parks audio diy tube Series User manual

ike 60W power amp manual
the diytube series

2
Disclaimer
Under no circumstances does Parks Audio LLC assume liability or responsibility for injury or
damages sustained in the assembly, test or operation of this PCB design or for damages to any
other equipment connected to it. Assembly and education is buyers responsibility. Parks Audio
LLC 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 500VDC) 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 terminal blocks when unit is powered or
plugged in.
Lethal voltages exist in the capacitors even after unit is powered down, so wait at least
ten minutes after unplugging to allow charge to dissipate.
Warranty Information
All goods purchased from Parks Audio LLC have a thirty (30) day warranty against defects from
the date of purchase.

3
Preparation
Before assembly some preparation needs to done. Parts must be purchased, a work area needs set
up and chassis decisions should be made. The axiom haste makes waste has never been more
true. Make sure your chosen transformers and the board will fit comfortably using the chassis of
your choice. Please use the bare PCB to make a template, or use the PCB directly on the chassis
as shown on the website, for placing socket holes and mounting holes. Also, plan where RCA
connectors, binding posts, standby & ON/OFF switches and the AC cord will be oriented on the
chassis. Small-grid graph paper is a handy template. Physically lay out the parts in a space equal
to your chassis to assure everything fits. Lastly, please note the PCB has two identical sets of
silkscreens allowing mounting of parts on either side, according to your construction technique,
but the tube sockets can be mounted only on one side. Typical construction is with the sockets
and bias trim pots on the top side and all other components on the bottom side.
Overview of the Schematic and Design
The design closely resembles the Eico HF-series which used a modified Mullard 5-20 circuit.
The Ike, or Eiclone (pronounced I clone) uses the 12AX7 as the voltage gain stage tube, as did
the classis Eico HF-87 and HF-89. This gain stage DC-couples to a 6SN7 long-tail pair phase
splitter driving a pair of push-pull EL34 tubes. It is possible to build either a fixed bias or
cathode biased unit using the uniquely configurable PCB. Also, the bias supply and grid resistors
in the standard design are compatible with alternate power tubes such as 6550s and KT88s.
Using the Assembly Drawing
The assembly drawing is a quick reference for locating components and the numbering scheme
for the connectors. Currently, the assembly drawing is of the bottom side of the PCB where most
of the components will be placed. The drawing also makes a good place to jot any notes during
construction.
Parts Selection
The stock components on the parts list will make a fine amplifier, but this hobby is DIY, so part
subbing is not discouraged. In fact, it is fully expected that some experimenters will come up
with great modifications  please share them with us when you do! Do keep any substitutions at
the same rating or higher. Be aware that some footprint sizes must be strictly adhered to,
especially the electrolytic capacitors. The power supply electrolytics in particular must have a
diameter of 25mm or less. A height of 30mm is preferred as it allows use of a two inch high
chassis.
Soldering
This PCB is a double-sided, plated through-hole design on .094 FR4 material with LPI (liquid
photo-imagable) solder mask and 2 ounce copper per side. When soldering these components, let
the solder flow through the hole to form a teepee on both sides of the board for an optimum
connection. Ground plane connections sink a lot of heat from the soldering iron, so take care to
do these well and you may have to touch up from the opposite side. Dont forget to use the
checkboxes on the parts list sheet. X through the box after you have stuffed the component in
place.

