JLM Baby Animal

[jmiller]

[quote author="JLM Audio"]

I'm not quite sure how to wire up the power/switch

Just need to run the +48v from the SMPS socket to the power switch and then from the power switch to the two 48v terminals on the baby Animal PCB. 0v from SMPS just wires to all 0v points. If you need a power LED use a 10k resistor in series with the LED.[/quote]

Thanks! I was kinda figuring this, but, you know- beginner's timidity!

 

[Lowfreq]

Thanks Joe, you're a legend!! :thumb:

[quote author="JLM Audio"]I gather you are using a NE5532 or 2520 etc for the opamp. Also because you are using a 48v power supply you only need to fit the opamp regulator.[/quote]
You're bang on the money on this one. I'm planning on building a couple of 2520's and a couple of melcors. I'll grab a couple of fabios 2520's that he's getting made up too, but for now I'll see how i go building some of my own.
[quote author="matta"]I know the 'Animal Pre' is not a clone and none of the above combination will in any way 'copy' them so that why I called them styled pres, drawing on them for inspiration. [/quote]
Thats kinda what i'm aiming for. An api styled pre, but without the output tranno. I was gonna go with the OEP option to start off with, but that group buy swayed me. :wink:
[quote author="JLM Audio"]Let me know what Cinemag transformer and opamp you are going to use and I will be able to help you work out RL,CL,RZ,CZ,RP,RG[/quote]
Ok, the tranno is the Cinemag CM75101APC, and the opamp will be some sort of 2520 or melcor. I have left the 8pin socket in too, both for jumping the pins as jmiller has done, but also in case i have any trouble with getting the 2520's finished or i cant get hold of any, i can chuck in the old NE5532 to at least get em running. But I'm definitley aiming for the 2520. :green:

I think I need to do a bit of reading of the tranformer and DOA metas tonight after work too. Just educate myself a little bit. :grin:

 

[OneRoomStudio]

[quote author="Lowfreq"]
But I'm definitley aiming for the 2520. :green:
[/quote]

I was thinking the same thing. Does anybody know a source for 2520's? I know they're probably hard to come by. If they're impossibe to get, what's the closest sounding substitution?

 

[Lowfreq]

Does anybody know a source for 2520's? I know they're probably hard to come by. If they're impossibe to get, what's the closest sounding substitution?

Fabio's the man for close version's of the 2520. He's got all the info on his website, if you're keen to build em yourself, and there's even a thread in the black market about having some pre-made & tested.

I'm sure his name will come up with a search with anything to do with api or 2520's.

regards,
Steve

 

[jmiller]

It's alive! But...

Output seems kinda low and it's buzzing. I'm looking into this now, but, any pointers? It's obviously a wiring fault but things look right. Of course, being a newb, I don't know for sure.

Is there a problem with not having the jacks attached to the chassis? I went the "pigtail" route as I described a couple posts back.

Here's what I've got for wiring:

Center pin of SMPS to bottom lug of Power Switch.
Two wires from top lug of power switch, one going to "+V" of each pre.
Two wires from negative lug of SMPS, one going to "0V" of each pre.
Lug one of the pot to "0V"
Lug three of the pot to "Gain"
Shield of XLRs IN and OUT to "0V"
Pin 2 of XLR In to "in+" of pre
Pin 3 of XLR In to "in-" of pre
Same for XLR out

DI is unconnected for now, and the connector on the pre is jumpered as directed on the PCB and schematic.

What have I screwed up?

 

[JLM Audio]

Center pin of SMPS to bottom lug of Power Switch.
Two wires from top lug of power switch, one going to "+V" of each pre.
Two wires from negative lug of SMPS, one going to "0V" of each pre.
Shield of XLRs IN and OUT to "0V"
Pin 2 of XLR In to "in+" of pre
Pin 3 of XLR In to "in-" of pre
Same for XLR out

All correct but you should have a 0v going to the case as well. We use a DC socket that does this when it bolts to the case as it is metal and not insulated. This may explain the buzz bit.

Lug one of the pot to "0V"
Lug three of the pot to "Gain"

OK if nothing is connected to the centre pin of the pot then the gain control will not work at the moment and the pre will be stuck at minimum gain no matter where you turn the pot. When looking at the pot from the back with the pins facing up. The left pin and centre pin join together. Wire the 0v to these 2 linked pins. The pin on the right goes to gain on the baby animal PCB. In reality 0v and gain wires can be swapped on the pot and it will still work the same. This should explain the low output.

