JLM Baby Animal

[bluemuze]

I have the BA4 'everything' kit with the JLM 1:4 input transformer and JLM 99V op amp. Before I start soldering, I have a few questions.

1. In the picture, components shaded red will not be populated. Components shaded yellow will be populated, but are not in the circuit in this configuration. The blue lines will be jumpered. Is this correct?

2. It looks to me like the resistor marked 1MEG on the PCB should be populated with a 220K resistor. Is this correct?

3. According to the input transformer table on the JLM Web site, CL should be 390pF. I didn't get that in the kit, but I did get 2 220pF capacitors which I don't know what to do with. What do I do?

Thanks.

Bob Miller

 

[bluemuze]

The BOM says that I should get 5 470uF 50v caps and one 330uF 63v cap. I've got 6 470uF 50v. I'll be running on 48v. Is this okay?

Thanks,
Bob Miller

 

[JLM Audio]

1. In the picture, components shaded red will not be populated. Components shaded yellow will be populated, but are not in the circuit in this configuration. The blue lines will be jumpered. Is this correct?

Yes that is all correct. You will also need to jumper C to E on the transistor position up the front of the PCB for 48v phantom power to work.

2. It looks to me like the resistor marked 1MEG on the PCB should be populated with a 220K resistor. Is this correct?

Yep

3. According to the input transformer table on the JLM Web site, CL should be 390pF. I didn't get that in the kit, but I did get 2 220pF capacitors which I don't know what to do with. What do I do?

CL = 220pF for fixed impedance and 390pF to 440pF is using variable impedance. All latest kits have an extra 220pF to make 440pF for the variable impedance option.

The BOM says that I should get 5 470uF 50v caps and one 330uF 63v cap. I've got 6 470uF 50v. I'll be running on 48v. Is this okay?

Yes. All BA kits come with 6 x 470uF caps now as 99% of BA kits are run on 48v. If you are going to run a 62v rail which is the maximum rail the JLM99v can run on. One cap needs to be changed to a 63v type.

Remember when using BA PCB dated 09/07 to do mods shown in jpg below.

 

[bluemuze]

Okay, I've got one working Baby Animal, three to go. I have another question though. With everything else on those nice screw terminals, I hate to solder the PCB to the phantom LED. Does anybody know of a part I can use to disconnect it? I'm thinking a little socket for the LED with a couple of leads I can solder to the switch. I don't know what to look for at Mouser, though.

 

[mischa]

hi, i already finished the BA once, and it worked ok. Then i finished the case and packed it in, now it doesn't work anymore :?

what'd i do wrong? If i connect a dynamic mic, it works alright. The voltages are not what they should be according to the sheet at jlmaudio.com at the @-points. I have the 24V working at the various points. the @ at the 6k8 resistor is there. just the 48V right at the output transformer don't show up.

my dc in is wired only on 2 lugs, one is not connected. one goes to 0v, and the other to 48V. both di-socket things are strapped, according to the instruction on the pcb. looking on the gain pot from the back with , it is wired with the 2 left lugs together going to 0v, and the right one going to gain.

any idea so far? should i come up with all the voltages i got?

thx! gerrit

 

[mischa]

hi, i already finished the BA once, and it worked ok. Then i finished the case and packed it in, now it doesn't work anymore :?

i have a jlm14 tran and a 99v opamp... di exists, but is not connected right now.

what'd i do wrong? If i connect a dynamic mic, it works alright. The voltages are not what they should be according to the sheet at jlmaudio.com at the @-points. I have the 24V working at the various points. the @ at the 6k8 resistor is there. just the 48V right at the output transformer don't show up.

my dc in is wired only on 2 lugs, one is not connected. one goes to 0v, and the other to 48V. both di-socket things are strapped, according to the instruction on the pcb. looking on the gain pot from the back with , it is wired with the 2 left lugs together going to 0v, and the right one going to gain.

any idea so far? should i come up with all the voltages i got?

thx! gerrit

 

[mischa]

hi, these are my voltages

and thats how my pcb looks like. nothing changed from the first working status. imagine the 99v opamp being fitted.

this was until 5 minutes ago when i falsely believed that i had to cut the bd681-jumper, because the table said it had to be nf. so i cut it, powered it up. of course it didn't work, so i put the jumper back in (soldered it together again). now, strangely, the led is not on anymore. where i had ~2 volts before on the point the led connects to the phantom switch, i now have 48 volts (on the very top right in the picture) :sad:

forgot to mention that the whole problem is that the condenser mic doesn't work. it works alright with my other preamp.

joe, i need your help.

 

[JLM Audio]

now, strangely, the led is not on anymore. where i had ~2 volts before on the point the led connects to the phantom switch, i now have 48 volts (on the very top right in the picture)

If you have 48v at the switch then phantom power should still be working fine. Sounds like the led has gone open circuit or a wire has broken off one leg of the LED. Also you do not need or want a ratio jumper fitted when using a JLM14. Make sure the black wire on the JLM14 is not connected to anything.

forgot to mention that the whole problem is that the condenser mic doesn't work. it works alright with my other preamp

This would mean you are not getting 48v at the switch or the 0v power feed to the BA PCB has broken off.

 

[TornadoTed]

First thanks to everyone who has helped me out in this thread.

I've finally finished my 12x JLM Audio Baby Animals.

I actually finished them a few months ago but I've had to wait until now to get the front panels powder coated and printed. I live in the middle of nowhere and there just isn't anyone around doing that kind of stuff.

They are all wired with Mogami cable inside and run off regulated 48v power supplies.