4
TIP: PCB Stuffing
You can use the flat end of the 10-pole connector as a lead bending tool. This works for
most of the parts. Do take care to not damage the meniscus of the components. Insert all the
components in each step before soldering, bending the leads down to hold them in place. This
allows one to fix any placing errors that might occur very easily. Use a good pair of snips to
remove the excess leads and then go to the next step.
1. Stuff all fixed value resistors onto the bottom of the PCB (diytube logo is lower left).
R27 & R28 can be substituted with a choke. A super-imposed footprint for a two-
pole connector is available for easy connection via spade terminals.
2. D1 & D2 are each made of two diodes. Solder them together in series before soldering
them to the PCB. Then stuff D1a-b, D2a-b & D3. Mind the orientation of the cathode,
which is represented by a stripe on both the silkscreen and the diodes body.
3. Stuff variable resistors if you are building a fixed bias design. If you plan to adjust these
from a hole in the top of the chassis, then place them on the top of the PCB (the socket
side  diytube logo is lower right)
4. Stuff C9 through C14. Mind the polarity. The board has + symbols to show where the
positive terminal from the capacitor should be placed even though it is the negative side
that is usually marked on modern electrolytics. The black bar should be aligned where the
silkscreen is marked NEG BAR.
5. Stuff C15, C16 & C17. Mind the polarity.
6. Stuff R46, the IRCL. Make sure it is not leaning on C10 or the terminal block because it
gets hot. Leave 1/2 of the lead length showing on the component side  this allows you
to bend the part away from C10 without damaging the meniscus.
7. Kink leads on C2, C3, C4, C7, C8 & C18 and stuff.
8. Before placing the ceramic tube sockets, prep the pin sockets with a junk box tube or
small nail. Dont pry and break the socket, but you dont want to damage a favorite tube
either. Then place and solder all the tube sockets  make sure they are mounted to the top
of the PCB (diytube logo is lower right). Make sure to use enough solder.
9. V1 has multiple configurations and needs to have a set of jumpers soldered in place.
Watch clearances around other pins. For a 12AX7 tube, solder a small, 1/4" piece of wire
from the square pad marked Z to pin 7 of the nine pin socket and do the same from
square pad Y to pin 6. For a 6SL7 tube, solder a 1/2 piece of wire from the square pad
marked Z to pin 6 of the nine pin socket and a 1/4 from square pad Y to pin 7.
10. Place and solder the terminal blocks. As with the sockets, use enough solder. If you are
planning to use a choke in the filter supply, I recommend using a two-pole block over-top
of the R27/R28 footprints and spade connectors on the choke leads. The terminal blocks
facilitate easy removal of the amplifier board for troubling-shooting or tweaks.

5
11. Adjust the both R15 and R16 with a DMM so that Pin 1 (closest to edge of the board)
and the wiper (the center pin) are within a few ohms of each other. You may hear a
clicking when at this furthest extreme  that is normal. Now the bias will be at max
voltage on first power up.
12. Connect Rx53 in series with Cx21 from the 8 ohm tap to ground. This provides a
constant load for the amplifier even into inductive loads.
13. Snip excess leads and compare your board to photos from the website. Carefully go over
your work, looking for:
a. cold solder joints (these will look dull)
b. solder splashes and shorts between socket pins
c. connections in which solder didnt flow to the other side (like ground plane
connections)
d. proper capacitor orientation
First Power Up
1. With the unit NOT plugged into mains AC, use the Voltage & Resistance Chart to
ohm out the board.
2. Disconnect J4-8 (the B+ to the output transformer).
3. Insure you have a fuse installed, and power up unit without tubes.
4. Compare J4 Main Terminal voltages with chart. They should be similar, though the
B+ will be higher (over 500V) as the circuit is not loaded.
5. Measure the bias voltage at test points TP1 and TP2. These should be at least -50V.
6. Power down and unplug the unit from AC mains. Let the residual B+ bleed off for ten
minutes before reconnecting J4-8 and inserting the tubes.
Adjusting Bias
WARNING: This is done while the unit is ON and IDLE. Take care and follow proper
high voltage safety rules.
With an insulated adjustment tool and a DMM (at low voltage setting), adjust bias pots
clockwise (up) or counter-clockwise (down) to get the voltage at TP1 and TP2 to be 550mV.
This means the cathode current is 55mA. Plate dissipation at idle equates to around 27W.
485V Plate Voltage * 55mA Cathode Current = 26.7W
Check again after a few hours use and readjust if necessary. Check again after one week, then
one month. It is highly recommended to place an in-line fuse, e.g. 1/2A Fast Blo, between the
B+ center and ground. In case of a runaway tube or other catastrophic failure, this may
protect your amp beyond the main fuse.

