Welcome to my Allen Amps Blackheart BH5H Little Giant™ Head Point-to-Point Kit upgrade page! The BH5H is a pretty nice, relatively inexpensive amp head built by Blackheart Engineering™. The head is made in China, but the heavy duty cab and steel chassis are a very good build quality, and make a great basis for mods!

Let's start off with the specifications and some initial impressions of the stock configuration. The amp specs are (from the Blackheart Engineering™ web site):

• 5W Single-Ended, Class A
• 4, 8, and 16 ohm Speaker Outs
• Preamp Tubes: 1 x 12AX7
• Power Tubes: 1 x EL84
• Solid State Rectifier
• Volume with 3 Band EQ
• Pentode (5W)/Triode (3W) Switch
• DC Power to filaments for super quiet operation
• 15 ply (18mm) thick-void free Plywood Construction
• 1W resistors in signal path, 2W & 5W resistors in power supply

1. Loosen the (7) Phillips head screws that fasten the back panel. Remove the back panel and sit it aside for installation later on.
2. Remove the (4) Phillips head screws on the bottom of the cabinet (located just next to each of the rubber mounting feet) that fasten the chassis to the cabinet. Slide the chassis out the back of the cabinet. Save the screws for installing the chassis later on.



3. Remove both the EL84 power tube and the 12AX7 preamp from the amp so they don't get broken.



4. Clip off the wire ties bundling the power transformer leads in the left end of the chassis.
5. Unplug the brown and white lugs from the circuit board (in the corner of the board behind the indicator lamp). They aren't even used in either circuit and will get tied off later on.
6. Unsolder or cut close to the board, the orange, red and blue leads that go to the 3W/5W switch. You want as much as the lead length left as possible so cut them close to the board.
7. Unplug the (4) lugs from the Power Switch. Remove the switch.
8. Install the new Carling Progressive switch. It looks very similar so don't get them mixed up.
9. Clip all the remaining leads that go to the circuit board and cut them as close to the board as possible so they are left as long as possible.
10. Clip all the leads going to the speaker jack circuit board on the back of the chassis. Remove the wire ties that bundle the output transformer leads. Cut the leads close to the board so they are left as long as possible.
11. Remove the (5) speaker jack nuts from the back of the chassis using a 7/16" nut driver. Remove and discard the speaker jack circuit board.
12. Remove the nut from the input jack on the front of the chassis using a 7/16" nut driver.
13. Pull the (4) knobs off the front of the amp and remove the nuts securing the potentiometers to the front of the chassis.
14. Remove the nut from the ground stud near the input jack and near the 16 ohm speaker jack using a 7mm nut driver. Save the nut for use later on.
15. Remove the (7) Phillips screws that fasten the circuit board to the chassis and remove the circuit board. Save the screws as they will be needed to reinstall the new board later on.



16. With the circuit board removed, it is easy to remove the indicator lamp. Remove it only if you intend to enlarge the hole to 11/16" for installation of the vintage type jewel pilot lamp. You really need an 11/16" chassis punch to do this. It could also be drilled or reamed out. If you don't want to modify the chassis mechanically, just leave the old indicator lamp installed. If you opt for the vintage pilot lamp, install it after you get the 11/16" hole made. To do the cleanest job for this, you probably need a "Unibit" step drill bit to fit this size. I do not have one of these, so used my variable speed rotary tool with a carbide bit. While this will work if you are very careful, it is more time consuming and won't give you as good of a result.



17. Drill the (4) potentiometer holes on the front of the chassis out to 3/8" diameter. NOTE: use a fresh/sharp drill bit to get the cleanest holes you can. You will have to debur the inside of the chassis after enlarging the holes. If you don't have a countersink or deburring tool, try using a large drill bit and turn it by hand to remove the "lip" left over from the drilling.
18. Clean all debris from inside the chassis after drilling.
19. Remove the (2) Phillips screws that fasten the output transformer to the chassis and remove the old output transformer.



20. Install the new Heyboer/Allen TO10B output transformer in its place and with the same color leads going through the grommets as the original and as shown on the drawing. Use the old screws and tighten securely. Pull the leads through the appropriate grommets and inside the chassis.



21. Install the (4) new full-size potentiometers with a lock washer on the inside and a flat washer and nut on the outside. Tighten securely with a 3/8" nut driver.



22. Install the knobs with their pointer lines properly aligned and tighten securely.
23. Install the insulated input jack with its black shoulder washer on the inside to "center" the jack in the hole and the insulated flat washer on the outside of the chassis. Then the metal flat washer and finally the nut. Tighten as securely as you can. It will slip due to the insulating washers.
24. Install the (3) insulated speaker jacks just like you did the input jack above and tighten securely. The black shoulder washers go on the inside. The insulated flat washers on the outside. Tighten securely.



