JLM Baby Animal

[crm0922]

How about running baby animal off batteries or something? It is small enough to make a very portable preamp. Like tripled 18V from 9V cells...or something like that. I have no idea, I'm sure that is a terrible waste of power. ;-)

Chris

 

[mr.jones]

[quote author="crm0922"]How about running baby animal off batteries or something? It is small enough to make a very portable preamp. Like tripled 18V from 9V cells...or something like that. I have no idea, I'm sure that is a terrible waste of power. ;-)

Chris[/quote]

I suppose you could do that if you wanted to, but I don't think it would work very well at all. You'll lose headroom running it off of +/-18V. I imagine it would eat the batteries really fast too.

EDIT: You could try this. You'd have to add an extra battery to each side to get +/-18V. Honestly, I wouldn't do it. You'll be changing batteries very often, you won't get 48V for phantom power, and the sound will suffer. For a portable preamp I'd just put the Baby Animal in a small enclosure and use the smaller of the two 48V power supplies on the BA page.

 

[mattmoogus]

[quote author="mr.jones"]I think my favorite thing about the hybrid is that Joe seemingly laid out the parts on the PCB so it looks like a one-eyed robot pirate grimacing at you. You may notice there's no smiley on the PCB unlike most of Joe's products, but it's OK. Why silkscreen a smiley face when the components can form a robot pirate instead? I don't know either.
[/quote]


Hehehe I never saw it before...it does look like a robot pirate! I reckon you should win a prize for that.
:green:

M@

 

[crm0922]

There are battery operated preamps on the market with 48V power for mics, and these run on batteries. Since the 48V is necessary for phantom anyways, I figured you might be able to run the pre off the supply once it is generated somehow.

In my post I suggested *tripling* 18V with a circuit of some sort and using the resultant 50+V, but again, there are many ways of making things work that I am not aware of.

My laptop uses a pretty small battery and runs for hours, I think batteries could power a preamp for a respectable period of time. They do make lithium disposable cells, after all.

Here's one that runs on 2 AA batteries:

http://www.sounddevices.com/products/mp1master.htm

Says it runs 24 hours w/o phantom engaged.

Obviously in a portable Baby Animal you'd want to use a monolithic opamp, not a class A power hog. ;-)

Chris

 

[mhelin]

LM5000 might help in DC/DC conversion to 48V:

http://cache.national.com/ds/LM/LM5000.pdf

There's a circuit for 48V out converter using 18-36V input (three 9V batteries in series for an example).

 

[greenmanhumming]

heres some pics of my build, nothing special but it works.

sound wise i perceived the 2604 JLM 1:4 combo to be very neutral with fast transients and a slight dry woodiness to the tone.

with the 99V its more fat and smooth with a pronounced low midrange..

each has sources its better on...

I also have a hybrid opamp to try, but i think i screwed up building it....

 

[mr.jones]

[quote author="mattmoogus"]I reckon you should win a prize for that.
:green: [/quote]

Weeeelllllll....I am planning to order another hybrid soon... :wink:

 

[greenmanhumming]

when i plugged my hybrid in the LED didn't light up.

i built it late at night and probably did something foolish. and i'm finding these little PCB's a bit fiddly after PTP tube amps...

i suspect that i put the LED in the wrong way around. I pulled it off the board and checked it and it now doesnt light up either way around on a battery so i think its blown.

Can someone confirm which way is the right way? i saw A on the board and thought that meant anode, but then tracing the circuit i think it should be the other way.

what value is this LED? is it 48v forward voltage??

also, in trying to get those transistors seated nicely and lined up with the edge of the board , i got one of them quite hot, how tolerant are they??

I'm not sure I dare plug it in to my BA now.

any more info on the hybrid would be very helpful.

i also dont know what DC servo is, and if i want it enabled or not? looks like some sort of NFB circuit?

 

[mr.jones]

[quote author="greenmanhumming"]i suspect that i put the LED in the wrong way around. I pulled it off the board and checked it and it now doesnt light up either way around on a battery so i think its blown.

Can someone confirm which way is the right way? i saw A on the board and thought that meant anode, but then tracing the circuit i think it should be the other way.[/quote]

A is for anode, and it is the longer of the two wires. If you had it wired backwards, it is almost definitely blown and you'll need to replace it.

what value is this LED? is it 48v forward voltage??

No...I don't think you can even buy LEDs with a forward voltage that high. Any standard LED that's the same size should work fine. I'm sure Joe or Matt will verify this as I'm not 100% sure.

also, in trying to get those transistors seated nicely and lined up with the edge of the board , i got one of them quite hot, how tolerant are they??