6
Ike PCB parts (one monoblock) Revised: 9/19/13
Tip: Put a dot in the checkbox if you have the part already as a quick
reference when ordering parts. X out the checkbox when you have installed
the part on the PCB.
Item QTY Reference Part Mouser Part Cost
______________________________________________________________________
1 R1 1K, 1/4W 71-RN60D-F-1K .11
1 R2 475K, 1/4W 71-RN60D-F-475K .11
3 R3,R17,R18 1K, 1/2W 71-RN65D-F-1.0K .26
3 R4,R41,R42 100, 1/2W 71-RN65D-F-100 .26
9 R5,R13,R14,R31, 100K, 2W 594-5083NW100K0J .10
R32,R33,R34,R35,R36
1 R6 1M, 1/2W 71-RN65D-F-1.0M .26
1 R7 18K, 2W 594-5083NW18K00J .10
1 R8 2K, 1/2W 71-RN65D-F-2.0K .33
1 R9 30K, 2W 594-5083NW30K00J .10
1 R10 33K, 2W 594-5083NW33K00J .32
2 R15,R16 25K Pot 72-T93YB-25K 1.59
2 R19,R20 15K, 1/2W 71-RN65D-F-15K .26
2 R21,R22 10, 1/2W 71-RN65D-F-10 .26
2 R27,R28 100, 2W 594-5083NW100R0J .10
1 R29 3.3K, 2W 594-5083NW3K300J .10
1 R30 200K, 2W 594-5083NW200K0J .10
1 R37 27K, 3W 283-27K-RC .21
1 R38 10K, 1/2W 71-RN65D-F-10K .26
2 R39,R40 wire jumper
1 R43 390K, 2W 594-5083NW390K0J .32
1 R46 IRCL 527-CL90 2.21
1 R49 3.3K, 1/4W 71-RN60D-F-3.3K .11
1 Rx53 10, 3W 283-10-RC .21
1 C2 .22uF, 250V 1431-2224K 1.03
2 C3,C4 .1uF, 630V 667-ECW-FA2J104J 0.55
1 C7 220pF, 500V 5982-15-500V220 .78
1 C8 470pF, 500V 5982-15-500V470 2.28
6 C9,C10,C11, 220uF, 400V 5985-380-400V221 4.32
C12,C13,C14
1 C15 22uF, 450V 647-UVZ2W220MHD 1.23
2 C16,C17 47uF, 250V 647-UVZ2E470MHD .93

7
1 C18 .1uF, 630V 5989-630V0.1-F .77
1 Cx21 .1uF, 250V 1431-2104K .64
5 D1a-b,D2a-b,D3 UF4007 Diode 625-UF4007-E3 .19
1 J1 3pin Term Block 571-14376645 1.39
2 J2,J3 2pin Term Block 571-14376644 .79
1 J4 10pin Term Block 571-114376644 5.23
Choke Filter Mod:
Omit R27 & R28. Add the following:
1 L1 1H, 240mA choke 553-C24X 8.77
1 J2 2pin Term Block 571-14376644 .79
100W Edcor Mod (not compatible w/ choke filter mod):
1 R8 1.3K, 1/2W 71-RN65D-F-1.3K .33
2 R27,R28 50, 3W 594-AC03W50R00J .10
1 R29 10K, 2W 594-5083NW10K00J .10
1 R49 7.5K, 1/4W 71-RN60D-F-7.5K .11
1 C7 .001uF, 630V 1431-6102K 0.41
1 C8 330pF, 500V 5982-19-500V330 2.76
1 C18 .12uF, 1kV 5989-1KV0.12-F 1.18
Go to www.mouser.com and log in to your account. Use Service & Tools > Parts
List Importer. Paste list into window and Import to My Current Order. CRTL-C
to copy. CTRL-V to paste.
/* start cut-n-paste */
71-RN60D-F-1.0K 1
71-RN60D-F-475K 1
71-RN65D-F-1.0K 3
71-RN65D-F-100 3
594-5083NW100K0J 9
71-RN65D-F-1.0M 1
594-5083NW18K00J 1
71-RN65D-F-2.0K 1
594-5083NW30K00J 1
594-5083NW33K00J 1
72-T93YB-25K 2
71-RN65D-F-15K 2
71-RN65D-F-10 2
594-5083NW100R0J 2
594-5083NW10K00J 1
594-5083NW200K0J 1
283-27K-RC 1
71-RN65D-F-10K 1
594-5083NW390K0J 1
527-CL90 1
71-RN60D-F-3.3K 1
283-10-RC 1
1431-2224K 1

