JLM Baby Animal

[Lowfreq]

[quote author="JLM Audio"]Was this with a old 30mm x 20mm type 99v ? As the New 99v are smaller than a 2520 at 1" square and should fit?[/quote]I had a Quick check and yep, they're the 30x20 type. Good to know that the newer ones will fit. :green:

I had fun doin some drums on the weekend. Got some very tight snappy sounds outta a Tama superstar birch kit. I may get some clips up once I've finished off the track.

Couple of dual 99v's on the oh's while my Baby A's worked on the snare top and bottom. :grin:

Very Nice............ Makes my job so much easier :wink:

 

[Schmilsson]

My last post got lost when the forum went down.
Here goes again:

What hole sizes do you use for the metal work?

I'm thinking:

Gain pots = 7mm
Toggles = 6,5mm. 11,5mm between the center of each switch???
DI = 12mm
DC = 8mm

 

[JLM Audio]

Sorry to hijack this thread, but i was wondering if the BA+impedance controls would be a good choice for older ribbons or not?

if yes, what combo would you recommend?

What combination would give the most gain? (And would that be enough for low output ribbon mics?)

Yes BA if you only need 60 to 66dB of gain. Best of all would be Dual 99v with impedance control added if you need more gain.

How does the load resistor on the secondary affect the input impedance?

The input load is reflected as the square of the ratio. So if you load the JLM14 secondary 1:4 ratio with 10k the input impedance for the primary will be 10k / 4 / 4 = 625ohm. With 100k / 4 / 4 = 6.25k.

I guess the ribbon mics want to see a pretty high impedance to work best, or am i way off here?

Running ribbons into higher input impedances lets them put out there full level and doesn't take off as much high frequency usually.

Couple of dual 99v's on the oh's while my Baby A's worked on the snare top and bottom.

Very Nice............ Makes my job so much easier

:grin:

What hole sizes do you use for the metal work?

I'm thinking:

Gain pots = 7mm
Toggles = 6,5mm. 11,5mm between the centre of each switch???
DI = 12mm
DC = 8mm

Yes that is all right but the gap between toggles is technically 11.7mm but there is a bit of tolerance in the 6.5mm holes so 11.5 will work fine.

 

[Schmilsson]

Nice pic!

So you drill them 6mm diameter, 11,7mm apart?
I still have some time altering my drawings before engraving.

 

[Lowfreq]

Just finished adding on the D.I kit to my Baby A, and made a few extension wires to attach the 99v op-amp off the board(Joe, i'll def have to get round to ordering some of the new shape), & added a cinemag CMOQ-2L oupt tranny.

Borrowed a freinds Musicman 1970somethin stingray bass, and sat there for an hour just jamming along with some tracks. AWESOME!! :thumb: :thumb:

I don't know what a API sounds actually sounds like(and i know i'm not using a 2520) but, HELL I DONT CARE WHAT ONE SOUNDS LIKE!!!! I know what a baby A with cinemags & a 99v sound like. and it's goooood. :grin:

 

[JLM Audio]

So you drill them 6mm diameter, 11,7mm apart?

6.3mm is the smallest hole the toggle will fit into

Borrowed a freinds Musicman 1970somethin stingray bass, and sat there for an hour just jamming along with some tracks. AWESOME!!

I don't know what a API sounds actually sounds like(and i know i'm not using a 2520) but, HELL I DONT CARE WHAT ONE SOUNDS LIKE!!!! I know what a baby A with cinemags & a 99v sound like. and it's goooood.

:grin:

 

[Schmilsson]

My dpdt switch got me confused.
How do I wire it up with a 10k resistor and a power led?

 

[mattmoogus]

Do you mean a power switch with a LED indicating when power is on?



M@

 

[Schmilsson]

exactly

 

[mattmoogus]

Joe has it drawn here:
http://www.jlmaudio.com/JLM Dual 99v wiring overlay.pdf

It doesnt matter which leg the 10k is connected to just as long as its in series with the LED. Also that layout shows ground being switched instead of the 48v, whereas in the BA pre youll probably be switching the 48v.


M@

 

[Schmilsson]

Some gear porn, got these together last night.
Thanks to Joe and Matt for answering about a thousand questions and neriks for the engraving!:sam:

But since it's my first build, damn right they're not working properly.
I'm gonna reread this thread first before starting asking stupid questions :wink:
Oh, btw, 6,2mm is the smallest hole the toggles will fit into, I had the panels made before I got your answer, I wouldn't recommend it though. :green:

 

[Jonkan]

eskimo, very nice work!! Alot cleaner than my first build (which btw also doesnt work 100%). My second build went alot smoother, and works! :green:

where did you get the case, and what did it cost you?

And how much did neriks charge for the engraving work?

Im in sweden too, im guessing you also hang on the "studioprylar & bygge" forum?

/Jonas

 

[Schmilsson]

[quote author="Jonkan"]eskimo, very nice work!! Alot cleaner than my first build (which btw also doesnt work 100%). My second build went alot smoother, and works! :green:

where did you get the case, and what did it cost you?

And how much did neriks charge for the engraving work?

Im in sweden too, im guessing you also hang on the "studioprylar & bygge" forum?

/Jonas[/quote]

Thanks!

The case is a Teko DS 2470, engraving 200SEK for both panels including all the holes.

 

[gevermil]

Looks great -
Is there a reason for the gain jumpers to be hooked up differently on the pcbs ?

 

[Schmilsson]

Not quite following you?

 

[mattmoogus]

Hey Eskimo, that looks fantastic! :thumb: Very neat case youve got there.

You say its not working properly, what are the symptoms? I notice you have the 1/4w 10ohm resistors in your kits which could have gone open when you powered it up. Weve had this a few times now so we now ship carbon resistors instead which seem to handle boot up better. This is the first thing Id be checking - make sure they still measure 10ohms in circuit.


M@

 

[Schmilsson]

I think I got it sorted, the 10ohms are fine, I've got some carbon backups though. The dc-socket wasn't connecting enough to the case, I wired it to one of the xlr's and now it's stable.
The pots are scratchy though, and everything seems a bit too eager to distort.
The DI seems really sensitive.
I need to fiddle some more before I know what's BA and what's me. :wink:

 

[gevermil]

Sorry , I forgot that you had one pre with a DI
Hence the difference in the IDC Socket .
Ill be quiet now

 

[mattmoogus]

Sounds like you have your soundcard/mixer set to -10 instead of +4?...

The pots will make a little noise especially when the circuit is still stabilising but it shouldnt be very loud unless youre running it into a -10 input.

M@

 

[yodermr]

hi all
got my 1st ba put together. worked thru a few mental lapses [put jumpers in, etc :wink: ] but i am left with a few issues that i'm not sure what to do with them. JLM99V/OEP262A3C

1. noise. high end ocililation. not too bad but not really acceptable. goes away for the most part when you put the 48v on. all my wires are twisted tightly

2. 48v doesn't work. light comes on, but no output with a condensor mic

3. with the pad ingaged the pre will get a pop and high frequency ossicitation when you get to the last 4 detents on the gain

even with the issues, it sounds kick ass so far :thumb:

thoughts :?: