The Ninja-Deluxe

[Steve Conner]

I've finally managed to make some progress on my Ninja-Deluxe amp project, though it's still nowhere near finished. It's built into a 5E3 cabinet from TAD, but that's about all it has in common with a 5E3: it's more like a tweed version of a Mesa-Boogified Princeton.

It uses the transformers and choke from a 1970s aluminium front Selmer Treble'N'Bass 50, so it has a diode bridge rectifier and will be good for 50 watts. If it weren't for the diode rectifier, I couldn't have fitted all this junk into such a small cabinet. On account of all the extra transformer iron and the big ceramic speaker magnet, it weighs in at 40lbs! The chassis is held in by four bolts to spread the weight more evenly: two through the top, and one through each side.

I'm keeping the basic T'n'B 50 circuit, except I added tube-driven spring reverb, channel switching, and an extra EF86 gain stage to one of the channels. I had already done these mods on the original T'n'B 50 head, but when a number of components went bad and there was nowhere to mount the reverb pan, I decided to take it completely apart and start again.

As with my last homebuilt amp, I made a subchassis on rubber shock mounts for the tubes, and fitted a cathode current meter. I made the chassis myself out of 1/8" aluminium, and the faceplate was laser cut and engraved out of 1/8" clear plexiglass. It will be edge-lit by bright orange LEDs when I'm finished with it.

[dai h.]

What sort of ninja amp is that? I see neither an ejector seat or coffee maker?

[bob p]

I've got two things to say about that amp:

1. I dig the cathode current meter.

2. Where's the Tesla Coil???

[Steve Conner]

Well, real ninjas got along fine without ejector seats or coffee makers. Unless they actually had them in medieval Japan, but they were so stealthy that nobody ever noticed.

Too bad TAD didn't do a 5E3 cabinet in black ninja tweed. :P

[Bruce / Mission Amps]

...

Too bad TAD didn't do a 5E3 cabinet in black ninja tweed. :P

As far as I know, Tad actually uses my 5E3 spec'd and lacquered tweed cabinet by KC's cabinet shop from MOJO Musical Supply here in the States... and KC does do them in black vinyl or fine grain lizard skin... I know because he has done them for me. (Sorry, no teeth softened, black shark skin)

[Steve Conner]

They may well do! I noticed the screws for the speaker had American UNC threads.

[Steve Conner]

The first layer of my cake of ninjasonic goodness is ready!

To make it more compact, but hopefully not too hard to service, I built the amp in two sections. The idea is that by undoing some screws and pulling out a multi-way plug, you can split the chassis in half for easy access to everything. I guess this would be uneconomical in a commercial product, but I don't really care.

The bottom part, which I've just finished wiring up, contains the power supply and the output and reverb drive transformers. For the multiway plug, I used the meanest industrial connector I could find (a 24 pin ITT-Cannon "Trident") since it has to carry the high voltage signals from the power tube plates to the O.T.

I tested the bottom part by itself. With 240V line voltage and no load, I got 475V of B+, -90V bias, and +13V on the "12V" rail. I left it running at 250V line voltage for a couple of hours, and nothing caught fire or blew out.

The next task is to build the top part, which consists of a shock-mounted bracket that holds the tube sockets and tag boards, together with the front panel. There'll be so many wires between the tagboards and front panel, that I decided to just solder them permanently in place.

[Steve Conner]

Lots more progress on this project

I got the power amp and PI working, and measured the output. The result was 40w with EL34s and the high screen resistor, 35w with 6L6GCs and low screen resistor, and 29w with 6L6GCs and high screen resistor. (the screen resistor arrangement is one 470 ohm per tube, plus a shared 1k that can be shorted out with a switch)

I also got the reverb driver amp working. I decided to go with the Oxford Electronics output transformer (RS part # 210-6475) and I found that it worked well driven by a 12AU7 in self-split with a 1.5k cathode resistor. It runs at a plate current of 5mA per side and gives about 0.1W before clipping. I was surprised to see it had a bandwidth from below 30Hz to above 100kHz, as I'd expected it to roll off seriously at the low end. It needs a lot of grid drive, 30V peak-peak, but I think I have that much available anyway.

Finally, I wired up the dirty channel and hooked it to the reverb driver amp which I connected to a speaker. I wanted to test this self-split output stage for another application in future. It was surprisingly loud and sounded pretty good! It also made a good job of playing bass guitar through headphones.

All that's left to do is the reverb recovery amp and mixer, and the clean channel.

[Steve Conner]

Well, it's done and working! I took it to the band's rehearsal space today and cranked it, and it was worth the effort!

I'm not sure quite what I've made or what it sounds like, but I like it...

[Sock Puppet]

That's very nice. No doubt you could post a sound sample then....

S.

[dai h.]

good job! what's the round thing by the toggles?

[trevorus]

It's kind of a shame you have that awesomeness of a faceplate showing toward the top. Either way, though, that thing looks absolutely stunning. I want to hear how it sounds!

[petemoore]

That's not a Deluxe...lol.
In France they call it a 'Royale'.
8 pack, bottles please ! ! ! ! ! ! ! !

[Steve Conner]

Hi all,

I managed to get a recording of it. It's not cranked, so all the distortion you hear is coming from the preamp in the dirty channel. I thought I would post it anyway, though. I believe in trying to make amps that have usable tones at all volumes, and I think this shows that it works fairly well at a volume you can use in an apartment, although the distortion does sound a little buzzy.

I'm just noodling around while messing with the controls on the guitar and switching channels. At about 2:09 I flipped off the 'fatness' switch on the dirty channel, which filters out bass and converts it to a scrawnier, nastier distortion, but would also help to clean up the bass when it was cranked.

The recording was done close mic'd with a SM57, and I placed it to get something that sounded similar to what I heard in the room.

I'll record it cranked up in our rehearsal garage next time I get the chance.

*P.S. The round thing next to the toggles is just a chrome knob off a guitar, that I put on the presence pot... Still waiting on the rest of the knobs arriving...

[dai h.]

hey it's pretty good. I like the clean in the beginning. Funny how you can also get that sort of fuzzy sound with solid state but for whatever reason it's more bearable sounding with the tubes.