Rockster Lives!

Express, Liverpool, Rocket, Dirty Little Monster, etc.

Moderators: pompeiisneaks, Colossal

Beerman
Posts: 81
Joined: Thu Mar 01, 2007 7:16 am
Location: Melbourne, Australia

Rockster Lives!

Post by Beerman »

Don't suppose anyone has built an Octal Rocket according to the Schematic posted in http://ampgarage.com/forum/viewtopic.ph ... er&start=0 this thread?

I'm working from schematic and layout at the following link. http://imgur.com/a/MSXkd

I'd love to see a picture of how the pots are wired.... I'm not convinced I've got mine right...

Picture here: [IMG:1024:768]http://i.imgur.com/ImXtm.jpg[/img]

I'm also hunting down another fault.... it keeps blowing fuses on start up.

An few build photos here: http://imgur.com/a/B1Bm9

Would appreciate any feedback from more experienced eyes.
Last edited by Beerman on Sat Mar 05, 2011 10:57 pm, edited 1 time in total.
__________________________________________
Cheers and Beers.
User avatar
M Fowler
Posts: 14017
Joined: Wed Jan 16, 2008 2:19 am
Location: Walcott ND

Re: Rockster Lives!

Post by M Fowler »

http://imgur.com/a/MSXkd

I can help you if you have questions rjguitar is out of town for awhile.

Mark
User avatar
M Fowler
Posts: 14017
Joined: Wed Jan 16, 2008 2:19 am
Location: Walcott ND

Re: Rockster Lives!

Post by M Fowler »

Here are shot of rj's amp I could only find one good one of the pot wiring.

Later you can shorten a lot of your wiring from the tube sockets if you wish.

Mark
You do not have the required permissions to view the files attached to this post.
Beerman
Posts: 81
Joined: Thu Mar 01, 2007 7:16 am
Location: Melbourne, Australia

Re: Rockster Lives!

Post by Beerman »

Thanks Mark.

Firstly...
[IMG:524:1052]http://i.imgur.com/mFSN7.jpg[/img]
Note the circled 5K...

[IMG:986:710]http://i.imgur.com/K0DwZ.jpg[/img]
Which doesn't appear here...

Where does it go?
__________________________________________
Cheers and Beers.
Beerman
Posts: 81
Joined: Thu Mar 01, 2007 7:16 am
Location: Melbourne, Australia

Re: Rockster Lives!

Post by Beerman »

Gotcha... you were a step ahead of me.

So it actually looks like this?
[IMG:408:728]http://i.imgur.com/8EoQ2.jpg[/img]

Thanks.

Still got to sort out the short (or other error) in the power supply... it keeps blowing the mains fuse on start up.

Don't suppose there is anything obviously wrong there that I'm just not seeing?

Will come back with any more questions when I'm past that issue.
__________________________________________
Cheers and Beers.
User avatar
M Fowler
Posts: 14017
Joined: Wed Jan 16, 2008 2:19 am
Location: Walcott ND

Re: Rockster Lives!

Post by M Fowler »

I do not use that 5k resistor just wire the wiper (middle) of the bass pot to the wiper of the 25kL mid pot.
You do not have the required permissions to view the files attached to this post.
Beerman
Posts: 81
Joined: Thu Mar 01, 2007 7:16 am
Location: Melbourne, Australia

Re: Rockster Lives!

Post by Beerman »

So it should look like this then? (From the inside)

[IMG:640:400]http://i.imgur.com/uDLfe.jpg[/img]

I note also that RJ has his Cut control wired opposite to me.
__________________________________________
Cheers and Beers.
User avatar
M Fowler
Posts: 14017
Joined: Wed Jan 16, 2008 2:19 am
Location: Walcott ND

Re: Rockster Lives!

Post by M Fowler »

Here is how I see it. There are two ways he has drawn this but I think this is less confusing.

Mark
You do not have the required permissions to view the files attached to this post.
User avatar
RJ Guitars
Posts: 2662
Joined: Tue Nov 14, 2006 3:49 am
Location: Los Alamos, New Mexico
Contact:

Re: Rockster Lives!

