FAQ's - Marshall JMP-1

		Voodoo Transformer FAQ's

Marshall JMP-1

See Below for Replacement Parts

Question Do you sell parts to the pubic? Answer: No we do not. Our business model is not set up to support this.

Question What do you recommend running the levels at in order to keep noise to a minimum?

Power Amp - We recommend setting the volume controls wide open / full up.
Preamp - We recommend using the "Level" control on the front panel as the over all System Master Volume. This should be set to approximately 9:00 to 10:00 for stage volume. The setting varies depending on the wattage of your power amp.
You must also adjust the internal volumes on each patch/channel.
Gain Patches - In order to keep noise to a minimum the "Volume" should not exceed 12. Adjust OD1 and OD2 to taste. Setting OD1 & OD2 to 20 will give you maximum gain.
Clean Patches - For maximum clean headroom and improved clean tones we recommend setting the "Volume" to 20 and keeping the front "Level" control set lower
Clean 1 - Only engage "Clean 1" and set to 12
Clean 2 - Engaging "Clean 2" will give you a Mid Boost with added breakup
Note - For all other settings please refer to Marshall JMP-1 User Manual

New Patch Question Do you program any new program patches? If so, where are they stored?

Yes we program (8) new patches for you free-of-charge. The settings numbers are; 92 - 99

FX Loop Question I’m interested in changing the FX-Loop on my Marshall JMP-1 from parallel to series. Is this possible, and if so are there any negatives to doing this? How much would the mod cost?

In our honest opinion; The effect loop on the Marshall JMP-1 is less than ideal. For the best results we recommend the following; Go out of your JMP-1 Main Output ---> Into your effects ---> Into your power amp.
Note - for best results all instrument and speaker cables should be high quality.

Stereo Output Question - I have a stereo power amp that I am using with the JMP-1 to drive (2) speaker cabinets. One output jack of the JMP-1 is going to the left side of the power amp and the other output goes to the right side. Both Level controls on the power amp are full up / on "10" but one speaker cabinet is louder than the other. Why is this and how do I resolve this?

Explanation - The "Level" control on the front panel of the JMP-1 controls how much output is sent to the Output Jacks. This control is what is known as a "Dual Ganged" control pot. IE: When you adjust the "Level" control you are simultaneously adjusting (2) control pots.
The problem is that both pots on the "Level" control are not matched. IE: as you increase the Level there will be spots where one side is louder than the other. All replacement pots have the same problem.
Solution - 1.) Adjust the rig to the desired stage volume. 2.) Use the power amp's Level / Volume controls to balance the volume.

Data Control Question - I would like to get the data knob (the component itself - not the plastic knob-cap) replaced – it turns rough and it skips numbers when turning so that it’s difficult to land on the patch you’re trying to select. Can this be fixed / replaced and how much would it cost?

In most cases the Data Control can be fixed / repaired.
We also routinely stock all proprietary Marshall parts for the JMP-1 preamps and can replace the control if need be.
Parts Cost - $49.95.
Labor Cost:
1.) $15.00 - If we are Modding the unit at the same time as we will already have the unit disassembled.
2.) $75.00 - As we have to disassemble the unit as well as reassemble.
Note - More times than not when the rotary Data control is damaged there are other things that are damaged on the front panel (IE: input jack, etc) so it may be wise to plan on an additional buffer of approximately $25.00. (See below)

Data & Level Control Knob Question Can you replace the actual knobs on either of these controls? If so, what is the cost?

Yes and the cost is $5.00 per knob.
Knobs may be ordered separately and shipped to you - Shipping & handling charges apply. To order please call 607-256-0465

Internal Battery Question My unit is old and is replacing the battery a good idea? If so, what is the cost?

Yes if your battery had not been replaced we advise that you have the battery replaced.
Part Cost - $6.95
Labor Cost:
1.) $0.00 - If we are Modding the unit at the same time as we will already have the unit disassembled.
2.) $50.00 - As we have to disassemble the unit as well as reassemble.
Note - If your settings are not saving properly or are reverting to stock factory settings, your need to replace your battery

Settings / Preset Backup Question I would like to save my internal patches, is there a way you can do this for me? If so, what is the cost?

Yes we can backup your stored settings
This is a service known as "Midi Dumping"
Process - A spare JMP-1 preamp is required to transfer or "dump" your settings into. Once remaining work has been completed we will dump the settings back into your JMP-1 preamp.
Price for Midi Dump Service $20.00

Return To Factory Settings I would like to revert my JMP-1 to factory Settings. How can I do this & will I loose my saved programs/patches?

Warning - Your edited sounds / patches / programs will be lost. if the unit is re-initialized. IE: write your settings down or "midi dump" to a back up unit before proceeding.
How to re-initialize / convert your JMP-1 back to Factory Settings - Hold down "OD1" & "Clean 1" then switch on power switch. Hold buttons until a program patch number comes up on the display.

Additional Parts Questions Do you stock or offer any other parts if my JMP-1 needs repair? If so, where are the prices?

Yes we have numerous parts we routinely stock for the JMP-1 preamps such as but not limited to;
"Level" Control Pot (on front panel) $8.95
Input Jack/Nut assembly on front panel $8.95
Hex Screws (holds top onto JMP-1, etc) $0.89
AC Power Connector $34.95
Midi Jack $12.95
Headphone Jack $2.95
On/Off Power Switch $10.95
Cap for Power Switch $5.95
Stock JMP-1 Power Transformer (not Mercury Magnetics Brand) $149.00
Rack Ear $34.95
Other parts & components available
Note - Pricing is subject to change without notice
Note - Addition labor charges for installation, etc may apply
We do not sell parts to the public. Pricing is provided for units shipped to us for Repair / Mod

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