Donna Rocket new builder questions V3 and V4

[Greg]

I am using Ron Worleys Rocket layout and many pictures to build my amp. I am confused about several things. On Ron's layout look at V3 pin 9. If you trace that (small green) wire from V3 pin 9 to V4 it looks like it goes to pin 4 but all pictures I see show the wire going to pin 5 on V4.

Also. Is the thing mounted to the chassis next to V7 grounding the PT wires or does it just provide a stable base for an extension. Why not just solder more wire to the PT leads to extend them?

Thanks guys...

[M Fowler]

The green filament wire from V3 pin 9 goes to V4 pin 4 then to pin four on the remaining V5 V6 V7. V4 pin 4-5 goes to V4 pin 5 (black wire) and then on to the remaining V5, V6, V7.

That terminal strip is not grounded it is bolted to the chassis and the two out side terminals are holding the OT brown filament 6.3v wires then on to the filaments of each tube.

First if you choose not to use this terminal strip and you have plenty of room on pins 4 and 5 of V7 then solder them there otherwise the real Rocket used the terminal strip as shown.

Mark

[Greg]

I understand what Ron's layout illustrates what I do not understand is that all the pictures I see...from Allyn...do not show that. Please look at the picture. Am I missing something?

Terminal strip...that's the ticket. I guess I should buy a few of those.

Thanks for the help

[M Fowler]

Greg,

If you go back and look at Allyn's submitted photos you will see that he does use the terminal strips as well. The third picture down.

Mark


https://tubeamparchive.com/viewtopic.ph ... ght=rocket

[Greg]

I understand the terminal strips function. I still am confused about V3 and V4
The pictures do not match Ron's layout. Unless I am missing something. Someone please take a look at this.

Ron Worley's layout:
V3 pin 9 wire goes to V4 pin 4.
V3 pin 5/4 (they are bridged) goes to V4 pin 5.
V5-7 are chained off that.

Several pictures I see show the opposite...V3 pin 9 to V4 pin 5.

Is this important?

[M Fowler]

Greg,

Keep the 12ax7s in the same polarity pin 9 to pin 9 and pin (4-5) to pin (4-5) on each preamp tube . But when you get to the EL84 (6BQ5) the filament pins are 4 and 5 you can connect to either one but after that keep those EL84s in the same polarity.

Filament polarity is most important with preamp tubes more so than the power tubes but generally it is standard to keep the polarity when wiring filament strings.

Hope this helps, if your having trouble with me helping you, I will let some one else take over.

Mark

[Allynmey]

Greg, it doesn't matter which way you do it. Just keep it consistant. On all preamp tubes I keep the same wire going to pins 4 and 5 and the same wire to pin 9. On powers, I keep pins 4 consistant and pin 5 consistant. However, it doesn't matter which wire connects pin 9 on the pres to the power tubes (pin 4 or 5) or pins 4-5 on the pres to either of the power (pins 4 or 5). Hope it clears it up.

[Greg]

Mark and Allyn
Thank you both for clearing this up for me. Consistency is the key. Sweet no rework. Just a heads up on the Donna Rocket build. It is going slow but great. I am having so much fun...more pics on the way.

[M Fowler]

Greg,

Your on the right track take it slow, watch the details and ask lots of questions. The guys on this forum are the best and helped me out everytime I needed it. I will check out your pictures, thanks.

Mark

[Ron Worley]

Sorry that I did not see this earlier...

Tim Hulsey drew this layout and yes- he does it backwards from what Allyn and the real Rocket do Pin 9 (all 12AX7) to Pin 5 (all EL84) and pins 4/5 on the 12AX7 to pins 4 on the EL84s..... It's a minor error and electrically moot.

As Allyn noted, keeping them consistent is the point so that it cancels the hum.

9-9-9-5-5
5-5-5-4-4

Make sense?

[Greg]

Makes sense now. Thanks again. I did not realize it made no difference. Actually I suspected that but do not understand why it makes no difference.
More questions coming...new thread