D-AOC PCBs - the building and help Thread

[radiance]

[quote author="Jim50hertz"]Hi Volker

In order to insulate the regs from the heatsink, what would one use?

Thanks

Jim[/quote]

RS components # 298-443

 

[Jim50hertz]

Thanks guys! :thumb:

 

[mikeyB]

Volker
Just had a email with Tat - any plans to incorperate super sidechain into design - this could then be included in tats new case.

And everyone
Regarding mains transformer - it may be worth the forum coming up with a "universal" transormer for valve projects eg 0-7 0-7 at x current for heaters and y volts at y current for HT. May be worth considering winding for 48V also. Extra windings for solid state sidechains etc would be nice but i think it gets "too" custom. If enough people are intersted, we could start getting some bulk pricing to drive cost down.
Any thoughts :?:

 

[[silent:arts]]

[quote author="mikeyB"]Volker
Just had a email with Tat - any plans to incorperate super sidechain into design - this could then be included in tats new case.[/quote]
no plans to change the PCB in any way :grin:
if you want options you can mount a switch for different slopes

 

[Purusha]

Volker, so it's possible to add a few caps on the rotary to replace the slope cap on the PCB?

 

[user 10827]

Im really not understanding this concept of different colour leds for compression curves?

im under the impression that the vatorol has the led and LDR built into it??

so when you are talking about blue leds and red leds what exactly do you mean?

very interested to know because it sounds like some thing id like to implement on mine..

best

Pete

 

[[silent:arts]]

[quote author="sinestaraudio"]
im under the impression that the vatorol has the led and LDR built into it??

so when you are talking about blue leds and red leds what exactly do you mean?[/quote]

Tomorrow I should have a little time to do a post with pictures and measurements about this.

 

[bernbrue]

Hi,
well, here are a few sound samples of a vocal ad lib recording, 1st one is as recorded, 2nd one compressed with the D-AOC. Furthermore the resulting waveforms can be seen here. The 16 year old female singer is one of my pupils, recorded at school with AT4033 Mic and Yamaha 01V96 Mixer. No further treatment. Happy listening.

Waveforms:

http://groupdiy.silentarts.net/D-AOC/dependonyouadlibs.JPG

and the samples:

http://groupdiy.silentarts.net/D-AOC/dependonyouadlibs.wav
http://groupdiy.silentarts.net/D-AOC/dependonyouadlibsDAOC.wav

regards
Bernd

 

[user 10827]

[quote author="[silent:arts]"][quote author="sinestaraudio"]
im under the impression that the vatorol has the led and LDR built into it??

so when you are talking about blue leds and red leds what exactly do you mean?[/quote]

Tomorrow I should have a little time to do a post with pictures and measurements about this.[/quote]

that would be lovely, look fwd to that.

best

Pete

 

[Purusha]

Sounds like a very nice opto too me. Thank you Bernd for the samples. :thumb:

 

[[silent:arts]]

MODDING THE SLOPES (& THRESHOLD)

a short story:

after building the first prototype I had a one (self made) problem:
I thought it doesn't compress. passed audio and measured well, but it just didn't want to compress. mhm.

I put in a (red) LED, paralleled to the Vactrol LED (to watch if it will light - since I was able to measure Audio at that point). There was no light, but - compression.

I emailed analag, kubi and viitalahde (since Jakkoo has a running build), and did some experiments while waiting for answers.

today I did some more measuring for this post:

test conditions:
Input 100%, Threshold 100%, Output adjusted for 0 dB Gain without compression.
(= this is although the minimum threshold before compression)

again, sockets were used paralleled to the Vactrol LED:

(blue LED antiparallel in this test)

at first:
analags circuit is working as is. my self made problem was the input level.
I tested with my nominal level of +6 dBu, and with the Input and Threshold full open: no compression. (rowan and jakkoo seams to like / have HIGH levels).

result:
with LEDs or Resistors paralleled to the Vactrol LED, you can mod the D-AOC for different slopes, and lower Threshold. use sockets to test what you like best, or if you want to be crazy: use a switch.

 

[user 10827]

fantastic!

very interesting, i might just do this...

what is anti parallel by the way?

thanks! genius!

 

[MartyMart]

[quote author="sinestaraudio"]fantastic!

very interesting, i might just do this...

what is anti parallel by the way?

thanks! genius![/quote]

+ to - and - to + parallel would be + to + and - to -

MM.

 

[user 10827]

i thought as much, when i really thought about what i was asking, there is only so much you can do with two connections!

 

[TomWaterman]

The mods look cool, will definitely try them out on a switch.

Happy accident as they say.

Why was it not compressing much with the input gain at max...there is a lot of range on the threshold control no? Why not just drop it? Was that a +6dBu input signal?

Is the input control purely an attenuator or does it have gain too?
Sorry haven't downloaded the schemo yet.

Cheers T

 

[Denyle Guitars]

Hmm, I think I go crazy and try a 100k pot with a blue led anti-paralleled across two lugs.

Thanks for the detailed explanation.

 

[Purusha]

Hm, maybe I should include some of this craziness in my front panel case design :grin:

 

[TomWaterman]

Just had a quick butchers at the schemo...

Input level is purely an attenuator at the input of the first tube grid.
But either I'm going mad or it is AFTER the gain reduction vactrol potential divider...hmm

-T

 

[[silent:arts]]

[quote author="TomWaterman"]Why was it not compressing much with the input gain at max...there is a lot of range on the threshold control no? Why not just drop it? Was that a +6dBu input signal?[/quote]
would be better to label it "compression" instead of "threshold".
with the compression potentiometer at 100% you have the lowest threshold, there is no compression at 0%.

Input Level at 100% and "compression" at 100% is the lowest threshold, without any mods compression will slowly start at an input level of +12.5 dBu.

[quote author="TomWaterman"]Input level is purely an attenuator at the input of the first tube grid.
But either I'm going mad or it is AFTER the gain reduction vactrol potential divider...hmm[/quote]
you are not going mad, you are right. and the "compression" control is after the Input level control :green:

 

[crisotop]

without any mods compression will slowly start at an input level of +12.5 dBu.

Any chance to lower the threshold (or the point where compression kicks in) without changing the compression slope? +12dBu is on the high side if you're working with a digital system.

thanks
christoph