2xel84 rocket

[Ken Moon]

Mark,

hahaha - a coworker just looked at your pics and said "he's got more wood than John Holmes"

[dartanion]

Here's a couple of photos of a Vapour 35 I just did for a client in So Cal. Cab is African Mahogany (fsc).

[dcribbs1412]

Really beautiful looking cabs guys
I think I might have wood envy...

[Colossal]

Dartanion,

Wow, I love that cabinet. What a great choice of wood. Simply elegant.

[M Fowler]

Ken that was good

Darin you can send that amp and speaker cab to my address you already have it thanks. That looks killer and I bet it sounds killer too.

[dartanion]

Thanks guys!

You'll have to fight the owner for it Mark.

It does sounds great. The owner is killer player and is doing some clips for me. It's loaded with short plate Amperex in V1 and V2, and long plate Telefunken in V3, and RFT 34s.

I do my cabs differently and I have talked about this multiple times before, but they are biscuit joined and sanded to 4000 grit then buffed. I do 3-5 coats of tung oil after 220 grit. Then again at final finishing. After that it's lemon oil for luster and buffed with thin coats of wax. Getting a nice shine and luster has more to do with how well the surface is prepared. Sanding makes all the difference as even at 1000 grit, the surface is like a mirror.

[M Fowler]

The only change I have made so far was to add another 1k 5w screen resistor so each EL84 has it's own rather then shared.

Run a shielded input wire. the grid resistor off the board and mount direct to tube short to get quieter.

Other wise a very worth while build and has a nice deep bass response, I am happy with this one. Mounted the chassis and added the feet today.

Mark

[loctal]

Love that African Mahogany cab! NICE.

[Deric]

Mark,

What value resistor did you use in place of the choke? 2k2?

Thanks

[M Fowler]

Yes I followed some known Marshall type values and the 2k2 seemed to be a good choice. Also, the 1k/25w can be used but I ran out of mounting room for such an enormous resistor and after consideration didn't think I need to go more than 3 watts.

[Deric]

Thanks!

So looks like you have 2k2, 22k, 10k, 10k. What size cathode cap did you go with on the EL84s?

Also, any reason not to mount the grid stopper on the input directly on the socket?

[M Fowler]

220uf/100v and 130R/10w

Yes 2k2, 22k, 10k, 10k.

I used 10k because I ran out of 9k1 is the only reason.

Also that old .0047 cap was used on the cut control because I ran out of those as well. But I have a bunch of old cap and I am going to use then more often from now on.

I actually moved 33k grid stopper from the board now to the tube socket and used shielded wire. Funny you asked

There may be a layout posted soon not by me but another member is working on one right now if he decides to share.

Mark

[Deric]

Thanks again

I have a layout done (I use a fancy-schmancy CAD program called Pencil and Paper ). I'm doing a 2-hole Rocket on the Cheap. Using MPS transformers, a Hammond 12x8x2 chassis and mostly parts scavenged from my bench. If it turns out OK I'll post the layout....

Thanks for all the help!!

[M Fowler]

Sounds good I just build on the fly and see what happens in the end.

Please note the wiring of the standby switch in my picture was pointed out to me to be wrong so make sure you wire that right.

Mark

[KT66]

Here's the layout of Mark's 2 X EL84 Rocket. Thanks go out to him for answering a few questions I had when I could not discern something from his pics. It's pretty much the stock circuit except for : 1) 2 EL84s instead of 4, 2) Screen resistors are 1k instead of 100R. 3) The first 3 filter caps are 33U instead of 40U, 4) 2K2 resistor instead of choke, 5) The last 2 power resistors are 8K2 instead of 9K1 and 6) Instead of 2 9K1s in series in the power rail, 1 22K is used. Oh, and there is no MOV.

Edit : The layout shows 2 1K screen resistors, but the gut shots of the amp show only 1 because Mark told me that he changed it to 2 after he took the pics, so I made the layout reflect that.

Happy building.