Let me know how you get on after changing the above bits

Why not offer some of the more popular combinations here so guys can try them, and re-edit the post as and when you work out more combinations.

I am going to make a table on the baby animal page for RL, CL, RZ, CZ, RP, RG for different transformers and also a table for what regulators and zeners are needed for different opamps and power supply volts so this is just a matter of look up the values.

 

[jmiller]

GOT IT! It's alive!!! :grin:

Firstly, the pot was incorrectly wired. I figured this out today when I tested it again- the pot didn't work at all. I desoldered the pot and started trying different wiring using alligator clips. After playing around a bit I got the pot, wiring 0V to lugs 1&2 and Gain to 3. Obviously, I had previously not had the wiper connected. Duh.

Most of the buzz was from having the unit plugged in to an AC outlet that was on the same circuit as the overhead lamp which was on a dimmer :roll: Plugging into a different outlet almost eliminated it, but it was there a tiny bit. I figured I'd work with it for now and post about it, but when I moved it into my studio and plugged it into my rack, the buzz went away.

So...

This thing sounds fantastic. Some of my mics that I previously didn't like at all now sound very usable. I've only tried it on a couple things, and my listening environment was a little tainted as I just temporarily plugged the output into a line in on my mackie, but even still- it's obvious that this is a terrific mic pre. The sound is very smooth, but without sounding "fuzzy" like some smooth pres often sound to my ears. The DI also sounds awesome. My P-Bass sounded spectacular and was the best sound I've got out of that bass, and my strat sounded great as well. My wife's lapsteel sounded really clear, and I'm looking forward to getting my brother in law in here to try his lapsteel through it. He's also a great guitar player and songwriter, so we'll be recording some of his stuff with this very soon.

I'm really stoked! This pre is a great value. I'm really shocked at how good they sound, and would reccomend them highly. I can't wait to do some real recording with them. I'll definitely report back when I've put them through their paces a little more. Now I'm going to have to get another kit for this Jensen JT-115k-E I have sitting here and try the Hybrid opamp... :thumb:

 

[MATTI]

Well, how does it sound and is the gain enough for ribbons?
Matti

 

[jmiller]

Woops! Looks like we were posting at the same time. Sorry...

[quote author="JLM Audio"]

Center pin of SMPS to bottom lug of Power Switch.
Two wires from top lug of power switch, one going to "+V" of each pre.
Two wires from negative lug of SMPS, one going to "0V" of each pre.
Shield of XLRs IN and OUT to "0V"
Pin 2 of XLR In to "in+" of pre
Pin 3 of XLR In to "in-" of pre
Same for XLR out

All correct but you should have a 0v going to the case as well. We use a DC socket that does this when it bolts to the case as it is metal and not insulated. This may explain the buzz bit.[/quote]

Okay. My DC socket is metal. As described in my previous post, the buzz is gone for now, but should I do this as an extra preventative measure? My DC socket has a third tab on it that's not used. Should I just run that to 0v? Those 0v terminals are getting pretty tight!

OK if nothing is connected to the centre pin of the pot then the gain control will not work at the moment and the pre will be stuck at minimum gain no matter where you turn the pot. When looking at the pot from the back with the pins facing up. The left pin and centre pin join together. Wire the 0v to these 2 linked pins. The pin on the right goes to gain on the baby animal PCB. In reality 0v and gain wires can be swapped on the pot and it will still work the same. This should explain the low output.

I got this as described in my last post. Sorry I didn't mention it sooner- I've been playing with my new pre

Thanks, Joe. It sounds awesome!

[quote author="MATTI"]Well, how does it sound and is the gain enough for ribbons? [/quote]

Like I said, it sounds really, really good. Keep in mind there are tons of different configurations possible for this pre. Check the original thread from Black Market for more details:
http://www.groupdiy.com/index.php?topic=13739

In the configuration I have, the gain is OK for ribbons but I would definitely like more. I tried it with my chinese OEM ribbons and it would be fine if I was using them on drums, but I might want more gain if I were using them on a soft voice. You can get more gain with different configurations. Oddly enough, my modified Oktava ML52-II sounded much better and had just enough gain to be happy.

So you could try a higher ratio transformer and get more gain (around 70dB). Of course, if you really need tons of gain you could get the JLM dual 99v pre, which has 80dB of gain. That's a metric buttload of gain, and it seems to me you could probably sing into a bare mic cable with that kind of gain! :razz:

 

[mattmoogus]

Nice one J!

