JCM800 2204 "Jeanie" and "Vickie" (twins)
I originally built these two amps to sell but that proved very hard to do.
I ended up selling one to The Sonic Arts Center where I work and another to a guy
in California who is enjoying it greatly.
They are just too expensive for me to make one or two at a time. Here is a bunch
of information that may help some of you independent builders out there.
Where to start? Okay, I guess I need names for these to amps. I thought about maybe Castor and Pollux as I am a Gemini, but I am not really into astrology. Also, amps
are traditionally named after women. Who are some famous women twins? Mary Kate and Ashley? Hell no! These are classy
amps and they need classy names. I guess I will go with Jeanie and Vickie after Jeanne and Victoire de Valois, twin
daughters of Henry II of France and Catherine de' Medici. Man, am I nerdy or
what! Every amp should have a history behind it, so there's the story of the names...
So lets get some parts! I will be doing black hand drilled turret boards and staking them with large
turrets. I ordered board material, The turrets, and a new staking tool from Ken over at Turretboards.com. Ken doesn't say much when I show
him my builds, but he ships fast and the quality of his stuff is top notch. Here's pics of the turrets and the staking
tool I ordered.
I have the layout modified from my last build. The orange resistors are going to be Vishay
Dale metal film and are supposed to be very accurate, yet very musical.
The tight tolerances will make the amplifiers sound very consistent.
The gray 2 watt resistors are metal oxide, and the lone blue resistor is a
3 Watt metal film. I got the idea to increase the wattage of this resistor from the
It will make the power supply section of the amp more robust. Click the picture of the layout for a bigger version!
I ordered a bunch of stuff today. The Vishay Dale resistors I got from a place called
They have great prices and great communication with their customers.
I ordered the metal oxides and the 3 Watt metal films from
Digi-Key. I ordered extras for future amp builds.
I ordered the chassis and a bunch of other small parts (fuse holders, impedance switches, voltage switches, etc.) from my main man
Nik Azam of Ceriatone. I owe Nik a lot for helping me when I was first starting building amps - he's the best!
I printed out the layout and taped it to the sweet black turret board material I got from Ken over at
Turretboards.com. I was going to drill it but I could not find my #33 bits. These are a very specific size for the turret to fit tightly so I ordered some more from Ken.
I got my bits and drilled the board. I got a new turret tool from
Turretboards.com and it presses the turrets in cleaner than the one I got from
Hoffman. Here are the twins in their zygote stage!
I got back to work on the twins. Parts are starting to trickle in and get lost as usual but I keep my chin up.
I decided to go insane on the power supply section and make it super heavy duty. Instead of a 1/2 watt
resistor, I am using a 3 watt metal film (the red component) I saw this on the
Dreamtone website and I figured I like heavy duty stuff. so I am putting it in. I am
also using 3 amp diodes instead of the usual 1 amp. These were tough to get into the turrets so I just widened them carefully with a drill bit.
I am building left to right and I just realized I don't have any 10uF caps! Oh well back to the online parts suppliers...
I started to mount some of the other components today. As I stated before I am using
Dale Vishay resistors throughout for very tight tolerances.
Some builders think these are too sterile sounding but I want very exact specifications and I will tune the amp to suit when it is completed.
uses these and their amps sound unreal, so I am confident the amp will sound awesome. I am also using all handmade
SoZo capacitors. These are only
available from Sozo and sound unreal. I have them in my Rachelle and the tone is like nothing else I have ever heard. Here's the boards so far.
I am going pretty slowly on these builds. I do not want to rush when I get 30 minutes free,
I want the amps to be perfect so I am really taking my time. I have been busy in my personal
life but I would rather go slow then have to retrace any shoddy work that comes with speed.
Still more components installed.
I got the rest of the components put in today on the turret boards. It's getting tough to keep the twins separate so
I wrote their names on the bottom with a gold paint pen. I thought carefully about this because I bet the ink
is conductive so I made sure I didn't connect any turrets! I also drilled out the indicator light hole to
accept a Fender style pilot light. Sorry purists,
but Fender got the light right. Plus you can change change the jewel
to reflect whatever mood you are in!