25. Install the black plastic hole plugs in the two unused speaker jacks. I didn't feel the stock (5) speaker jack set up was properly marked or explained. This way, each jack has the true impedance requirement indicated. Use only one jack at a time but always have one jack plugged into a speaker load to prevent damage to the output transformer.



26. Install the (2) Belton molded 9-pin tube sockets to the bottom of the circuit board using 4-40 by 1/4" machine screws installed from the top side of the board and with #4 Keps nuts on the bottom of the board where the tubes will get plugged in. It is important that the hardware be installed correctly so that only the heads of the screws are near the lugs of the sockets on the top of the board. Study the orientation and photo of the board to make sure you get the sockets installed on the correct side of the board (it is not a symmetrical board and must be turned just one certain way) and that you get them rotated correctly so the "missing 10th lug" is in the correct location. If you don't get the board and sockets oriented and installed correctly, you won't be able to complete this kit.



27. I measure the resistors with my digital volt/ohm meter and tape them down to a sheet of paper, then write the values down to make it easier and faster to find the correct one when populating the eyelet board.



28. Start populating the board with the smaller resistors and capacitor and work your way up to the largest. Form the leads for a component so they can fit between its two eyelets. Bend the two leads toward each other on the bottom side of the board while holding the component firmly against the board. Getting the slack out of the leads helps hold the components until they get soldered. Start trying to install wire leads as shown on the layout drawing. You may want to start soldering connections so you can trim their "under the board" leads to get them out of the way and hold the soldered components firmly in place. The watch-for here is to make darn sure you have EVERY lead or wire that goes in that eyelet actually in that eyelet BEFORE you solder it. They are much harder to get in after you solder and realize you missed a lead.



29. Notice there are some jumper leads that go between certain points on the underside of the board. They are indicated on the layout drawing with dashed lines. You can use the extra component leads for the shorter connections and use insulated lead wire to make the longer connections, keeping them as short as possible.



30. When soldering a plastic insulated wire lead, keep the insulation 1/16" away from the solder joint. In other words, strip enough insulation from a wire lead before you solder it so there is about 1/16" of bare lead showing. This keeps the plastic insulation from melting into the solder joint and contaminating it.
31. I find it helpful to bend the tube socket lugs out 45 degrees. Keep the component and wire leads you solder to the tube socket lugs out near the end of the lugs. It is OK to bend a lead 90 degrees to help hold it in place for soldering but don't "hook and crimp" leads around lugs as it makes them very difficult to undo if rework or repairs or mods are attempted later on.
32. Use the long leads of the filter capacitors to run under the board to the next eyelet on the negative or ground end. This keeps you from having to install separate little jumpers on top of the board. All the ground leads of the filter capacitors must be jumpered together as shown on the layout drawing.
33. Make sure you install the electrolytic capacitors with the correct polarity as shown on the layout drawing. Also, the diodes must be installed with the correct polarity.
34. Install the full-wave-bridge rectifier into the 4 eyelets shown on the layout. The AC leads will have to be formed one way and the + and - DC leads another way so they can go down through the 4 offset eyelets. Solder the + and - leads and trim all 4 leads off on the bottom side of the board. The green leads from the power transformer will get soldered to the 2 remaining eyelets along with the AC leads already in there.
35. Solder all circuit board eyelets and socket lugs making sure all connections have been made as sown on the layout. Some eyelets will NOT get soldered yet because they don't have all of their leads installed (mostly on the left end of the board which will connect to the power transformer leads after the board gets installed in the chassis).
36. Trim off any unwanted leads from the under side of the board. Use flush cutting pliers. Make sure you only trim the leads that should get trimmed off and don't trim off any by mistake that should have been left there. This is your last chance to carefully inspect the bottom of the circuit board for errors in wiring as you won't be able to see under it once installed and wired.

NOTE: I find it easier to install and solder all the front and rear chassis mounted components (i.e. pots, speaker jacks, grounds, etc.) before putting in the circuit board in the chassis .. just so I have extra room. If you choose to do this, you will have to skip around in the following steps - so just make sure you do all of the steps if you choose to follow this path!


37. Once you are convinced that you have installed every component onto the board in the correct location, that electrolytic capacitors and diodes are installed with the correct polarity, that all jumpers (both above and below the board) have been installed as called for on the layout and that you have trimmed off all the unwanted leads under the board then you are ready to install it into the chassis. Install the new point-to-point wired circuit board into the previously prepared chassis and secure it using the (7) Phillips screws that held the original circuit board in place. Get all 7 started good before tightening any of them. Once they are all started, tighten them all securely.
38. Twist, trim, strip and solder the (2) red power transformer leads to the eyelets indicated on the layout.
39. Twist, trim, strip and solder the (2) green power transformer leads to the eyelets indicated on the layout. The 2 middle or AC leads of the FWB rectifier should be in those 2 eyelets already.
40. Twist, trim, strip and solder the (2) yellow power transformer leads to the pilot lamp lugs as shown.
41. Trim, strip and solder the orange, red and blue leads from the 3W/5W switch to the board as shown on the layout as well as the red and blue output transformer leads.
42. Solder the yellow, green and brown output transformer leads to their appropriate speaker jack lugs as shown on the layout.
43. Connect a green ground wire between the chassis ground point and the ground lug of each speaker jack as shown.



