JLM Baby Animals

by **chris p** » Wed Aug 23, 2006 3:45 pm

I suggested the topic, so I guess I'd better start.

I'm building 4 JLM baby animals with the JLM 1:4 input tranny and JLM 99V opamp, powered by the JLM +48V supply.

Stock standard, except for that I'm replacing the 10k RL resistor with a front-panel switched resistor chain to yield values of 4k7, 9k4, 19k4 and 39k4, which should give impedances of 300?, 600?, 1k2? and 2k4?.

These are for mic'd guitar cabinets, so I'm not building in the optional DI. I'm not even mounting the socket, just wire linking the two sets of two pins that Joe suggests to link with jumpers.

Biggest hint so far? The JLM power supply has an internal fuse, but I'm adding a 500mA fuse inline with the +ve power (4 BA's at, say, 100mA each) 'cause accidents happen when you build stuff.

by **mfdu** » Wed Aug 23, 2006 5:11 pm

mmmm i am soooo eager to build some of these.

i have a couple of spare OEP input trannies left over from a previous build (opto compressor) and a pile of 2520 opamps, but i'd love to try a couple using the JLM input trannie and the JLM opamp as well.

let me know how it goes. not the build - the JLM gear seems great to build, according to all reports.

it's the sound. it's all about the sound.

chris
mfdu

by **Barney Loveland** » Mon Aug 28, 2006 10:28 pm

Hey guys,
I have one of purusha's custom qaud pre racks on the way and think that a few JLM baby animals are just around the corner. I have built a pair of 1290's which are sound great and went to together like lego! Can highly recommend JLM.

barney

by **mfdu** » Tue Aug 29, 2006 9:41 am

hey barney

what quad pre racks do you mean? are they the green pre, or is that yet another one?

chris.

by **Barney Loveland** » Tue Aug 29, 2006 11:02 pm

He is the guy from prodigy site selling drilled and screened empty racks. The one I have on the way is for 4 pres with volume, pad, 48v, phase and a di on each channel. Sorry for the confusion. They are perfect for the JLM ba's.

by **mfdu** » Wed Aug 30, 2006 9:57 am

og that's right - he does dual mono pultec cases and stuff too.

personally, i enjoy the metal work side of diy . . .

have you checked out joe's pre-screened cases at JLM? they are cheaper than the bog standard Jaycar cases, and i would be pretty sure they'd work out cheaper than purisha's cases (after postage from the slovenic states, that is!!!)
but purisha certainly seems to have taken everything into account for his boxes.

personally, i like the idea of building a pair of fully trannied baby animals with DI's into a tough metal drop-box, so i can dump it down anywhere i want - along the lines of the U.A. mono tube or solid state channels, you know? or the hamptone pre boxes.

cop ya later.

chris.

by **chris p** » Wed Aug 30, 2006 2:30 pm

Hey there Chris (mdfu)

If you haven't already, check out the BA build site at Prodigy - there's a few that have been built that way, and they look great (as well as sound great).

by **mfdu** » Thu Aug 31, 2006 9:56 am

that's it - there's a couple of little beauties shown on that topic.

i do like the concept of dual (or quad) pre's with DI's in a drop box. very commando.

i got a couple of old metal boxes left behind by the previous owner of this house - old woolsley spare parts tins and stuff.

or how about four pre's done into a round chrome air-cleaner body (ex-valiant)? that'd be pretty cool.

enough - i gotta get back to work prepping the music room.

chris.

by **chris p** » Tue Oct 03, 2006 10:21 pm

YEEHAAAA

I'm all done. Four minimalist JLM BA 1:4/99V class A discrete transformer input variable impedance preamps. I worked with the JLM 48V DC supply, didn't bother with the DI option ('cause I have enough external DI's), and so each build was really pure (shown below without the input tranny, 99V amp or the 390pf load capacitor).

The variable impedance was achieved by replacing the transformer load resistor with a switched resister array, with values to give 300 ohms, 600 ohms, 1.2kohm and 2.4 kohm impedance.

Unfortunately, this for me counts as a neat wiring job!

The front panel closeup shows the layout.

And here it is

Sounds sooooo nice. I need to get the right hand side decal replaced from the switch labels on (to read "Baby Animal Mic Pre Kit" to match the left hand text). This rubbed off on my laser printer cartridge. But apart from that, I'm a happy camper.

by **astrovic** » Wed Oct 04, 2006 12:18 am

That is totally sweet man - and a hell of a clean job too!!

by **mfdu** » Wed Oct 04, 2006 9:28 am

yeah - very clean. what trannies did you use (they look sowter-ish) and did you go the jlm 990 doa's on all channels?

inspiring - i'm just waiting for joe to get back from holidays and confirm my order request so i can get started. . .
unsure if i'll be doing the quad pre's into a valiant air-cleaner tho . . .

chris.

by **toddd** » Wed Oct 04, 2006 11:03 am

expect me bugging the crap out of you when i get some time/motivation to start...

by **chris p** » Wed Oct 04, 2006 11:30 am

Hi Chris Mdfu

All channels use the JLM 1:4 input trannie and JLM 99V discrete opamp (which is a single, not a dual, and hence the absence of about 6 components on the PCB).

