JLM Baby Animal

[Regis]

Salivating :shock:

 

[JLM Audio]

I'm looking at the second board, the NEUTRAL, and it looks like it is a version of this http://www.forsselltech.com/JFETMP1.PDF but with single ended output (2x2SK289, OPA2604, JLM99V as out driver). Am I right? Did you use DC servo for the output circuit? (somewhere under the JLM99V a chip?)
I'm very interested because I started to design a board for something similar, but in this case I would preffer to buy from you.
Give me please more details about the NETRAL.

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.

Whats the difference between the dual 99v and the dual BA?

Difference is BA Dual (BAD) 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.



Below is a small Power switch and LED PCB that comes in the full BA everything kits now to make that even simpler.

 

[Schmilsson]

That is so awesome!
Why couldn't you have the dual option when I got mine?! :wink:
No worries, I love my pair.

 

[Adam]

:shock: Awesome stuff Joe! i want it.... :thumb:

 

[Purusha]

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.

Would it be possible to insert passive Pultec EQ as well?

I was looking at your website, but I guess it's still not updated. What will be the cost for a BAD KIT and when will you have them availble for order? Might order two for a start :wink:

 

[mattmoogus]

[quote author="Purusha"]
Would it be possible to insert passive Pultec EQ as well?[/quote]

Thats what the man said!

I was looking at your website, but I guess it's still not updated. What will be the cost for a BAD KIT and when will you have them availble for order? Might order two for a start :wink:

Theyre still prototypes and it will be a few weeks before we get the production boards back and have kits ready to send/website info/prices etc. Rest assured yall will be notified with theyre ready to go!
Ther are a few other wicked kits coming out soon aswell.


M@

 

[Purusha]

Better double check everything, that is my moto :green:

Ther are a few other wicked kits coming out soon aswell.

It would be nice to know more about this so we can plan ahead :grin:

 

[Lowfreq]

[quote author="mattmoogus"]
Ther are a few other wicked kits coming out soon aswell.[/quote]You mean you don't have enough already? :wink:

Just when I was trying to ease myself away from doing so much DIY......................................................................................

Oh well, I guess the adiction continues :green:

 

[mattmoogus]

[quote author="Lowfreq"]
Just when I was trying to ease myself away from doing so much DIY......................................................................................
[/quote]


No I find its best to admit youre sick and just enjoy it :razz:


M@

 

[Lowfreq]

Can you tease my disease with any hints of these projects? :wink:

 

[chrissugar]

Thank you Joe for the info.
I'm looking for a capacitorless version of this preamp, wich means differential PSU and DC servo, so it looks like unfortunately I will have to make my own PCB. :sad:

chrissugar

 

[mattmoogus]

No cant say anything except theyre going to be bloody useful and there isnt anything quite like them that I know of...wont be long till we can say though.


M@

 

[chrissugar]

I'm absolutelly sure the NEUTRAL preamp is excellent, do not misunderstand me. All your kits are great and very well designed.
I have lots of different preamps, so at this moment I'm for the most transparent mic preamp possible for audiophile classical orchestral recording. And for me that means no transformer and no capacitors if possible.

chrissugar

 

[barney]

Here's my diy latest, thanks to JLM for fab sounding pre's, I have 2 1:4JLM 99V and 2 1:4JLM with the OPA2604, but soon to be hybrid. Thanks also to Purusha for the rack. Cheers

 

[mattmoogus]

Nice one! Neat wiring man.

To show the images in the post body, hit the Img button at the top of the post form (next to URL) then copy the link to the image in and hit the button again to close the code.
Looks like this without the spaces:

M@

 

[barney]

Thanks Matt.

 

[Purusha]

Hey Barney, I see you filled up the QUAD. Nice job and nice knobs. They must cost a fortune :grin:

Just a small suggestion. The cut out for the power in the back is made for a regular IEC with a fuse so you'll have to improvise a bit to close it. I took a flat black piece of plastic and cut it into a square, made a hole and screwed it on back panel from the inside. But hey, this is DIY, so you'll be fine :wink:

 

[barney]

Hey Purusha, yes am planning on making a small panel to fill the iec hole, have already drilled the hole ready to bolt it on, was just too excited to get them fired up that the cosmetic for the back of the rack was not a high priority. Cheers

 

[Purusha]

For variable impedance on BA JLM 1499111 combo I need 100K LIN or LOG pot? Probably LIN but I am not sure.

Anyone?

 

[mattmoogus]

Log


M@