I would guess they get pretty hot, though I haven't checked mine to find out. I used a pair of needlenose pliers and grabbed all three pins at once right next to the casing and bent them down. Everything fit perfectly.

Make sure you didn't bridge any of the solder pads. The Hybrid has two modes, a Class A mode and a class A/B mode. The LED lights in class A but not in A/B. A/B mode is enabled by soldering two pads together on the back--I think the two square ones toward the middle. Again, I'm sure Joe or Matt will clarify this.

Check for any solder bridges that shouldn't be there. There're a lot of parts packed into a tiny space, and it's easy to make a mistake.

Cheers,
Chris

 

[JLM Audio]

have a spot for a zener(30-47v) and a similar one that just says 47. Im assuming you put the pair of transparent resistor looking things there(i know...can you say newbie!?) but i also have two of those things that are separate and slightly different.

With a large power supply you will need to fit the * regulator parts to give 48v phantom power. But the # regulator parts will not need to be fitted only a jumper between C and E of where the #BD681 would have been. The zener diodes which are red glass types all have different values on them as we include 33v, 36v and 2 x 47v ones with the kit. If you are not sure on the values off the zeners add 1N to the front of the number on them and Google it and it will tell you what they are.
http://www.jlmaudio.com/Baby_Animal_Mic_Pre.htm

also i have two slots for a BD681, and only one BD681G part. Saw something on the thread about wire jumping these for 48v, but ive got the big power supply. Thanks for takin the time you all!

I have just checked the kits and some of the new batch have only got 1 BD681 transistor instead of 2 which we have now fixed. If any one needs 2 please send me a email with your address and I will shoot you one. But most situations you will only need one or none. The web site has tables on what regulators to fit with what combinations.

How about running baby animal off batteries or something? It is small enough to make a very portable preamp. Like tripled 18V from 9V cells...or something like that. I have no idea, I'm sure that is a terrible waste of power. ;-)

You could run the baby animal of 6 x 9v batteries but it would be better probably to run the smallest 12v gel seal battery with a DC to DC converter. I know I can get one that run on 9v to 18v and gives regulated 48v out for about $30+AUD. That way you could recharge it easily from a car or charger. If you have a modern condenser mic it probably can run off 12v to 48v phantom. So you could use a OPA2604 or NE5532 and run 18v with 2 x 9v batteries to run phantom and the opamp and it would work just fine.

Can someone confirm which way is the right way? i saw A on the board and thought that meant anode, but then tracing the circuit i think it should be the other way. what value is this LED? is it 48v forward voltage??

The led should drop 1.8v to 2v and will light in class A mode. A does mean Anode which is the long leg of the LED. Putting this in backwards would most likely kill the 2 output transistors or at least burn the 2 x 10ohm resistors at bias would now be 48v instead of 2v. If you solder the 2 square pads that join to the 1N4007 diodes then the hybrid will turn off the LED and go into Class A/B mode. If you solder the 2 x square pads under the PCB closest to the IC then DC servo will be enabled which is pointless on the Baby Animal as its output sits already at half the voltage rail.

also, in trying to get those transistors seated nicely and lined up with the edge of the board , i got one of them quite hot, how tolerant are they??

They are very hardy so it would be hard to hurt them with the heat.

i also dont know what DC servo is, and if i want it enabled or not? looks like some sort of NFB circuit?

It is for circuits run +/- rails so no output cap is needed as the servo will trey to keep the output of the opamp at 0v but in the baby animal it has no use so leave the 2 square solder pads near the IC not joined.

i suspect that i put the LED in the wrong way around. I pulled it off the board and checked it and it now doesnt light up either way around on a battery so i think its blown.

If you use a battery to test a LED it will need to be 3v or more and have a 1k resistor in series. If you use 3 or more volts with no resistor you will kill the LED while testing. If you use a 1.5v battery it will not light the LED either way so it will not test it anyway.

 

[greenmanhumming]

EDIT: i realised i was misunderstanding some stuff.

so with no pads jumpered it should light the LED and operate in class A?

so it should have lit up when i first installed it, so i must have done something wrong, if only maybe blowing the LED checking its polarity before installing.

I now can't find any errors in what i originally built, but i think i messed up with trying to fix it, one of the 10r resistors is slightly burned, which i hadnt noticed till you mentioned it.

maybe i'll replace the LED and output transistors and try again...

is there any way to test the output transistors? they are only about 10p each, but i would have to order them from somewhere and pay shipping.

