2xel84 rocket

[dcribbs1412]

Thanks Mark and KT66
going on the to do ASAP list
Happy Turkey Day

[M Fowler]

Ryan that came out very good, great job on the layout and for asking questions especially when you discovered my standby error, thanks.

Mark

[dcribbs1412]

Mark
did you happen to get any voltage readings?

Dartanion's smaller 18w PT is 260/290 so I am starting with the 290 since I didn't want to put in a HT switch on this amp

nice build by the way
Thanks again

[M Fowler]

I did but I will redo the voltage readings and post okay.

I want to remove the amp from the cabinet and slightly enlarge my cabinet mounting holes to better position the amp in the cabinet anyway.
Slightly too tight to one side and it needs to be centered you know!

Mark

[argonaut]

Thanks to Darin I received my lower powered transformers.

Anyone else building one of these two EL84 Rockets?

Mark

Hi Mark,

By coincidence, I happened to complete a 2-el84 rocket about the same time you finished yours. I just now noticed this thread. Nice looking build!

I used some vintage iron and ended up doing it PTP only because I didn't feel like changing the blade on my tablesaw to slice up some g10. I'm waiting on my faceplates and it's getting to be that time of year to get the woodshop fired up to make some headshells. I have quite a few completed chassis' laying around waiting to be fitted.

Anyway, the only significant difference I see between our builds is in the power supply. I used a 270-0-270 PT, 5Y3 rectifier, 1k 10w resistor instead of a choke, and 33uf, 20uf, 10uf, 10uf, 10uf for filtering. I wanted to keep the voltage low and saggy...love it!

I can take pics and actual voltage readings if anyone would like.

[M Fowler]

argonaut,

Hey that sounds like a great amp and the 275-0-275 with 5Y3 and lower filtering I bet works quite well.

Pictures is always good and I like PTP.

Mark

[ronman]

Which Transformers are you using on the mfower's 2x el84 rocket.also is the layout correct.what rectifier tube .

Thanks

[M Fowler]

Using 18w Heyboer transformers supplied by Dartanion see beginning posts.

The rectifier I am using is the GZ34 but you could use EZ81 or others.

The layout is correct but I am questioning the 2k2 not being connected between the main filter caps and B+2 cap used in place of a choke.

Wire from recto tube should go to the stand-by switch, then OT to stand-by switch together with wire from the main filter caps.

Mark

[ronman]

Isn't it hooked up the same in this layout

[argonaut]

argonaut,

Hey that sounds like a great amp and the 275-0-275 with 5Y3 and lower filtering I bet works quite well.

Pictures is always good and I like PTP.

Mark

It turned out pretty wicked. The clean to mean is extremely touch sensitive and evenly balanced like the express. It's a mean little bugger...plenty of volume as well.

I turned the house upside-down looking for the camera. I'll post pics when it eventually turns up.

[M Fowler]

I found my amp to have a nice bass response which I was pleasantly please about. Adjust the treble and cut control and dial in nice tone.

Kind of interesting that I find my Spitfire, 18w Marshall and 18w Rocket all to be more fun to play then the big brothers? Humm I must be getting old and not needing 100 watts anymore. Yeah right

Mark

[Deric]

Just noticed that in the layout posted, the bass pot is wired wrong. The middle and outside lug should not be jumpered and the outside lug should be grounded.

I think......

[M Fowler]

Well the outside pin is grounded to the pot and the wiper has 10k mid frequency resistor to ground so electronically it is the same.

I rewired my standby switch to rectifier wire to standby switch and from switch to B+ cap. OT red wire to B+

The 2k2 resistor is in place of a choke so that goes between B+ and B+2 caps.

Mark

[Zippy]

I found my amp to have a nice bass response which I was pleasantly please about. Adjust the treble and cut control and dial in nice tone.

Kind of interesting that I find my Spitfire, 18w Marshall and 18w Rocket all to be more fun to play then the big brothers? Humm I must be getting old and not needing 100 watts anymore. Yeah right

Mark

In the Dumble-clone world, there has been much chatter regarding 2- vs 4- tube output sections - issues revolving 'round "complexity" in the tone, etc.

Might you comment on the differences you hear between your 2-EL84 and the 4-EL84 (assuming all else equal)?

[M Fowler]

Zippy, I am terrible at describing what I hear to others.

Each of my Rockets, six all together, have been build differently from each other. Only one amp is the traditional TW build 240-0-240 Edcor and Dynaco A-470-S 4k3).

One is running 6L6 pair 36w, One is running EL34 pair 60W, one is KT66 pair 36w, one is quad of EL34's ?80w, and the current amp with pair of EL84s 18w.

The quad EL34 is definately the tone pleaser that covers everything I need in an amp highs, mids and lows with nice blend of short decay reverb. It gets dirty about noon and if I switch in my boost option it gets the harmonic thing (ZZ-top) even sooner. Running Edcor 100w iron.

Mark