Building a Rocket - Layout Check for group build

[dansamp]

I haven't compared the two schematics side by side but it appears to me that the Rocket is a lot closer to a
Vox AC30 than most people think
as far as I can remember the main difference with the Rocket is just higher P/S capacitance for a tighter bass response
I may be way off base

Dan......

[UR12]

I haven't compared the two schematics side by side but it appears to me that the Rocket is a lot closer to a
Vox AC30 than most people think
as far as I can remember the main difference with the Rocket is just higher P/S capacitance for a tighter bass response
I may be way off base

Dan......

The Rocket is very close to the Vox. Kind of makes ya wonder who the real cloner was.

Those higher value caps are also the reason that they need to be right after the recto and before the standby switch as mentioned by Fischerman and Ron. The rating on a GZ34 is 60uf max for the first input cap. Ken used 80uf. Putting the caps after the recto and before the standby switch lets them charge up gradually as the recto comes up to temp. If you put them after the standby switch you would be asking a lot of the GZ34 and this would be a potential problem with the Hybrids. This is also the reason for the bleader resistor on those caps because if the power is turned off with the standby in the open position there would be no path for the caps to discharge causing a potential high voltage safety hazzard on the caps for anyone servicing the amp. I wish I had more time to talk about Rockets but I have a lot of other irons in the fire and just don't have the time at the moment. Good luck with your builds

[dansamp]

also I remember reading somewhere that Ken wouldn't build one unless he had a real mullard GZ34 rectifier for it
he believed that only the mullards could hold up in a Rocket
most likely due to the very stiff B+1

[RJ Guitars]

...The Rocket is very close to the Vox. Kind of makes ya wonder who the real cloner was.

Those higher value caps are also the reason that they need to be right after the recto and before the standby switch as mentioned by Fischerman and Ron. The rating on a GZ34 is 60uf max for the first input cap. Ken used 80uf. Putting the caps after the recto and before the standby switch lets them charge up gradually as the recto comes up to temp. If you put them after the standby switch you would be asking a lot of the GZ34 and this would be a potential problem with the Hybrids. This is also the reason for the bleader resistor on those caps because if the power is turned off with the standby in the open position there would be no path for the caps to discharge causing a potential high voltage safety hazzard on the caps for anyone servicing the amp. I wish I had more time to talk about Rockets but I have a lot of other irons in the fire and just don't have the time at the moment. Good luck with your builds

Dana,

I thank you for adding to our build... we are lucky to have positive input... I've been pretty open to posting everything for people to help us with the build. I'll plan to keep up that policy and solicit help with this build...

Critics be kind I am one of you!

If we look at Ken Fishers own Trainwreck sales brochure on page 3, we'll find that he all but says it straight out - The Rocket is a clone of a VOX AC-30.

really interesting read...

http://blueguitar.org/new/schem/trainwr ... atalog.pdf

rj

[Fischerman]

That's interesting because if KF didn't use a power board and just put the dropping resistors right on the filter cap terminals then I don't see how he could charge the first cap in standby UNLESS he wired the OT center tap and choke directly to the SB switch. So that might be a clue as to how he may have wired that (unless I'm mistaken).

Eric, all, I hope my amp didn't derail your or the groups goals. Some people like to copy other guitar players and others just like to do their own thing...same with amp builders I guess. I think there's enough info to do a reasonable clone though. You have the preamp pic and can even see the ground wire for the cathode resistor in it. You can also see the ground wire and ground lug for the filter caps in that pic. Then look at Express/Liverpool pics...stack the filter caps like that except put the dropping resistors right on the positive terminals of the filters. Wire the transformers similar to that except use the tube rectifier. Wire your power tubes like a Liverpool. There's probably other info that I missed (I knew I wasn't cloning so may not have paid close attention). But I think if you put all the pieces together...draw it out...14 times...then draw it again...you should be pretty close. By the time I build my amp I've drawn/redrawn it out so many times I know it like the back of my hand. Even think about what wires you're going to bundle together and where you'll tie-wrap them...everything.

[Richie]

If we look at Ken Fishers own Trainwreck sales brochure on page 3, we'll find that he all but says it straight out - The Rocket is a clone of a VOX AC-30.

Ah yes, but different transformers and little things can completley make the amp have a different tone or flavor to its overall sound. And as he said was designed aroung strats and teles,and early celestion type speakers.

If you've ever put a fender OT in a marshall or vise versa..you'll see it changes how the amp sounds and reacts..