Sorry I have not been here in a while folks. My old drummer from the
Joe Popp band passed away on September 14th and I
have had a hard time recovering. I am also recording an album with my band
The Hornrims. I will finish
these amps up soon!
Here are some pictures of the chassis together.
Here is Vicki...
Here is Jeanie...
Here is a finished chassis. I don't know which one!!!
I was not able to continue a step by step blog of these amps but here is more information.
Look at my other JCM800 blogs if you need any more information.
Here are some shots of the outside of the amp. It differs from a
JCM800 in that I house the amp in a Plexi style small head box.
This is in my opinion the best looking Marshall head cabinet ever made.
The cabinet is made by Mojo and is of the highest quality.
It is covered in black levant and is trimmed with gold piping.
The back of the amp has a gold tone grill. I replaced stock Mojo chrome screws
with brass ones that have trim rings - looks a lot nicer!
Here is Jeanie with her back off. All tubes are purchased from
Doug's Tubes and this guy knows his stuff!
The power tubes are a matched set of JJ KT77.
The KT77 has a more articulate sound and better highs and lows than an EL34. In my opinion, they make the crunch sound less mushy.
The preamp tubes are Tung-Sol 12AX7 Reissue in V1, and
Electro-Harmonix 12AX7 in V2 and V3.
All preamp tubes have balanced triodes. I chose the Tung-Sol for the gain characteristics.
It really adds a beautiful break up compared to the other 12AX7s I have tried.
The Electro-Harmonix 12AX7 is known for being very durable with low microphonics.
I chose them in V2 and V3 to bring reliability to the amp. They sound great in these positions as well.
A close up of the back of the amp. There is a voltage selector and an impedance selector for flexible
connectivity. There are also 2 speaker jacks and easy access to the amps 2 fuses.
A close up of the logo. It is laser cut white Plexiglas and attached with three brass screws.
A close up of the front panel. Notice the Fender Style pilot light.
It makes it easy to change lamps and jewels (the glass lens).
The face plate is gold plexiglas and the indicator numbers go up to 11!
An extreme close up of the Carling long bat toggle switches. I also use the expensive Plexi style chrome trim rings on the switches.
A beauty shot of the completed chassis. The transformers are actually Plexi 50 watt specification from the finest
transformer maker in the world - Mercury Magnetics of California.
The power transformer is a Mercury Magnetics ToneClone P4550JT-G2, the output transformer is a Mercury Magnetics
ToneClone O50JM, and the choke is a Mercury Magnetics ToneClone MC10H.
A beauty shot of the completed chassis from the back. High quality Belton Micalex tube sockets are used for all tube positions.
A shot of the steel chassis with extremely beefed up hardware. I use all stainless steel hardware everywhere on the amp.
I also incorporate stainless Nylok nuts wherever possible. OT and Choke are mounted with 1/4" bolts and all
4-40 hardware has been increased in size to 6-32 where possible. This makes the amp very sturdy and resistant to shock damage.
The stainless hardware means no rusty hardware ever! Notice the heater wires that are carefully twisted to reduce hum.
The turret board is hand drilled and turrets set by hand. There are also no extraneous turrets doing nothing.
A chassis shot with all premium components. Capacitors (yellow components) are
Sozo Mustard Cap Premium Line
and are only available from Sozo directly. Don't confuse these with the common standard line - these are the best made!
The resistors (brownish-orange components) are Vishay Dale metal film
military spec and have the tightest tolerances in the business.
The amp will sound good for a long time as these maintain there value over a longer period.
The black components are the famous Sprague Atoms electrolytic caps and are considered the finest in this position.
The two gray resistors in the bottom of the shot are 2 watt metal oxide. Instead of connecting to wires
that usually flop around under the turret board, I have installed 2 extra turrets to provide stability and reliability.
CGE Potentiometers are used. These pots are considered the closest to the coveted CTS type found in Marshalls from late '67 on.
You can also see the incorporation
of a ground buss bar that provides a very consistent ground source. It is routed to a single point
on a transformer bolt eliminating the possibility or ground loops.
F&T Cap Cans are used. These are the best made!
The soldering throughout is top notch. I am not bragging but I have been soldering for over 20 years
and I hand wire studios for a living. No cold solders on this baby!
