JLM Baby Animal

[mattmoogus]

Do you get the hum only when there is no mic plugged in? Or only with a dynamic mic and not the condensors? If the transformer primary is floating it will pick up hum.

The hum should be significantly quieter than the hiss, I think the ones we built in the workshop had close to no audible hum at all.



M

 

[jmiller]

[quote author="mattmoogus"]Do you get the hum only when there is no mic plugged in? Or only with a dynamic mic and not the condensors? If the transformer primary is floating it will pick up hum.[/quote]

Hi, Matt. I did notice the difference in noise level if a mic is connected or not, both hiss and hum. If a mic is connected, generally there is no noise.

I think my 57 is actually picking up the hum. I am not getting it with my other mics, either dynamic or condenser. The hum from the preamps only seems to exist with a 57 connected, or with nothing at all connected which doesn't matter.

As far as hiss- there is almost no real audible self noise from pre1. Pre2, on the other hand, makes a fair bit of hiss. With the gain up, the hiss is kinda loud. The difference with a mic connected or not is almost negligible (the hiss "darkens" a TINY bit if you connect a mic). The level of hiss doesn't change if the pad is engaged (the pad does effect mic level, however). It is only on this one pre doing this. Would defluxing possibly help this?

Other than that, everything is solid :thumb: . I have DIY post-natal depression: my project is pretty much done and I have nothing to work on now!

 

[eskimo]

Perhaps a more general question but I couldn't find much in the meta or by searching. Are there any parts that need to be far away from each other or is that no biggie since the psu is external?

 

[mattmoogus]

On the baby animal? Not really, if you use an output transformer Id keep it away from the input transformer but other than that...nothing else I can think of.

J, Im still thinking about youre problem and one of us will reply soon!


M@

 

[eskimo]

The baby animal yes, I'm planning to use your jlm111dc.
As far as possible from the input trafos, ok.
So this is bad?

What about wiring, the 48v cables near the output trafos, is that ok?
I'm sorry, I better go to the electronics 101.. :guinness:

 

[mattmoogus]

No thats ok because the input transformers for the left channel arent near that channel's output transformer. The 1:4 is pretty well sheilded anyway so its not such a problem. They dont have to be as far away as possible, just not right next to eachother. If youre building the BA this wont be a problem as the input transformer mounts on the PCB.

Its one of those things that you have to play with if your layout is causing problems but most of the time youll be fine.


M@

 

[eskimo]

Thanks for all the help!
I'll be ordering my pair next week. :grin:

 

[mattmoogus]

J, try swapping opamps and see if the noise follows the opamp or stays in that channel.

Also, are you absolutely sure youre test path/procedure is the same for both channels?


M@

 

[unheardof]

Can anyone tell me the height of the Baby Animal PCB with the JLM transformer on it? I'm looking at enclosures, and while I know it will fit lying flat in a 1U rack, most of the project boxes are 1" or 2" high.

 

[jmiller]

[quote author="unheardof"]Can anyone tell me the height of the Baby Animal PCB with the JLM transformer on it? I'm looking at enclosures, and while I know it will fit lying flat in a 1U rack, most of the project boxes are 1" or 2" high.[/quote]

I don't know the exact height, but I would suggest that you look for an enclosure that is 1u high and 1/3 space or so. That way when you want more, or would rather have it in a rack, you can mount them together instead of having a bunch tabletop boxes everywhere. You can perhaps put two SMPS sockets on the back, one to connect to the PSU and one for daisy chaining to other future B.A. pres :grin:

Seriously, though, I would still look for something that can mount cleanly on a universal rack tray, going back to my "planning for the future" philosophy.

Matt, I am going to try your suggestion a little later after I do some work. Thanks!

 

[needlz]

[quote author="jmiller"]
Seriously, though, I would still look for something that can mount cleanly on a universal rack tray, going back to my "planning for the future" philosophy.
[/quote]

Do you know of a manufacturer who makes empty 1/3 1U size project enclosures (ie hammond)? I have piles of stompbox type hammond boxes but would love to start using ones I can rack mount.

cheers

 

[unheardof]

[quote author="jmiller"]I don't know the exact height, but I would suggest that you look for an enclosure that is 1u high and 1/3 space or so. That way when you want more, or would rather have it in a rack, you can mount them together instead of having a bunch tabletop boxes everywhere. You can perhaps put two SMPS sockets on the back, one to connect to the PSU and one for daisy chaining to other future B.A. pres :grin: [/quote]

Yeah, I should have mentioned we were first looking at half-rack boxes, but the ones I found (by hammond) were about the same price as a full rack box, roughly $50 or so. Either one would be a nice option, the full rack offering more room to expand. However, we were looking at smaller boxes just because they are so much cheaper ($15-20). I haven't been able to find one that is 1.75" high, most are 1" or 2". That's why I was wondering about the height requirement. Good idea about the daisy chaining.

 

[JLM Audio]

I seem to still be getting a tiny bit of very low-level hum. I need to check it in another environment to be sure. It's very low (mixer channel and monitors need to be cranked to hear it), but I'm trying to think of the accumulative effect. Interestingly, it doesn't seem to be there when I have a condenser mic plugged in with phantom power turned on.

Input transformers when not plugged into a mic will pick up any near by power transformers but when loaded by a mic should be fine. To prove the pre short pins 2 & 3 of the input XLR and check for hum. If you still have hum try moving the mic pre while listening just in case the gear under it has a power transformer that is direct coupling with baby Animal input transformer.

I also occasionally and very faintly pick up a radio station. I can control it a bit with where I put the mic/cable. I've had this problem in my room before, but is there any good way to eliminate it?

Try the shorting pin 2 & 3 of the input XLR trick above to see if any radio pickup goes away but in a steel case the Baby Animal should not have any RFI problems. When having RFI problems with a bit of audio gear it is good to move the input and output leads separately to work out where the RFI is getting in. As it can use the audio output as a RFI input just as easily as the audio input.

Also, should I deflux the boards? There's a little bit on the PCB bottoms from all the soldering. I have some defluxing solvent but I didn't want to use it without asking first.

With normal flux there is nothing of very high impedance on the Baby Animal PCB so it should not be necessary to clean it off.

Are there any parts that need to be far away from each other or is that no biggie since the psu is external?

No. Just don't use unshielded input and output wires and twist them all together or you could make the mic pre an oscillator at high gain.

What about wiring, the 48v cables near the output trafos, is that ok?

The 48v from the SMPS is DC with very little ripple on it so there are no problems having it near anything.

Can anyone tell me the height of the Baby Animal PCB with the JLM transformer on it? I'm looking at enclosures, and while I know it will fit lying flat in a 1U rack, most of the project boxes are 1" or 2" high.

The JLM14 is 24mm high and 22mm diameter + 1mm spacer to hold it off the PCB. 25mm (1") from the top of the PCB. The PCB is 1.6mm thick and the two bolts for the JLM14 sit out 3mm under the PCB.

 

[jmiller]

Thanks, Joe.

Today I completely redid my I/O connections. I didn't have a lot of confidence in their mechanical stability, particularly the inputs. No more hum, no more excessive hiss. I tried the shorting pins 2&3 trick for grins, and noticed the difference, though I had kinda noticed this already on my own.

I'm still getting RFI, but this has nothing to do with the pres themselves. I've had this problem in all kinds of equipment ever since I've been in this location. It changes when I move either the inputs OR the outputs. Interestingly, it diminished a bit when I took the bottom off the case. It also doesn't seem to be a problem when condensers are used. The level of RFI is at it's worst when the gain is at full. But again, this is not a problem with the pres as much as a problem with my location. I'm going to be looking into this over the next few days as it's kind of a hinderance, but most of my critical tracking is out of house lately anyways. I just seem to be in a hotspot.

Once again, the baby animals are awesome! Looking forward to building more eventually.

:sam:

 

[bluesgirl]

Hi everyone,

Im new here and I am real interested in the baby animal. I emailed Joe with some questions but I haven't gotten a reply yet. I am not that experienced with building so if I sound stupid sometimes please keep my lack of exp in mind. I did build a ssm2017 mic pre with free eagle software for the pcb, put it together and it works. But my main problem is power supply. Don't have a good one and really don't know how to get one together. I wanted to build a set of JH990c's but was really concerned about getting the pw supply. I found the JLM site and I think it is really cool.

Alot of my questions were answered by reading the posts on this forum but I still have these few things not answered. I imagine there will be more questions later also. :wink:

Does anyone know what I will need to power the baby animal other than what comes with the full kit? I am confused about that.


Do I get the full kit and also purchase one of the world pw supplies listed on the page or what?

Is the OEP262A3C a better transformer since it costs more?
JLM 1:4 Input transformer
OEP262A3C Input Transformer

And also can the JH990c work with the BAnimal (i know it has to be 24v) using the same pw suppy and the JLM 1:4 input transformer?

is there a peak led or how hard is it to add?

If I were to order two of these could I get a matched pair of the JLM99V opamps?


Thanks

 

[eskimo]

I'm less experienced than you but I'll bite.

Do I get the full kit and also purchase one of the world pw supplies listed on the page or what?

Yup

Is the OEP262A3C a better transformer since it costs more?
JLM 1:4 Input transformer
OEP262A3C Input Transformer

I guess it's because they make the JLM14 and loads of them.

