D-AOC PCBs - the building and help Thread

[Soeren_DK]

? ??? ???

 

[ilfungo]

"3) (Forrsell only and unconfirmed, as it seems someone suggested raising the 4.99k and 1k resistors (series and shunt) to 49k and 10k before the opto's resistor (here in series, see schamatic) to reduce difference between individual optos. ."


Ciao Silent:art
do you think can help me to better match the opto?
can create problems forD-AOC?
Thanks

 

[[silent:arts]]

Gentlemen,

note: I'm neither the designer of the circuit nor the designer of the mods, I only did the PCB.
but I'm sure the designer of the circuit (analag) and who did the mods (kubi) know what they do ;D

1. Does it mean that if I install 2 vactrols more I don't need to increase the Cx04?

loads of people didn't increase Cx04 and are happy

2. Do I need to compare vactrols?

good luck

3. Can I use the Lundahl LL5402 as output trafo?

haven't tried one, but why not?

"3) (Forrsell only and unconfirmed, as it seems someone suggested raising the 4.99k and 1k resistors (series and shunt) to 49k and 10k before the opto's resistor (here in series, see schamatic) to reduce difference between individual optos. ."


Ciao Silent:art
do you think can help me to better match the opto?
can create problems forD-AOC?

I would leave all resistors like they are. even kubi didn't any change there 

optos and stereo tracking (this is LA2A related, but it is opto too):

[quote author="hejsan"]Have you checked if the matching is satisfactory? Did you somehow match the t4b's?

I didn't match the T4b's (since I only have two of them :green: )
but I matched all resistors for both channels.
the tracking is fine - oddly better without the stereo link switched in :? , but still within 1dB.
the gain reduction Metering doesn't track fine, but who cares ...[/quote]

hope this helps ;D

 

[dingo]

Hello!
here some picture my D-AOC finished!!
with lundahl 5402  on input and output like gyraf pultec  configuration
meters from old pioneer rt1100 modified with orange led and channel led
sounds great  !!!!!   meters not tracking well on gain reduction
on input a little  v-u meter buffer like jlm
little fan for air flow  

 

[ilfungo]

Great!!!!
Soft - Hard ?

 

[dingo]

ciao il Fungo!!
yes soft compression with valtec +blu led  no more 3 db gain reduction full open
hard comp. with valtec+blu led+valtec reverse more than 20db gain reduction full open
un saluto!
dingo.

 

[Script]

Hey, thanks for the pics. Looks great

 

[ilfungo]

thaks Dingo grazie!!!

 

[Soeren_DK]

Thanks for the answers... 

@dingo

Did you wire the Output trafo in 2:1 ratio? Should it be 4:1 instead?

Cheers
Søren

 

[dingo]

hello SOEREN!

I have wired the in and out trafo like in the gyraf pulteq eq
sound great  no bass lost
i am not using r 10k on input trafo and 2,2k on out trafo for the moment
i am not shure how effective  they are?
maybe someone can help  on  the resistors utility ?
dingo.

 

[lolo-m]

hello SOEREN!

I have wired the in and out trafo like in the gyraf pulteq eq
sound great  no bass lost
i am not using r 10k on input trafo and 2,2k on out trafo for the moment
i am not shure how effective  they are?
maybe someone can help  on   the resistors utility ?
dingo.

The resistors are used to fix the load on the opposite side of the transfo... The 10k fix a minimum load of 600 (if wired 1:4) on the input. As you may plug your gear to a 10k load, the 2k2 fix the proper load on the tube side. If not the reflected load of the tube would be 40k. It's not a real problem but some tube arrangements are sensible to that kind of load changes...
I hope I'm clear because I'm really tired  :-\.

 

[[silent:arts]]

dingo, very nice build - and I like your added features

 

[dingo]

thank you!!!
really like the banner 

hello SOEREN!

I have wired the in and out trafo like in the gyraf pulteq eq
sound great  no bass lost
i am not using r 10k on input trafo and 2,2k on out trafo for the moment
i am not shure how effective  they are?
maybe someone can help  on  the resistors utility ?
dingo.

The resistors are used to fix the load on the opposite side of the transfo... The 10k fix a minimum load of 600 (if wired 1:4) on the input. As you may plug your gear to a 10k load, the 2k2 fix the proper load on the tube side. If not the reflected load of the tube would be 40k. It's not a real problem but some tube arrangements are sensible to that kind of load changes...
I hope I'm clear because I'm really tired  :-\.

thanks for the resistor info!!
i would try the resistors and check if there some difference on sound!!

 

[Soeren_DK]

hello SOEREN!

I have wired the in and out trafo like in the gyraf pulteq eq
sound great  no bass lost
i am not using r 10k on input trafo and 2,2k on out trafo for the moment
i am not shure how effective  they are?
maybe someone can help  on   the resistors utility ?
dingo.

The resistors are used to fix the load on the opposite side of the transfo... The 10k fix a minimum load of 600 (if wired 1:4) on the input. As you may plug your gear to a 10k load, the 2k2 fix the proper load on the tube side. If not the reflected load of the tube would be 40k. It's not a real problem but some tube arrangements are sensible to that kind of load changes...
I hope I'm clear because I'm really tired  :-\.

Where should the resistor be placed for the output trafo? Should I change a resistor on the board or is it something to add directly on the 5402 trafo?

Cheers
Søren

 

[lolo-m]

Where should the resistor be placed for the output trafo? Should I change a resistor on the board or is it something to add directly on the 5402 trafo?

Cheers
Søren

For the output transfo there is 2 options :
10K on the tube side
OR
600 on the output side

But the designer didn't put any. I would bet it is worthless  :...

PS: The input doesn't need any resistor addition as it is already on the PCB .

 

[flintan]

Could someone confirm to a colorblind that the one with dual vactrols is the most sensitive curve in this plot?  :-\

http://www.silentarts.de/DIY/D-AOC/KubiMod.GIF

 

[MartyMart]

Could someone confirm to a colorblind that the one with dual vactrols is the most sensitive curve in this plot?  :-\

http://www.silentarts.de/DIY/D-AOC/KubiMod.GIF

Kubi mod is indeed the lowest curve in the plot ( would be a dark green )

MM

 

[flintan]

Thanks! I thought it was some kind of brown :-\ Have problem with green, brown and red..

 

[flintan]

Re matching of vactrols. Wouldn't that be rather easy if you set up a test jig with a couple different voltages and then just measure the resistance at each setting. This would not take attack/release time into account but will hopefully make for a lot better matc than 25% re diode current and photoresistor sensitivity. The downside is you have to buy lots of vactrols but on the other hand, they would be quite easy to sell here.

What do you think? I'll finish my compressor (have some minor adjustments) and see if i get lucky or not re stereo tracking. If not i'll try to match vactrols.

 

[babyhead]

I wonder if any sockets could be mounted on the PCB for the vactrols. A DAOC with a matching jig...

Maybe 2 SIP sockets with trimming?