4W
1 R6 150K, 1/2W
1 R7 5.6K 1/4W
2 R8, R14 1M 1/8W
1 R9 10 hm 1/8W
2 R10, R11 47K 2W
2 R12, R13 100K 1/4W
1 R15 500K Pot
1 R16 47K 1/2W
1 C1 0.22uF 600v
1 C2 120pF
1 C3 330pF
2 C4, C5 0.1uF,600v
1 U1 LM334Z Integrated Circuit
Other Parts
2 Ceramic Gold Plated 9 Pin Sockets
V1 5751 Tu e
V2 12BH7 Tu e
Additional 10 ohm 1% resistors for ias metering (required for
implementation of individual tu e ias alancing) and resistors for the 6550
sockets (1K 1/4W) are included. These extra items do not go on the board.

DIY Tube Poseidon Mk 3 Board - TubeZone Assembled -Instructions Page 4

DIY Tube Poseidon Mk 3 Board - TubeZone Assembled -Instructions Page 5

DIY Tube Poseidon Mk 3 Board - TubeZone Assembled -Instructions Page 6
Note: This diagram shows the original twist-lock can capacitor. If you have
the SDS La s capacitor oard or other power supply upgrade, please refer
to documentation for your oard or upgrade.

DIY Tube Poseidon Mk 3 Board - TubeZone Assembled -Instructions Page 7

DIY Tube Poseidon Mk 3 Board - TubeZone Assembled -Instructions Page 8
Assem led Board Installation Instructions
The same instructions apply for oth Mk2 and Mk3
•1. Remove bottom cover of amplifier and all tubes.
•2. Turn Amplifier upside down. Before removing the original Dynaco PC board, it's a good
idea is to tag a number on each wire that goes to an eyelet or pad with the corresponding
number. This will help prevent errors in reassembly. Also at this time, check any of the
original wiring that is going to be used, over the years, the wiring may have become
unusable. Replace wiring where necessary.
•3.Unsolder all wires from board, also resistor(s connecting ground side of input jack(s to
board.
•4.Unscrew bolts (or drill out rivets in factory-wired unit , remove old PC board.
•5.Bolt in the new board. Use 6-32 screws and nuts if old ones not available, these are
available at neighborhood hardware stores like Ace and True Value.
•6.Note that all terminal numbers on the conversion board correspond to the original Dyna
eyelet numbers, except where the eyelet numbers are not used on the new board.
•7. Remove any 15.6 ohm resistors found between the pin 8 or pin 1 of the 6550's and
chassis ground. Remove wires connecting between pins 8 of the pairs of 6550's if
present. Install 10 ohm 1/4 watt resistors between pin 8 of each 6550 and chassis ground
(or star ground if you are using star grounding . The small resistors serve a dual function,
besides metering cathode current for bias setting, they serve as a fusible link to
disconnect the tube in the event of a tube short or failure. Please avoid the temptation
to replace with larger parts. (and try to politely ignore any well-meaning advice you may
hear to the contrary . Wires may be installed from pin 8 of each 6550 socket to empty
lugs on the power takeoff socket (as shown on the diagram or a pin jack, for outboard
bias measurements.
•8.There should be jumpers soldered between pins 1 and 8 on each 6550 or EL34 socket.
EL34's will not ias or operate properly without these jumpers installed. On 6550,
pin one grounds the metal base collar.
•9. Reconnect and solder all other wires (not resistors to terminals as numbered. See list
on next page to dou le-check your connections.
•IMPORTANT: A 1K resistor goes from Pin 6 to Pin 5 on each 6550 or EL34 socket -
the amp won't work without these installed. No other connections should e made
to pin 6 or 5 on these sockets.

DIY Tube Poseidon Mk 3 Board - TubeZone Assembled -Instructions Page 9
Using the schematic as a map, the following list of connections to terminals on the new PC board
will help if you have any doubts about which wire goes where
Please Note The Following:
There is no specific terminal for power for PAM preamps. If you need a power-takeoff for a
PAM-1 preamp, you'll need to attach a 22K 1 W resistor from Terminal K to pin 5 on the power
take-off socket.
There is no equivalent of terminal 4. The original wire to pin 4 of the 6550 or EL34 tube may be
removed.
•A : To left channel RCA input jack.
•B : To outside (ground case lug of RCA input jack, 10 Ohm ground isolation resistor to
pin 3 of left channel power takeoff socket, if used, other ground connections if needed.
•C: Other ground connections, connect this to one of the ground lugs on the can capacitor
or to the ground connection on the power supply capacitor board (such as the SDS Labs
board .
•D and E: To pins 1 & 2 of left power takeoff socket, or pins 2 & 7 on one of the 6550 or
EL34 tube sockets. This is filament line for the board.
•F: To pin 6 of inboard 6550 or EL34 tube
•G:To pin 6 of outboard 6550 or EL34 tube (Tube the striped wires from output
transformer connect to
•H: To center lug of bias control. (Bias supply connection
•I:To 16 Ohm tap of speaker terminals.
•J: To lug 3, quad section filter cap, or corresponding lug/pad on capacitor board. (330
volt source
•K: To lug 4, quad section filter cap or corresponding lug/pad on capacitor board. (430 volt
source
Before going onto the iasing step, get a large dummy load or a pair of cheap speakers
(meaning ones that you won't miss if they are damaged and hook them up to the proper
impedance outputs. Avoid running the amplifier with no output load (even shorted is preferable to
open Note that even if all the voltages check out properly, oscillation (audible, subsonic or
ultrasonic and or intermittent connections can damage speakers. Always check out repaired
amplifiers on dummy loads or expendable speakers first. Dummy loads can get hot, watch out!