I did this because first, its the best combo for the variable impedance, and I wanted to get some really low Z for my tube mics; secondly, it gives a sound really close to the classic Neve but with more bass clarity; and thirdly its quite rock'n'roll, and I wanted enough of this flavour to do kick, snare, lead and rhythm guitars.

For those interested, the impedance works by reflecting the value of the load resistor back through the input tranny, divided by the square of the tranny ratio. So with these 1:4 trannies, the impedance presented to the mic is the value of the load resistor divided by 4 squared, ie 16. So the rotary "impedance" switch is wired to give resistances of 4.7k, 9.4k, 19.4k and 39.4k at the four positions, and then simply wired in place of the recommended 10k (=600ohm) RL resistor.

I plan on doing another set of 4 to add to this: 2 with lundhal trannies, 99V opamps and a JLM 1:1:1 (wired as 1:2) for high gain (around 75db) applications and vocals, and 2 with OEM trannies and JLM Hybrid opamps (with front panel switching between class A and class A/B) to give some flavour options. This is still a bit down the DIY list though.

by **JLM Audio** » Thu Oct 05, 2006 9:20 pm

Hi Chris
Looks great. Nice clean build. Enjoy :D

If you use a Lundahl in your next BA's make sure it is a LL1578 as it gives lots of gain and great tone.

by **Barney Loveland** » Sun Oct 29, 2006 10:57 pm

Here's my version of the Baby Animals, all with JLM 1:4 input trannies, 2 with 99v opamps, 2 with OPA2604 chips at the mo.

by **chris p** » Mon Oct 30, 2006 8:16 am

Now that's the sort of neat wiring job to which I aspire!

How do you rate the OPA's against the 99V's?

by **Sheer Noise** » Mon Oct 30, 2006 9:06 am

They look great Barney.

I'm very close to doing almost the same thing.

Dave.

by **JLM Audio** » Tue Nov 07, 2006 10:57 pm

Barney's build is A1 :-)

Below is for those who didn't see this over at The Lab on the baby animal thread.

Thanks everyone Baby Animals Sold passed 500 last week. So I thought I would put up a photo of two new BA family prototypes. The new BA type PCB's run on the same 48v to 62v power rail as the original BA and fit straight into the same position.

The BA Neutral (BAN) is for building several versions of the Graeme Cohen Mic pre topology like Amek/SSL/Forssell/Green mic pres use but redesigned to run on one 48v to 62volt power rail. The PCB can take LM394 dip or can, MAT02, 2 x 2SK389, 2 or 4 x BC550C etc as its discrete front end. Working around a OPA2604A, NE5532A dual dip etc. The output stage can be JLM99v, Hybrid, 990, 992, 993 etc with output transformer if you want fully floating balanced output or OPA2604A, NE5532A etc for electronically balanced output stage. Has input stage trim pot to better balance transistor/fet match which is adjusted simply with a multimeter held between the two TP1 and null for 0v. Also a output swing trim that centres the output of the output stage opamp to half volts to give best maximum +/- swing. This is another 0v null trim while holding the multimeter on the 2 TP2 points. There is no servo as there is always half the supply rail volts on the output so a output cap is always needed and the trim pots do the DC offset trimming.

Difference between Dual 99v and BA Dual (BAD) is 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.

Joe

by **chris p** » Wed Nov 08, 2006 7:54 am

Congrats on the sales benchmark, Joe - although I'm not at all surprised.

The great thing about the BA design is its flexibility - and the two new models will only enhance that.

Good luck with them.

by **astrovic** » Wed Nov 08, 2006 9:51 pm

Dammit Joe - I've been working on getting a couple of channels of Baby Animals as a Christmas present and you go and give me more choices??? :)

As always, looks great and congratulations on the sales!

by **Andrew** » Thu Nov 09, 2006 12:37 am

ooh I just ordered a baby animal, was I number 500 Joe?

Those BA's look so easy to build I think everyone who's having a "everything I build keeps blowing up/not working day" go and buy one, build it, enjoy it for inspiration & motivation on those harder diy projects.

by **mfdu** » Thu Nov 09, 2006 9:00 am

dang joe - here i was about to place an order.

how long till the two new BA models are available?

chris.
(mfdu)

by **JLM Audio** » Fri Nov 17, 2006 2:30 pm

I would think it would not be until early January by the time we fully test these and get the final run of PCB's. Remember the BA Dual will be almost twice the price of the Normal BA and the BA Neutral is a purepath pre which is only really suited to room recording and classical in my books but Amek and SSL lovers might think otherwise. So the normal Baby Animal will still be the one that will suit most peoples needs best.

