1. Manuals
  2. Brands
  3. TubeDepot Manuals
  4. Musical Instrument Amplifier
  5. JTM45+
  6. Assembly manual

TubeDepot JTM45+ Assembly Manual

Styled 50w tube guitar amp kit
Hide thumbs
Table of Contents

Advertisement

Quick Links

Download this manual
Learn
ASSEMBLY MANUAL
JTM45+ "
50W Tube Guitar Amp Kit
(with some great "
Build
Play
" Styled
" styled mods)
1686 Barcrest Dr., Memphis, TN 38177
www.tubedepot.com
Click
Click
here to
here to
watch
watch
the
the
assembly
assembly
video
video
recommended level of difficulty
Version 4.2
24 January 2014

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the JTM45+ and is the answer not in the manual?

Questions and answers

Summary of Contents for TubeDepot JTM45+

  • Page 1 Build Play assembly assembly video video ASSEMBLY MANUAL recommended level of difficulty JTM45+ “ ” Styled 50W Tube Guitar Amp Kit (with some great “ ” styled mods) Version 4.2 24 January 2014 1686 Barcrest Dr., Memphis, TN 38177 www.tubedepot.com...
  • Page 2 The Author, Publisher or Seller assume no liability with respect to the use of the information contained herein. For permission and other rights under this copyright, contact TubeDepot.com. TubeDepot.com...

  • Page 3: Table Of Contents

    Turret Board / Chassis and Wiring …............Chapter 8 Testing …...................... Chapter 9 Final Assembly …..................Chapter 10 Schematic ….…....…..............Appendix A) Resistor and Capacitor Codes ............... B) Soldering Hints ..................C) Amplifier Care and Feeding ..............D) Mods …....................TubeDepot.com...

  • Page 4: Preface

    But before we get started, a safety review … Robert Hull Director of Technical Services TubeDepot.com Before continuing, PLEASE READ the following: We are continually making improvements to this assembly manual in an effort to provide the best instructions possible. Therefore, when...

  • Page 5: Chapter 1 Safety

    - DISCLAIMER - TubeDepot.com, it's employees, officers, shareholders, investors and subsidiaries accept no liability for any damage(s), injury(s) or death incurred from or while building or using this kit.

  • Page 6: Tools And Supplies

    As with any construction project, there are certain recommended tools and supplies. The following are the tools and supplies NOT provided with the kit but are needed for completion. These are expected to be provided by the builder. TubeDepot.com The following is our recommended list: part number...

  • Page 7: Chapter 3 Parts Inventory

    9 pin SK-B-VT9-ST-C shield, tube socket, miniature 9 pin SK-PCP socket, tube, octal chassis mount SK-B-VT8-ST grommets, rubber 1/2" chassis hole P-GROMMET-1/2 bolt, metric, M6x30mm, stainless steel MS-M6X30MM flat washer, metric, M6, stainless steel BP-M6-WASHER captive nuts, M6 BP-M6-CAPTIVENUT TubeDepot.com...
  • Page 8 47K / 1/2W, 1% metal film R-273-47K 51K / 1/2W, 1% metal film R-273-51K 56K / 1/2W, 1% metal film R-273-56K ← mod. 68K / 1/2W, 1% metal film R-273-68K 82K / 1/2W, 1% metal film R-273-82K 100K / 1/2W, 1% metal film R-273-100K TubeDepot.com...
  • Page 9 - cabinet, 1x12 combo Marshall style CAB-MAR18 speaker, 12",(various 75W speakers) our secret hidden stock 1/4" phone plug, Switchcraft P-280 P-280 1 ft. techflex, yellow TS-PTNO-1-4 2 ft. wire, 18 AWG, stranded, hi-temp PVC - white HTPVC-18-STR-WHITE TubeDepot.com...

