Rocketus Addus Reverbus

[RJ Guitars]

Hey guys,

I was thinking Reverb in a Rocket would be a good idea way back... then read about Normster's Rocket-Reverb amp. Well this at least proved it was a maybe a good idea even if it wasn't original.

As I made a few more thoughts about this along comes Rawnster and makes a beautiful sounding Reverberated Rockster. Now I know this is a good idea but forget anything about originality.

Then at some point it occurs to me that maybe it would be cool to put together some sort of simple idea for retro fit so that the masses might add reverb to their Rocket, should they desire it.

So I made the plan and even drew it out on CAD... seems now I can't find it though. I decided to proceed without the CAD. Time will tell if it's a good idea or no. I kinda remember it all in my head (I think).

I've added one tube to the chassis, a transformer, and a couple phono jacks. I'll be figuring out the component locations on the fly using the left over half tube of V2 for the recovery stage.

There isn't a good choice for the pot yet, maybe replace either the mid control or the cut control... still undecided.

should be educational if not fruitful,

rj

Edit - August 2011. I have moved the schematics and Layout drawings for the Rockster build onto this first post. I will edit in the latest and greatest as the amp is developed further. You should find that as errors or improvements occur some of the references to those issues will be "fixed" and not included in the latest and greatest drawing iterations.

One exception to the addition of the latest and greatest documentation will be to include a look at the early layout so that the "add reverb" technology used is still apparent to those wanting to accomplish a similar build will have some guidelines. Later iterations of the layout are going to show the "Rockster Reverb" where the Reverb was added from the onset rather than as a modification to an existing design.

[rawnster]

Nice one, RJ. Looking forward to see how you shoehorn the one-tube reverb circuit in a traditionally built rocket. I've tried to get it into mine, but haven't been successful.

[M Fowler]

rj on your Rocket chassis there is plenty of space to add another 9 pin tube socket between PI and V2 without worryng about heat.

There are so few components to add in for a retro fit, that it makes for a great mod.

Mark

[RJ Guitars]

Well, I finished and it works. It adds a nice compliment to an amp that sounded pretty good already.

From the pictures you can see that this is the amp that I have done many tweaks and experiments on so it's hard to tell where one ends and the next stops. However, there are very few parts in a reverb circuit so this was really a pretty simple mod.

Having said that, when I first finished it I was humbled to learn I am human and much to my disappointment, it didn't work. In fact, nothing worked, the amp was quiet, dead quiet. It took a little detective work to figure out that I had an error on the return circuit and had run the signal to ground. Both the dry and the parallel reverb were silent... I killed it!#@%^#^%

I figured out the grounded signal problem on the return circuit and and then had to do some additional detective work because I still couldn't hear the reverb. I checked everything a half dozen times and was happy that I had the circuit right and left it alone for the night.

It was late last night when I was trying this all out and it wasn't until today when I could turn up the amp that I determined the reverb was working, it just wasn't very strong. Now I had some hope and as it turned out the reverb tank I was using wasn't matched to the rest of the circuit. I tested it with another reverb tank and viola, it worked much better. After that I switched the drive tube from a 12AT7 to a 12AX7 and dropped a bit of resistance from the signal path and then that mismatched tank started to work a whole lot better. I still need a matched reverb tank but my bruised pride is feeling better and the amp is sounding very cool.

This is a rough and dirty way to accomplish this and ultimately I plan to make up a cleaned up version that uses a small circuit board and looks more professional. I'll draw it all up with a set of instructions for those that care to give it a shot. I'll probably offer it in a package as the AdaVerb package for those that just want the quick and polished Readers Digest version.

Now maybe some of you hawk eyes out there will see something else that I missed and since I am already humbled, your kindness in pointing out a problem will likely be well appreciated and maybe save me further pain from my own mistakes.

Enjoy...

rj

[M Fowler]

Good job rj, glad you got it figured out.

I finished up my junk pile 80w Rocket Reverb tonight and played it for 2 hours couldn't stop myself.

Edcor 300-0-300 450mA PT
Edcor 3k3 100w rating
Hammond 158L choke
Fender replacement reverb driver mojo 776 (989 0949)
8AB2A1B medium decay short tank
Parts I had sitting around
Running GT EL34's sounded better than JJ 6L6

Mark

[RJ Guitars]

I finished up my junk pile 80w Rocket Reverb tonight and played it for 2 hours couldn't stop myself. Mark

I love those "use what you have amps"... in the true spirit of Ken Fischer. I bet you don't have any trouble hearing that thing from across the room! And How about those Edcor output trannies? Only a real "Iron Man" can appreciate those... and have what it takes takes to move the amp around.

Looks like a nice clean build. Did you stick to the Basic Rocket circuit or is this your own circuit altogether?

I've had some over-sized 2 hole and 4 hole chassis on the back burner for a while. I figure either a quad like you've got or else a pair of KT-88's like Rob Breyerton used in his most recent whopper amp. I figure this is the logical follow up to my 2 watt V-2 sub-miniature Rocket.

Nice work and thanks for the good photos.

rj

[M Fowler]

rj, thanks for the words.

You should recognize the board you gave me that one.

The circuit is Rocket and we all usually come up with our own way of builting the PS for convenience sake. I actually didn't want to cut that nice board off so decided use the end for lower uf caps all wired underneath.

The rest is just wired looking at Asteroid layout, Normster's layout, and Allynmey's Express 80 layout for ideas.

The Edcor trannies work great rj, nothing wrong with their iron at all. The voltage on them is posted as 300-0-300 but they read 310-0-310 which ok with me.

Mark

[Structo]

Nice work guys!

Mark I'll bet that amp has some punch to it.

[M Fowler]

Tom the amp does have some nice punch and has a great gain tone I love hard to describe but I want to try it out on my upcoming gig into a 4x12 loaded with Celestion English Vin 30's. If that sound is off I have a 212 with greenback/G12H open back.

Rj, I had noticed a while back that Normster or Brownnote had a retro fit reverb for the D'lite it only takes one turret strip mounted off the tube socket for cap and resistors, plus the obvious other parts naturally.

Mark

[Structo]

Yeah I think this is the layout for that.

[angelodp]

Tom, that layout apparently ( James over at BrownNote ) has a lot of details missing.

[RJ Guitars]

Normster is an awesome builder and that is a slick implementation. Very much the same idea. In our case we are adding one tube for the reverb driver and then using the leftover stage of V2 as the recovery. I'm don't think the ODS has the leftover half triode so I assume that is a true 1 tube reverb... I didn't really look at it in depth though. It does give you a good idea of how few parts it takes to make a reverb circuit.

At any rate, my final implementation will share a bit with with the Brown note retro fit reverb for ODS.

I ordered a new reverb tank and bag tonight. I believe I can put it all into my existing head cabinet and then we should be off to the reverb races...

rj

[Zippy]

Well, I finished and it works. It adds a nice compliment to an amp that sounded pretty good already.

I still need a matched reverb tank but my bruised pride is feeling better and the amp is sounding very cool.

Whew... That's a relief.

Good for you! Afternoon coffee is on me.

[ChrisM]

Hey RJ or Mark, got a schem for this one tube reverb your adding?
I might add some verb to this 15W, Rocket/Vox/DC-30 amp I thinking about building.

[RJ Guitars]

Hey RJ or Mark, got a schem for this one tube reverb your adding?
I might add some verb to this 15W, Rocket/Vox/DC-30 amp I thinking about building.

Chris, this is from Rawnsters earlier post on this topic... https://tubeamparchive.com/download/file.php?id=10313

thanks,

rj