 

[greenmanhumming]

Another question:

has anyone built BA's using both the OEP transformer and the JLM?

what is the difference in sound? Joe?

I'm wondering about 2 more channels with OEP's

the OEP has a bit more gain too, so would compensate for using the 99v without a OT.

It's a bit early to tell, since i'm still getting used to them, but i might be looking for a little more sparkle or shimmer or something in the top end, and i wonder if the OEP would give this.

I like the controlled sound i'm getting from these preamps, but sometimes its just a bit too restrained in the top. OTOH my m-audio DMP3 pre's sound pretty good, but have a fairly (over) enthusiastic top end, so i could just use those when i want that sound, its probably less accurate but flattering on some things. Or i could use a hyped sounding mic through the BA's..

 

[mattmoogus]

If you have a Hybrid running and you want more sparkle/brightness/speed try changing it to class A/B mode.

Also if you have the 1:4 xformer, try deloading it (change RL to anything from 20k to 100k).

The OEP does have a different top end to the 1:4, you could say its brighter, kinda, but that doesnt really describe it properly. It does roll off down low earlier than the 1:4 though. The best way to know is to try it and see.



M@

 

[greenmanhumming]

I've mostly been using the 99v, i've also used the 2604

i havent got my hybrid working yet.

I like the smoothness of the 99v, and the 2604 gives plenty of speed... its not so much brightness as something sparkly about the quality of the highs.

I don't feel that either the 99v or the 2604 actually lack highs, but the 2604 is very dry and fast and the 99v is smooth and nice but i'm looking for something slightly more pronounced. I'm not in anyway unhappy with the sound, just adjusting my ideas, and looking for best of all worlds of course...

 

[greenmanhumming]

another idea i had when looking at the hybrid schem, is:

what about a version that doesnt have the DC servo, and has basically two channels of the basic class A only circuit. use the other half of the 2604 that was used for the DC servo, and add two more power transistors instead of the DC servo components, then it could be used in balanced mode, kind of like the 2604 in the basic BA.

would that work? would it sound good? would it be a total current hog? would there actually be any advantage?

 

[mattmoogus]

[quote author="greenmanhumming"]another idea i had when looking at the hybrid schem, is:

what about a version that doesnt have the DC servo, and has basically two channels of the basic class A only circuit. use the other half of the 2604 that was used for the DC servo, and add two more power transistors instead of the DC servo components, then it could be used in balanced mode, kind of like the 2604 in the basic BA.

would that work? would it sound good? would it be a total current hog? would there actually be any advantage?[/quote]

Were waaaaay ahead of ya on that one :grin: :thumb:

M@

 

[mattmoogus]

[quote author="greenmanhumming"]I've mostly been using the 99v, i've also used the 2604

i havent got my hybrid working yet.

I like the smoothness of the 99v, and the 2604 gives plenty of speed... its not so much brightness as something sparkly about the quality of the highs.

I don't feel that either the 99v or the 2604 actually lack highs, but the 2604 is very dry and fast and the 99v is smooth and nice but i'm looking for something slightly more pronounced. I'm not in anyway unhappy with the sound, just adjusting my ideas, and looking for best of all worlds of course...[/quote]

Well, try the loading and A/B options and see how you go.

Just wondering though, have you heard the sound of the pres in a mix yet? Often I only really get a know a pre once Ive heard something recorded with it mixed and mastered, and on the stereo in our boat/car/workshop etc.

Also Im wondering what mics/sources youre listening to?


M@

 

[greenmanhumming]

you are right i havent really done whole songs using just these pres yet.

I have done some lead vox using the 99v and JLM1:4 which sounds really good, but tends to get overshadowed by tracks recorded with brighter pres, not to mention tracks with hashier messy pres like all my earlier stuff using a mackie mixer.

the one test song i have done using only JLM pre's practically mixed itself, i hardly had to do anything. needed less compression etc too.

so you are quite right about that! The JLM pres sound more relaxed and solid and maybe more vintage, I'm not sure if i will want something more sparkly or not when i really get used to them. So its fairly premature speculation at this point, but its good to know what the options are!

I am using Rode NT2000 on vox. Rode NT5's on guitar and bouzouki, sometimes the NT2000 on zouk too. AKG c451 on fiddle and viola. I'm saving up for a C414. Any comments or suggestions about that mic lineup?

 

[greenmanhumming]

details??

Were waaaaay ahead of ya on that one :grin: :thumb:

 

[mattmoogus]

[quote author="greenmanhumming"]details??[/quote]


Not THAT far ahead :wink:

M@