Building a Rocket - Layout Check for group build

RJ Guitars · Post by **RJ Guitars** » Fri Apr 18, 2008 12:10 am

ROCKET Group Build

You guys have done it... I have another name added to the list to make it an even 12 guys... A couple are still soft on commitment, but I'm hoping for their sake they make the plunge.

All the hard work has been done in putting together the build specs and parts ordering although there is still time to add a chassis to the machine shop queue if we have more requests.... Once the chassis' go into production, it's a different story - could be anytime.

I'll post progress notes as things move along...

rj

Ron Worley · Post by **Ron Worley** » Fri Apr 18, 2008 12:10 am

RJ-

I will help you on the BOM, I assume that you are using my Express version as a starting point??? (Thanks again Gearhead!!). Send me what you have (including a clean Schematic and layout that I can read) and I will look her over / add to it.

As an aside, I will do the Liverpool too at some point... I just started a new job, so time is a tad tight...

Ron

Lonely Raven · Post by **Lonely Raven** » Fri Apr 18, 2008 2:47 am

Ron,

You rock with all the work you put into the BOMs!

Fischerman · Post by **Fischerman** » Fri Apr 18, 2008 11:52 am

I asked RJ about this in an e-mail but I think it's a good discussion point. Which schematic? I noticed a few key differences in the two Rocket schemos I've seen.

One has a 50pF treble cap, a 10K 'tail' resistor on the tone stack, and the 'mid' cap is .022uF, a 68K cathode resistor on the cathode follower, and the power supply is similar to an Express (i.e. series string) aside from the tube rectifier.

The other one (the hand drawn one by Mark Abbott) shows a 500pF treble cap, a 1K 'tail' resistor on the tone stack, a .0022uF 'mid' cap, a 56K cathode resistor on the cathode follower, and the power supply is different (all preamp/PI nodes are in parallel...all tapping off of the screen node).

There may be other differences but those are just the ones I can think of offhand.

Ron Worley · Post by **Ron Worley** » Fri Apr 18, 2008 9:46 pm

Lonely Raven wrote:Ron,

You rock with all the work you put into the BOMs!

Aw schucks, it weren't nothin'...

I'm not as technically amp savvy as many here, so I help with the stuff I do know how to do!

Ron

guitarsnguns04 · Post by **guitarsnguns04** » Fri Apr 18, 2008 10:15 pm

I definately appreciate it..thanks!

RJ Guitars · Post by **RJ Guitars** » Sat Apr 19, 2008 3:39 am

Hello Forum, As the Rockit build parts finally go into production I have some time to consider and sort out some of the schematic values.

As Fisherman mentions in a couple posts earlier, there are some variations in the available Rocket schematics.

One thing that I am trying to track down is a proper choke for our build... I know that some knowledgeable guys say you don't even need one but I don't want to deviate too far from the KF design on this build.

There are a handful of choices but ultimately there is the VOX specific replacement (15Henrys and 100mA) and then a bunch of others (4-10 Henrys and 90-200mA). Of course the non VOX type are about 2/3's the price...

Does anyone have a good grasp for what we will will hear between the following: A VOX specific choke, A optional replacement choke, or no choke?

If I understand things correctly this choke simply takes some ripple out of the power supply.

Any thoughts,

rj

The choke options I found:

1 http://store.triodestore.com/ch90ma4hfe.html

2 http://www.mouser.com/Search/ProductDet ... x3OA%3d%3d

3 http://www.mouser.com/Search/ProductDet ... 7xBA%3d%3d

4 http://www.mouser.com/Search/ProductDet ... aP3g%3d%3d

5 http://www.mojomusicalsupply.com/item.a ... id=MOJO777

6 http://www.mojomusicalsupply.com/item.a ... id=8022100

gearhead · Post by **gearhead** » Sat Apr 19, 2008 4:41 pm

Ron Worley wrote:RJ-

I will help you on the BOM, I assume that you are using my Express version as a starting point??? (Thanks again Gearhead!!). Send me what you have (including a clean Schematic and layout that I can read) and I will look her over / add to it.

As an aside, I will do the Liverpool too at some point... I just started a new job, so time is a tad tight...

Ron

So cool. Look forward to the Rocket BOM.

FWIW, until Ron does his most excellent BOM-work for the Liverpool, this one might get you started:https://tubeamparchive.com/download/file.php?id=4312

Definitely cross reference to Ron's Express BOM for the latest part numbes and sources.