The Neve Style ones use a JLM14 input transformer, JLM99v opamp and a JLM111DC output transformer

The API Style ones use a Cinemag CMMI-8PCA input transformer, real API 2520 opamps and a JLM111DC output transformer

I will do some sound examples when I get some time between the 2 types of JLM and the Pacifica's and add it here if anyone is interested.

 

[indigom]

[quote author="TornadoTed"]First thanks to everyone who has helped me out in this thread.

I've finally finished my 12x JLM Audio Baby Animals.

I actually finished them a few months ago but I've had to wait until now to get the front panels powder coated and printed. I live in the middle of nowhere and there just isn't anyone around doing that kind of stuff.

They are all wired with Mogami cable inside and run off regulated 48v power supplies.

The Neve Style ones use a JLM14 input transformer, JLM99v opamp and a JLM111DC output transformer
[/quote]

Very savvy work on the outside, good job!
-Jay

 

[Jonkan]

Question: Can i use a 22R resistor for the RGain in the baby animal for more gain total if i use a 99v opamp, or will it probably be unstable and oscillate at higher gains?

Thanks!
/Jonas

 

[Lowfreq]

[quote author="TornadoTed"]I will do some sound examples when I get some time between the 2 types of JLM and the Pacifica's and add it here if anyone is interested.][/quote]
Yes, very Interested :thumb:

The Pacifica gets a lot of praise in the net, but cost around $3500 here in New Zealand. I would feel more more smug about myself if the Baby Animals held their own against them....... I think Mine worked out to only cost me about $100NZ per channel to build. :grin:

 

[yosh]

Hi, I have a Hybrid opamp hum problem.

I built 4 channels of BA: 2 lundahl 1578XL / hybrid, and 2 JLM 1:4 / 99v. They sound lovely, however, I have some hum problems on the two hybrid channels. I have no such problems on the 99v channels. If I swap the 99v opamp into the lundahl pcb and the hybrid into the JLM 1:4 pcb, the hum moves with the hybrid opamp. Please note: I am using pcbs made prior to the 09/07 date referred to earlier. I've checked and rechecked things like polarity on the caps and diodes. All are correct. BTW, the lundahls are wired 1:10. I get signal from the mics, but when using ribbons, for example, the hum becomes a problem. Any ideas?

-Josh

 

[TornadoTed]

[quote author="Lowfreq"][quote author="TornadoTed"]I will do some sound examples when I get some time between the 2 types of JLM and the Pacifica's and add it here if anyone is interested.][/quote]
Yes, very Interested :thumb:

The Pacifica gets a lot of praise in the net, but cost around $3500 here in New Zealand. I would feel more more smug about myself if the Baby Animals held their own against them....... I think Mine worked out to only cost me about $100NZ per channel to build. :grin:[/quote]

For all my good intentions I just never seem to have the time. I am still planning on doing the comparison but I'm afraid everyone will have to be patient!

 

[JLM Audio]

Question: Can i use a 22R resistor for the RGain in the baby animal for more gain total if i use a 99v opamp, or will it probably be unstable and oscillate at higher gains?

RG cannot be any smaller for the 99v but you can go to a smaller RG if you are using high gain normal opamps like the OPA2604A, Hybrid, 990 or 2520.

Hi, I have a Hybrid opamp hum problem.

When using the Hybrid in the BA you should leave off the 47uF cap closest to the BD139 and leave the DC servo pads unsoldered.



COMING in April
It is called MAC (Micro Auto Compressor) and it is finally finished.
PCB is 64.5mm x 35.5mm in size. It is roughly twice the size of a GO between PCB or half the size of the BA PCB.

Getting 5 seconds to update the website now that is a different story.

 

[Jonkan]

Thanks! Way cool compressor. hard question, but how does it sound?

/J

 

[skipwave]

Hi Joe,

How close to the Forsell opto sidechain is your comp? Looks like you went with a fullwave rectifier, and only two opamp stages (one 2604). One inverting and one non, each driving a fullwave bridge into the LEDs?

It's as though you read my mind; I was just figuring out how to integrate the Forsell opto with a BabyAnimal mic pre. I'm making a small box for traveling with an mbox mini. I had settled on using the LDR as the shunt R in a U-pad on the output.

Thanks for another thoughtful product!

Brian

 

[buschfsu]

well after some experimenting ive settled on

2x oep / 99v

2x 1:4/2520 cinemag output (1 ch with DI)


jlm guys suggested the oep /99v at aes in nyc and i love it

i haven't put the api style cinemag OTs in yet but there shouldn't be any mods for putting them in right?

thanks

 

[Purusha]

I HAVE A PROBLEM I CAN'T SOLVE ON MY OWN :?

One of my BAs with 1:4 + 99V + 1:1:1 doesn't work anymore.
There is almost no sound coming through, just a lot of noise.
I noticed the noise increases when I turn my variable impedance
knob CW. Otherwise the V seem to be correct and Opamp works OK.

Any suggestions?

 

[TornadoTed]

Here ya go, photos of the inside of the Cinemag CMMI-8PCA, API 2520, JLM111DC.

This was my first ever project and I know it isn't as neat as a lot of jobs I've seen but it works fine. I could have got it neater if I had mounted the output transformers all the same way. I was advised that it would have been fine but I thought I'd be over paranoid and mount them at 90 degrees to each other.

I had to leave the legs of the API 2520 long as it only just fits in with the Cinemag transformer on a slight angle. 11 of them worked straight away, 1 channel had a bad capacitor that took 2 minutes to trace and fix!