Millett Hybrid MOSFET-MAX V1.2 Design and Layout
by Colin Toole		 Last revised:
7/11/2011		 BOM by
Tom Blanchard		    
PART ID    QTY SOURCE PART NO EACH TOTAL SOURCE PART NO  EACH   TOTAL 
                     
BASIC MILLETT                    
RA1L/R 5K Ohm Trim Pot 2 Mouser 72-T93YA-5K $1.21  $     2.42 DigiKey 490-2888-ND  $     0.85  $     1.70
RA2L/R, RA4L/R 1K ohm 4 Mouser 71-RN55D-F-1.0K $0.08  $     0.32 DigiKey CMF1.00KHFCT-ND  $     0.17  $     0.49
RA7L/R 1M ohm 2 Mouser 71-RN55D-F-1.0M $0.08  $     0.16 DigiKey CMF1.00MHFCT-ND  $     0.17  $     0.49
CA2L/R* 1000uF 16V Electrolytic* (18mm dia max)[1] 2 Mouser 647-UKZ1E102MHM $1.07  $     2.14 DigiKey P12366-ND  $     0.59  $     1.18
CA4L/R, CA5L/R[2] 1800-2200uF 35V Electrolytic (18mm dia. max, 15mm leads max)[3] 4 Mouser 647-UHE1V222MHD $1.38  $     5.52 DigiKey P12410-ND  $     1.30  $     5.20
CA3L/R, CA6L/R, CA9L/R** 0.22uF Film Cap 15mm leads 6 Mouser 505-M10.22/250/10 $1.11  $     6.66 DigiKey P3224-ND  $     1.28  $     7.68
CA7L/R* 1000uF 35V Electrolytic* (18mm dia. Max)[4] 2 Mouser 647-UKZ1H102MHM $1.76  $     3.52 DigiKey P12400-ND  $     0.76  $     1.52
CA8LR** 0.22uF Film Cap (20mm leads max)[5] 2 Beezar.com VitaminQ 0.22uf 100V $2.50  $     5.04 Beezar.com VitaminQ 0.22uf 100V  $     2.50  $     5.00
                     
CCS:                    
QA1L/R, QA2L/R 2N5087 PNP small signal[6] 4 Mouser 512-2N5087_J18Z $0.11  $     0.44 DigiKey 2N5087-ND  $     0.19  $     0.76
RA8L/R 1.13K ohm   Mouser 71-RN55D1131F $0.10  $        -        
RA9L/R 11.3K ohm   Mouser 71-RN55D-F-11.3K $0.10  $        -        
Optional selection: results in CCS current of 0.65 ma                  
RA8L/R 1.15K ohm 2 Mouser 71-RN55D1151F $0.11  $     0.22 DigiKey CMF1.00KHFCT-ND  $     0.17  $     0.34
RA9L/R 11.5K ohm 2 Mouser 71-RN55D1152F $0.11  $     0.22 DigiKey CMF10.0KHFCT-ND  $     0.17  $     0.34
                     
MISC:                    
R1 (optional) 10 ohm, 1W resistor[7] 1 Mouser 282-10-RC $0.19  $     0.19 DigiKey 10W-2-ND  $     0.18  $     0.18
RA5C/L/R (RLED's) 2K ohm 1/2W[8] 3 Mouser 293-2K-RC $0.09  $     0.27 DigiKey 2.0KH-ND[9]  $     0.26  $     0.78
                     
LED1 3mm super-brite, ColorChange 1 Beezar.com special color change $0.75  $     0.75 Beezar.com special color change  $     0.75  $     0.75
LEDL/R Tube LED's, 3mm ultra-high, 5500 mcd - Blue[10] 2 Beezar.com various colors $0.25  $     0.50 Beezar.com various colors  $     0.25  $     0.50
                     
POT 50K AUDIO TAPER POT 1 Beezar.com ALPS RK27 $16.00  $   16.00 Beezar.com ALPS RK27  $   16.00  $   16.00
                     