  • Page 10: Chapter 4 Cabinet Preparation

    Step 5 – Once the pilot holes have been drilled, drill the final 5/16” hole down the center of each of these holes. Step 6 – With a hobby knife, clean the edges of the holes by cutting off any excess vinyl covering left from the drilling operation. photo 4.2b TubeDepot.com...
  • Page 11 (photo 4.3b). Step 6 – Apply the final shielding tape strip along the upper edge of the first tape, photo 4.3b overlapping about 1/8” (photo 4.3b). Step 7 – With a hobby knife, Clear the mounting holes of shielding tape. TubeDepot.com...
  • Page 12 Step 5 – Slide the length of yellow Techflex over this twisted pair right up to the center conductor of the plug (photo 4.3b). Step 6 – Slide the 3” length of 3/8” heat shrink up over the photo 4.3a Techflex up to the center conductor of the plug (photo 4.3b). TubeDepot.com...
  • Page 13 Step 3 – Install a single #8 flat washer on each of the four mounting screws prior to installation. Step 4 – Install the four mounting screws through the speaker mounting holes into the baffle board. Firmly tighten down. photo 4.4a TubeDepot.com...

  • Page 14: Chassis Preparation, Assembly And Wiring

    Step 2 – Use a center punch to mark the point to be drilled. Step 3 – Drill the 5/32” holes at each of these marks and debur the holes. Step 4 – Remove all remaining protective plastic covering from chassis. TubeDepot.com...
  • Page 15 Make sure to include the #6 solder terminals on the power tube sockets. Note alignment of sockets and which #6 screws and nuts are used with each socket (drawing 5.4b). flatten here TubeDepot.com...
  • Page 16 Step 1 – Use an electric drill to twist together 3-1/2 feet of 20AWG black and 20AWG red wires. The resultant dual twisted wire should be about 3 feet long. Step 2 – Wire the filaments for the preamp and power tubes. Review the following drawings for method description (drawing 5.5a & 5.5b). TubeDepot.com...
  • Page 17 Drawing 5.5a Drawing 5.5b TubeDepot.com...
  • Page 18 (with rear lock washer). Refer to drawing for proper component alignments (drawing 5.15c). Step 7 – Install IEC AC power entry connector into the square cut out on the back of chassis TubeDepot.com...
  • Page 19 Step 7 – Wire the HV center tap (red with yellow stripe) to the grounded solder terminal G1 (drawing 5.11a or 5.11b). Step 8 – install a wire (recycled wire from filament center tap) between the AC IEC connector and the appropriate grounded solder terminal G3 (drawing 5.11a or 5.11b). TubeDepot.com...
  • Page 20 5.11a TubeDepot.com...
  • Page 21 5.11b TubeDepot.com...
  • Page 22 Step 17 – Twist a red and an orange 20AWG wires together to form a 10” twisted pair cable. Step 18 – Wire the orange wire of this cable to the rectifier switch and the red wire to the B+ fuse holder (drawing 5.12b). TubeDepot.com...
  • Page 23 Step 19 – Run these wires along the chassis to the can caps and solder the red wire to the juncture of the wire from the choke and the 10K resistor on the can cap (drawing 5.12a). Step 20 – Solder the orange wire to the terminal at the opposite end of the 10K resistor. drawing 5.12b TubeDepot.com...
  • Page 24 Step 9 – Install the two resistors on the rear of the feedback switch (drawing 5.13a). Step 10 – Install a 20AWG wire between the 4 ohm tap of the impedance selector switch and the feedback selector switch as shown (drawing 5.13a). drawing 5.13a TubeDepot.com...
  • Page 25 Step 21 – Run the shielded cables from the jack assembly to the appropriate terminals of V1 tube socket and trim to length. Step 22 – Strip 1/2” of the insulated jacket off the ends of these two shielded cables and separate the shield and center conductor. TubeDepot.com...
  • Page 26 Solder the cap lead to the drawing 5.15a back of the pot (drawing 5.15b). Step 8 – Solder the 100pF capacitor on the bright volume control (drawing 5.15b). Step 9 – Wire the remaining controls as shown (drawing 5.15b). drawing 5.15b TubeDepot.com...
  • Page 27 5.15c TubeDepot.com...

  • Page 28: Turret Board Construction

    Refer to the pamphlet: NOTE “How to Make Top Quality Turret Boards (with simple tools)” http://site.tubedepot.com/pdf/turret_boards_v1.pdf Turret Board Component Installation Step 1 – Solder the four separate under-board 20 AWG jumper wires between T61 and T53; T56 and T41; T50 and T44; T44 and T30 (drawing 6.2a).
  • Page 29 Be creative at points where more than three leads are soldered into the NOTE same turret (turret T34 – see photo 6.2e). Send end of manual for component changes and modifications. TubeDepot.com...
  • Page 30 See end of this manual. Turret Board Wire Installation Step 1 – Install each colored 20AWG wire to the appropriate turret at the length specified according to drawings 6.3a and 6.3b. drawing 6.3a TubeDepot.com...
  • Page 31 6.3b Step 2 – Twist the wires from T43 and T37 together for about 4 inches. When the board is installed into the chassis, these wires will be routed underneath the board along the chassis toward the power tubes. TubeDepot.com...

