Xits X10 = liverpool half power?

[Lonely Raven]

Nope, I'm not Dr Scientist...if I were, I wouldn't be struggling with following amp builds.

He's just a cool dude I chat with online, and I enjoy his products.

[Masco]

...and these are the values for a 440R choke:

B+1: 331.8
B+2: 324.76
B+3: 192.76
B+4: 162.76
B+5: 147.76

Fairly large voltage drop at B+3, what's up w/ that?

[surfsup]

the 22k resistor drops 22V per mA, so I have 0.006A being pulled through that resistor, if you change it to 0.005A (2mA for the PI and 3mA for the two preamp tubes) the numbers are:

B+1 331.8
B+2 324.76
B+3 214.76
B+4 184.76
B+5 169.76

I don't know what the PI tube would draw so that's why I posted all the values I was using.

[pamaz67]

i was looking at the schematic nr2 and seems that the grid connection at the el84 is at pin 9. seems that is not correct to me.
Pls swap 2 and 9.

Paolo

[Colossal]

i was looking at the schematic nr2 and seems that the grid connection at the el84 is at pin 9. seems that is not correct to me.
Pls swap 2 and 9.

Paolo

Excellent catch Paolo. I have revised the schematic to include some other changes as well.

Thanks.

[Colossal]

All:

Here is the latest schematic revision (version 2, rev 1). Changes include:

1) Updated V2a/b from 12AX7 to 12AU7 (Azatplayer).
2) Noted which resistors were carbon film. All others metal film. (Colossal).
3) Revised indicator LED circuit (Azatplayer). LED resistor looks like 24R. Proposed LED math added (Colossal).
4) Changed 1k choke resistor (X10 ver1) to a choke (X10 ver2) (Colossal)
5) Revised pin designations on EL84s (Paolo).
6) General housekeeping.

If anyone sees anything else that needs changing/revision, let me know.

Thanks!

[pamaz67]

Thanks Colossal.

[surfsup]

Colossal and pamaz, you guys have confused me...

On the JJ and Phillips datasheets the cathode (k) is marked as pin 3, here are both images condensed into one:

[img:500:200]http://chicagocadcam.com/ChrisHahn/schem/EL84k.jpg[/img]

Pin 9 is clearly marked as a grid connection on both. So why is 9 now the cathode on the schematic? What am I missing?

[M Fowler]

Pin 3 is the cathode on a EL84.

[Colossal]

Typo corrected.

[loctal]

This is a great thread. Keep up the solid work. I am pulling the parts together as it progresses.

Does anyone know what size taps are needed to mount the power switch and input jack to the chassis?

[surfsup]

Are you drilling and tapping? That would depend on the switches you are using. I think mine are 5/8" and 20 threads per inch but I'm just drilling a hole and mounting using the threaded ring

[loctal]

I want to drill and tap the chassis for the on/off/standby switch and the switchcraft input jack. Those amps look really cool with the smooth face plate. The chassis I made for the amp is made from 1/8 inch thick aluminum and measures 15X8X2.625. I intend to use the layout that is posted in this thread with the VVR. I will include a cut control. For the turret board, I am going to try eyelets to facilitate changes.

[pamaz67]

by the end of this week I'll receive a power transformer ( 280-0-280) and I'll be able to fire up my amp ( a 30w versione BTW).

As soon as I'll do it, I'll report the results.
At the moment I'll try two output transformers from the same italian vendor, both made in AC30 style. (see www.inmadout.com)
Sorry I've not the tools to record samples........

Paolo

[surfsup]

pamaz, some questions:

did you use 1M MV pot?
What about the RC filter values after the PI?
Did you ground the two 220k resistors?
Choke or 1k R?
What voltages are you expecting for B, B1-B5?

I am going to do a slope resistor switch on mine:

[img695]http://chicagocadcam.com/ChrisHahn/schem/x10_option.jpg[/img]