Looks neat, glad you like the sound too! What you said about it being smooth but without the fuzzyness of other 'smooth' pres is exactly what I thought.

You should be getting a shade over 60db with the 1:4 input and 99V, does that sound about right?

Appart from using a higher ratio input transformer to get more gain, you can also use a stepup output transformer like our 1:1:1 (or any other type that can step up) to get an extra 6db, which should give just enough gain for ribbons on a quiet source.

On that thread in the black market Ive listed some different configs and what gain and sound you would expect to get from them.


:thumb: :guinness:


M

 

[jmiller]

[quote author="mattmoogus"]
You should be getting a shade over 60db with the 1:4 input and 99V, does that sound about right? [/quote]

Something around there. My condensor mics seem happy with the gain around halfway or so. A 57 seems good around 3/4 or so. It's nice, clean gain, too. It sounds really good turned way up whereas some pres can start to sound funky if you push them too much.

Appart from using a higher ratio input transformer to get more gain, you can also use a stepup output transformer like our 1:1:1 (or any other type that can step up) to get an extra 6db, which should give just enough gain for ribbons on a quiet source.

I was thinking about this. It would be cool to do this eventually. It's still enough to use a ribbon on a guitar cab or drums, though.

Can't wait to play with it more!

 

[Schmilsson]

Come on. more pics! :grin:

 

[Lowfreq]

Actually i might be able to take some pics. Nothing drastically different to what we've seen so far however.

anyway, onwards with the questions and learning..................................................................................................................................................................................................

I've been looking over the schematic as much as possible, just to try and understand the workings a bit more. I tend to struggle with schems seperating whats the audio singal path and whats the rest, but I think the Baby A is so nice and simple even I get it. :shock:

So just for example with the caps, would I be right in saying that the only caps that the audio signal go's through are CZ(if used), CL, the 47pf and the 470uf's before output pin one, and also pin three?
My main reason for asking is, that in my hunt for good quality caps(rubycon,nchicon etc) in the 470uf rating, i've found that a lot of em are 12.5m diameter, which makes for a bit of a squeeze and caps kinda hanging off the side of the board, where as quite a few general purpose panasonics are 10mm. Now I don't want to start a what cap is best kinda thing here coz there's so many threads on that already, but I'm more interseted in learning what the caps actually are doing in this curcuit. I understand that Low ESR is better, etc, but I could buy some really expensive caps that may not effect the signal as much as my ignorance would lead me to beleive. Does that make sense?

I think the Nichion HE series has a 470uf/50v thats 10mmx16mm, if thats any help to anyone else sourcing their own parts like me. There is also another on thats 16mmx15mm which wont be useable. Mouser lets you choose between the two, but i've found that RS only has one on offer and they dont't seem to tell you what dimensions you're getting. I could be readin it wrong however. Anyway, I hope that helps anyone. :grin:

Greg said something earlier about the 47pf's being for high frequency stability. And the 0.1uf you've already explained to me. :thumb:
The loading thing is something I know we'll get to later.

The other thing i was goin to ask was, about the connection between pins 7 & 4 on the IC, as in the JLM1:4,99v shem. Now I'm goin to be using a 1/4" jack output rather than a quasi balanced xlr, (due to a chassi that I scored for free with jack outouts already fitted, and that my inputs into my computa are mostly rca's)
Can i get away without the jumper as there's no pin3 for me, or do i still need the jumper anyway? My guess would be no jumper........ .....

Well, hopefully i can find my flatty's camera and put up some pics of the build, albiet mid process for all to see.

I will be back

Steve

 

[jmiller]

Really cool that you're sourcing your own parts, Steve! I'm going to do that next time. Can't wait to see yours.

[quote author="eskimo"]Come on. more pics! :grin:[/quote]

Well, here's a shot of my Potentiometer Wiring 101 experience:

The pencil is there to prevent the board from flexing when I try to get all those wires in the screw terminals.
Good times.

I'm eager to see someone elses now :grin:

 

[mattmoogus]

Joe will probably have something to say about this, but with regards to the caps, the main consideration is getting the right type (low ESR) and the right size. If you do this the caps will function properly in the circuit as Joe designed it, and if theyre the right size and pressed hard to the board they wont rattle around and become unreliable over time.