Post by RJ Guitars »

Beerman - Welcome to the Rockster world... I was supposed to be over on the other side of the world this week but those plans are on hold for now. Mark knows these things better than i do so maybe he can help us sort this out...

The schematic you have is using a mid control borrowed from another circuit... it's not what i ended up using on my build though. I would have to look at that build to see if I still have it the way it is in Mark's photo.

For future reference keep in mind that going back to the old Matt Taylor Rocket Schematic is a good way to sort out the preamp on the Rockster. I think it is most useful to go back to the original Rocket schematic and see what the mid control was doing there.

There is no pot on the original Rocket amp, just a 10K to ground off of the Bass control.

Then if we simply replace that 10K resistor with a 25K pot, then we have created a mid control. I'm not sure if this is a conventional mid control, but it will work.

I added a 5K resistor to the tail of the mid pot so that it wouldn't bottom out when it went to zero resistance.

Also, I have a 250K pot for the bass control on a lot of old schematics, I think it's always best to use a 1 Meg for that.

After we are sure my drawings are right, I'll make the "fixed" schematic rev available to anyone who wants it... next we can go after the layout.

rj
You do not have the required permissions to view the files attached to this post.
Good, Fast, or Cheap -- Pick two...

http://www.rjguitars.net
http://www.rjaudioresearch.com/
http://diyguitaramps.prophpbb.com/
User avatar
RJ Guitars
Posts: 2662
Joined: Tue Nov 14, 2006 3:49 am
Location: Los Alamos, New Mexico
Contact:

Re: Rockster Lives!

Post by RJ Guitars »

Beerman wrote:... I note also that RJ has his Cut control wired opposite to me.
that's an interesting part of the Rocket amps... I think the cut control works backwards.

Unless mine is a pre "fix" photo -- more knob=more cut

Let me know if that agrees with what you find.

rj
Good, Fast, or Cheap -- Pick two...

http://www.rjguitars.net
http://www.rjaudioresearch.com/
http://diyguitaramps.prophpbb.com/
User avatar
M Fowler
Posts: 14017
Joined: Wed Jan 16, 2008 2:19 am
Location: Walcott ND

Re: Rockster Lives!

Post by M Fowler »

More knob brighter the tone.

My Dizzy 30 works the opposite more knob deeper tone.
Beerman
Posts: 81
Joined: Thu Mar 01, 2007 7:16 am
Location: Melbourne, Australia

Re: Rockster Lives!

Post by Beerman »

Thanks again Mark - and RJ now too...

I'm back onto my power supply issue - it looks like I have an intermittent short on the HT (300-0-300) and the 5v winding.

With side loading on the leads it kept on blowing fuses. Have untwisted, and 'relaxed' all the leads, and now it works.

Guess I'll take it off and have a look to see what goes on...
__________________________________________
Cheers and Beers.
User avatar
M Fowler
Posts: 14017
Joined: Wed Jan 16, 2008 2:19 am
Location: Walcott ND

Re: Rockster Lives!

Post by M Fowler »

Hmm not sure what you have going there.
User avatar
M Fowler
Posts: 14017
Joined: Wed Jan 16, 2008 2:19 am
Location: Walcott ND

Re: Rockster Lives!

Post by M Fowler »

Another way to wire the tone controls
You do not have the required permissions to view the files attached to this post.
Beerman
Posts: 81
Joined: Thu Mar 01, 2007 7:16 am
Location: Melbourne, Australia

Re: Rockster Lives!

Post by Beerman »

RJ Guitars wrote:Beerman - Welcome to the Rockster world...

After we are sure my drawings are right, I'll make the "fixed" schematic rev available to anyone who wants it... next we can go after the layout.

rj
Thanks RJ.

I'm Graham in Melbourne - I bought most of these parts from you just before Christmas last year.

The PT is the Edcor EM0726-240. I've got the end bells off, and everything looks fine, no bad smells. The Primary winding leads feel solid, as do the 6.3, and the HT, but the 5V leads feel different - like they are not attached quite as well.

I've already cut the leads - so I imagine that any warranty Edcor may have offered is gone...

Will investigate further and let you know what I find.
__________________________________________
Cheers and Beers.
Post Reply