  • Page 32: Turret Board / Chassis And Wiring

    Step 7 – Connect the ground wires from the input jacks and master volume to the buss ground of the turret board. Step 8 – Connect the longer ground wire from the G1 grounding terminal to turret T31. Step 9 – Connect the shorter ground wire from the G1 grounding terminal to turret T53. TubeDepot.com...
  • Page 33 7.1 TubeDepot.com...

  • Page 34: Chapter 8 Testing

    T63 and T65 (polarity is not important). Step 6 – There should be about 7 VAC as measured at these two turrets. Step 7 – After 5 min. of trouble-free operation, remove the AC power by disconnecting the AC TubeDepot.com...
  • Page 35 Step 7 – Adjust the meter range to the 200V range. Touch the red meter lead to T20. The voltage here should read 157V (+/- 25V). Step 8 – Touch the red meter lead to turret T36. The voltage here should be +35 V (+/- 10V). TubeDepot.com...
  • Page 36 Step 6 – Slowly turn up the “high treble” channel and listen to the sound source. Adjust the volume to verify that the level goes up and down accordingly. Step 7 – Repeat the same for the #2 input (s) and the “normal” channel control. Step 8 – If everything checks good, turn off the amp. TubeDepot.com...

  • Page 37: Chapter 9 Final Assembly

    4 input / no master volume style amps. - The effectiveness of the tone controls will change at different volume levels. Because of this interaction between the tone controls and the volume, it will take some experimentation to really dial in the sound of the amp. TubeDepot.com...

  • Page 38: Chapter 10 Schematic

    Schematic TubeDepot.com...

  • Page 39: A) Resistor And Capacitor Codes

    Below are photos and descriptions of various resistors that could be used in your project. Metal Oxide 2W Carbon Composition 1/2W Carbon Film 1/2W Metal Oxide 3W Metalized Film 1/2W Wire Wound 5W Carbon Composition 1W Wire Wound 8W Metal Oxide 1W TubeDepot.com...
  • Page 40 Gold +/- 5% Green 100,000 Green Green Black +/- 2% Blue 1,000,000 Blue Blue Brown Brown +/- 1% Violet Violet Gray Silver Gray Orange White Gold White Yellow Green Blue Violet Gray White Metalized Film 1% and 2% types TubeDepot.com...
  • Page 41 2nd line: 160V = voltage rating (160V) 3rd line: 0834R = batch / date code 104 = .1ufd 684 = .68ufd 103 = .01ufd 223 = .022ufd 473 = .047ufd 102 = .001ufd 222 = .0022ufd 472 = .0047ufd TubeDepot.com...

  • Page 42: B) Soldering Hints

    4. When applying the soldering iron to a connection to be made, it is important to lay the tip in such a position that the maximum surface area of the tip is against the connection. In this way, the maximum heat is transferred to the connection in the TubeDepot.com...
  • Page 43 This has become a broken connection. The solution is to always scrape the gold plating off of a potential connection, down to the base metal, prior to soldering. This will guarantee a faithfully soldered connection. TubeDepot.com...

  • Page 44: C) Amplifier Care And Feeding

    – 5751; (high gain – amplification factor = 70) Power tubes: – EL34 - 6550 - KT77 - 6L6 / KT66 / 5881 / EL37 (w/ slight amplifier modification. Contact me for more information – tech@tubedepot.com) Rectifier tubes: – GZ34 - 5AR4 - 5R4 - GZ37 Applications The laboratory environment is nice, but life experiences are better.

  • Page 45: D) Mods

    “fine tune” the installation of these tubes. 11. The more obscure mods – effects loop; reverb; variable B+ control; balanced line out; they are all possible … some more difficult than others. For any questions regarding mods, contact: tech@tubedepot.com TubeDepot.com...

Table of Contents