We have at the moment almost finished testing the dINgo and PEQ1 PCB's etc. Info below for those who missed this at the lab.

The JLM Universal IO PCB currently known as dINgO shown below can be used as a balanced in to unbalanced out and unbalanced in to balanced out with gain at the same time. It takes a 218* VCA IC direct on the PCB for a VCA comp and runs it of the +/-24v to 34v rails so no other power rails are needed. Can have terminals for in and out or Neutrik Series A PCB connectors direct to the PCB. Also has a hard bypass relay and terminals so you can just use it to balance any unbalanced equipment in and out.

Full circuit fo JLM dINgO here
http://www.jlmaudio.com/JLMdINgO.pdf

The I/O 10 pin IDC on the dINgO can plug into and power our
JLM PEQ1 passive EQ PCB (as shown below)
and soon
JLM T filter EQ PCB (Sontec/GML type eq)
JLM VCA Comp side chain front panel PCB
JLM Opto comp PCB.
JLM Volume Controller PCB.

Below is a our small VCA PCB that has the same pinout and size as a 202 but can be built with inverting buffer opamp on board or not and also has up and down control voltage scaler on it so it can replace any 202 type. It also fits direct into auditronic consoles to upgrade there VCA PCB. Takes 1 to 4 x 218* VCA's and has parts so the VCA can run directly on +/-24v to +/-34v.

Joe

JLM Audio
Capturing Audio without Injury
www.jlmaudio.com

by **Barney Loveland** » Wed Nov 29, 2006 4:22 pm

Hey sorry for the delay about the differences, still getting used to them. The 99v jlm 1:4 is amazing, very smooth, and slick sounding, HIGHLY recommended. The opa 2604 channels are also very good, more snappy sounding, not as smooth in the highs but a slightly tighter bottom end. These are only my ramblings and have not had a good session through that i could play with them.

xmas projects include a pultec, and a G9 all going to plan :-)

by **astrovic** » Thu Nov 30, 2006 9:43 am

Cheers Barney

Where'd you get those knobs from? I've been looking for cool silver knobs, and those are, well, cool silver knobs :)

by **Barney Loveland** » Thu Nov 30, 2006 2:17 pm

Hey astrovic,
The funky silver knobs are made by Kilo International, i bought them from RS, but i think you can get them cheaper from Allied or Digikey from the US even after shipping costs!!! Next time. They come in silver and black, matte or gloss, very classy i reckon.

by **astrovic** » Thu Nov 30, 2006 5:21 pm

Thanks Barney!

Just looking around digikey - there are 8 pages of Kilo International knobs to look at there. By the time I'm finished I will have seen more knobs than the janitor at the local footy club :) Makes me wonder which team I bat for these days...

by **Barney Loveland** » Thu Nov 30, 2006 11:53 pm

Yeah they make a few knobs!! The one's i used are the HD series, i also like the JD ones. You'll probably recognize both of them as some famous gear makers use them too.

by **astrovic** » Thu Jan 18, 2007 12:46 am

Well, anything you guys can do, I can do...also:

Only one channel at the moment - it's a gradual acquisition. This channel is a JLM99v with a JLM 1:1:1 transformer.

My front panel design wasn't too special - a couple of miscalculations haven't done me any favours. In particular, I don't have any option as to how I place the DI, and it is perilously close to the top of the trafo. So long as everything is tightly screwed in, I'm ok, but I have to be careful. I also have some minor things to do to finish this channel off (like tying down the black wire on the trafo.

Thanks Barney for the advice on the knobs. They don't go as well as I'd have liked with with the aluminium coloured panel, but that was because I changed my paint colour half way through.

Otherwise - great stuff and just sounds sweet as. Very happy with it.

To follow soon - a dual G1176 and a GSSL!

Cheers guys

by **astrovic** » Fri Jan 19, 2007 10:56 am

I had some fun with my little beast last night - I was tired from slaving over a temperamental G1176 for a couple of hours, so I pulled out my trusty Fender Gemini acoustic with 8 month old strings on them, matched it perfectly with my Shure SM58 (all I had at hand), plugged it into the Baby Animal and on into Logic, and let 'er rip...

Geez it sounded good. Really good. For a Gemini and a SM58, obviously, but dammit it was right there. I've struggled for years with the desire to record, because I couldn't pull a good tone...but this just re-kindled the fire.

Great stuff, Joe - very happy camper! :)

JLM Baby Animals

JLM Baby Animals

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