NAD: Mojotone British 800 2204
Posted: Fri Sep 22, 2023 4:53 pm
Surfing Reverb several months ago and a Mojotone kit built 2204 that looked to be very nicely modded/upgraded showed up on my screen. It was assembled/hand-wired by an amp enthusiast from McKinney, TX in 2022 operating under the name of Jasper Amplification. The owner of the amp was doing a big gear purge and was letting things go at very good prices. After watching some youtube footage of these Mojotone kit builds and watching a video of this specific amp that Jasper Amplification made, I decided to take the plunge. The amp arrived several days later. I plugged it in and could tell it definitely had the bones, but I didn't like any of the mods (a PPIMV, a gain boost and a mid boost). I called my tech and after talking through things with him, I decided to get this thing totally back to stock. I gave him the amp and the schematics and let him go to town..."do whatever you have to do to get this thing sounding like a healthy JCM 800 2204 should!" While he was doing that, I started making plans to completely turn this thing into my own personal ultimate custom amp.
I went round and round for a while with aesthetics ideas, got several Mojotone logos made for me (in both their official font and in the Marshall font) but ultimately settled on using the actual Marshall logo, because this amp is Marshall's full on 2204 circuit and schematics (well, the amp was built using Mojotone's schematics, but my tech referenced both the Mojotone schematics and Marshall's and changed things in favor of the Marshall schematics as he went along), so putting their logo on it seemed right...and it certainly LOOKS right!
I contacted Mojotone and had them make me custom front and back faceplates (I settled on using BRITISH 800 instead of JCM 800 because Mojotone calls this kit the British 800 kit, I replaced Jim Marshall's signature with my own, and I listed Mojotone as the manufacturer, the name and company of the man who originally hand-wired this amp, and my tech on the back faceplate). I also had Mojotone send me Marshall feet to use for a new headshell. I purchased a proper 11" Marshall logo online from Amplified Parts. I then sent the logo and the feet to Sourmash for them to install on a 2204 headshell, I even paid extra for real Marshall tolex (it's worth the extra time and expense!).
Several days into it and my tech called me to let me know that he had the amp back to stock based on the schematic, but it was pretty much all treble and he didn't think I'd like it. I asked him to make any changes necessary to make it sound like it should. He ended up doing the following changes:
Increased fizz cap value from 47pf to 120pf
Added .002uf fixed resonance capacitor to negative feedback
Changed 1000pf bright cap to 100pf
Reduced 2.2uf V1 cathode bypass capacitor to 1uf
Changed bias resistor to allow for adequate bias adjustment
Installed external bias test points
I got the amp back and blammo...absolutely incredible sounding. Big, Heyboer, Plexi grade PT, OT and Choke give it that wonderful, in your chest feel. It's insanely loud...just like a proper 2204, it goes from no sound at all to uber loud with barely anything in between. Mojotone's coupling caps are great...no need to change them at all. JJ power and preamp tubes throughout (I've got a ECC82 in V2 to tame the gain a bit so I can run the pre-amp on 8 like I usually do).
Plate voltage: 417
Bias 17.5W per tube (70% dissipation)
42mA at cathode
My headshell came in yesterday and now the whole thing is complete. I LOVE THIS AMP!!!
PHOTOS (external only...sorry...it looks awesome inside!):















I went round and round for a while with aesthetics ideas, got several Mojotone logos made for me (in both their official font and in the Marshall font) but ultimately settled on using the actual Marshall logo, because this amp is Marshall's full on 2204 circuit and schematics (well, the amp was built using Mojotone's schematics, but my tech referenced both the Mojotone schematics and Marshall's and changed things in favor of the Marshall schematics as he went along), so putting their logo on it seemed right...and it certainly LOOKS right!
I contacted Mojotone and had them make me custom front and back faceplates (I settled on using BRITISH 800 instead of JCM 800 because Mojotone calls this kit the British 800 kit, I replaced Jim Marshall's signature with my own, and I listed Mojotone as the manufacturer, the name and company of the man who originally hand-wired this amp, and my tech on the back faceplate). I also had Mojotone send me Marshall feet to use for a new headshell. I purchased a proper 11" Marshall logo online from Amplified Parts. I then sent the logo and the feet to Sourmash for them to install on a 2204 headshell, I even paid extra for real Marshall tolex (it's worth the extra time and expense!).
Several days into it and my tech called me to let me know that he had the amp back to stock based on the schematic, but it was pretty much all treble and he didn't think I'd like it. I asked him to make any changes necessary to make it sound like it should. He ended up doing the following changes:
Increased fizz cap value from 47pf to 120pf
Added .002uf fixed resonance capacitor to negative feedback
Changed 1000pf bright cap to 100pf
Reduced 2.2uf V1 cathode bypass capacitor to 1uf
Changed bias resistor to allow for adequate bias adjustment
Installed external bias test points
I got the amp back and blammo...absolutely incredible sounding. Big, Heyboer, Plexi grade PT, OT and Choke give it that wonderful, in your chest feel. It's insanely loud...just like a proper 2204, it goes from no sound at all to uber loud with barely anything in between. Mojotone's coupling caps are great...no need to change them at all. JJ power and preamp tubes throughout (I've got a ECC82 in V2 to tame the gain a bit so I can run the pre-amp on 8 like I usually do).
Plate voltage: 417
Bias 17.5W per tube (70% dissipation)
42mA at cathode
My headshell came in yesterday and now the whole thing is complete. I LOVE THIS AMP!!!
PHOTOS (external only...sorry...it looks awesome inside!):