DIY Tube Poseidon Mk 3 Board - TubeZone Assembled -Instructions Page 10
Biasing Instructions:
Note: Always use test loads on your speaker terminals, e.g. an 8 ohm
power resistor. Be sure to have the RCA inputs loaded or shorted.
The first steps make sure your bias supply is working, is semi-balanced, and
won't cause a melt down on first power up. Maintenance biasing can go directly
to step #5.
1 Remove your 5AR4 and power the amp. The bias voltage will appear
immediately at J6 and J21 on the diytube PCB. Adjust the control on the amplifier
chassis so that these voltages go as negative as possible (eg -55VDC , but
adjust to have the voltage the same on both test points. You can use the preamp
socket pins 2 or 3 as your DMM ground.
2 Turn the unit off. Replace your 5AR4 rectifier. Turn on unit.
3 Because adjusting one side usually changes the bias on the other side, you
will now start ping-ponging between the sides adjusting the wire wound pot and
measuring one of the bias points on that side unit you near 500mV.
4 Now that you are around 500mV on all the tubes, stick your DMM probes in
pins 5 & 8 of the preamp socket. You are measuring the small voltage difference
between the biasing of the 6550 or EL34 pair. Now adjust the R15 balance
control until the voltage you read is zero or near zero difference. You might end
up changing the scale of your DMM to the 300mV region.
5 Now repeat step #3, but adjust chassis control to produce to 700mV (for 6550
or KT88 or 600 mv (for EL34 across the 10 ohm resistor.
PS: Please note that the multi-turn trim control (R15 used on the board does not
have end stops. If turning the control one direction does not seem to have any
effect, try turning the control the other direction. Before shipment the controls are
set by me at roughly mid-point.

DIY Tube Poseidon Mk 3 Board - TubeZone Assembled -Instructions Page 11
Simple Bias Trou leshooting:
•1.One set of tu es draws excessive ias current ( iaset too high). Swap the
offending pair of tubes with the tubes from the other side/amp. If the problem follows the
tubes to the other side indicates probable bad tube. If the problem remains on the side
where it was originally, possible bad tube socket or bad connection in grid bias circuit
(often open bias control on that side.
•2. All tu es ( oth anks) draw excessive current ( iaset too high). Check voltages in
bias circuit. If they appear normal (usually will create negative voltage of 30 to 40 volts at
eyelets # 6 and 21 on ST70, 50-60 volts on eyelet 3 on Mk3 , then check for excessive
voltage drop (use a high impedance voltmeter to check this such as a VTVM across the
100K (Mk2/Mk3 or 270K (ST70 grid resistors. If a drop of more than a few volts is found
on only one, or on one of each pair, indicates severe tube unbalance or possible
defective tubes. If found on all tubes indicates that amplifier must be modified for lower
DC grid circuit resistance (reduce value of the grid resistors to accommodate the tubes
you have chosen. If no excessive voltage drops found across these resistors, and other
bias circuit voltages appear normal, indicates type or brand of tube used requires
modification to bias circuit to be used in this amplifier. (ie: 10K or 1K resistor between
control & bias diode must be made a smaller value
•3.One tu e glows red or orange. Swap the offender with another tube on either side
(keep track of which one you swapped! If condition follows tube, this indicates a
probable defective tube or possibly bad solder joint inside the tube pins (which may be
fixed by heating the pins/terminals with soldering iron . If condition appears in the same
socket with a different tube indicates either a bad or wrong connection to that socket or a
bad socket. Try re-soldering connections to socket terminals.
•4.Biaset won't go high enough. Generally either means output tubes are worn out,
5AR4 rectifier tube is worn out (or you are using another tube in place of a 5AR4 or the
10K resistor from the bias controls to ground is either defective, not connected or out of
tolerance (value too high . This could also be caused by a bad or internally
cracked/damaged bias control. Occasionally even new tubes do not draw sufficient
current, in this case, either replace the 10K bias controls with a higher value, or reduce
the value of the 10K or 18K resistor going to ground from the bias controls (try a 5K or
similar in ST70, 10K in Mk3 .
For further help, you can contact Uncle Ned at Tu eZone y phone at 773-782-6145, y
email at http://www.tu ezone.net/contact/index.html ,
or research answers or post a message on the DIYtu e Mk3 Poseidon discussion
oard at: http://www.diytu e.com