D-AOC PCBs - the building and help Thread

[Hank Dussen]

Cinemags are good.
So are the Hairball meters. There are lots of VU meters around. As I believe you live in the US (you should add this to your profile) maybe some US guys can point you to some cheap VU-meters.

About the switches: you only need 1 pole but Uraltone doesn't make these so 2 pole will of course do.
The ones in your link already have the resistors soldered, which is easy but these are 100k log and you also need 500k log. So you'll have to buy 'empy' ones and calculate the resistors. There's a spreadsheet here somewhere for that.
BTW you can mod the switches so they have a stop: http://www.groupdiy.com/index.php?topic=40384.msg499957#msg499957

 

[jsefer]

Cinemags are good.
So are the Hairball meters. There are lots of VU meters around. As I believe you live in the US (you should add this to your profile) maybe some US guys can point you to some cheap VU-meters.

About the switches: you only need 1 pole but Uraltone doesn't make these so 2 pole will of course do.
The ones in your link already have the resistors soldered, which is easy but these are 100k log and you also need 500k log. So you'll have to buy 'empy' ones and calculate the resistors. There's a spreadsheet here somewhere for that.
BTW you can mod the switches so they have a stop: http://www.groupdiy.com/index.php?topic=40384.msg499957#msg499957

Thanks, I belive that it is added to my profile  8) Will definitely look into these switches, the guy on ebay has 100 and 500k available, thanks for your time, and yeah, at this point, my last milestone is selecting a decent VU meter that works with out much messing around.

 

[Script]

I ordered Mullards for my d-aoc, can't wait to get 'm in and find out if it really makes a difference.  ;D

Have the Mullard Buizen arrived already? Can't wait to hear about your impression.

 

[trancedental]

Just wondering which ECC82 / 12AU7 is used in the sidechain, a quick look at the schematic suggests the socket nearest the vactrols / meter terminals at the front of the PCB. I'm short of a pair & I'm assuming that the sidechain valves are not in the audio signal chain so don't need to be the best quality super expensive ones available?

Powered up the build for the first time with 4 very old knackered Mullard valves fitted & the voltage readings seem fine, I've got 249DC without the two other valves installed which seems within range, heaters are OK.

Just need to get another pair of ECC82's to finish this off & I'm short of one Sifam meter since one of my pair doesn't seem to work anymore!!!! :

 

[dagoose]

I ordered Mullards for my d-aoc, can't wait to get 'm in and find out if it really makes a difference.  ;D

Have the Mullard Buizen arrived already? Can't wait to hear about your impression.

Yes they have and i must say that it makes a subtle yet noticaeble difference.
It just sounds a bit more 'pro' now, can't give it another description. I'm happy with it!

 

[jsefer]

Im building an all telefunken unit, w ecc801s and 802s, will post up my impressions when its done.  ;D

 

[jsefer]

Can anyone confirm the height of the build, I see alot of 2U unit but I want to confirm it will fit in the case that im purchasing... 87.1MM (3.4") is the height of the 2U case that Im purchasing.. Is this enough clearance??

 

[jsefer]

Where did you get the illuminated power switch!!!

Finally had time to finish the late Christmas present i made myself, wanted to make it look fancy for my first Tube project, i think that's mission acomplished, but don't know if i'll do on my next build tough  :. Had some tiny issues but all is good.
I got to thank Volker and Analag for the project, Franck @NRG for all the panel work Danke Schoën to you guys i'll have an Augustiner on this one, PROST!
Also like to thank Mad.Ax for his help and clarifications (merci monsieur) and all of you guys here for the inspiration and help also, without the forum i wouldn't even have tought about all this.

On quick sound check, i was pleased by the sound and compression, i'll use it as is for some time and tweak on taste, i just have a low HT when all tubes are in 188V at R128  ???, but all works as expected, all matched as possible etc....

 

[zayance]

Where did you get the illuminated power switch!!!

http://fr.farnell.com/marquardt/1555-3102/rocker-switch-red-dp-150/dp/1831119

 

[Holger]

Can anyone confirm the height of the build, I see alot of 2U unit but I want to confirm it will fit in the case that im purchasing... 87.1MM (3.4") is the height of the 2U case that Im purchasing.. Is this enough clearance??

Yes, that should work.

 

[trancedental]

Can anyone confirm the height of the build, I see alot of 2U unit but I want to confirm it will fit in the case that im purchasing... 87.1MM (3.4") is the height of the 2U case that Im purchasing.. Is this enough clearance??

Yes, that should work.

The underneath of the pcb to the top of the valves is about 70mm on my build so add the length of the spacers & clearance  above the valves & compare to the inside height of your case. Some 2U cases are deeper inside than others

 

[ilfungo]

Lundahl LL1521
Can work as input?
Thanks

 

[jsefer]

Im going to put all the curve mods on a pcb, and hook up a 1p 8 position rotary switch to have a curve selection going from soft to hard...

I figure putting a 1k trimmer on each will allow me to really fine tune the curves so they are exactly the same on both channels.. Extra work but worth it in my case.


