D-AOC PCBs - the building and help Thread

[jbvdwal]

First post here!

One that was built for me, gave the ghost some time ago, but its probably also cause R1 isnt looking all to healthy? haha

Right channel gives slight signal albeit not effected by in/out and compression, left side nothing.

I'll probably give it out to pieter kloos from void studio to fix, just wanted to see opinions on this here first.

 

[Hobbyist]

First post here!

One that was built for me, gave the ghost some time ago, but its probably also cause R1 isnt looking all to healthy? haha

Right channel gives slight signal albeit not effected by in/out and compression, left side nothing.

I'll probably give it out to pieter kloos from void studio to fix, just wanted to see opinions on this here first.

Welcome jbvdwal,

Doesn't look so good.. In most cases i've seen here, that resistor gets very hot. You should connect at least a 10 watt resistor away from the board. That helped for me. It has been explained here before as well.

Cheers

 

[Potato Cakes]

Hello, Everyone,

I have a stuffed board that has been sitting in a box for some time and soon I would like to complete it. I still haven't determined which transformers to use and wanted to see if of those who have built these with the intent on using it for mastering applications could share your findings regarding transformer preference in this circuit.

Thanks!

Paul

 

[Hobbyist]

Hello, Everyone,

I have a stuffed board that has been sitting in a box for some time and soon I would like to complete it. I still haven't determined which transformers to use and wanted to see if of those who have built these with the intent on using it for mastering applications could share your findings regarding transformer preference in this circuit.

Thanks!

Paul

I'm very happy with 4x Lundahl LL1540 in my unit 

Cheers

 

[Neko Neko]

So i've had my DAOC up and running for about a year now. Absolutely love it and it had been a joy when mastering. Also my first valve build but very nice to build. Did the threshold mods and kubi mods except dual vactrol.

Just a few loose ends to sort out and could do with a bit of help.

1. Heat - This might just be me but this thing kicks out a lot of heat. The power transformer (Dual G pultec toroidal one from don audio ) gets warm to the touch, including the mounting bolt. I am using a separate one for the relays and meter lights. The regulators are all ok to touch and mounted to the chassis. The 6.3v one gets a bit warm over time but is using the back panel for dispersion. I have made vent holes in top but that hasn't helped that much. 

Now is this normal or should i be worried? I expect quite a bit of heat for the 6 valves but the power transformer feels like a red flag for me.

2. Hum - There is a low hum with no signal passing through. The hum is inaudible when the compressor is being used but i would like to reduce it further if possible. I have used following star ground scheme, relay gnd, XLR pin 1 and chassis tab, main pcb gnd and  IEC earth all go to one point near the IEC inlet. This normally setup works great for me. 

I have the mains power switch in the centre of the front panel and the wiring runs close to the main pcb and wiring. I've tried to separate as much as possible but i wonder if this is the cause?

3. stereo tracking - Now i'm not to bothered by this but worth a mention. Both channels can be set to track ok together without stereo switch engaged. Once the switch is engaged though the right channel will always be 1-3 db behind the left in compression amount.  Anything to be done here or just the way it is?

Any help much appreciated.

Here's some shots before i tidied up the wiring. 8)

 

[Neko Neko]

The guts

 

[Pusch3l]

1. The Toroid meets the Spec from first post?

2. Did you use an Spectrum Analyser where the hum is?

3. Anywhere in the Thread is a Post about replacing Rx26 with a trimpot and add a trimpot to the Vactrols.

Greets

 

[Neko Neko]

Yes the toroid meets the spec unless i've overlooked something.

Primary: 2 x 115v (230v)
Secondarys:
220V 0,1A
9V 2,5A
5V 0,5A

2. The hum is around classic 60Hz.

3. Thanks for this i will give it a try!

 

[Pusch3l]

Since the Toroid is from Aaron it has a mu-metal shielding. Did you try place it flat on the bottom of the case? If that helps nothing i would put an eye onto the Carnhills. Theyre not shielded..
DaveP wrote somehting about Transformer placing  on GDiY.

 

[Neko Neko]

Thanks for all the suggestions everyone.

Didn;t think about the carnhills being unsheilded, space is pretty tight inside so not much room to move them about.

I haven't tried moving the toroid so will give that a try. it is from don Aaron but i'm not sure if its shielded type or not.

I measured the hum on a spectrum analyser.

First one is no signal, interestingly it covers 60-125Hz.

Second one has 1kHz sine passed through and compression happening, as you can see the hum drops a lot and is barely audible, it's still there though.

 

[Neko Neko]

and the 1KHz one...

 

[Silvas]

Hello guys,

Has someone here experimented with alternate, maybe more silent HT PSU's on the D-AOC ? I mean, it is not a noisy unit by any means but in a mastering setup it could use some extra dB's of less noise I've done extra shielding, trafo rotating and such but i wonder if the noisefloor can be further improved by the means of a different PSU. 

 

[rock soderstrom]

Hello guys,

Has someone here experimented with alternate, maybe more silent HT PSU's on the D-AOC ? I mean, it is not a noisy unit by any means but in a mastering setup it could use some extra dB's of less noise I've done extra shielding, trafo rotating and such but i wonder if the noisefloor can be further improved by the means of a different PSU. 

Hi, I do not know your setup but If you really need less PSU noise for mastering I would outhouse the transformer or the whole PSU..

 

[Silvas]

Hello guys,

Has someone here experimented with alternate, maybe more silent HT PSU's on the D-AOC ? I mean, it is not a noisy unit by any means but in a mastering setup it could use some extra dB's of less noise I've done extra shielding, trafo rotating and such but i wonder if the noisefloor can be further improved by the means of a different PSU. 

I just answered my own question and installed a discrete PSU on it., derived from Kingston's  M670 PSU.  Speaking strictly of noise, no difference really. Maybe 1dB lower, measured. Trafos and shielding will have much more impact (i did some mumetal shields a few months ago and reduced a bit the hum). however, i'm curious about how the discrete PSU will affect the overall unit's sound (if it affects it at all).  Will report back after a few months of continuous use Going back to the original PSU is just a couple solder joints away.

 

[[silent:arts]]

Will report back after a few months of continuous use Going back to the original PSU is just a couple solder joints away.

Yes, please report back your findings  8)

 

[dagoose]

After like 8 years, my transformer is dieing. It started with humming (mechanical) but found out that the 9v for the heater is (even unloaded) giving me something like 5v AC and could come up again to 9v afte cooled down.  Not good... I'm a bit worried about the rest of the winding as well, so I was looking for a source for the transformer as a drop in replacement, but it looks as if they are all out of stock.

Anyone with a source for this in the EU?

 

[[silent:arts]]

Greetings to the Müller family, and ask for R2-0060-0016 (or design your own if you want different specs)
http://www.mueller-rondo.com/ansprechpartner.html

 

[dagoose]

Greetings to the Müller family, and ask for R2-0060-0016 (or design your own if you want different specs)
http://www.mueller-rondo.com/ansprechpartner.html

Thanks I wil do that! Any idea how much that transformer is?

 

[[silent:arts]]

No. Bought mine 10 years ago, and it was a higher quantity.

 

[dagoose]

I just ordered it, 38 euro ex vat so a pretty decent price.  8)