Auditronics PSU question

[nacho459]

I just picked up a couple of 110B modules and need to build a PSU.

http://avensonaudio.com/tech/auditronics/audiotronics_110b.pdf

According the schematic it looks like the module wants a +24v and a +/-15v. I also want a +48v for phantom.

Do any of you have a schematic for something like this?

 

[Gus]

The 24V does something with IC3 if I read the schematic correctly.

I would use the ssl tech 9k power supply and use the unregulated side of the +15 part for the 24 V. I would use a a 24 V zener circuit or a 7824. to reg the voltage. I like that circuit I used it in my 2 channel green pre.

Use heatsinks with the 3 term regs.

 

[nacho459]

I searched around here and can't find the schematic you're talking about. I also am a real novice and don't really understand power supplies with voltage doublers and regulators and all that jazz. I just understand basic tube power supplies rectifiers, filter caps and that stuff so please speak slowly and with great detail.

thanks all

 

[Gus]

http://www.studio21.ch/diy/ssl9k/DIY_9k_preamp.pdf

 

[BradAvenson]

You don't need the 24 volt logic supply. Just jumper it to the +15 volt and it will run the led's a bit dimmer. You can also use the solo switche for the phantom power. I racked up a pair and thought they sounded really nice.

 

[JLM Audio]

This power supply will do what you want (+48v, +15v & -15v).

http://www.jlmaudio.com/JLM Power Supply.htm

And yes connecting the +24v terminal to +15v and linking the 24v common to power supply common is all that is needed to run the EQ in, Solo & Channel on LED's. Also remember to change R1 & R2 from 20k to 6.8k to bring the phantom power up to modern specifications.

Joe

 

[nacho459]

So the 24v just powers the LED's? I didn't look at the schematic that close.

Joe how much is shipping to the US? does the $35 kit include the transformer or just the stuff on the PCB? Thanks

 

[JLM Audio]

The kit is just the PCB & PCB parts. Air mail to the USA for one kit is $8USD. AC/DC kit parts list http://www.jlmaudio.com/ACDC Power Supply Kit.txt

Digikey has the transformers you need to drive a couple of these channels. You can use there external wall mount transformer 20vac 800mA MT7170-ND $9.80USD or if you need a case earth use there 20vac 600mA MT7106-ND. These keep the 60Hz AC outside the box so no hum is injected into the audio input transformers and heard at high gain settings.

http://dkc3.digikey.com/PDF/T051/1377.pdf

Or you can use there Mini Toroidal Transformers 22vac - 0v - 22vac 15va or larger. Like TE62055-ND. The toroid needs to be positioned as far away form the audio input transformers as possible.

http://dkc3.digikey.com/PDF/T051/1378.pdf

Joe

www.jlmaudio.com

 

[PRR]

> The 24V does something with...

It only lights the "Channel On" LED. In a huge console, you like to know if channels are killed, and you may be switching channels on/off while "live" in other channels and you don't want to hear LED clicks in the live channels.

So they give you an LED and they give it a separate power-rail.

But for two channels stand-alone, you probably don't want the channel-kill function at all. Find the S-3 position that lets signal through, then bust the knob off of S-3. Or cut-jumper S-3's pins to bypass it. If you like the LED, it can eat 15V power fine. And if you are not switching "live", then clicks in the +15V rail are not a problem. If you don't need the LED, just ignore the 24V connections.

 

[Gus]

trace the 24V line it goes to R51 and R49 when the eq is out? and R51 and the caps of the eq when the eq is in.

 

[JLM Audio]

The thick track shows that it is a common or 0v trace. All commons need to be connected together. So in reality R51 is just the base drive for Q4 and when switched to the common holds the Transistor & LED off. The other half of the switch connected to R49 is the Eq in/out switch which just switches to the common so is completely separate from the 24v rail.

Joe

www.jlmaudio.com

 

[nacho459]

Well, I got Joe's Power supply up and running, and my Par Metal chassis came in the mail yesterday, so now all I have to do is rack 'em up. I'll post pics when I'm done.

I'm also gonna be putting output transformers on these to balance the signal. Any one have any good reason why I shouldn't just save some money and use the JT-11-FLCF? The only difference I see from the $90+ transformers is the THD. I'm not much of a spec guy but is a 0.002 THD worth the extra money? Will the JT-11-FLCF sound like Radio Shack transformers? I mainly do rock so harmonic distortion isn't really something I have ever worried about or really understood.
Please someone enlighten me.

 

[nacho459]

Hello? anybody out there?

 

[Samuel Groner]

JT-11-FLCF is an excellent choice. Remember that the last improvement is always the most expensive one - it's easy to get a transformer from 2% THD down to 0.2%, but not so easy from 0.02% to 0.002%. That's why there is a big price gap.

Even with the cheapest Jensen you have a less colored transformer than many highly priced units.

Samuel

 

[nacho459]

thanks! :guinness: