JLM Baby Animal

[SUPERMAGOO]

hello.

I built the baby animal with dual jlm99v and oep26 works perfect and has only a problem only when the "phamtom" is turned on.
move the gain pot is a sound as if the potentiometer was dirty.
when I disconnect the LED indicator phamtom this problem disappears.
any idea that may be happening?

 

[okgb]

Sounds like DC is getting on to the pot ?
check any coupling caps

 

[SUPERMAGOO]

if.
correct!
Sound is a DC in the potentiometer.
but checked and everything is fine.
I suspect that I am not placing the LED in the right place.
The only thing that is not clear where it goes.

 

[Veseli]

Hi, I'm building two Baby Animal Pres with DI and just have finished and tested the first one.
Both of them are :
JLM 1:4             
JLM 99V                       
JLM 1:1:1   (wired 1:2) 
JLM DI        (new type)            
BA PCB + parts     
JLM PSU  (smaller, 48 volts)

So, I was very careful and triple checked every detail before soldering and mic pre sounds and works great !!!
But when I removed the jumpers and plugged the ribbon cable from DI to it, the DI (and mic pre) doesn't work.
No signal from DI at all, and when I turn the gain to the max I hear sort of sine oscilation like short wave radio.
I checked and replaced the DI with other DI board I also finished and had a same result.
Tryed to turn the ribbon cable other way, no help.
I have put two 220 pF caps in parallel to make variable load but still haven't find the right pot for it, not sure if it has anything to do with this...
Haven't bridged the IC socket pins cause I'm using output transformer...
Haven't test the voltages yet, was impatient to try it and when it worked from the first fire up I thought its not necessary.
DI board doesn't have to be connected to 48 volts separately ? Only through ribbon cable ?
If anyone knows where to look and where to measure please help.

 

[Veseli]

No signal from DI at all...

Finally, its all right.
Joe replied to my email and, from the photo I've sent to him he noticed that I have turned the IDC header the other way on the DI pcb. I have changed that and it works like a charm now.
Great preamps indeed ! My Allen&Heath console pres are nowhere near Baby Animal color, clarity, headroom and presence. I will go for couple of more soon, to build a 12 channels rack for drums recording.
I highly recommend these preamps for home studio recording.

 

[Purusha]

I am glad it works now!

BTW, I would not stop at saying Baby Animal preamps are good for home studio projects but they are good for any studio project  8)


Guys, I am still trying to get some info on how to implement the original Marinair trafos with BAs. Any info on this?

 

[wolfgang]

Hello Purusha!

I think there should be no problem!

Use the right zobel network which is 180pf for the 10468 i think. but i dont know about the right load resistor.
Also the LO1166 has 0,01uf with 1K5 in series across the secondary in the 1073 schematic.

Greetings,
Wolfgang

 

[Veseli]

BTW, I would not stop at saying Baby Animal preamps are good for home studio projects but they are good for any studio project

Of course, I agree on that completely Purusha !
I wanted to encourage people in home studio domain that this is a way to go in order to make high quality recordings. Big studios usually already have "big" preamps
But surely this is high end recording preamp desirable in any project.
So, you are "injecting" the original Neve Marinair transformers in BA ?
Let us know how it worked out, and also in comparison to JLM iron.
Cheers from Sarajevo, happy new year to all !

BTW, I've put a simple round black knobs on your BA case, it looks very elegant... I'll send you a photos...

 

[SUPERMAGOO]

here are some recordings using the baby animal in the guitars.

http://magooamps.googlepages.com/una_vez_mas.mp3

 

[skipwave]

Went ahead and jumped the ic's. 

You did what? Installed a jumper? From where to where?

Powered up and with phantom off and no opamps, all my voltages are spot on except that C15 is 48V instead of 24V,

The schematic linked from JLM's BA page, that you already have, contains all the info you need (including voltage readings): http://jlmaudio.com/Baby%20Animal%20Dual%20Mic%20Pre%20Schematic.pdf

> C15 should indeed have 48VDC on its positive leg.

and C12 is 0V instead of 24V. 

> C12 is the output DC blocking cap on the positive leg of the second opamp. It won't have any volts on it without the opamp installed.

this forum is starting to melt my brain a little!

That's normal. My brain gets very gelatinous after hours of harvesting info from this forum. Take a break. have a beer.

Also, does turning on phantom with no opamp fitted destroy the 10R (R22)?

> No it won't destroy anything. You should absolutely turn it on and meter it. The 10R is a dual purpose part. A fuse and the R of an RC filter stage. It won't burn unless your opamps draw too much current. They will only do that if something is wrong, like the output is shorted. Hopefully the resistor smokes before your opamps do. There were also some documented cases of the 10R burning as a result of the inrush current to charge up all those power supply caps. It went undetected because metal film resistors don't get nice and charred looking like regular old carbon film type do. Use carbon film.

Being that BAD's are power with an outboard DC supply is that why no one uses a fuse?

Yup.

 

[analogica]

Oh mate, what a niiiiiiiiice front panel!!!

  simply beatifull...

 

[dufo]

guys,

Hi, Will not be at thestudio for a few days, hence these questions, rahter than trying it right now myself...

I have a BAD, but I did not use shielded cable for the ins and outs from the PCB. I also did not tie both Pin 1's to 0V chassis ground!! Dont know how I missed that!

Seems to be working fine though. Should I replace them with shielded cable? Im installing a BA to go with it and will use sheilded cable for it so probably a good Idea to change to shielded on the BAD as well?

The BA didnt work when I fired it up, no signal of any sort. On re reading this thread, I have discovered I didnt install the jumper on the IC socket. Would this cause the unit not to work at all?

Lastly, there is one wire going from the gain pot to 0V. Is this 0V on the PCB, or 0V ground to the chassis?

thanks!

 

[JLM Audio]

Seems to be working fine though. Should I replace them with shielded cable? Im installing a BA to go with it and will use sheilded cable for it so probably a good Idea to change to shielded on the BAD as well?

NO it will be fine the way it is as long as it is in a metal box. Best to twist the three input wires together and do the same for the output wires but do not twist the in and out together for the BAD otherwise you may get oscillation at high gain.

The BA didnt work when I fired it up, no signal of any sort. On re reading this thread, I have discovered I didnt install the jumper on the IC socket. Would this cause the unit not to work at all?

The jumper from pin 4 to pin 7 will only help to keep noise out of a balanced line whn no output transformer is not used. Without it you will still get audio.

As aways if you cannot get one of our kits working send me Macro on Clear well lit in focus photo's of the top and bottom of the PCB and your wiring and I will usually have to going in no time at all.

Lastly, there is one wire going from the gain pot to 0V. Is this 0V on the PCB, or 0V ground to the chassis?

Anywhere 0v is will work but the 0v at the BA back edge of the PCB is the best.

 

[dufo]

thanks joe.

Seems I have other problems to fix first. Measuring the supply poer at the plug (unplugged) measures 48V DC. Sweet. However plug it in and measure inside the case at the connector and its 25V Ac ??????? Now either Im a moron.......and thats more than possible, or something funny is going on. Obviously I cant do any meaningful V tests till I sort this. Incidently, My BAD seems to be working fine, or at least it seemed to me it was, not so sure now.

 

[Dennisb]

Hi,

I am also building a Baby Animal with JLM transformers. I have tried to search the thread but I havn't read the whole thread so please bare me

On the JLM14 input transformer, what do you do with the black cable? If I follow the schematics and the overlay I get the others but how do I connect the black cable? Or do I just cut it?

Thanks!
D.

 

[Veseli]

On the JLM14 input transformer, what do you do with the black cable? If I follow the schematics and the overlay I get the others but how do I connect the black cable? Or do I just cut it?

Yeah, you cut it and make sure it doesn't touch anything, so isolate the end with some tape.
I haven't cut it, actually, I isolated the end and wrapped it around the other wires so it makes everything a bit more solid.

 

[Dennisb]

Thanks a lot man!

D.

 

[spyder_hobo]

This seems to be the place to post any Baby Animal questions so here it goes.

I'm planning on building a Baby Animal Dual to match a Gain Hungry B&O Ribbon Mic(modded with RCA ribbon and Lundahl LL2912 output) and was looking for some transfo combination advice. I'm primarily recording quiet sound sources acoustic guitar vocals and don't want to get a whole lot of coloration.
I'm thinking of going:
oep, hybrid x2, JLM111
Any one have any experience with this combination? or suggestions?

 

[rodabod]

I'm thinking of going:
oep, hybrid x2, JLM111

I'd worry about noise performance first. The Hybrid has a OPA(2)604 front-end, so the OEP at 1:6.45 would probably work quite well with respect to noise. Otherwise, get a 990 and run a 1:2 or 1:2.5 at the input. Going with a dual will give you a shit-load of gain, just keep the front-end quiet.

 

[spyder_hobo]

hey rodabod
Can the oep run at 1:2?
how about the output iron? needed?
thanks!