8
667-ECW-FA2J104J 2
5982-15-500V220 1
5982-15-500V470 1
5985-380-400V221 6
647-UVZ2W220MHD 1
647-UVZ2E470MHD 2
5989-630V0.1-F 1
1431-2104K 1
625-UF4007-E3 5
571-14376645 1
571-14376644 2
571-114376644 1
/* end cut-n-paste */
Ike Chassis parts (one monoblock) Revised: 9/19/13
Item QTY Reference Part Mouser Part Cost
_______________________________________________________________________
1 SW1 Neon Power Switch 112-R13-66B-G 1.38
1 IEC Power w/ Fuse 161-R3014-E 2.19
1 2A Midget Fuse 504-GMA-2 0.48
1 3-Prong AC cord 545-P004-006 3.99
1 12X10X2 Chassis 546-1441-29BK3 25.60
1 (omit if FPE) 12X10 Bottom 546-1431-29BK3 11.90
1 RCA Red Jack 568-NYS367-2 1.88
2 Red binding post 164-R119R-EX 1.83
1 Blk binding post 164-R119B-EX 1.83
2 Red Test Points 530-105-0802-1 0.72
1 Black Test Points 530-105-0803-1 0.72
8 Standoffs 1/4X1/2 534-2210 0.33
4 .625 Bushings 836-2073 0.16
/* start cut-n-paste */
112-R13-66B-G 1
161-R3014-E 1
504-GMA-2 1
545-P004-006 1
546-1441-29BK3 1
568-NYS367-2 1
164-R119R-EX 2
164-R119B-EX 1
530-105-0802-1 2
530-105-0803-1 1
534-2210 8
836-2073 4
/* end cut-n-paste */

9
Ike Tubes, Transfomers, Nuts & Bolts (one monoblock) Revised: 9/19/13
Item QTY Reference Part Triode Part Cost
______________________________________________________________________
1 V1 12AX7/ECC83 12ax7tesla $10.95
1 V2 6SN7 types 6sn7 $11.95
2 V3,V4 EL34/6550/KT88 JJ-EL34-MP $32.49
1 V1 9pin PCB Socket 9pinpccer $2.35
(0.750 diameter, ceramic)
3 V2-V4 8pin PCB Socket pcceroctsckt $2.50
(1" diameter, ceramic)
From www.mouser.com:
1 T1 Hammond 274BX Power Transformer $87.95
1 T2 Hammond 1650N Output Transformer $127.50
or
From www.edcorusa.com:
1 T1 Edcor XPWR036 Power Transformer $78.81
1 T2 Edcor CXPP60-MS-4.2K O.T. $73.02
I source these locally at Ace Hardware, or use boltdepot.com (pn# included).
10 #6 x 1/2 sheet metal screw 18-8 SS 2300
16 #6-32 x 1/4 machine screw 18-8 SS 5316
8 #8-32 x 1/2 machine screw 18-8 SS 1346
8 #8 flat washers 18-8 SS 2943
8 #8 K-Lock nuts 18-8 SS 12020
2 #6-32 x 1/2 machine screw 18-8 SS 1336
2 #6 K-Lock nuts 18-8 SS 12019

A
A
B
B
C
C
D
D
E
E
4 4
3 3
2 2
1 1
215V
445V
6.3VAC A
6.3VAC B
6.3VAC A
6.3VAC B
NF
NF
6.3VAC A
6.3VAC B
Bias V
Schematic Page 1
Fixed Bias EL34 Ike
Main Circuit
diytube
C7 220pF
R5
100K
R21
10
R13
100K
V2
6SN7
h''
8
g'' 1 g
4
a5
h
7
k'' 3
a'' 2
k
6
R17
1K
R14
100K
R22
10
R8 2K
R6 1 MEG
R18
1K
V3
EL34
g3 1
h1
2
h2
7
g2
4
g1
5
p3
k
8
V4
EL34
g3 1
h1 2 h2 7
g2
4
g1
5
p
3
k8
R9
30K, 2W
C2
.22uF
R10
33K, 2W
V1
12AX7
h''
5
g'' 2 g
7
a6
h
4
hT
9
k'' 3
a'' 1
k
8
R7
18K,2W
R1 1K
C8
470pF
R4
100
R49
3.3K
J3 Output Transformer Hookup
1 2
J1 Input
1 2 3
R2
475K R3
1K
J2 Output Transformer Hookup
1 2
R16 25K
R15 25K
R19 15K
R20 15K
C4 .1uF
C3 .1uF