Different caps have different sounds yes, but as long as you use the right kind for the job its doing and dont buy the cheapest crap you can find, youll be fine.

Having a well designed circuit with good sounding key parts (transformers+opamps etc) is SO much more important than upgrading caps and that kind of thing. If the circuit is great and working properly it will sound great no matter what caps you put in.


Also, youre using 5532s right? Theres no big problem with using an unbalanced TS jack out, but youll loose the extra 6db of level youd get if you ran the 5532 balanced. Of course if youre going into an unbalanced soundcard youll loose it anyway so its no biggie.


M

 

[jmiller]

If I were in your situation, I would still use a balanced 1/4" TRS connector for the output, and just wire an adaptor to keep semi-permanantly hooked up to the back. This way, if you ever upgrade your soundcard you won't need to open up and retrofit your pres. Or, you could find yourself taking your pres to another studio or something and having connectivity issues. Always plan for the future is my motto with this kind of stuff.

I was going to put balanced TRS jacks on the outs of mine, but I decided to do XLR, and I took some cable that was left over from wiring up the pres and I made a couple XLR female to TRS male adaptors that just live on the back. That way, if for some reason I want to connect to XLR, I only need to remove the adaptors. It's easier to remove it than it is to find, make or buy one in a pinch. I remember one very important sound gig involving the california governor and a few dozen businessmen from Korea, and I had to drive all over Long Beach to find just such an adaptor or there would have been no audio for their ceremony (opening the largest shipping port on the coast at the time). I found them in the nick of time, but it made me paranoid about things like that.

Just thought it was worth mentioning...

 

[Lowfreq]

I've been trying to upload some pics of my progress to my website, but there seems to be some problem with my dial-up weirding out over too much data transfer.
I'll try a sneaky upload at work tomorrow. :wink:

J. I had a quick look at the inside of the chassi to check out what the connectors are that it already had, but alas they're just TS.
Good idea though.

 

[Lowfreq]

Ok here are some mid project pics.
Quality of photo's is pretty bad. I had to make em small so uploading would work.

Anyway, welcome to my lab/studio/storageroom/sleepng quarters.
Sheesh!! I just noticed that I had my Contact lense solution and hair product sitting by my Mytek. :shock: Very bad Steve, very bad!!

Here's the free case I scored. Some old switching thing used for shop displays. Eventually I'll get a new front panel for it, but for now it'll work just fine. Check out the funky 70's looking flooring!!

Here's a look at the back. Looky at all the connectors. That'll save me $10 and a bunch of drilling. :wink:

Lets open her up and see if we've got some TRS going on there. Nope!! just TS. :sad:

A look at the heart of this project. Again the photo isn't too clear here, but I do think you'll agree with me that the orange connectors look very fetching against the green pcb. :wink: How "Queer eye for the straight guy" is that?!?!?!?
You may also noticed that I've already put in the RG, RP even though we havent done the cinemag/2520 calculations yet. I have an excuse!! I forgot that I'd ordered the cinmeags and for some reason lept thinking I was going down the OEP route(following Joes parts list). Just a blonde moment there . And I'm not even blonde!!
Anyway, I was able to get all this done, just from left over parts from other projects(except the 0.1uf cap)

[quote author="mattmoogus"]Also, youre using 5532s right?[/quote]I'm only goin 5532's if I have trouble with making/sourcing some 2520's. that's why I was wondering about not doing the quasi balanced signal. The signal with a DOA would be unbalanced right? And that would take away the need to link pin 7 & 4 me thinks.
I'll start building some 2520's & maybe some melcors while I wait for the cinemags to arrive.

Anyway, hope ya'll enjoy the pics!!

 

[mattmoogus]

Ah yes, my mix up!

I dont think youll miss the quasi balanced output as long as you keep your cables to a reasonable length. Anyhow quasi balanced will only work if youre going into a balanced input, which you arent anyway!

Itll be really interesting to hear what it sounds like with a 2520 + Cinemag. :thumb:


M

 

[jmiller]

Looks cool, Steve! :thumb: I like how in depth you're getting and really learning about the circuit. I hope do do this with another B.A. kit and different transformers and opamps.

Anyhow, couple curiosities:

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. 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?

Today I put a larger metal SMPS socket in- the original one was a little smaller than the hole that was already there, so I figured a larger one that made better contact with the case would be good. It also looks better. I also drilled a couple more holes in the front panel and installed LEDs for phantom power, and a "pilot light".

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.