Rocket w/ Reverb

[Richie]

From the last pic

On the board far left, i see the cathode cap but where is the resistor?

Nevermind, i went back to look at the drawing...

[M Fowler]

The reverb driver connects to B+2.

And reverb circuit B+5

Your using the 250v secondary taps I see.

I will have to use chrome to download the pictures.

[azatplayer]

Mark u should place a little 'c' after the M in your name.
McFowler! Has a kinda superbad ring to it

[amplifiednation]

Hey guys.

Here's a couple things I think might make a difference in my build.

1. I realized I have the cap stack connected to the wrong lug on the rectifier socket, lug 2 instead of 8. So I need to make that change today. Yikes big miss.

2. I do have the caps all grounded but i currently have them grounded all together to one ground which I'm thinking is not sufficient and doesn't correspond with the layouts either. So I am going to separately ground each "level"...OR should I separately ground them in a different fashion?

[M Fowler]

You do not have to change either one in my opinion.

Mark u should place a little 'c' after the M in your name.
McFowler! Has a kinda superbad ring to it

My middle name is Craig

[amplifiednation]

[quote="M Fowler"]You do not have to change either one in my opinion.

There must be something I'm missing if my b+3-5are so low. I don't have any power tubes in the amp yet. Does that matter?

I think I need to read that tutorial on taking readings. Based on my miss on heater readings I want to make sure I'm taking these the right way before I waste too much of you guys' time. I have read all the safety precautions but that is about it

[M Fowler]

In the Trainwreck files section Ron Worley has a Express build guide that instructs on how to first fire up your build.

You take your readings of the HT without tubes in to verify your getting the voltage specified by the transformer specs.

Then you install all of your tubes preamp and power tubes. To get accruate readings there has to be a load (the tubes).

Mark

[surfsup]

wouldn't voltage drop even more after installing the tubes?

[M Fowler]

Yes but if you don't have tubes in how can you get measurement?

[amplifiednation]

Yes but if you don't have tubes in how can you get measurement?

I had preamp tubes in. no power tubes though. my plate voltages seemed waaay off, like i had something complete miswired. i gotta get out of this prison of an office and back to the build.

[Richie]

if your voltages are low, look for things like first, a bad tube. then plate resistor. If you have the wrong value say in place of a 100k.

or if your supposed to ahve a 1.5k cathode resistor and instead have a 150ohm. that will drop the voltage or a miswiring of something can cause it.

Take it a step at a time,and measure your resistors. make sure they are the correct value.

[surfsup]

Hi Mark, how's it going today? On my axHO I dug up my old measurements. with tubes out, I got measurements very close to the schematic:

B+: 258.3 264
B1: 257.2 259
B2: 251.1 250
B3: 234.4 234

with tubes in, they all dropped (still running low V on this amp, don't know why). with tubes:

B+ 228.2 : 264
B1 220.5 : 254
B2 212.3 : 250
B3 198.5 : 234

Anyway, as my HO is not fully "solved" I'm not sure what is right yet. So that's why I was asking. I am assuming with no tubes, the V readings should match the math - but as usual, I'm sure I'm wrong...I was just asking with tubes in I thought the readings would drop even more.

[azatplayer]

You do not have to change either one in my opinion.

Mark u should place a little 'c' after the M in your name.
McFowler! Has a kinda superbad ring to it

My middle name is Craig

Hahahaha!

[amplifiednation]

My voltage without tubes (with rectifier in) seems to be much higher and consistent. 343 at the recto. 335 to 337 on b+ on all caps and preamp plates 343 on the screens and 335 on the power tube sockets. I think I have a bad tube. When I get some el84s on friday I hope to have a working amp. I think everything is good. I have some new preamp tubes I will put in then too

[M Fowler]

surfsup

It all depends on how you changed values in your build compared to the schematic your reading from and how far out the resistor values are +/- 10% or 20% and the values used on your dropping string. You can change the dropping string.

Many times we have to adjust values to get the voltage we desire. I pay more attention to plate and screen voltages. Then I go forward to the preamp if oscillation or problems occur.