VTL/R TUBES 2 Beezar.com 12AE6/A (gain of 14) $5.00  $   10.00 Beezar.com 12AE6, 12AE6A  $     5.00  $   10.00
      Beezar.com 12FK6 (gain of 7) $5.00   Beezar.com 12FK6    
      Beezar.com 12FM6 (gain of 10) $6.00   Beezar.com 12FM6    
  Tube Matching 2 Beezar.com   $2.00  $     4.00        
SOCKET 7-PIN MINI TUBE SOCKET - Gold 2 Beezar.com 7-Pin Mini $2.00  $     4.00 Beezar.com 7-Pin Mini  $     2.00  $     4.00
Terminal Block 2pos see below for INPUT Control 0 Mouser 571-2828362 $0.45  $        -   DigiKey ED1930-ND  $     0.62  $         -  
Terminal Block 3pos 5mm (or 5.08mm) 3[11] Mouser 571-2828363 $0.42  $     1.26 DigiKey ED1931-ND  $     0.93  $     2.79
1/4" Stereo Jack Neutrik NMJ6HCD2 1 Mouser 550-22302 $1.10  $     1.10 DigiKey ----    $         -  
Optional selection: recommended for MOSFET DB's                
Fuse Clips, PCB mount 5x20 fuse clip, 0.2" horiz. lead spacing 2 Mouser 534-3519 $0.13  $     0.26 DigiKey 486-1173-ND  $     0.15  $     0.30
Fuse 5x20mm - 1A slo-blo optional, your choice[12] 1 Mouser       DigiKey      
                     
PCB Circuit Board 1 Beezar.com n/a $25.00  $   25.00 Beezar.com n/a  $   25.00  $   25.00
                     
                     
POWER SUPPLY                    
RR1 120 ohm 1/4W 1 Mouser 71-RN55D-F-121 $0.08  $     0.08 DigiKey CMF121HFCT-ND  $     0.17  $     0.49
RR2 2K ohm 1/2W 1 Mouser 71-RN60D-F-2K/R $0.09  $     0.09 DigiKey P2.0KW-1BK-ND  $     0.23  $     0.23
RR3 1K ohm trimmer pot 1 Mouser 72-T93YA-1K $1.20  $     1.20 DigiKey 490-2874-ND  $     0.85  $     0.85
PF1 Polyfuse, resettable radial 0.75A 72V 1 Mouser 650-RXEF075 $0.38  $     0.38   RXEF050-ND  $     0.44  $     0.44
CR1A, CR1B 2200uF 50V Electrolytic (18mm dia max) 2 Mouser 647-UHE1H222MHD6 $1.72  $     3.44 DigiKey P12393-ND  $     1.30  $     2.60
CR2 1uF 63V Box cap 1 Mouser 75-MKT1817510064 $0.77  $     0.77 DigiKey 478-3367-ND  $     0.45  $     0.45
CR3A, CR3B, CR3C, CR3D 100pf C0G Axial Ceramic 4 Mouser 581-SA102A101JAR $0.11  $     0.44 DigiKey 478-3141-1-ND   $     0.19  $     0.76
  100pF NPO Ceramic Disc (optional)   Mouser 140-50N5-101J-RC $0.08  $        -   DigiKey 399-4199-ND  $     0.28  $         -  
                     
CR4 82uf 35V Electrolytic (6.3mm dia max) 1 Mouser 647-UPW1V820MED $0.28  $     0.28 DigiKey 399-3579-ND  $     1.50  $     1.50
                     
DR1A, DR1B, DR1C, DR1D Schottky MBR360, 60V 3A Rectifier - AXIAL 4 Mouser 863-MBR360RLG $0.30  $     1.20 DigiKey MBR360-ND  $     0.64  $     2.56
DR2, DR3 1N4002 2 Mouser 512-1N4002 $0.06  $     0.12 DigiKey 1N4002/54GICT-ND  $     0.69 [13]  $     1.38
VREG LM317T 1 Mouser 511-LM317T $0.39  $     0.39 DigiKey LM317TFS-ND  $     0.48  $     0.48
Heat Sink Wakefield #647-15ABP (1.5"h) 1 Mouser 567-647-15ABP $1.53  $     1.53 DigiKey 345-1032-ND  $     2.03  $     2.03
                     
