Rocket Group Build project

[Clyde]

Vox choke is 20H, which is what I'll be using in my AC30/Rocket invention.
I'm using the full MM TX set, 4.2K OPT. It should work do you think?

[UR12]

Vox choke is 20H, which is what I'll be using in my AC30/Rocket invention.
I'm using the full MM TX set, 4.2K OPT. It should work do you think?

Sounds like it should work great, Clyde!! I've got the same choke (Heyboer copy) for my build but I'm going with a 5.2k tranny that I have laying around. I am also going with the Liverpool power supply layout and Moose's PT running the 260v windings.

[philmanatee]

I used the 20H MM coke on mine. Phil

[UR12]

OK Guys ...... Sorry for the lag in this thread. I had a little health setback and am just now getting back on my feet. I took one of Nic's Liverpool chassis and converted it for use in the Rocket by punching an additional hole for the tube Recto. I also drilled the extra holes for the choke. I'm using a Heyboer AC30 style choke with 4 mounting holes. I used the pic of the back of Malou for figuring out where to place the choke on the chassis. I also had BnP Lasers make me up a faceplate as I want to build this in a more traditional style cab instead of the Cherry TW style so this thing can be gigged without worring about scratching the nice cab.

Since there are no gut shots of the Rocket, I decided to go with a Liverpool style power supply board. The power stages for the Rocket and Liverpool are the same and I thought this would be a good fit. I have ommitted the 1k Resistor and the SS diodes from the board but all of the rest of the components have remained. I am also thinking that I may go back and add Power scaling to this amp sometime after it is finished.

Here is a few pics of where I am at with the build.

[Zippy]

But someone, and I forget who now, suggested alternate values. In particular, the treble cap reduced from 470pf to 47pf, which gets rid of the mid peak. This also resulted in too much bass, so the first coupling cap was cut from 1nf to 500pf. This sounds really great for clean and mild over drive conditions. Crystal clear with excellent string separation and chimey in the top end.

So, the "bright" switch is really changing the treble cap and the first coupling cap to switch between the two above settings. It actually makes too big a change to the character of the amp to call it a bright switch.

Anyway, figuring out exactly what tone stack values to use to get the true sound desired seems to be the challenge. I'll try to find the original discussion and add a link...

I recall that the info was presented by tubedogsmith. The threads were "4 x el84" and "el84 rectifier amp".

[Zippy]

But someone, and I forget who now, suggested alternate values. In particular, the treble cap reduced from 470pf to 47pf, which gets rid of the mid peak. This also resulted in too much bass, so the first coupling cap was cut from 1nf to 500pf. This sounds really great for clean and mild over drive conditions. Crystal clear with excellent string separation and chimey in the top end.

So, the "bright" switch is really changing the treble cap and the first coupling cap to switch between the two above settings. It actually makes too big a change to the character of the amp to call it a bright switch.

Anyway, figuring out exactly what tone stack values to use to get the true sound desired seems to be the challenge. I'll try to find the original discussion and add a link...

I recall that the info was presented by tubedogsmith. See threads #1280 and #199.

[philmanatee]

Lookin' good Dana! Phil

[Beerman]

So guys.... How are they coming along? Gonna post some progress reports? Just curious...

[UR12]

I finally got a Rocket up and running. I know it has been a long time coming as I am sure Mark Abbott can attest. I feel like I have reached a milestone with 3 of the 4 TWs under my belt.

Just my luck that the new pics of the Liverpools would come out after I had already built my PS board. I used the old style layout that was used in Ginger instead of the pics that posted recently showing yet two more different configurations. I figure as long as you use any of the liverpool configurations it should work fine. I have a Siemens in V1, a Tunsgram in V2 and a EI in V3 . For EL84s i dug through my stash and found 2 NOS sylvania and 2 NOS GEs. They actually don't sound to bad together. This amp also has a Stancor A3800 5K OT .


My son's band practiced tonight and I had their guitar player check it out through a 4x12 (4 ohm) loaded with greenbacks. It sounded sweet! Nice clean tone and then when you crank it a bit you get a little growl. The Tone controls take a little getting use to (must be the Vox top boost thing) and the hi cut is a nice feature. The amp is very quiet with no hums and a slight hiss when cranked.

Here are a few quick pics

[Jackie Treehorn]

Given the general preference for authenticity, it's interesting that no one is choosing the Hammond 158L choke.

[johnspeck]

The Tone controls take a little getting use to (must be the Vox top boost thing)...

Try cranking the volume, running the treble all the way down, bass barely up until it fills out the tone a bit, cut to taste. This produces the most midrange, and sounds really nice for overdriven tones.

[ODwan]

Hello,
please be sure to post some soundclips of your Rockets! There aren't so many round here and I would really like to here what a Rocket sounds like.
Greetings,
Timo

[UR12]

Jackie

I had the AC30 choke laying around and figured it might work nice on this build. I may have to give the Hammond a try if I do another one. It is interesting to note that Paul didn't use the choke or tube recto and Diana turned out nice by all reports. Since Ken didn't use the choke with anything but the Rocket maybe it was his way of keeping a better regulated current source for those bass notes. I am a little mystified that mine has as much nice clean ballsy bass as it does. I wasn't expecting that looking at the schemo.

John

Thanks! I'll definately give that a try. It's been a long time since I listened to a Vox amp live but this amp really does have the "Vox thing" going on. It was funny last night when my son's band's guitar player fired this thing up. He was using a line 6 box and pedal board going through a Morley wah and a fender SS 112 combo amp. He plugged straight into the Rocket with his guitar and his first comment was " now that's the sound I have been looking for............ I want one"

Timo

I promise I will post some clips but it may be a few weeks getting there. I don't play guitar and usually take my amps over to my brother's to have him wail on them mercylessly to check them out. He is a little laid up at the moment and can't play. As soon as he gets better or I can find someone else to do some clips I will post them here. I just got a new Boss BR-864 that I want to try out.

You guys are the greatest and I really appreciate all of your input and comments. I'll be looking at some of the mods now that Paul and Tubedogsmith and a few others have shared to see what gives with those. I can see why some have called the Rocket their favorite amp. After building the Express, Liverpool and now the Rocket I'm not sure I have a favorite. I like them all for what each one does best.

[Shermock]

Hello Dana!

I've been watching this thread with great interest, as I have a buddy who's waiting for me to build him something useful into an old combo he has. I'm wondering what the overall volume of a Rocket is compared to the Express. I was so surprised with the Express volume, I couldn't believe 2 EL34's could get that loud! Does the Rocket fall into that same category, or....is it (hopefully) quieter?

Nice looking build, can't wait for clips!

Best regards-

Shermock

[UR12]

Hello Dana!

I've been watching this thread with great interest, as I have a buddy who's waiting for me to build him something useful into an old combo he has. I'm wondering what the overall volume of a Rocket is compared to the Express. I was so surprised with the Express volume, I couldn't believe 2 EL34's could get that loud! Does the Rocket fall into that same category, or....is it (hopefully) quieter?

Nice looking build, can't wait for clips!

Best regards-

Shermock

It's putting out about the same as a Liverpool (25 - 30W) which is loud in my book. It had no problem keeping up with a loud drummer and a bass player. It might be a tad quieter as the gain is not as much in a Rocket compared to the Liverpool but it's still loud. There is one good point, this amp is perfect for power scaling.