Rocket in a Blues Junior format!
Moderators: pompeiisneaks, Colossal
Rocket in a Blues Junior format!
OK so i am building this beast. Chassis real estate is very hard to come by. I am limited to where i can place the tranny's. If I put them in the wrong place they will hit the speaker magnet. Please check the pics and let me know what you think of the iron palcement. The PT is already drilled and mounted but the OT and choke are not drilled yet. If you think this placement is going to be a problem please give me some ideas to better lay out this thing.
You do not have the required permissions to view the files attached to this post.
Re: Rocket in a Blues Junior format!
The only way to know is to listen with the headphone trick or scope. You CAN place transformers nearly touching, and orient them so the hum is zero, or you may get terrible hum because your trannies are not exactly on axis with respect to each other. Also, the placement of the choke can bend the fields and can influence the hum. I've demonstrated this happening!
I build and repair tube amps. http://amps.monkeymatic.com
- JazzGuitarGimp
- Posts: 2357
- Joined: Mon Jul 23, 2012 4:54 pm
- Location: Northern CA
Re: Rocket in a Blues Junior format!
What xtian said. The headphone trick is really easy to do, and it truly tells the whole story.
Lou Rossi Designs
Printed Circuit Design & Layout,
and Schematic Capture
Printed Circuit Design & Layout,
and Schematic Capture
Re: Rocket in a Blues Junior format!
Hopefully a 4 banger! Loud amps, small boxes. Viva the '70s.
I can't wait to see this finished.
I can't wait to see this finished.
Re: Rocket in a Blues Junior format!
I've done it where the OT on one side of chassis and PT on other end with choke between so I could clear the speaker.
Or PT then choke and then OT no transformer interaction.
Or PT then choke and then OT no transformer interaction.
Re: Rocket in a Blues Junior format!
I've never worked with one of those, but I'm sure you'll get it just right. Looking forward to seeing it when it's done. Looks great so far! 
Re: Rocket in a Blues Junior format!
This Rocket tribute is one of my recent builds; it's very quiet, even though the chassis is cramped, crammed with extra stuff, and the transformers are not where Ken put 'em. I did not use the headphone trick, so probably got lucky.
You do not have the required permissions to view the files attached to this post.
Re: Rocket in a Blues Junior format!
Looks good like something right out of the 1950's. Like the CE can caps and how you arranged every component.
And I have never used the headphone trick, why bother.
And I have never used the headphone trick, why bother.
Re: Rocket in a Blues Junior format!
You can usually get away with sticking the choke on the inside too if you're really strapped for space on top.
Re: Rocket in a Blues Junior format!
Thanks, Mark. I was actually going for that look, as you might be able to tell from the crinkle black front panel and cream chicken heads.
Greg - I offer this gut shot to show how I crammed everything into a narrow chassis, though yours might be a tiny bit narrower.
Have fun with the build.
Greg - I offer this gut shot to show how I crammed everything into a narrow chassis, though yours might be a tiny bit narrower.
Have fun with the build.
You do not have the required permissions to view the files attached to this post.
Re: Rocket in a Blues Junior format!
Problem with my build is that the tubes are on the narrow edge of the chassis. I have plenty of real estate but then i cant use it for trannys cause of the speaker. I will try to get some pics tonight.
Re: Rocket in a Blues Junior format!
OK here's a couple more pics. Keep in mind that the cab is upside down in the pics. The chassis is just in place unsecure but it gives a good indication of the amount of space I have.
You do not have the required permissions to view the files attached to this post.
Re: Rocket in a Blues Junior format!
Yup need to mount the OT on other side. You can run the OT wires on out side of the chassis for a ways and then into the chassis. Henry at Redplate amps taught me that trick. 
But in your case there is plenty of space to run the OT wires without getting input-output noise.
But in your case there is plenty of space to run the OT wires without getting input-output noise.
Re: Rocket in a Blues Junior format!
OK Just wanted to post an update to this project. I am still waiting for the grill cloth and handle to arrive but I got the cabinet painted. I was going to buy Metallic Ice Blue Lacquer from ReRench BUT that is $16/can plus shipping and I found a darker blue metallic paint at Lowes for $6/can out the door. So I used the Lowes stuff and if I don't like it I can always paint over it with the Nitro and some primer. Also have to paint the baffle flat black.
I also may change the speaker to a Fane AXA12 AlNiCo Blue
[img:320:240]https://farm4.staticflickr.com/3928/15392733956_6d4f5d4225_n.jpg[/img]P1240994 by gbucha, on Flickr
[img:320:240]https://farm3.staticflickr.com/2947/15229024919_d832d08ede_n.jpg[/img]P1240978 by gbucha, on Flickr
I also may change the speaker to a Fane AXA12 AlNiCo Blue
[img:320:240]https://farm4.staticflickr.com/3928/15392733956_6d4f5d4225_n.jpg[/img]P1240994 by gbucha, on Flickr
[img:320:240]https://farm3.staticflickr.com/2947/15229024919_d832d08ede_n.jpg[/img]P1240978 by gbucha, on Flickr
Re: Rocket in a Blues Junior format!
Forgot to mention I am waiting for a VVR board from Dana Hall for this amp.