Walwart 24VAC, 1000ma Walwart for MOSFET 1 Mouser 553-WAU24-1000 $11.95  $   11.95 DigiKey ----    $         -  
Power Socket 2.1mm Insulated Socket
(must be isolated from case)		 1 Mouser 163-4302-E $1.38  $     1.38 Radio Shack 274-1563  $     1.99  $     1.99
SPST Switch Black Rocker w/round hole & thread 1 Mouser 103-R13-135A-02-EV $1.18  $     1.18 Radio Shack 275-693  $     2.99  $     2.99
                     
                     
Headphone RELAY-DELAY                    
RM1 2M ohm[14] 1 Mouser 71-RN55D-F-2M $0.19  $     0.19 DigiKey CMF1.00MHFCT-ND  $     0.17  $     0.49
CM1 0.1uF X7R 1 Mouser 21RX310-RC $0.19  $     0.19 DigiKey 399-4329-ND  $     0.21  $     0.21
CM3 470uF 35V Electrolytic (10mm dia. Max)[15] 1 Mouser 140-HTRL35V470-RC $0.26  $     0.26 DigiKey 493-1285-ND  $     0.36  $     0.36
DM2 SA48C 1 Mouser 576-SA48C $0.22  $     0.22 DigiKey 1N4148FS-ND  $     0.07  $     0.07
VRM1 24VDC Linear Regulator, TO-92 1 Mouser 512-MC78L24ACP $0.22  $     0.22 DigiKey Not normally stocked  $     0.15  $     0.15
QM2 MPSA14 1 Mouser 512-MPSA14 $0.12  $     0.12 DigiKey MPSA14-ND  $     0.29  $     0.29
RELAY Omron 24V DPDT Relay G6A-234P 1 Mouser 653-G6A-234P-DC24 $4.31  $     4.31 DigiKey Z106-ND  $     4.68  $     4.68
                 
                     
INPUT Control                    
RS1, RS2, RS3, RS4 1K ohm 4 Mouser 71-RN55D-F-1.0K $0.08  $     0.32 DigiKey    
CS1 0.1uF X7R 1 Mouser 21RX310-RC $0.19  $     0.19 DigiKey    
DS2 SA48C 1 Mouser 576-SA48C $0.22  $     0.22 DigiKey    
VRS1 24VDC Linear Regulator, TO-92 1 Mouser 512-MC78L24ACP $0.22  $     0.22 DigiKey    
SW1, SW2 Omron 24V DPDT Relay G6K-2P-DC24 2 Mouser 653-G6K-2P-DC24 $3.79  $     7.58 DigiKey    
Punch-Down Blocks 3-pos PCB IDC Punch-Down Block 2 Mouser 651-1706183 $1.37  $     2.74 DigiKey    
2-pos Terminal Block 5mm screw terminal block 1 Mouser 571-2828362 $0.45  $     0.45 DigiKey    
                     
