jensenmann

Re: [BUILD] STA LEVEL PCB OFFICIAL BUILD & HELP THREAD
« Reply #400 on: December 20, 2018, 12:17:50 PM »
Next one: there are ground loops if you wire your Sta Level according to the wiring diagram on the first page of the thread.

Filament supply/ground is fine if you follow the wiring diagram. Just make sure your switch for bias adjustment is opening the contact if momentarily pushed.

V+ supply and it´s ground is fine, too. Since it supplies the light bulb and the relays only it has no connection to audio anyway, so it´s not relevant. But be aware of the relay board ground wiring. There are several possible ways to ground that thingy. The best way is to tie pin 1 of both XLR in and outs directly to the starground. That´s the shortest path to ground. But you should use shielded wire inside the box to connect both XLRs to the relay board as well as the main PCB to the relay board. The shield of those four wires should be tied to ground at one side only! E.g. connect all four shields to the relay board but not to the XLRs and the main board. Then tie the relay board to the starground. This way you have no groundloop which is what we want.

Bias and HT supply:
The bias supply gets its voltage from the output of the HT (B+) supply via two wires: B+ and B-. B- is the wrong name since it´s actually ground. But it´s necessary to understand that both supplies have a common ground, just look at the schematic. Now if you wire the B+ output to the main PCB with two wires and the Bias supply with another two wires then you already have a groundloop because on the main PCB both ground connections are tied together via the ground plane. So leave one of those ground wires unconnected.
The main PCB and the PSU needs to be connected to starground. There are two provisions to do so: the ground connector on the main PCB next to the bias voltage input as well as the ground connection on the HT PSU board next to the HT Trim resistor. Connect only one of these two grounds to the starground. Otherwise you get a loop from starground to the main PCB, then via the bias or B+ ground to the PSU PCB and then from it´s ground connection to starground again.

Jens
Quote from: PRR
The tubes of course don't care what frequency they distort


zayance

Re: [BUILD] STA LEVEL PCB OFFICIAL BUILD & HELP THREAD
« Reply #401 on: December 21, 2018, 10:36:04 AM »
Quote
C9 in the B+ PSU is rated at 400V. That´s too low. I measure 422V DC here. Theory says 300V AC x 1,4 = 420V DC after the bridge rectifier. So make sure that you use 450V rated caps for C9.

Good catch.  ::)
Well the BOM gives hints if what can be used, and people can fit whatever they like, Bernd and i don't go into the "kits" thingy so...
Dunno if all went 400V Caps way here, depends on the provider, some might have no other choice than 450VDC etc...

But thanks for shimming in and giving hints and infos, always welcome.
BOM Will have update on today.


T

madreza

Re: [BUILD] STA LEVEL PCB OFFICIAL BUILD & HELP THREAD
« Reply #402 on: February 04, 2019, 07:56:33 PM »
Hi Everyone ,
and thanks to Bern and Tony for that project , that's awesome!
so glad , I'm almost there :D

a few questions :
I have Sowter In/Out Tranny  /  Avel Lindberg Power Trans.
6383 Tube
voltages seem to be fine
the input is wired 1:8
so , I have to leave the input pad soldered , reduce the Bias voltage to , around 20V , and use a T pad pot for the Output , right ?
and what about the R32 ? Do I need to set a 20K pot also ? with a 4.7K to the ground ? or can just use a regular resistor for that ?
any other changes ?
oh , and I have a Simpson 27  0.1 DC mA ( do i just have to calibrate it with the trimmer on the PCB or do I have to do any changes ? )

Thanks Guys

Cheers
« Last Edit: February 04, 2019, 08:18:16 PM by madreza »
Knight 1: We are now no longer the Knights who say Ni.
Knight 2: NI.
Other Knights: Shh...
Knight 1: We are now the Knights who say... "Ekki-Ekki-Ekki-Ekki-PTANG. Zoom-Boing. Z'nourrwringmm.

bernbrue

Re: [BUILD] STA LEVEL PCB OFFICIAL BUILD & HELP THREAD
« Reply #403 on: February 05, 2019, 08:41:27 AM »
Yes, use the input pad and T pad output pot, bias voltage 16-20V, depending on how the compressor behaves. R32 is the bias resistor, right?  Well, you might get it right with a fixed resistor. When you have to crank up the input pot too much, reduce value of R32. 100 uA meter  should work fine with onboard trimpot.
Cheers
Bernd

madreza

Re: [BUILD] STA LEVEL PCB OFFICIAL BUILD & HELP THREAD
« Reply #404 on: February 05, 2019, 03:14:10 PM »
Cool thanks for your reply :)
So I just try and replace R32 by something around 18K and see if it works !?
Knight 1: We are now no longer the Knights who say Ni.
Knight 2: NI.
Other Knights: Shh...
Knight 1: We are now the Knights who say... "Ekki-Ekki-Ekki-Ekki-PTANG. Zoom-Boing. Z'nourrwringmm.

