JLM Baby Animal

[JLM Audio]

Matt or Joe, i'm awaiting a pair of boards impatiently....Now i have 2 API output transformers by CJ could this work fine in the BA?

Yes they will work fine as 1:2 or 1:3.

I'm getting a good signal through 3 channels, but no signal at all through one channel. I've got proper voltages at the opamp pins and high resistance between each pin and 0V. I've got conductivity between my xlr pins and the board. What other areas would you recommend me troubleshooting?

To make sure you are getting the primary of input transformer test with a ohmmeter between pin 2 & 3 of the input XLR with the pad off and you should have about 20 to 50ohm depending on transformer and between pin 1 & pin2 6.8k and pin 1 & pin 3 6.8k. If you still have no luck send to my normal email address clear well lit macro on photo's so I can see if I can spot the problem.

It can with a JLM14 and JLM111DC output transformer do 86dB of gain

It can, or it will?

This is for New Baby Animal Dual or Dual 99v only. You will not get this out of a normal Baby Animal.

Hi Joe, i received my Baby Kits yesterday they are ready to be racked but still got one question as i have 2 API output transformers that i want to use with the BA. Is there anything i should know or should i dive? ]

Wire the API primary to +out and 0v and use the API as 1:2 or 1:3 for more gain.

One more thing.....i have a 10k resistor left by kit, is that cool??

If you have used the 27k for the input transformer then yes there will be a 10k left over. Otherwise you will have a 27k left over.

For the record: i'm gonna put one 990c by JH and the other a 1731....again anything i should know before doing it??

The JH 990c needs no change but the 1731 will need the on board opamp reg fitted to cut the voltage down.

 

[Jonkan]

If you have one of fabios DIY 1731, it can very well run at +/-24v.

/J

 

[ChrioN]

Are there any differences between the new BA and the Dual 99v? The Dual 99v looks like a sucker to wire up and finnish, if compared to a simple BA....
Also, when will it come out?

 

[JLM Audio]

If you have one of fabios DIY 1731, it can very well run at +/-24v.

If it can run on +/-24v then it can just be plugged in the same as the 990c.

Are there any differences between the new BA and the Dual 99v? The Dual 99v looks like a sucker to wire up and finnish, if compared to a simple BA....

This is explained on page 34 of this thread

Quote:
Whats the difference between the dual 99v and the dual BA?

Difference is BA Dual (BAD) it designed to run on one 48v to 62v power rail and has no servo options on the PCB, no remote relay switching and no A and B output for switching between single and dual mode. Otherwise is it similar. It can with a JLM14 and JLM111DC output transformer do 86dB of gain which allows you to insert a passive EQ in the trim/fader/insert point on the BA dual and makeup the 16dB loss of the EQ and still have a 70dB mic pre. or same goes for inserting a opto comp etc.

Also, when will it come out?

January

 

[ChrioN]

Great. I don't know if I should order 2 BAs now or wait and buy 2 BADs instead... :?

Do you know an estimated price for BAD with all parts and in and out jlm transformers?

 

[mattmoogus]

Joe said the BAD is likely to be twice the price of the BAS, but we dont know yet.


M@

 

[3nity]

Joe what could be the reason causing 2 identicals BA to not passing sound?????

 

[JLM Audio]

Joe what could be the reason causing 2 identicals BA to not passing sound?????

Wow that is a wide open question :grin:

Need to tell me input transformer type and opamp type and did you get all the right voltages shown on the overlay PCB on the BA web page? Have you wired your XLR's right ? Remember Male and Female XLR's are mirror images pin wise.

If everything voltage tests ok and you have checked your wiring and still no go then send clear, well lit, macro on, In focus large photo's to my normal email address of the wiring and top and bottom of the PCB and I will get you up and going.

 

[Jonkan]

ok, one more question.

Im not shure what to use for the CL cap if im using 1:10 beyer caps. It will first try it with variable impedance with a 47k in series with a 470k log pot as recommended by Joe.


Would someone take a guess here, as i dont have a way to check frequency response over here.

220pf or 390pf? or something else?

Im looking in the beyer trafo catalog at the different freq graphs, but im not shure how the variable impedance part will affect the circuit, so i dont know if that info really applies or not.

Or is this one of those time where you have to just go by ear and fiddle around?
/J

 

[3nity]

well yeah sorry for that wide question!
Alright input transformer is a OEP A262A3c,Opamp John Hardy 990C.
Joe all voltages are good...all i got is a big hum..???

