Rocket Clone,voltages w/ Head cab pics!

[keithrick]

Hi guys,

I decided to build the Rocket. I have completed populating the board. I am using AB 1 watt resistors for mojo in this build. I am going to work on the Power Supply Board today. Still trying to figure it out!

Here is a quick picture of my completed board. Let me know if you notice anything out of wack! (besides the Mallory 150 series .1uf )

Note: I do have some Vishay Dales RN65's laying around. Do you think I should use them for the plates?


****Edit**** I have attached the updated layout. Please let me know if you see any issues!

Right now I am trying to decide the best placement of my cathode bias resistors. I was considering behind the preamp tubes or glued to the side chassis beside the PS board. Any thoughts or critiques are welcome. As I will be continuing on Sunday!

[gearhead]

Where'd you get the perfboard?

[Noel Grassy]

Ditto to the message above!

[keithrick]

Got the board from Allynmey. He had it listed in the For Sale section w/ fleas.

BTW- he also had some Mallory caps for sale as well!

[philmanatee]

I just put the fleas in my perfboard for my tremrocket last night. I gave up a lot of real estate for the trem circuit so my power supply is really gonna be tight. Hopefully I can keep up with you! Phil

[ODwan]

I would not use the RN 65s in this build. Stick with CC or CF resistors, but maybe give it a try!

Timo

[keithrick]

I just put the fleas in my perfboard for my tremrocket last night. I gave up a lot of real estate for the trem circuit so my power supply is really gonna be tight. Hopefully I can keep up with you! Phil

Phil, Don't worry about me getting ahead I don't have my chassis yet from Kombonking. It's been over a month and no word or response .

Timo, I agree! I am using the 1 watt CC first as seen on the board. If noise is an issue I'll start substituting the RN65's and or Carbon Films on the plates.

[ODwan]

I just put the fleas in my perfboard for my tremrocket last night. I gave up a lot of real estate for the trem circuit so my power supply is really gonna be tight. Hopefully I can keep up with you! Phil

Phil, Don't worry about me getting ahead I don't have my chassis yet from Kombonking. It's been over a month and no word or response .

Timo, I agree! I am using the 1 watt CC first as seen on the board. If noise is an issue I'll start substituting the RN65's and or Carbon Films on the plates.

I found that substituting 1Meg grid leak resistors with less noisy ones yields good noise reduction without changing tone that much.

Timo

[keithrick]

Bump see new pic on original post.

Right now I am trying to decide the best placement of my cathode bias resistors. It will be a have a 1/2 power switch. I was considering behind the preamp tubes or glued to the side chassis beside the PS board. Any thoughts or critiques are welcome. As I will be continuing on Sunday!


Thanks for looking!

Keith

[philmanatee]

Hopefully I'll get a chance to progress on mine this weekend, I'll post pics if I do. Phil

[Allynmey]

Looks nice to me keith, keep us updated. I am finishing my Liverpool this week and will build a Rocket next.

Allyn

[keithrick]

Fired her up and she sings! I have a couple of issues to correct. Volume and treble pot are wired backward and I need to add the 47pf acoss the PI plates. Here are the voltages.

Notes:

Wired per my preamp layout. 1K 50watt resistor for choke. Wired for half power i.e. two 130ohm 25 watt resistors w/250ohm bypass caps. JJ EL84 tubes, Sovtec 5AR4 rectifier.


Should I try to get 220ohms bypass caps?

300v on tube plates!

Is this the correct way to bias? Measure voltage across cathode resistors (10 volts) and divide by resistance (130ohms) to get .076ma per pair of output tubes or 38.5ma per tube.

300v*38.5ma= 11.54watts of dissapation!

I know cathode biasing is different then fixed and higher numbers can be used, but is this safe?


B+1=318v
B+2=298v
B+3=231v
B+4=207v
B+5=202v

V1 plate (1) 90v
V2A plate 128v
V2B plate 207v
V3A plate 184v
V3B plate 183v


If there is any other reading anyone wants let me know.

[philmanatee]

Right on Keith! I'm right behind you, hoping to fire up by Sunday if all goes well. How does it compare to the Express? Phil

[Richie]

the voltages seem a bit low.. What trannys did you use..got an finished pic of the amp innards?

[keithrick]

Look when I started this amp lookied like one that Allyn would have wired and went downhill from there!

Here are some pics of the amp. Still need to add the indicator light and the impedance selector.