The power section has been beefed to industrial strength. Instead of the standard 1 watt resistor it has a 3 watt!
The standard 1 amp rectifier diodes have also been upped to the 1N5809 fast recovery 3amp variety. The power
section is 3 times as robust as stock.
Some close ups of the turret board from left to right.
The cathode resistor (farthest to the right) has been lowered to 8.2k to slightly increase gain.
A close up of the presence pot wiring.
Power transformer and power switch wiring detail.
Shielded wire is used from the inputs all the way to V1 tube socket. The 68K resistors have been
mounted on the turret board instead of hanging off of the input jack for a sturdier design. You can also see in
this picture that the treble peaking circuit has been eliminated. This is a common modification to make
the amp sound better at lower volumes. It also unclutters the signal path from the guitar to the first gain stage.
JCM204 Builds #3 & #4 - Jeanie and Vickie
Modifications over a standard JCM800 kit
* Elimination of treble peaking circuit
* Cathode resistor slightly lowered from 10K to 8.2K
* Power supply overbuilt by 3 times of specification
* Hand drilled turret board with hand pressed turrets - no unneeded turrets
* No effects loop or reverb to keep the signal path as pure as possible
* Mercury Magnetics transformers and choke
* SoZo Premium Line Mustard capacitors (not to be confused with the standard line)
* CGE Potentiometers - closest to original CTS Marshall pots
* F&T multi-section cap cans
* Vishay Dale metal film resistors
* PTFE Wire Through out 18 Gauge on heaters 20 Gauge elsewhere
* Fender style 6.3 volt pilot light with glass jewel
* Carling long bat switches with plexi trim rings
* Belton Micalex tube sockets
* Cliff 1/4" jacks
* Built by Mojo Musical Supply to original small box Plexi specs
* Finger jointed Baltic Birch - very strong
* Black levant covering with gold piping
* Rear cover chrome screws replaced with brass and brass trim rings
* High quality steel Plexi style chassis
* All hardware oversized stainless steel
* Use of stainless Nylok nuts wherever possible
* 1/8" black fiberglass
* Hand drilled and turrets hand set
* V1 Tung-Sol 12AX7 Reissue with matched triodes
* V2 and V3 Electro-Harmonix 12AX7 with matched triodes
* V4 and V5 JJ KT77 matched pair
Here is the recording rig. Read more below!
This amp was built for crunch! The clips provide many different examples of the crunch sound that
the amp specializes in creating.
The twins are very versatile amps. They can even to a pretty good clean. If you reduce the volume know on your guitar the
amp cleans up very nicely as well. I find by using the volume knob I don't require channel switching.
So you can see how this amp really sounds I kept the recording set up simple. I used a Digidesign
Mbox with Pro Tools 7.3.1 cs4 software and a Shure Beta 57. No effects or pedals of any kind were used!
The guitar is a Fender
California Series Telecaster
with a single Dimarzio
Virtual Hot PAF DP214 F spaced pickup in the bridge. The guitar volume control is a
push-pull type to make the pickup a single coil. The strings
are Ernie Ball Power Slinkys.
The cabinet is a
StoneAge Custom Cabinets 2X12"B"with a closed back.
The speakers are Southbay Ampworks Scumback.
The left speaker in the 2x12 is actually a Scumback H55 bas cone and the right speaker is a Scumback H75. I mic'ed the right cone
for all recordings. The speakers are 8 ohms each and are wired to provide the amp a 16 ohm load.
Clip 01: Low End Crunch 1
Clip 02: Low End Crunch 2
Clip 03: Low End Crunch 3
Clip 04: Mid Crunch 1
Clip 05: Mid Crunch 2
Clip 06: Mid Crunch 3
Clip 07: Scoop Mid Crunch 1
Clip 08: Bright Crunch 1
Clip 09: Bright Crunch 2
Clip 10: Bright Crunch 3
Clip 11: Bright Crunch 4
Clip 12: Bright Crunch 5
Clip 13: Lead 1
Clip 13: Lead 2
Clip 14: Clean 1
Clip 14: Clean 2
Clip 14: Clean Jazzy
Clip 14: Clean Single Coil
JCM800 2204 "hell"
JCM800 2204 "Prototype"