Whistle Rock Audio ML12 preamp BUILD/HELP thread!

[Chris-audio.com]

Can anyone please tell me which power transformer to hook up to the ML12 PSU? 110in 24 out? Not really sure and want to try purchase the correct thing. thank you so much.

 

[TillM]

Look in the thread there was also discuss some options.

 

[Rocinante]

If you go to mouser, and look up a avel 24v toroidal you'll get one of the ones you need listed. Probably want 25va too depending on how many Mic preamps you are powering.

 

[dp]

Thinking about building a couple of these.

Question about power transformer... this will work or is 50VA overkill?

http://www.antekinc.com/as-0518-50va-18v-transformer/

I have used Antek power supplies for some tube guitar amp builds in the past and have been happy with the results. That 50VA is only $17.50! A 25VA 20V transformer is also available for only $11.

Also, sort of related... could the ML12 PSU PCB be used for the EZ1290 project as well? Like, if I made an external PSU could I use that one PSU to power both projects?

Thanks all.

 

[TillM]

Yes this will work.
But also 30va should work.
Maybe also 25va, but I’m not sure.
The ML12PSU would work with the ez1290, but you can’t take it with the ML12.
Only if you also use your ML12 with 24v rail instead of 16v.
But then you have to look, that your DOAs can take 24v.

 

[dp]

OK Cool. Thanks TillM.

 

[dp]

I have a couple 2U donor rack chassis, so if I start small I want to be able to upgrade them down the road. Looking a little deeper at the thread here, it looks like maybe this is the general rule-of-thumb?

2x18V with 10VA current per preamp?

 

[dp]

Yes this will work.
But also 30va should work.
Maybe also 25va, but I’m not sure.
The ML12PSU would work with the ez1290, but you can’t take it with the ML12.
Only if you also use your ML12 with 24v rail instead of 16v.
But then you have to look, that your DOAs can take 24v.

Couldn't I use set up rails 1 & 2 to +/-16V and rail 3 to 24V to use both ML12's and the EZ1290 with just one ML12 PSU?

I have seen the JLM and Five Fish PSU kits but I can source the parts and P.T. for a lot cheaper if use the Antek power transformer. Are there any other good alternatives?

 

[TillM]

then you will need a extra rail for the phantom power +48v rail.

 

[dp]

I'm sorry I thought I posted a reply about this earlier... I must not have hit submit.

But, I emailed DIYRE last week and asked... and yes just as I suspected what I propose will work just fine with that Antek 18V/50VA PT... two channels of the ML12 and two channels of the EZ1290 pres, building them one at a time as I get the funds.

It's a 4-rail supply. Rails 1&2 are +/- adjustable, rail 3 is adjustable, and rail 4 is fixed at +48V for phantom power.

https://www.diyrecordingequipment.com/collections/parts/products/ml12-psu-power-supply-pcb

So, the ML12 PSU PCB would be a great option for those who would like to do a mix of different preamps in the same enclosure. 

 

[TillM]

it has 4 rails !
thanks for letting me know, then I've to check again, how I wired it up.

 

[dp]

What do you guys think of this for an external PSU enclosure for the ML12 PSU board? Should work fine with a torroidial transformer for 4 channels? It's only $21.39...

https://www.circuitspecialists.com/metal-instrument-enclosure-la-6.html

 

[TillM]

yes this will definitely work

 

[dp]

yes this will definitely work

Nice. Thanks. That's less than half the price of the Hammond recommended box from the BOM!

I'm getting all my BOMs in order for an external ML12 PSU and one channel ez1290 in a 2U rack chassis with plans to first add an ML12 pre and then add 2nd of each down the road.

 

[computerlen]

The page is not found-comes up.

 

[Whoops]

What happened to the Whistle Rock website?

 

[Bobby Baird]

6 channel. Front panel mock up. Hope to build this soon!

 

[TillM]

Be careful if you want to use the t pad from Capi or Hairball.
But if you use the front I uploaded (it seems like), then it will work

 

[redear]

Hey folks. So sorta a longer story here.
I’ll star with this, I’ve been doing a lot of reading and so I think my idea will work, but would like to run it by someone to make sure.
So I purchased a home made set of 4 preamps, I got it for a great deal and so in that sense I am not unhappy, however, as they are right now I just don’t use them.
They have Jensen JA-16-a input transformers and use the Millennia MM990 op amps. Both of which can be seen in the photos I hope to include.
However. When built I think they were intended to be used in VERY loud situations and that is simply not how I work.
In stead of chasing down the circuit with no schematic, I sorta thought I might be better off buying 4 PCBs, some output transformers and making something I can use.
So, is there a reason I should not use this IT and DOA combo in this circuit, and what changes would be needed to the BOM?
Thanks in advance.

P. S. It came with a power supply but it’s noisy (like it hums) so i will be building a new one of those too...

 

[Whoops]

When built I think they were intended to be used in VERY loud situations

Why do you think that?
Whats the problem? you gave no information

It came with a power supply but it’s noisy (like it hums) so i will be building a new one of those too...

The hum can be from a lot of different places and reasons.
Why do you think the PSU is noisy?

Hum can be from a bad ground connection, or a ground loop.
Hum can be also electromagnetic interference from the Power transformer,
it's better to understand first wheres the source for the noise, your PSU might be totally fine


I think you should probably do a seperate thread for your problems and for what you want to accomplish as this thread is for the "Whistle Rock Audio ML12 preamp" project only