                     
MOSFET's - Note: see Millett MAX webpages for BJT Diamond Buffer                
RB1L/R NOT USED - DB Version ONLY - jumper out              
RB2L/R, RB3L/R 1K ohm 4 Mouser 71-RN55D-F-1.0K $0.16  $     0.64 DigiKey CMF1.00KHFCT-ND  $     0.17  $     0.68
RB10L/R, RB11L/R 2.2 ohm 2W Metal Film 4 Mouser 594-5083NW2R200J $0.32  $     1.28 DigiKey P2.2W-2BK-ND  $     0.28  $     1.12
RB12L/R 1K ohm Trimmer Pot - different value 2 Mouser 72-T93YA-1K $1.20  $     2.40 DigiKey 490-2874-ND  $     0.85  $     1.70
RB4L/R, RB5L/R, RB6L/R, RB7L/R, RB8L/R, RB9L/R, RB13L/R 100 ohm 14 Mouser 71-RN55D-F-100 $0.16  $     2.24 DigiKey CMF100HFCT-ND  $     0.17  $     2.38
RB14L/R 22 ohm[16] 2 Mouser 71-RN65D-F-22.1 $0.51  $     1.02 DigiKey CMF22.1HFCT-ND  $     0.17  $     0.34
QB1L/R 2N5486[17] 2 Mouser 512-2N5486 $0.11  $     0.22 DigiKey 2N5486GOS-ND  $     0.46  $     0.92
QB2L/R*** 2SJ74BL[18] 2 Beezar.com 2SJ74BL    $   12.40 Beezar.com 2SJ74BL    $   12.40
QB3L/R*** 2SK170BL[19] 2 Beezar.com 2SK170BL  [20]   Beezar.com 2SK170BL  [21]  
QB4L/R, QB6L/R 2N5087 PNP small signal[22] 6 Mouser 512-2N5087_J18Z $0.11  $     0.66 DigiKey 2N5087-ND  $     0.19  $     1.14
QB5L/R, QB7L/R 2N5088 NPN small signal[23] 6 Mouser 512-2N5088TA $0.06  $     0.36 DigiKey 2N5088BU-ND  $     0.18  $     1.08
QB8L/R alt. MOSFET IRFZ24N[24] 2 Beezar.com IRFZ24N/IRF9Z34N $3.50  $     7.00 Beezar.com IRFZ24NPBF-ND $3.50  $     7.00
QB9L/R alt. MOSFET IRF9Z34N[25] 2 Beezar.com IRFZ24N/IRF9Z34N  [26]  $        -   Beezar.com IRF9Z34NPBF-ND  [27]  $         -  
CB1L/R 220pF C0G ceramic - 5mm lead spacing[28] 2 Mouser 80-C317C221J1G5CA $0.28  $     0.56 DigiKey 399-4221-ND  $     0.27  $     0.54
                     
Heat Sink Aavid #531002B02500G (1-1/2"h.) 4 Mouser 532-531102B25G $1.14 4.56 DigiKey HS352-ND  $     1.37  $     5.48
  Aavid #531002B02500G (1"h.)[29]   Mouser 532-531002B25G $1.06   DigiKey HS190-ND  $     1.25  
                     
ENCLOSURE                    
PCB: 134.1W x 152.4L (mm) Hammond 1455T1601 1 Mouser 546-1455T1601 $25.57  $   25.57 DigiKey HM903-ND  $   23.57  $   23.57
        TOTAL   190.56   TOTAL    $ 168.35
                     
* These are consensus boutique electrolytic cap positions:
Use Nichicon Muse ES from Beezar.com, Bdent (CA7) &  Handmade Elec (CA2), or both from Michael Percy,
Elna RFS Silmic from DigiKey, or Black Gate N or NX from PartsConX or Soniccraft
** These are consensus boutique film cap positions, the selection choices are many.
However, be very careful what you put in CA9 - see the website on "boutique."
*** These JFETs form a complementary pair as the signal inputs to the diamond buffer.  
They must be matched for current to keep the buffer in balance.  Sources include Beezar.com and AMB Laboratories
[1]
Thomas M. Blanchard:
Cathode Bypass Cap - in the signal path, so boutique cap may benefit.  Also - CA9L/R is the film bypass cap for this position
[2]
Suggest 1000uF for "symmetry"
[3]
Thomas M. Blanchard:
You can go up to 1800uf 35V with these and still stay under 1" height with FM's and the newest UPW's (both 1800uf). 1000uf should be viewed as a minimum.

[4]
Thomas M. Blanchard:
Output coupling cap - directly in signal path, boutique cap may benefit
[5]
Thomas M. Blanchard:
Cathode Bypass Film Cap - in the signal path, so boutique cap may benefit.  Also - CA7L/R is the electrolytic bypass cap for this position
[6]
Note: you should probably purchase about 50 - 100 each of the 2n5087/88 transistors.  Matching for the CCS may be particularly critical.

