New 2xEL84 Rocket

[BLT]

With bulb limiter plugged in I went through the the initial voltage checks and everything was as it should be, until with all tubes in I switched it off standby. I never saw a flicker of a light all through the previous tests, but now the bulb went bright, and back down to a dull glow, then slowly began to brighten again. As it brightened the pilot light slowly went dim, then out. I made note of the secondary voltages and all the B+s. The other voltages seemed appropriately low but I didn't write them down. I couldn't help myself and plugged in, turned it up a quarter turn, and it sounded really good; quiet and clean. Here's a few pics for you to maybe see something I haven't.

[ampgeek]

The "ramp up" and down of the limiter bulb with tubes in is perfectly normal.

Double check the rating of your pilot light to make sure that it matches the supply it is connected to. Your description sounds alot like a DC bulb connected to 120V AC supply. Don't ask why I know!!

Looks like you did a good job. Your initial sound test appears to confirm that!

Rock on,
Dave O.

[BLT]

Thanks Dave,
The indicator light is rated 125VAC and is hooked up with the mains.

[dorrisant]

Thought I saw something but I was wrong... Nice looking build, btw..

Tony

[BLT]

Thanks Tony,
By the way, 80 VAC from the limiter.

[BLT]

Here's the voltages. Looks like I hit the projected numbers. Sounds great and now I just need to figure out how to finish it. I don't want this to sound like I'm accepting an award from the academy, but I just want to thank some of the people who offer help on this site. When I left broadcasting back in the '80s, my skills as an engineer were no longer needed. So, it's been a while since I had a decent soldering iron and anything but a cheap multimeter. This has given me an opportunity to get back some of the knowledge lost over the last 25 to 30 years.

[BLT]

To anyone who has used the Classictone 40-18056 PT on one of these builds, how warm does it get in the course of an hour?

[dcribbs1412]

Congrats BLT
Nice looking build and
glad its sounding good.
I will be using the 40-18035 PT which is the lay down version of yours
in an upcoming build.

D

[BLT]

DC, what build are you going to do with the 40-18035?

[jazbo8]

Here's the voltages. Looks like I hit the projected numbers.

A bit confused, the actual voltages range from 10-27% over the expected, shouldn't they be a bit closer?

[M Fowler]

Those expected voltages are from someone's four EL84 Rocket build and who know's which PT they used as a basis, I've seen everything from 480vct to 600vct PT's used in Rockets.

[M Fowler]

To anyone who has used the Classictone 40-18056 PT on one of these builds, how warm does it get in the course of an hour?

Yes I've used that PT several times and it does not get hot to touch and the only PT I've ever had too hot to touch was a sizzling Sears Silvertone 1482 PT.

Oh and those guys that bad mouth Magnetic Components (MC) transformers can leave them for me and buy the expensive Mercury.

[jazbo8]

Those expected voltages are from someone's four EL84 Rocket build and who know's which PT they used as a basis, I've seen everything from 480vct to 600vct PT's used in Rockets.

So the "expected" voltages shown in the worksheet above were not based on the actual Rocket? (I've not looked, but there is probably one somewhere on TAG). Just want to get a clarification...

TIA,
Jaz

[dcribbs1412]

DC, what build are you going to to do with the 40-18035?

BLT,
Going to try a 6V6 express circuit.

Seems like the original voltage chart is from Ron Worley.
I think he used a Toneslut PT with 250V/280V taps which would explain the lower voltages compared to BLT's 290V taps.

Not sure there is clarification in that voltages do matter and if its close and sounds good run with it. Might be an idea to roll some tubes to see if voltages come down a few volts, after that dropping string and or zeners.
Just to see if the lower preamp voltages give up more tonal goodness.JMO

D

[M Fowler]

http://ampgarage.com/forum/viewtopic.ph ... 18w+rocket has voltage chart on page 2

http://ampgarage.com/forum/files/rocket ... er_156.pdf

Layout: http://ampgarage.com/forum/files/2xel84 ... 61_599.pdf

This thread is where it all started for me with 18w Rockets. http://ampgarage.com/forum/viewtopic.ph ... sc&start=0