Dual La2a - [silent:arts] version

[[silent:arts]]

since Frau Müller doesn't mark the beginning and end of secondary windings you have to measure it

sorry, I'm wrong. I've mistaken the two Heater windings with the 250V windings
(I measured the heaters to have them in phase, but this is not necessary)

just wire it like this:

[waldorfcave]

gracias amigo

[waldorfcave]

...so i just started wireing the unit, and i have some questions for the hook up of the switches and pots

- the "LIMIT/COMP" switch when it is open Comp or Limit

- the "GAIN RED" is this the switch for the vu-meter mode
when it is open displays the vu Output or Gain Red

- How should i connect the PeakReduction and GainPot

love LArs

[[silent:arts]]

- "LIMIT/COMP": open = limit, closed = comp. haven't used it yet, and haven't seen much difference in the compression curve while meassuring

- "GAIN RED" is the gain reduction meter output. there is aother 2pole Molex next to the output cap behind the relay. this is the VU output. wire both to a 2pole switch, go from the switch to the VU Meters and don't forget to put one 3K9 resistor before the meter.

the gain and peak reduction potentiometers are connected one to one.
pin 1 on the Molex is GND, as it is at the potentiometer.

[[silent:arts]]

and if you use sowter output transformers:

I have had problems with gain over "7" (may be this grid stopper thing), but I changed the gain pot to a 22K log in series with a 75K resistor to get an easier to adjust gain range (still 26dB gain - enough for a compressor / limiter).

[waldorfcave]

...fuck my tube are not lightning

i have no heater voltage. the trafo brings 7 AC but somewhere it disapeares.

the neon lamp shines

[waldorfcave]

maybe i´m stupid but the heater voltage goes after the 100r resistors straight to ground?

can someone tell me where i can measure the next spot where the hv is?

[[silent:arts]]

Yes, the heater goes to ground via the 100r (but you used the holes right after the terminal block, before the 100r resistors ?)
or wait, maybe you did not know you have to wire the heaters like in Drips v1 ?

should look something like this, or better (the silicon cable I used is not good drilled together:


Take the tubes out and measure each heater terminal block input to ground if you actually have 100r. the PCB Billex made for me had a short at one side to ground (I checked the PCB Bernd send me for this, and it was right - but you never know).
[edit: with no power transformer connected of course]

the neon lamp is on the HV rail, if it shines it has more than 65V - that's good.

the best place to measure the HV (High Voltage) is the left side (looking from the front) of R129 or R229.

[bernbrue]

Hi,
Heater voltage is AC and after a closer look to the solder side of the pcb it seems, that the heaters (H1L, H2L, H1R, H2R) have to be wired by hand. Is that right Volker?
regards
Bernd

[bernbrue]

Volker, you are too fast

[waldorfcave]

damm, sure now erverything is clear

[[silent:arts]]

I hate this undocumented projects

[waldorfcave]

yes volker you are the man

after all my questions this projekt is very well documented


thx

[waldorfcave]

ok...this thing is running and compressing.

gain ratio have to be tuned like volker said (i use sowters) i do it later....

one problem is, that my unit hums a bit. more then it is ok for me

it comes not from the powertransformer, i can move it from side to side and nothing happens.

maybe the ac heaters under the pcb?

i have measured the heater against ground, and i only have around 60 ohms
resistance between ground, but volker said it have to 100R?

maybe this is the fault?

maybe someone has an idea where to look first....

i will try and try

[[silent:arts]]

mhm, no hum here.
is it on both channels ?
can you do a photo of your ground pattern ?