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diytube Stereo 35 Rev D   

 

 

 

Revised: November 30, 2008 

 
 
Item 

QTY 

Reference 

 Part 

  Mouser 

Part 

 Unit 

Cost 

 

_________________________________________________________________________ 
 

Note: I’m assuming this is the area people will improvise most, and with parts they have 
on hand. I highly recommend parting out a Dynaco SCA-35 as these are the same 
transformers found the in the highly regarded Dynaco ST-35.  

 
 

‰

 

V1 

  12AX7 

varieties 

  

‰

 

V2 

  12AU7 

varieties 

  

‰

 

4 V3,V4,V5,V6 

  6BQ5/EL84/7189/6p14p 

 

‰

 

V1-V6  

 

9pin PCB Ceramic Socket  

 
 
 

‰

 

T1 

 

 

Dynaco PA-774 Power Transformer 

 

 

or 

‰

 

T1 

 

 

Hammond 270HX Power Transformer 

 

 

 

 
 
 

‰

 

T2,T3  

 

Dynaco Z-565 Output Transformer (8 & 16 ohm) 

or  

‰

 

T2,T3  

 

Triode Electronics 4 & 8 ohm Z-565 Output  

or 

‰

 

T2,T3  

 

Hammond 1650F Output Transformer 

 

 

Note: Hammond 1650E (8k) and 1620 (6.6k) have been used as well. 
 
 
 
 
 
 
 
 
 
 
 
Triode Electronics --   

 

http://www.triodeelectronics.com/ 

Angela Instruments --   

 

http://www.angela.com/ 

Antique Electronics --  

 

http://www.tubesandmore.com/ 

Handmade Electronics --  

 

http://www.hndme.com/ 

 

 

 

Triode Electronics 

Angela Instruments 

Antique Electronics 

Handmade Electronics 

Dynaclone PA774 $64.95 

Hammond 270HX $73.00 

Hammond 270HX $73.05 

Hammond 270HX $69.31 

Dynaclone Z565 $69.95 

Hammond 1650FA $105.00 

Hammond 1650F $55.22 

Hammond 1650F $66.70 

9pin Ceramic PC  $2.35 

EL84 Quad $60.00 

9pin Ceramic PC  $2.50 

9pin Ceramic PC  $1.25 

Sovtek EL84 quad $37.95 

6189W JAN $15.00 

EI EL84 quad $31.80 

Sovtek EL84 quad $36.00 

12AX7  $9.95 

Hammond Chassis Stocked 

12AX7  $6.95 

12AX7  $7.95 

12AU7  $9.95 

 

12AU7  $4.75 

12AU7  $5.95 

 

 

 

Hammond Chassis Stocked 

 

 

 

 

 

 

 

 

 

Summary of Contents for stereo 35

Page 1: ...diytube stereo 35 power amplifier rev d INSTRUCTIONS FOR ASSEMBLY OPERATION Price 10 00 ...

Page 2: ... 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 i...

Page 3: ... a 12AX7A and a 12AU7 The 12AX7A is a voltage amplifier that directly drives the 12AU7 a cathodyne phase splitter The only other meaningful change is the replacement of a single cathode resistor and capacitor with four individual resistors and capacitors A larger value resistor in series with a variable resistor parallels the main cathode resistor providing a range of 320 450 ohms per cathode This...

Page 4: ... of the cathode which is represented by a stripe on both the silkscreen and the diode s body 5 Stuff C5 C6 C7 C8 Mind the polarity The board has symbols to show where the positive terminal from the capacitor should be placed Note that many modern caps have only the terminal marked usually with a stripe running down one side If you choose to substitute the diameter must be no more than 10mm Use a s...

Page 5: ...citor orientation Initial Impedances When it Doubt Ohm it Out These are without connections to the terminal blocks When connected those readings that will differ will be in brackets Different transformers will have different readings this one is a PA 774 J1 1 2M 94 2 2M 94 3 200K 4 200K 5 GND 6 GND 7 100 50 8 100 50 9 10M 10 10M J2 1 10M 2 10M 3 GND J3 1 10M 2 10M 3 28 3K 1 ohm J4 1 10M 2 10M 3 28...

Page 6: ...tance is 20 3K set to 28 3K if using the 16 ohm tap as feedback as in the original Z565 3 Probe your DMM from J3 pin 3 left channel to ground and adjust R31 until the resistance is 20 3K set to 28 3K if using the 16 ohm tap as feedback as in the original Z565 4 Your feedback is set Adjusting Bias 1 With the unit off probe your DMM from V3 pin 3 the cathode to ground Adjust R22 until you measure 40...

Page 7: ...s adjusted with the ʹoutsideʹ test point Adjust R19 until the voltage is 350V or 350mV 8 Probe your DMM set to DC volts from the test point which is sandwiched between the R25 R28 to ground V5 is adjusted with the ʹinsideʹ test point Adjust R28 until the voltage is 350V or 350mV 9 Probe your DMM set to DC volts from the test point which is sandwiched between the R25 R28 to ground V6 is adjusted wi...

Page 8: ...ins 4 5 6 A 100 ohm 1W resistor Mouser 281 100 can be soldered on the underside of the board between pins 1 2 on J2 J3 J4 and J5 for triode operation Do not attach any UL taps to pin 2 on these connector blocks if you do this Do not populate C20 C21 If you are using a filament supply with a center tap and choose to use the center tap do not populate R40 and 41 These are for non CT filament supplie...

Page 9: ...W 71 RN65D F 1 0K 0 31 4 R19 R22 R25 R28 10K Pot 72 T93YB 10K 1 32 1 R29 300K 1W 594 5083NW330K0J 0 32 2 R30 R31 100K Pot 72 T93YB 100K 1 44 2 R32 R33 3 3K 3W 72 RWM410 3K3 5 0 51 4 R34 R35 R40 R41 100 3W 72 RWM410 100 5 0 48 2 R36 R37 Jumper Use cut leads 0 00 2 R38 R39 150K 1 2W 71 RN65D F 150K 0 31 1 R42 Inrush Limiter 527 CL90 1 72 4 R43 R44 R45 R46 10 Ohm 1 4W 71 RN60D F 10 0 09 4 C1 C2 C3 C4...

Page 10: ... 22 11 08 or 1 12X10X2 Chassis 546 1444 29 26 02 1 12X10 Bottom 546 1434 29 11 08 Note Due to the small quantities of nuts bolts you might want to buy these at your local hardware store The Mouser parts are nickel plated and in boxes of 100 Don t forget solder spade connectors etc 1 RCA Red Jack 161 0251 EX 0 87 1 RCA Black Jack 161 0252 EX 0 87 4 Binding Posts 164 4205 2 06 2 Binding Posts 164 42...

Page 11: ...3 Triode Electronics 4 8 ohm Z 565 Output or 2 T2 T3 Hammond 1650F Output Transformer Note Hammond 1650E 8k and 1620 6 6k have been used as well Triode Electronics http www triodeelectronics com Angela Instruments http www angela com Antique Electronics http www tubesandmore com Handmade Electronics http www hndme com Triode Electronics Angela Instruments Antique Electronics Handmade Electronics D...

Page 12: ...9 7 4 5 1 6 8 k g g2 a h h i c i c i c V6 EL84 3 2 9 7 4 5 1 6 8 k g g2 a h h i c i c i c C4 0 1uF J4 Output Transformer Hookup 1 2 3 R16 470K R23 470 C21 15pF C3 0 1uF J5 Output Transformer Hookup 1 2 3 R27 1K R24 1K R28 10K 1 3 2 R15 470K R26 470 R46 10 R25 10K 1 3 2 C8 470uF C16 27pF R30 100k 1 3 2 V3 EL84 3 2 9 7 4 5 1 6 8 k g g2 a h h i c i c i c R19 10K 1 3 2 R18 1K R21 1K R22 10K 1 3 2 J6 R...

Page 13: ...y 16 2004 Title Size Document Number Rev Date Sheet of 320V 6 3VAC A 6 3VAC B R42 Keystone CL 90 C12 120uF C10 120uF C11 120uF R35 100 3W D1 UF4007 D2 UF4007 J1 CON10 1 2 3 4 5 6 7 8 9 10 R37 05 3W ww R36 05 3W ww R33 3 3K 1W R32 3 3K 1W R41 100 R40 100 R34 100 3W C9 120uF R29 300K ...

Page 14: ...red yellow red SW1 Connect pin 1 to the fuse pin 2 to the primary and pin 3 to J1 10 as the neon bulb is in parallel to the primary winding green white black diytube Stereo 35 PCB Rev D Connect directly to chassis Signal ground floats but should be strapped to earth ground during testing J2 1 2 3 J3 1 2 3 J4 1 2 3 J5 1 2 3 J1 1 2 3 4 5 6 7 8 9 10 J7 1 2 Right Channel F1 Left Output Transformer Lef...

Page 15: ... pin 3 to J1 10 as the neon bulb is in parallel to the primary winding green white black diytube Stereo 35 PCB Rev D green grn yel green blk yel grn yel yellow Just think green yellow to green and black yellow to black grn yel Connect directly to chassis Signal ground floats but should be strapped to earth ground during testing GND 1 J7 1 2 J5 1 2 3 Left Output Transformer Right Output Transformer...

Page 16: ... Number R ev Date Sheet o f Doc B Stereo 35 Power Supply A 4 4 Sunday November 30 2008 R33 3 3K 1W R36 jumper R37 jumper JP1 JUMPER C10 120uF C9 33uF JP2 JUMPER C11 120uF C12 120uF R32 3 3K 1W J7 Choke 1 2 R41 100 R40 100 J1 CON10 1 2 3 4 5 6 7 8 9 10 R42 Keystone CL 90 R29 300K ...

Page 17: ... as the neon bulb is in parallel to the primary winding green white black diytube Stereo 35 PCB Rev D green grn yel green blk yel grn yel yellow Just think green yellow to green and black yellow to black grn yel Connect directly to chassis Signal ground floats but should be strapped to earth ground during testing yellow yellow yel blk J5 1 2 3 Left Output Transformer GND 1 8 OHM 1 GND 1 Power Tran...

Page 18: ... Number R ev Date Sheet o f Doc B Stereo 35 Power Supply A 4 4 Sunday November 30 2008 R33 3 3K 1W R36 jumper R37 jumper JP1 JUMPER C10 120uF C9 33uF JP2 JUMPER C11 120uF C12 120uF R32 3 3K 1W J7 Choke 1 2 R41 100 R40 100 J1 CON10 1 2 3 4 5 6 7 8 9 10 R42 Keystone CL 90 R29 300K ...

Page 19: ......

Page 20: ...9 250 4 250 1 000 0 156 0 640 3 650 1 500 0 300 0 300 0 550 1 750 4 625 3 480 1 260 ...

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