Rocket in progress (finished and up and running)

[RJ Guitars]

You probably know this, but I'll risk stating the obvious...

I always fire mine up with no tubes initially so I can see if my voltage string makes sense. I tend to use new caps so I don't do any "reforming" but using a light bulb limiter can usually help you learn about problems without extensive smoke and sparks.

If all this goes well with no tubes then I proceed onward.

rj

[strat_addict]

Another quick question, how does everyone here bias the tubes for their Rocket?

[RJ Guitars]

Another quick question, how does everyone here bias the tubes for their Rocket?

Maybe I don't understand the question, but the Rocket is self biasing so you really don't have to do anything. The 50 Ohm bias resistor and the tubes themselves determine the actual bias on the tubes. You can change that by using something besides a 50 Ohm resistor but generally speaking you shouldn't need to do that. Let me know if I misunderstood the question, otherwise everything should be on autopilot.

rj

[paulster]

Another quick question, how does everyone here bias the tubes for their Rocket?

The correct answer is very hot!

And RJ's above.

[CapnCrunch]

Another quick question, how does everyone here bias the tubes for their Rocket?

Is this a trick question? If not. The tubes in the Rocket (both pre-amp and power) are Cathode biased, some marketers call it "self biasing". If you used the resistor values listed in the build documents from TAG, then your bias will be O.K. Some use different values to increase power tube life. Bottom line is you don't need to "bias" the Rocket unlike the Express which is fixed bias and requires adjustment. Kind of oxymoronic that "fixed" bias is adjustable, but.......................

If these concepts are new, do a search on this site, there are a number of threads that discuss cathode and fixed bias. Randall Aiken's site is also very informative, though quite technical.

[CapnCrunch]

Hah,

Yeah, what Paulster said

[ChrisM]

You probably know this, but I'll risk stating the obvious...

I always fire mine up with no tubes initially so I can see if my voltage string makes sense. I tend to use new caps so I don't do any "reforming" but using a light bulb limiter can usually help you learn about problems without extensive smoke and sparks.

If all this goes well with no tubes then I proceed onward.

rj

With no tubes there is no load though and the dropping string voltages are really wacky. ???

[RJ Guitars]

With no tubes there is no load though and the dropping string voltages are really wacky. ???

Agreed - you will have unloaded values and not what you expect with the tubes in. I use the no tube process to look for sparks and smoke at first then move on to see if I really have ~6.3 volts AC at the heater lugs, and some believable values of higher voltage DC at each of the B+ nodes.

Just a simple sanity check that lets me see if I have wired up the B+ to all the right places, also tells me if my power and standby switches are operating as intended.

Talking to myself among others here...be aware at this point that you have charged up the filter caps and the "potential" exists to shock yourself even after you turn it off and unplug it.

rj

[strat_addict]

Tries the bulb limiter tonight. I used tubes. The bulb came on and the pilot flashed and then didn't come on at all. The tubes didn't glow in any fashion. At this point, would it be best to just call my tech up since I don't know about cap safety?

[strat_addict]

Tries the bulb limiter tonight. I used tubes. The bulb came on and the pilot flashed and then didn't come on at all. The tubes didn't glow in any fashion. At this point, would it be best to just call my tech up since I don't know about cap safety?

I lied. I tried it with my guitar and a speaker and it made noise. The good kind. It works and sounds like it should.

[marcoloco961]

Tries the bulb limiter tonight. I used tubes. The bulb came on and the pilot flashed and then didn't come on at all. The tubes didn't glow in any fashion. At this point, would it be best to just call my tech up since I don't know about cap safety?

I lied. I tried it with my guitar and a speaker and it made noise. The good kind. It works and sounds like it should.

Hmmmmmmmmmmm.... according to what I see in the pics, the 2 blue wires on pins 1 and 2 of V1 are reversed. Plate is wired to the volume knob (from what I can tell) and your B+ is wired to the grid???? Also the wire ends of pins 2 and 3 are dangerously close to each other. I don't think I would leave it powered up as is.

I don't know if I should take you seriously or not after this last post. If you do not know about bleeding the voltage from the circuit, then YES, take it to a tech before trying to do anything else to it!!!!! Dying from a high voltage electrical shock is no laughing matter.

[strat_addict]

Tries the bulb limiter tonight. I used tubes. The bulb came on and the pilot flashed and then didn't come on at all. The tubes didn't glow in any fashion. At this point, would it be best to just call my tech up since I don't know about cap safety?

I lied. I tried it with my guitar and a speaker and it made noise. The good kind. It works and sounds like it should.

Hmmmmmmmmmmm.... according to what I see in the pics, the 2 blue wires on pins 1 and 2 of V1 are reversed. Plate is wired to the volume knob (from what I can tell) and your B+ is wired to the grid???? Also the wire ends of pins 2 and 3 are dangerously close to each other. I don't think I would leave it powered up as is.

The blue wires are fine, I know it looks weird but its just a different wire placement, thats something I double checked. 2 and 3 are close, its something I already fixed. Are you talking about B2+? That wire is placed correctly according to the layout. I also checked all wires going to volume knob and they look correct. I sounds exactly like everyone here described, there's no extra noise or hum anywhere. Wouldn't something like that happen if I didn't get it correct?

[M Fowler]

V1 is definitely wired incorrectly and you need go back over those issues.
You have pin one going to the volume pot when it should be pin 2.

V2 is wired correctly as well as the PI (V3).

[strat_addict]

V1 is definitely wired incorrectly and you need go back over those issues.
You have pin one going to the volume pot when it should be pin 2.

V2 is wired correctly as well as the PI (V3).

It has a loop underneath the preamp board.

EDIT: looking back at my pics, it does look wrong but when you're actually looking at it, its right.

[M Fowler]

Follow pin 2 that is going to R6 and pin 3 is going to R5 cathode bias resistor and pin 1 is going under the board to the volume pot right?