bernbrue

Re: [BUILD] STA LEVEL PCB OFFICIAL BUILD & HELP THREAD
« Reply #405 on: February 05, 2019, 03:27:08 PM »
Yes  :)
Bernd

madreza

Re: [BUILD] STA LEVEL PCB OFFICIAL BUILD & HELP THREAD
« Reply #406 on: February 09, 2019, 01:16:27 PM »
One more question. When the VUmeter shows -20dB GR , does the track s volume should be -20dB lower ?  Or we should have more level as we push the input gain to make it compress more ?
( is my question clear ? In my head it is 😃)
Knight 1: We are now no longer the Knights who say Ni.
Knight 2: NI.
Other Knights: Shh...
Knight 1: We are now the Knights who say... "Ekki-Ekki-Ekki-Ekki-PTANG. Zoom-Boing. Z'nourrwringmm.

bernbrue

Re: [BUILD] STA LEVEL PCB OFFICIAL BUILD & HELP THREAD
« Reply #407 on: February 09, 2019, 02:20:43 PM »

madreza

Re: [BUILD] STA LEVEL PCB OFFICIAL BUILD & HELP THREAD
« Reply #408 on: February 16, 2019, 11:23:04 AM »
Ok , everything is almost fine.
I have the signal thumping when it compresses when in dual or triple mode

It comes for sure from the 6AL5
When I take it out , everything is fine ( except it is not compressing )
Checked the bias voltage : 18.6V

Could that be a bad tube ?
I M pretty sure that at first it was working fine.
Knight 1: We are now no longer the Knights who say Ni.
Knight 2: NI.
Other Knights: Shh...
Knight 1: We are now the Knights who say... "Ekki-Ekki-Ekki-Ekki-PTANG. Zoom-Boing. Z'nourrwringmm.

madreza

Re: [BUILD] STA LEVEL PCB OFFICIAL BUILD & HELP THREAD
« Reply #409 on: February 23, 2019, 12:41:32 PM »
So , tested the tube on a tube tester , and it s in perfect shape.
Knight 1: We are now no longer the Knights who say Ni.
Knight 2: NI.
Other Knights: Shh...
Knight 1: We are now the Knights who say... "Ekki-Ekki-Ekki-Ekki-PTANG. Zoom-Boing. Z'nourrwringmm.


Le Roux

Re: [BUILD] STA LEVEL PCB OFFICIAL BUILD & HELP THREAD
« Reply #410 on: March 01, 2019, 11:52:48 AM »
Is ptfe 20 awg ok for heater wires? Or should 18 awg be used?

Thanks

dmp

Re: [BUILD] STA LEVEL PCB OFFICIAL BUILD & HELP THREAD
« Reply #411 on: March 01, 2019, 02:28:10 PM »
Is ptfe 20 awg ok for heater wires? Or should 18 awg be used?
Thanks

Add up how much current is going through the wire than look up the resistance / temperature rise for different AWG.
The current is calculated by the heater current required by each tube (check the datasheets)
I would use thick enough wire that you do not have much resistance / temperature rise.
The resistance is usually spec'd as ohms / length, so the shorter the wire the less overall resistance.


Le Roux

Re: [BUILD] STA LEVEL PCB OFFICIAL BUILD & HELP THREAD
« Reply #412 on: March 03, 2019, 04:42:11 PM »
I have no idea how to wire the bypass switch that came from Steve.
Is it just the extra gang goes to the output?
Anyone?

Also, jumpers on the relay board.
Do I jump all three?
Using the 5V as I’m using sowters

Thank
Neil
« Last Edit: March 04, 2019, 10:51:03 AM by Le Roux »

pzjones

Re: [BUILD] STA LEVEL PCB OFFICIAL BUILD & HELP THREAD
« Reply #413 on: March 08, 2019, 01:21:33 PM »
Hi This is a pic of my bypass board. Hope it helps.

Le Roux

Re: [BUILD] STA LEVEL PCB OFFICIAL BUILD & HELP THREAD
« Reply #414 on: March 09, 2019, 02:55:55 PM »
Helped me! 🙂

Thanks
Neil

Le Roux

Re: [BUILD] STA LEVEL PCB OFFICIAL BUILD & HELP THREAD
« Reply #415 on: March 17, 2019, 01:17:11 PM »
Hello all

This is where I am stuck at the moment.
Those special pots that was included in Steve's groupbuy.

Any help with wiring??  ;D

The input pot has a push/pull switch for the two terminals on the end. Not sure where they go?
I believe they're supposed to be a bypass.

The output pot, do we connect all 3 terminals together and wire the same?

Thanks
Neil

pzjones

Re: [BUILD] STA LEVEL PCB OFFICIAL BUILD & HELP THREAD
« Reply #416 on: March 17, 2019, 03:27:17 PM »
Hi Neal. If you look at the photo of my bypass board you will see the black and yellow wires that form the switch that opens or closes the 5v supply to the relays. One leg is taken to the switch terminals on the rear of the dual pot switch on the front panel this provides switching for the 5v relay power. I can send you some more pics if you need more help.

Cheers Paul


Le Roux

Re: [BUILD] STA LEVEL PCB OFFICIAL BUILD & HELP THREAD
« Reply #417 on: March 17, 2019, 08:06:35 PM »
I get it!

Thanks Paul   :D

Cheers
Neil