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

Please correct me if Im wrong, Im trying to determine the order of the softest to hardest curves, my guess is:
1. No Mods
2. Blue Led Parallel
3.Red Led Parallel
4. 100k resistor
5.1k. resistor
6.Blue Led Anti
7. Kubi Mod

Quoting Zayance "EDIT: I went for Blue//; 1K ; 100K ; Blue anti// ; Red anti//, that is what it seems to be for now, going from Soft to Hard." Im just a dummy and I dont see how this works out... Please some one educate me..

Thanks

 

[jsefer]

Can anyone confirm the height of the build, I see alot of 2U unit but I want to confirm it will fit in the case that im purchasing... 87.1MM (3.4") is the height of the 2U case that Im purchasing.. Is this enough clearance??

Yes, that should work.

The underneath of the pcb to the top of the valves is about 70mm on my build so add the length of the spacers & clearance  above the valves & compare to the inside height of your case. Some 2U cases are deeper inside than others

Great thanks guys for the quick reply

 

[zayance]

Quoting Zayance "EDIT: I went for Blue//; 1K ; 100K ; Blue anti// ; Red anti//, that is what it seems to be for now, going from Soft to Hard." Im just a dummy and I dont see how this works out... Please some one educate me..

You mean for the wiring?

Well lets say if you were using only two selections, red anti and Blue//, you would use a DPDT switch right?
Two pole because a LED has two poles,  + and  -.
So if you use a rotary switch, mine was a 2x6 Lorlin, wich means a 2 pole 6 throw, then you wire
+and - of the Vactrol LED side to the poles of the Switch, and solder the LED poles according to the rotary switch, and the the // or anti// you want.
This combination i think it achieves a half wave rectifier i guess, i actually wanted to try with a full wave rectifier there, but didn't bothered the mod.

BTW, this is not my approach of it, members of this forum have tought about that way before i did it.

 

[jsefer]

Quoting Zayance "EDIT: I went for Blue//; 1K ; 100K ; Blue anti// ; Red anti//, that is what it seems to be for now, going from Soft to Hard." Im just a dummy and I dont see how this works out... Please some one educate me..

You mean for the wiring?

Well lets say if you were using only two selections, red anti and Blue//, you would use a DPDT switch right?
Two pole because a LED has two poles,  + and  -.
So if you use a rotary switch, mine was a 2x6 Lorlin, wich means a 2 pole 6 throw, then you wire
+and - of the Vactrol LED side to the poles of the Switch, and solder the LED poles according to the rotary switch, and the the // or anti// you want.
This combination i think it achieves a half wave rectifier i guess, i actually wanted to try with a full wave rectifier there, but didn't bothered the mod.

BTW, this is not my approach of it, members of this forum have tought about that way before i did it.

Thanks for the reply, Im not confused about how to wire the Mods, I was looking for some input on the sequence of the mods to go from soft to hard.... I want to wire it so that the 8 position switch selects from soft to hard, so I want to know from the curves in the example wich comes first and wich comes last...

 

[zayance]

Well not much calculations there, it's audio so i used my ears, and i found that going with my quote was what was acting as more Soft to Hard, and that even red anti is actually harder than Blue anti, depends on diode used also i guess...
I actually first went with Silent arts curve, and it was not acting right so....
It's the beginning of the Curve that is more noticeable to the ears, and to the reaction of the compression (attack)
Best to know is to try it out, and hear for yourself.

 

[dagoose]

Quoting Zayance "EDIT: I went for Blue//; 1K ; 100K ; Blue anti// ; Red anti//, that is what it seems to be for now, going from Soft to Hard." Im just a dummy and I dont see how this works out... Please some one educate me..

You mean for the wiring?

Well lets say if you were using only two selections, red anti and Blue//, you would use a DPDT switch right?
Two pole because a LED has two poles,  + and  -.
So if you use a rotary switch, mine was a 2x6 Lorlin, wich means a 2 pole 6 throw, then you wire
+and - of the Vactrol LED side to the poles of the Switch, and solder the LED poles according to the rotary switch, and the the // or anti// you want.
This combination i think it achieves a half wave rectifier i guess, i actually wanted to try with a full wave rectifier there, but didn't bothered the mod.

BTW, this is not my approach of it, members of this forum have tought about that way before i did it.

I think that for disconnecting the second vactrol for the standard mode the only thing you have to do is disconnect the led on one side. I think it doesn't matter which side but the leg going to ground might be the easiest thing to do. Am i correct? 

 

[Blue Jinn]

Finally i finishing my D-AOC !!
posting some picture , the only problem is the gain reduction metering when the unit is set on link mode.
one channel seems to compress more than the other one
if someone solving this problem please let me know
Many thanks to Silent Art ,Kubi and all the people of this fantastic forum !!
Thank you all
Fabio

Did you use Schaefer for the frontpanel? Would you mind sharing the fpd file if so? That is a nice looking build.

 

[jsefer]

Build update.. coming along nicely, waiting for vu, edcor power, and cinemags for i/o