 

[mattmoogus]

Hey Jonkan, that cap is to stop the opamp from oscilating at high gain or when the transformer is unloaded. All you have to do is try a value, say 330pF, and see if it oscilates with the controls at any setting. Youll know its oscilating if it suddenly makes a hissing sound as you adjust one of the pots. If it does this at any setting, increase the cap value until it goes away. Also, sometimes the opamp's stability will change as it warms up so leave it on for a while once you have a value that seems to work and see if its still stable when its warm.

M@

 

[Jonkan]

thanks!

Im also trying to find out how to connect the beyers properly.

The beyers are color coded like this:

black=start of primary
red=end of primary
yellow=secondary start
blue=secondary end


Is this correct for the beyer (so that i can follow the pics on the jlm site):
Black wire= red on jlm 1:4
red=green
yellow=yellow
blue=blue

I always forget which side goes to ground, and which is positive on a transformer.


Another question: I am using the jlm output transformer for two of the preamps together with jlm99v opamps. But i mounted all the parts on the pcb even though not all of them are needed. Will this affect soundquality at all???

I want to connect the output transformer so that i use the 0, and plus connections. But do i have to desolder stuff to make it work properly? Or can i just leave it?

I dont want any unnecessary caps in the signal path if possible.
/J

 

[mattmoogus]

Well, the top of the primary is yr + input and the top of the seconary is yr + output...so that sounds right...

Ummm...Im not sure what you mean about desoldering 'stuff' to make the output transformer work properly. It doesnt matter if you put all the reg parts on the board, as long as you used the 47v zeners it will just mean the input voltage will be regulated to 47v. It wont effect the sound at all and there are no superfluous caps in the signal path.


M@

 

[3nity]

Matt or Joe how does it come that my BA doesn't make sound but a hum with condenser but with dinamic they do sound good???

 

[Jonkan]

Not the regulators, im talking about these parts (quoting joe):

but if you are using a 99v etc you can leave off the the 470uF 50v cap in the centre closest the opamp and the 2 x 10k resistor under the DIP opamp closest to it. As well as the lower 47pF and 51R. Also the 10k above RL can be left off. This removes all the -out and inverting amp parts. So the output transformer connects to +out and 0v wired as 1:2. You will also not need the wire across pin 4 to pin 7 of the DIP IC.

I made a mistake and soldered these to the pcb already.

But perhaps i can just leave out the link between pin 4 and 7 on the dip socket, and leave all these parts on?

/J

 

[mattmoogus]

Yep you dont need those parts but theyre not effecting anything by being there so its not a problem. You dont need the link because youve got an output transformer and so have no need for quasi balanced out.
Just wire the output from + out 0v and leave the - out not connected.

M@

 

[3nity]

i started playing with the pre and a condenser mic and as i touch the transformer it started to sound...
Joe for a picture it would be later cuz my wife took the camera today at work..

 

[bluezplaya]

Matt, I am using a 2520 on my 2 of my Baby Animals. I noticed that on the JLM site the diagram shows that I would need a 33v zener to be fitted. Did that zener come with the parts kit? If so, I'll have to dig that little bag of extra goodies out.

BTW, KHStudio helped me get my PM2K channel strip working and I put the EQ mod on it. Pretty nice!

Adam
:sam:

 

[3nity]

Got my pres working for good, the problem was a in a missing ground pin 1 of the input to 0V.

I did some tests between my John Hardy 990c, BB OPA2604, Signetics 5532 and finally a Melcor 1731, Guess who won???

John Hardy i find it to clean to my ears, good on all frequencies.
BB OPA2604 and Signetics NE5532, was hard to tell the difference but the main thing it's their gain, higher that JH 990c!
Melcor 1731 was the winner i really like it, somooth mids, sometime a little pronounced and good low end!!

I'll really like to try more maybe a JLM 99v or an hybrid...

Thank you JLM for capturing and bringing audio without injuring my pockets!

 

[mattmoogus]

Hey Adam, glad youve got yr PMs working! Feel free to post your thoughts on the eq mods when youve had a chance to play with them more...
If youre using a real 2520 youll need to fit that zener and the reg parts or youll blow it up. Apparently the Fabio version can run on +/-24v tho so you wont need it if thats what you have.


3nity, nice quote can we use it?! :grin:
Congrats on getting them going, hopefully youll get many years of good recordings out of them.

M@