Also, prices change constantly.  Look for the lowest price specific part numbers at the time of your order.
[7]
Thomas M. Blanchard:
Heater Resistor, used to knock down the voltage to the heaters if high supply voltages (30VDC) are used.  10 ohm = -1.5V, 20 ohm = 3.0V.  Optional, but it must be jumpered if not used.
[8]
Thomas M. Blanchard:
2K puts the power in the 1/2W range and doesn't seem to hurt the brightness.  I burned some LED's on the prototype sizing this too close..
[9]
DigiKey:
Qty of 5
[10]
Since LSDiodes has stopped selling LED's, Team Millett MAX has not found a vendor to recommend for every case.  LED's are plentiful, however.  Simply select the highest-rated MCD LED that uses 20ma current and is a T1, 3mm LED.
[11]
Note: the production MAX board has positions for three terminal blocks - one input and one output. However, the punch down blocks below are required if you use input source switching.
[12]
There are too many variables to predict what size may be needed.  The fuse is useful for protecting your Class 2 plug-in transformer (AC walwart).  1A SLO-BLO should be your starting point.  If you want to reduce or increase it from there, or experiment with a fast blo, that's up to you.  Be careful, however, or protecting the fuse may become the goal instead of the other way around.  Because of the high bias currents needed for the MOSFET-MAX, Team Millett MAX recommends the use of a slo-blo fuse.
[13]
Thomas M. Blanchard:
min qty 10
[14]
Recommendation:
R*C for RM2 and CM3 should equal ~300 or greater. Greater values will result in greater delays.
[15]
Recommendation:
R*C for RM2 and CM3 should equal ~300 or greater. Greater values will result in greater delays.
[16]
Thomas M. Blanchard:
This is the output resistor.  Jumper this position unless you have noise problems or desire greater gain reduction.
[17]
Thomas M. Blanchard:
Use of this JFET only is recommended.  Matching is helpful, but the trimmer should be able to balance the Left and Right channel differences that may exist.
[18]
Thomas M. Blanchard:
This is one of the two signal input JFETs.  It is critical that QB2 and QB3 be matched with each other for current.  (See the MOSFET-MAX website for the JFET matching procedure.)  Preferrably, they should also be matched between the Left and Right channels as well.  This means that matched "quad" sets are desired.
[19]
Thomas M. Blanchard:
This is one of the two signal input JFETs.  It is critical that QB2 and QB3 be matched with each other for current.  (See the MOSFET-MAX website for the JFET matching procedure.)  Preferrably, they should also be matched between the Left and Right channels as well.  This means that matched "quad" sets are desired.
[20]
Thomas M. Blanchard:
Sold at Beezar.com in matched quads, only.
[21]
Thomas M. Blanchard:
Sold at Beezar.com in matched quads, only.
[22]
Note: you should probably purchase about 50 - 100 each of the 2n5087/88 transistors.  Matching for the CCS may be particularly critical.

Also, prices change constantly.  Look for the lowest price specific part numbers at the time of your order.
[23]
Note: you should probably purchase about 50 - 100 each of the 2n5087/88 transistors.  Matching for the CCS may be particularly critical.

Also, prices change constantly.  Look for the lowest price specific part numbers at the time of your order.
[24]
These MOSFETs seem to be more plentiful and cheaper at Allied Electronics and Newark than at Mouser and DigiKey.  However, MOSFETs can have a higher failure rate when bought in bulk and should be tested prior to installation.
[25]
These MOSFETs seem to be more plentiful and cheaper at Allied Electronics and Newark than at Mouser and DigiKey.  However, MOSFETs can have a higher failure rate when bought in bulk and should be tested prior to installation.
[26]
Price is for complementary pair
[27]
Price is for complementary pair
[28]
Thomas M. Blanchard:
These compensate the lower capacitance of the N-channel mosfet - Q8 - to the same as the P-chanmnel Q9.  Solder across the gate and source of QB8L/R by soldering into the adjacent BJT pads.  
[29]
Thomas M. Blanchard:
Taller heat sinks are the normal default with MOSFETs because of the higher bias current required.  However, it is possible to use 1" heat sinks with the MOSFET-MAX.  Refer to the MOSFET-MAX website for specific precuations to take in the use of the shorter sinks.