Ron Worley · Post by **Ron Worley** » Sun Apr 20, 2008 1:16 am

I will do the Liverpool BOM pretty soon- it will be a minimal amount of work since the Express is so similar.

Started a new job last Monday, so I'm pretty buried....

Ron

dr. who · Post by **dr. who** » Sun Apr 20, 2008 5:40 am

thanks to all for the bom's and such...this site kicks ass!!!

RJ Guitars · Post by **RJ Guitars** » Mon Apr 21, 2008 2:15 pm

Rocket Guys,

This week I'll be taking a more in depth look at all the info I have collected from the various sources and compare schematics and layouts. If anyone has some more authentic Rocket build info they are free to share, send it along. We are getting a good compilation of info and there seems to be some consistency to it.... hopefully that is an indicator that the original Rocket builds here had some insider info.... we may never know for sure.

If you get the urge to know more - look at a VOX AC-30 schematic and isolate the top boost channel.... I'm hoping to draw this out and look at it next to the other schematics I have.

I added a few chassis' to my order and can still add to the order until Thursday this week. Additional transformers and chokes are an unknown at this time (Heyboer TW spec) that order is already in. Send a note ASAP if you'd like to join in.

rj

UR12 · Post by **UR12** » Mon Apr 21, 2008 3:43 pm

RJ Guitars wrote:Rocket Guys,

This week I'll be taking a more in depth look at all the info I have collected from the various sources and compare schematics and layouts. If anyone has some more authentic Rocket build info they are free to share, send it along. We are getting a good compilation of info and there seems to be some consistency to it.... hopefully that is an indicator that the original Rocket builds here had some insider info.... we may never know for sure.

If you get the urge to know more - look at a VOX AC-30 schematic and isolate the top boost channel.... I'm hoping to draw this out and look at it next to the other schematics I have.

I added a few chassis' to my order and can still add to the order until Thursday this week. Additional transformers and chokes are an unknown at this time (Heyboer TW spec) that order is already in. Send a note ASAP if you'd like to join in.

rj

Since you are taking an in depth look maybe you can answer a question that I have wondered about regarding the rocket. Since most of Ken's builds used solid state rectos it might make sense that his power tranny didn't have a 5v winding for the tube recto. Are you sure the Rocket had a choke? Maybe what we are seeing is actually a 5V filament transformer.

RJ Guitars · Post by **RJ Guitars** » Mon Apr 21, 2008 6:52 pm

UR12 wrote:Since you are taking an in depth look maybe you can answer a question that I have wondered about regarding the rocket. Since most of Ken's builds used solid state rectos it might make sense that his power tranny didn't have a 5v winding for the tube recto. Are you sure the Rocket had a choke? Maybe what we are seeing is actually a 5V filament transformer.

Dana, It is absolutely possible it's a 5V Tranny, I am hoping someday we will know for sure. There are indicators that Mark Abbott had seen inside a Rocket... much of what I know is following him. Also, In KF's own words, this was designed around an AC-30 so the assumption that he used the AC-30 choke may come from that statement.

As near as I can research it out, the original transformers used in the Rocket were Pacific 250-0-250... I do not know if they had a 5V winding or not? That might tell us a little more.

My last assumption would be that KF would have tried to get a 5V tranny closer to the power supply components... but that is pure guesswork on my part.

It's also interesting to read what KF had to say about rectifier tubes, especially the GZ-34 in the "Trainwreck Pages".

Good question... I'll be curious if can sort this out.

rj

guitarsnguns04 · Post by **guitarsnguns04** » Mon Apr 21, 2008 10:07 pm

Good observation Dana. It is interesting when you only know little parts of the big picture. I am keeping a close eye on this as it proceeds to see where it goes. I am looking forward to it. Keep up the good work RJ.

RJ Guitars · Post by **RJ Guitars** » Wed Apr 23, 2008 5:19 am

Tube Amp Archive

Building a Rocket - Layout Check for group build

The 12th man has joined us

Re: Building a Rocket - Layout Check for group build

Re: Building a Rocket - Layout Check for group build

Re: Building a Rocket - Layout Check for group build

Re: Building a Rocket - Layout Check for group build

Re: Building a Rocket - Layout Check for group build

I am Choking... so to speak

Re: Building a Rocket - Layout Check for group build

Re: Building a Rocket - Layout Check for group build

Re: Building a Rocket - Layout Check for group build

Collecting and comparing Schematics and Layouts

Re: Collecting and comparing Schematics and Layouts

Re: Collecting and comparing Schematics and Layouts

Re: Building a Rocket - Layout Check for group build

Good Rocket Archives to read and re-read