44. Crimp a ring terminal on one end of an 8" green wire and a crimp on insulated female quick disconnect terminal on the other end (for use in the next step).
45. Connect the other ground wires shown (including the black OT wire and the green wire going to the upper left lug on the new progressive power switch) to this same chassis ground point using crimp-on ring terminals. Fasten to the ground stud with the original nut and tighten securely with a 7mm nut driver.
46. Wire the 1 meg and the 33K resistor to the appropriate terminals of the input jack (note the shorting jumper between the ground lug and the center switch lug on the jack) and install the input jack with the black shoulder washer on the inside and the flat insulated washer on the outside. Then the flat washer and finally the nut are installed. Tighten securely will trying to keep the jack from turning.
47. Wire the other end of the 33K resistor to pin 2 of the preamp tube as shown.
48. Crimp (4) 8" green ground leads into a ring terminal and fasten this terminal to the chassis ground stud near the input jack. Install the original nut and tighten with a 7mm nut driver.



49. Trim to length and solder one of the green ground leads to the eyelet in the upper right corner of the circuit board.
50. Trim to length and solder another green ground lead to the ground lug of the input jack.
51. Trim to length and solder another green ground lead to the left lug of the VOLUME pot.
52. Trim to length and solder the remaining green ground lead to the left lug of the MIDDLE pot.
53. Solder a jumper between the center lug of the TREBLE pot and the right lug of the VOLUME pot as shown.
54. Solder a wire between the center lug of the VOLUME pot and pin 7 of the preamp tube as shown.
55. Solder one end of the 500pf silver mica capacitor with heat shrink tubing and solder it to the board as shown. Solder the other end to the right lug of the TREBLE pot.
56. Solder one end of both the .022uf yellow capacitors. Solder this end to the same eyelet as shown on the layout.
57. Solder the other end of one of the .022uf yellow capacitors to the left lug of the TREBLE pot along with a short jumper wire. Solder the other end of that jumper wire to the center lug of the BASS pot as shown.
58. Solder the other end of the remaining .022uf yellow capacitor to the center lug of the MIDDLE pot along with a short jumper wire. Solder the other end of that jumper wire to the left lug of the BASS pot as shown. This should complete wiring of the volume and tone controls.
59. Crimp an insulated female quick-disconnect lug onto the end of the orange power transformer's HV secondary center tap lead (which enters the chassis through the lower left grommet) and then connect that lead onto the left center lug of the power switch as shown on the layout.



60. Plug the black power transformer lead onto the right center lug of the power switch as shown.
61. Plug the brown lead from the IEC power input connector on the back onto the upper right lug of the power switch as shown.
62. Remove the blue lead that is plugged onto the middle lug of the IEC power cord connector on the back and discard this lead.
63. Locate the blue power transformer lead (which enters the top left grommet) and plug its connector onto the middle lug of the IEC power cord connector.



64. Bundle up the loose PT wires along with the unused white and brown PT leads and fasten with a wire tie similar to the way it was originally.



65. Give all of the hardware a good once over to make sure you didn't miss tightening something.
66. Carefully install the 2 tubes back into their sockets. Install each tube's retainer. I found that the tube retainer bases were a tight fit, putting friction on the tubes when trying to insert them. So I loosened the mounting screws on the retainer bases and then inserted the tubes. Then tighten the retainer base screws after you have inserted the tubes.
67. Carefully install the chassis back into the cabinet and fasten it in place with the (4) screws you removed from the bottom originally. Tighten securely.
68. Install the back panel using the (7) screws that came with it. Tighten securely.



69. Plug in a suitable speaker load to one of the speaker jacks. Use only one jack at a time but ALWAYS have a speaker load connected any time the amp is turned on.
70. Plug in the new 12 foot long right-angled power cord.
71. Turn the Volume down and flip the power switch from OFF to its center or STANDBY position.
72. After about 30-60 seconds, flip the power switch from its center or STANDBY position to its ON or PLAY position.
73. Plug in a guitar and adjust the controls as desired. 0-5 on the MIDDLE control is the normal middle control. Above 5 is the RAW control. I suggest turning the volume down when switching the 3W/5W switch.

So the results?? I found this kit to be much less "harsh" or "biting!" Seems to have smoother response with all the same speaker combinations used in the stock configuration testing. You also have more tonal variations with the RAW switch - allowing you to lift out the tone stack. There seems to be more "punch" with hard pick attack or power cords. I'm still experimenting with the possiblities and sounds with this little amp, but the upgrade is a definite improvement!

If you are unhappy with the tones you're getting from your stock Little Giant™, you should consider upgrading the internals with all or part of this kit from Allen Amps.