[txbluesboy]

Well I'll just throw in my two cents here. If you think your being left in the dark here' wait until you decide to try a Dumble clone. My last project was was an ODS and I bought a chassis and board set from someone on that forum, a very smart person that sold a very nice chassis and boards set, but if you needed help on how to build it you were out of luck. The feeling there was if you could'nt take the time to study all of the threads and figure it out for yourself, maybe you should take up golf or something. At first this kind of hacked me off, well maybe even more than just at first. However I did manage to muddle through it, and I learned a whole lot more than I would have if someone had handed me a perfect schematic and layout. Anyway I'm not sure there is one perfect schematic, there probably are not two of the original amps that are exactly alike.
Anyway I would just like to say I'm very happy to be involved in this group project. I for one am building my amp just the way I want it.
Hope ya'll do the same!!!!!!! Thanks RJ

[Fischerman]

Richie,
Did you build yours pretty much just like a Rocket or were there any significant deviations? I thought I saw it written somewhere that your Rocket is an exceptional sounding amp. What trannies did you use?

One thing I have noticed is that when I look at the various schematics I see different values for the first triode. Many schematics say 220k/1.5k but whenever I see a board or layout that is supposedly 'the most correct' I see 100k/3.3k. Look at Dana's board that he posted earlier...100k/3.3k. Maybe this varied but if you're going for a clone then I'd just use the values in the Rocket preamp pic.

[RJ Guitars]

I had someone ask me if I would help design a layout for a traditional Rocket Power Supply - Absolutely . I am entirely in favor of all things that add to the Rocket info base...

I suspect someone has the Liverpool layout in CAD, but as far as I know it has never been incorporated into a complete Rocket build chassis drawing. I can do that with a reasonable level of professionalism and with your blessing and assistance, I'll gladly draw this up... Some of you may have gathered this, but I'm not intimately familiar with Stack O' Caps technology - I will need your help.

Would it be reasonable to begin with the schematic that Ron Worley pointed to recently - https://tubeamparchive.com/files/liverp ... es_305.pdf

Let me know what you think... as long as you say it in the positive format.

rj

[Ron Worley]

RJ-

Just take that Liverpool schematic, wire in the tube rectifier (I have read somewhere that it's a 5AR4 instead of a GZ34, but don't know for sure) and chassis mount the Metal 50R 25W gold metal power resistor to the left of V4 (looking from the back of the chassis). Mount the 100V 220uf cap across the power resistor, and you're there. The rest is essentially the same as far as I know. (the experts will know).

I am posting a new BOM with a bunch of corrections as well.

Ron

[dansamp]

Just out of curiosity does anyone know what type of tremolo was used in the TremRocket ???
I was thinking since this isn't a straight clone and since it has been discussed to split the C/F between V1 and V2
then that would leave 1/2 of V2 that could be used as tremolo ???

any thoughts ??

of course that would mean a new face plate

Dan.........

[Fischerman]

(I have read somewhere that it's a 5AR4 instead of a GZ34, but don't know for sure)

They are one and the same...just different designations of the same tube. Just like we're using EL84/6BQ5 for power tubes. See here.

[Ron Worley]

I knew that they were similar, but did not realize that they were one and the same..... Thanks for the info Fischerman!

Ron

[Lonely Raven]

I received my Rocket chassis yesterday.

Interesting finish on the aluminum. Very industrial lookingg.

RJ, you didn't have to put the boards in and install transformers and all that! Thanks though! Saved me some time.

So, while I *really* want to build a proper Rocket clone, now that I've seen all the work that went into the power supply board, I'm torn between doing the stack-o-caps or just using this power board that RJ put together for us.

I'm *very* eager now to get this thing humming!

Thanks for letting me be a small part of this project guys!

[Fischerman]

you didn't have to put the boards in and install transformers and all that! Thanks though! Saved me some time.

I think he put it together like that just to make it easier to box up and ship. You should really use washers on both sides for all the trannies/choke...the washers spread the load and make it much stronger...this Aluminum is pretty soft. I used Nyloc nuts (#8-32) for all the trannies And you'll have to remove the boards to wire everything right anyway. Many of my components wouldn't fit...the jacks, pots, and impedance selector all would not go into those tiny little holes. Fit check EVERYTHING. And you'll probably have to drill a hole or two (ground bolts?). Plus the chassis really should be cleaned, I used Rubbing Alcohol. I guess what I'm saying is that you probably should fully disassemble it, do any mods to it you need to, then clean it and reassemble it. Also...these Heyboers don't work well with grommets (because the endbells rest flush with the chassis leaving no room for a grommet underneath) so make sure the holes for your trannies are very smooth.

EDIT - If you look in my pics you'll see that I use #4 keps nuts for all the sockets. Even so...I also put a dab of blue Loctite on each of these mounting bolts (if you look close you can see a little blue residue on a few). I also used blue Loctite on the standoffs for the boards. It's up to each individual but I prefer a little overkill in the mechanical department. These things will be vibrating a lot...well...let's hope so.