TW Rocket

[Blues Hound]

Been wanting to build a Rocket for a while, so I have started.

Waiting on the last few parts, which should be in this week.

PT, OT and Choke from RJ.

Here are some pictures.

[dcribbs1412]

Look great Blues Hound

[Blues Hound]

Thanks D...still waiting on 40uf caps and the fuse holder.

Installed the 220uf 100v cap yesterday and started on a face plate.

Steve

[Blues Hound]

Caps arrived....one down one to go...

[Blues Hound]

From what I read in the 'Tube thoughts from Ken' thread, it looks like I will be spending more on tubes than for the amp parts!!!

Any recommendations?

Fuse holder came in...should be complete this weekend, with out tubes...might have to a second out on the house...

Steve

[dcribbs1412]

If you believe the "burn in" of an amp
I would suggest some new production JJ's or the like
get it sounding decent then check some reputable dealers
for some real NOS tubes. YMMV
www.hitestguitars.com
www.kcanostubes.com

D

[Bob S]

If you can find them at a decent price any more, look at the Russian 6p14P-EV
Tubes. They used to be cheap, but I think the supply dried up.
They will take a beating & sound very good.
Oh & Sovtek GZ34s have been reliable - for me anyway.

[M Fowler]

I use JJ tubes for everything but the rectifier now switched to Sovtek GZ34 due to reliability problems with JJ rectifier tubes.

[Blues Hound]

Gentlemen, thanks for the recommendations, I will be getting the JJ EL84's and Sovtek GZ34...have some NOS Mullard, GE and Raytheon 12AX7's for V1, V2 and V3.

Will look into the Russian 6p14P-EV.

Thanks again,
Steve

[Blues Hound]

Bob, are these close to the 6p14P-EV's?

Thanks,
Steve

[RJ Guitars]

That is a good looking build. Seems like you really kept to the simple and basic Rocket circuit which IMHO tends to always work well.

I like those Russian 6p14P tubes... I sell them as break in tubes and use them in all my EL84 builds. I think they sound really good. I think they are also the standard tube in the Z-Wreck which might be part of the supply issues.

I'd like to see your voltages when you get done and also get your thoughts on that Mercury Magnetics Dynaco clone OT. This thing should sound really nice!

[Blues Hound]

Thanks, RJ, finished her over the weekend, including a face plate...first one I have ever made.

Have not fired her up, still waiting on the EL84's and GZ34.

Will post pictures later in the week.

Still need to name her too...

Steve

[Blues Hound]

Here are some pictures of the finished amp.

Had to re-wire the impedance switch, had the 8 ohm and 16 ohm reversed.

[Blues Hound]

Tubes came in and fired her up and voltages look good, but low volume from the amp...

Have gone through the wiring twice and cannot see anything glaring, other than the ground I had left off of the 56K resistor which brought the voltages in line for the most part.

Here are the voltages:

Outlet = 121.1 VAC

B+1 = 302.0 VDC
B+2 = 294.6 VDC
B+3 = 220.0 VDC
B+4 = 190.0 VDC
B+5 = 186.8 VDC

HT at GZ34:

Pin 4 = 258.7 VAC
Pin 6 = 28.5 VAC

Pin 2 and Pin 8 at 302.0 VDC

Heaters at 6.13 VAC

V1:

Pin 1 = 152.2 VDC
Pin 2 = 0
Pin 3 = 2.409 VDC
Pin 6 = 90.3 VDC
Pin 7 = 1.6 mV
Pin 8 = .644 VDC

V2:

Pin 1 = 190.9 VDC
Pin 2 = 152.6 VDC
Pin 3 = 152.2 VDC

V3:

Pin 1 = 175.2 VDC
Pin 2 = 28.97 VDC
Pin 3/8 = 43.1 VDC
Pin 6 = 173.0 VDC
Pin 7 = 28.34 VDC

V4, V5 V6 and V7

Pin 3 = 8.84 VDC
Pin 7 = 295 VDC
Pin 9 = 295 VDC

50 ohm/25w Cathode Resistor

From comparing to the Voltage chart Allyn put out, things for the most part look good, with the exception of V2 Pins 2 & 3.

Any ideas on what would be causing the V2 issues and low volume?

Thanks in advance,
Steve

[martin manning]

GZ34 pin 6 is a typo.

V1 pin 1 and pin 3 both look high. Is the pin 3 cathode resistor a 1M2 instead of a 1k5?

V2 is ok. Pin 2 (the grid) should be the same as V1 pin 1 (and it is), and pin 3 (the cathode) should be just a bit higher (and it is).

EL84 dissipation looks good.