Click here for a PDF with tips on proper soldering.
Frequently Asked Questions
Click here for troubleshooting tips for the Trill Tremolo.
Yes. We have provided a schematic showing how to connect a 1MA pot acting as a variable voltage divider (instead of a 1ML pot acting as a variable resistor) for a more dramatic "intensity" control effect.
Trill Intensity Modification
The optional capacitors allow you to modify the high pass filter in the circuit. A greater value of capacitance will allow more low frequencies to pass, while a smaller value will block more of the lower frequencies.
You will need the following tools:
- Wire Strippers
- Needle Nose Pliers
- Cutting Pliers
- Desoldering Pump
- Solder (60/40 rosin core)
- Soldering Station
- Phillips Head Screwdrivers
- Slotted tip screwdrivers (3mm tip)
- Digital Multimeter (DMM)
- Alligator Clip Test Leads (to fit DMM)
- Channellock Pliers (or similar type)
- Miniature Round File (fine cut)
This amp kit uses a Hammond Manufacturing "300" Series world power transformer. It can be wired for the various voltages used around the world.While the instructions are only written for United States wiring (120V, 60Hz), you may be able to figure out the wiring for your country.
The Yellow Jackets YJS (normal or triode) model is the correct tube adapter to use with the MOD 101. Using Yellow Jackets in your MOD 101 will allow you to use EL84 power tubes in place of the 6L6GCs or EL34s. They will also reduce the maximum output power from 60 watts to between 18 and 30 watts (YJS normal) and to between 6 and 18 watts (YJS triode).Because Yellow Jackets convert the power stage to Class A auto-bias configuration, you do not need to change the amp\'s bias pot when using the Yellow Jackets.
Generally, the EL34s will allow for a little easier breakup than the 6L6GCs and they will have a tighter more straight-forward low and mid body. Of course, each power tube brand and type will bring its own personality to the mix. We highly recommend trying different brands and types of tubes to find your favorite.
The 60 watts of power output can really come in handy when playing in a large impromptu jam session or at a gig with limited PA capabilities. But at low volume or with the use of a power attenuator, the amp will still sound excellent at levels that will not drive your neighbors crazy.
The amp was designed to be basic and classic allowing for warm clean tone at low volume and transitioning gradually into rich power tube overdrive distortion at higher volume, while encouraging the builder to experiment with basic circuit variations to find their preferred tone. Many amp builders and guitar players have found that the quality of tone is degraded more and more with the addition of internal effects and channel switching. (Also, more effects and more tubes make the amp more of a workout to carry around.)
The kit comes with a black powder coated steel chassis which is pre-punched. Because the steel is punched before being coated, you will need to file away the coating around the holes to allow for conductivity between connections made to chassis ground. (This is a step included in the instructions).
The kit comes with Hammond Transformers 374BX and 1650P.
There is no FX loop, but the amp sounds great with effects pedals.
The kit comes with a rotary impedance switch allowing you to change the output impedance to 4, 8, 16, or 20 ohms. This gives you the flexibility to use different speaker configurations and not waste output power or damage the amp.
The power amp is fixed biased for Class AB operation with an adjustable bias pot. (The instructions will guide you through setting the bias for both 6L6GC and EL34 power tubes).
Yes, all the parts are included for the different circuit variations.
The Mod 101 has a solid-state rectifier.
Yes, the last section of the instructions gives details on the modifications which can be implemented by using the included extra components. The following is a list of the modifications:
- Tone Stack Mod
- Input Voltage Divider Mod
- Negative Feedback Mod
- Bypass Cap Mod
- Power Tube Mod
Yes, if you follow the EL34 set up initially, then you can switch to 6L6GC tubes without changing any other components. It\'s always a good idea to check the bias when changing power tubes. (The bias can be checked and adjusted with just the steel cage removed and using a volt meter - the instructions will explain this process.)
No, the instructions do not explain a modification for changing the power tubes from fixed bias to cathode bias.
Yes, other preamp tubes may be used in place of the 12AX7 in position V1. (For example: ECC803, 12AT7 and 12AU7).
No, the instructions do not explain a modification for changing from full wave solid state rectification to tube rectification. (Although, the Hammond 374BX power transformer does come with an extra secondary winding not used in the kit).
Yes, you can use the following power tubes which are substitutes for 6L6GCs and EL34s
- 6L6GC substitutions: 5881 and KT66
- EL34/6CA7 substitutions: KT88 and KT77
Check the fuse. It has probably blown do to excessive current draw. A blown fuse measures as an open circuit from end to end and usually happens when something else in the circuit is wrong. The fuse is a protective device, so if your fuse has blown, check your work to see what may have gone wrong.
A low 60 Hz hum can be the result of:
1)The power transformer\'s filament winding center tap (TR1 green/yellow wire) has come loose.
-Check to make sure this wire is connected properly and not just hanging on by a cold solder joint.
2)You may have a faulty tube in V1. Sometimes a bad preamp tube will amplify the filament's AC frequency.
-Remove the tube in V1 (ECC83) to see if the hum goes away.
Yes. The parts are not included with the kit, but we have provided a schematic and layout drawing for how to add a "post phase-inverter master volume" (PPIMV) control in the MOD 101 "File Downloads" section.
Yes. This is most likely due to the shared cathode of the V1 preamp tube. The parts are not included with the kit, but you can easily split up the cathodes by using the instructions provided in the MOD 101 "File Downloads" section.
Yes. The pot in the Piledriver circuit has a DC voltage across its terminals and this makes the pot sound "scratchy" when you turn the knob. We have provided a schematic showing how to isolate the pot from DC voltage by adding a 47uF cap and 1.5K resistor at the MOSFET source terminal.
Piledriver Scratch-less Gain Pot Mod Schematic
No. It comes with the Hammond Mfg 269EX power transformer which is only designed for 120V wall outlets (USA). Hammond does sell a 369EX version which has primary winding options to work with any wall voltage in the world, but it would require you to drill new mounting holes and determine which primary winding wires to connect for your country. We have provided a chassis hole modification drawing which offers a suggestion for how to accommodate the slightly larger footprint of the 369EX.
The MOD 102 cannot be ordered to include a 369EX in place of the 269EX.
World Power Transformer Mod 369EX
Yes. If you find it necessary to have a standby switch, we have provided a layout drawing and schematic for how to replace the SPST power switch with a 3 position progressive toggle switch to control both power and standby with one switch.
Power + Standby Switch Modification
Yes. We have provided a schematic for how to add a headphone jack to the output of the MOD 102.
Headphone Jack Mod Schematic