 

[mattmoogus]

Hey J, good news about your noise probs! Sounds like you might have to build a Faraday cage around your house tho! :razz:


Hey Bluesgirl,

If you can build a 2017 pre then you can build a Baby Animal eeeeasy.

The PSU is extra to the cost of the full pre kits. You can use any well filtered 48V supply, the ones we sell are just a neat solution if you dont want to worry about the power side of things, just plug in and go.

The 990c will work fine in the BA pre as far as I know. Joe will correct me if Im wrong.

Better transformer? It depends how you define better. The OEP is bigger so it can handle more level before clipping, but this isnt a problem as you have a pad on the BA that will allow it to take line level in with any transformer. The JLM 1:4 actually has a flatter response, especially down low, compared to the OEP. It also behaves its self much better with different loads, allowing you to play with changing the input impedance as weve been discussing in this thread http://www.groupdiy.com/index.php?topic=15439

Sound wise, I prefer the 1:4 on drums, bass and electric guitars and the OEP on vocals and accoustic guitars, but either will sound good on anything. Really.

Our 1:4s are cheaper because we buy hundreds of them at a time directly from the source. Also theyre smaller which means less materials and shipping.

You wont need a peak LED on the BA as it has so much headroom that youll be clipping your recorder or other gear well before the BA clips. So yes, you can have a peak LED, but its on the next bit of gear in your chain. :wink:

All 99Vs are matched and can be used for true stereo processing applications.


If I may reitterate this point, we dont have tiers of quality in our products like most companies do. If we sell something cheaper than something else, its because its less complicated and costs us less, not because weve compromised quality to make it cheap. You can put a BA pre up against ANY other pre out there (I mean this) and it will compare, usually favourably. I just wish this stuff was around when I was a poor student trying DIY! :green:


M@

 

[jmiller]

[quote author="mattmoogus"]Hey J, good news about your noise probs! Sounds like you might have to build a Faraday cage around your house tho! :razz:
[/quote]

I'm on the market for some stylish foil hats. :wink:

Bluesgirl,

The JLM1:4 is definitely nice. You won't be disappointed either way. I chose the 1:4 for simplicity's sake, with the intention of building some pres with other transformers later. But either one you chose, I'm sure you will be happy.

 

[bluesgirl]

[quote author="mattmoogus"]
Hey Bluesgirl,

If you can build a 2017 pre then you can build a Baby Animal eeeeasy.

The PSU is extra to the cost of the full pre kits. You can use any well filtered 48V supply, the ones we sell are just a neat solution if you dont want to worry about the power side of things, just plug in and go.
M@[/quote]
How does the PS hook up? Is it a thingy like regular wall warts or just wires?

If it is a wall wart thingy I suppose I would have to get a wall wart female jack for the thingy?

If I purchased the less expensive 48v PS how many pre's could I power efficiently and would the sound quality suffer at the lesser voltage?


Hmm! Now Here's a thought.
If I got the bigger PS and ran 2 JLM99v's at the higher voltage (What is it 32v?) and added 2 more pre's with JH990c's later, which only take +-24v, can the PS be stepped down to 24v just for the JH990 and the 99v stay at 32v using the same supply?


[quote author="mattmoogus"]
You wont need a peak LED on the BA as it has so much headroom that youll be clipping your recorder or other gear well before the BA clips. So yes, you can have a peak LED, but its on the next bit of gear in your chain. :wink:
M@[/quote]
I Like that. Very cute :wink:

I really think I'm sold on the BA :thumb:

Oh! And does JLM ship? UPS?

You guys are great here. Very helpful. I really appreciate your help. :grin:

Thx,

bluesgirl

 

[mattmoogus]

Its definitely a thingy, but its not a wall wart. Both PSUs we sell are inline boxes with an IEC jack on one end and a captive lead coming from the other. All the pres we make ourselves have 5pin XLR power connectors, but I believe the smaller PSU has a DC plug and the larger one comes with a 5pin XLR. Have to check with Joe on this. Either way its not a big deal. If you can solder a mic lead you can terminate any of these connector options.

Ill have to ask Joe how many pres the smaller PSU will run, but Id guess at 4x 99V pres without any problems. The smaller PSU is still 48v just less current than the big one. Wed never sell or reccomend to you a PSU that would cause the sound quality of the pres to suffer for the sake of being smaller or cheaper. Even if we felt nasty that day. I promise!
:grin:

If youre going to run 990c and 99V pres in the one box you may as well run them all on +/-24v. Unless you really really want the extra headroom, you probably wont notice a difference in sound. You sure as hell wouldnt need a peak LED then though!

Yes we ship, all quotes are by Australia Post airmail. I think UPS would be more expensive...not sure...

Yes the lab is cool isnt it!


M@