JLM Baby Animal

[JLM Audio]

Ok, I'm stupid, I had the pot wired backwards. When looking at the pot as described above, the ground terminal is on the left.

There should be no ground to the impedance pot. Only the 2 wires from RL's pads with a resistor in series.

 

[yosh]

Ok, no ground. That makes sense. Thanks Joe.

I love the way the 99v sounds like it is, but if I think the 100 ohm resistor makes an interesting change, then I might add a switch to switch it in and out of circuit. Just another sound design option. Thanks!

-Josh

 

[mattmoogus]

Just remember that youll loose a fair bit of level and the pre will clip earlier with 100ohms across it. This is really something to try for fun and use occsasionally as it will detrimentally effect the pre's performance/specs. But if it floats your boat then go for it. We just dont want to see people building them with 100ohms always across the output and wondering why they dont work properly!
Also, it may be worth trying larger values if you find 100ohms is too much. I was watching a THD graph of a 99V pre yesterday while holding 470ohms across the OT secondary and the relationship between 2nd and 3rd harmonics changed quite a lot, with 3rd staying the same and 2nd roughly doubling.


M@

 

[greenmanhumming]

I've just ordered 2 more channels of BA's from Joe, they are going to have OEP transformers, and probably 99v's

I'm about to order my OEP transformers (from farnell), and I thought I'd get some different IC opamps to try as well, I see from the website that the NEC etc are not plug and play due to requiring a lower voltage.

anyway there seem to be different versions of the same opamp that say different voltages!

will this one work?

http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=1106091&N=0

what about this one?

http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=2349644

both say only +15V, or do they mean each side?


heres a 36v LM 833

http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=3343650&N=0

does that mean each side or total, and would it work with the 48v supply?

heres a 15v LM833

http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=630998



also heres is a opa2604 that says only 15v, but we run our 2604's on 48v

http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=1097431


as you can see i'm confused! and any clarification about which opamps will work or are worth trying would be great!

 

[rodabod]

Those are the nominal supply voltages for each rail (+ and -).

Check the datasheets for maximum permissable voltage supply.

I'm sure they will all be fine. Try the NE5532 / OPA2604.

 

[JLM Audio]

Nominal volts is just that. It doesn't mean you cannot run the IC higher if the IC has a higher maximum voltage specified. NE5532AP has a +/-22v maximum, LM833 has a +/-18v maximum and OPA2604AP has +/-25v maximum.

All the info on how to set the regulators in the Baby Animal kits to suit NE5532AP , LM833 and OPA2604AP and heaps of other opamps is in the first table on the Baby Animal web page on our site here.

http://www.jlmaudio.com/Baby_Animal_Mic_Pre.htm

To run IC's that run on lower voltage than 48v the # regulator must be fitted and the 30v zener (+/-15v) or 36v zener (+/-18v).

 

[greenmanhumming]

cool, I get it now.

I had a look at some datasheets.

some don't seem to specify maximum supply voltage, but most do.

so is there an easy way to switch the regulator in and out to try out different opamps?

or should i compare with running the 2604 at the lower voltage?

is there a performance degradation running the 2604 at the lower voltage or does it just reduce the headroom/maximum output level? which is excessive anyway right?

 

[JLM Audio]

If you are trying different opamps fit the # regulator transistor and # 10k with no zener this will give with a 48v supply 48v - 1.4v = 46.4v to run the OPA2604 and JLM99v. Then by switching zeners in you can have any voltage you want quickly. The voltage set is the zener volts - 1.4v. A centre off toggle would give you roughly 30v/48v/36v with the 30v and 36v zeners already in the Baby Animal kit.

But be careful as higher than maximum volts on any IC is basically instant death to the opamp.

 

[greenmanhumming]

or for simplicity I could install the regulator to set the voltage to 30v and just plug and play, the 2604 would then be close to its nominal voltage, which surely is not a bad thing?

 

[Purusha]

Can someone explain to me if Cinemag CMMI-8PCA input tranny will work with BA with 2520 and Fabio's API output tranny?

 

[Purusha]

Oh, it does work :thumb:

Checked the JLM BA webpage...

 

[mattmoogus]

[quote author="Purusha"]Oh, it does work :thumb:

Checked the JLM BA webpage...[/quote]




:thumb: :thumb: :thumb: :thumb: :thumb: :thumb: :thumb: :thumb: :thumb: :thumb:




M@

 

[nick96]

Hi there, I have made 4 baby animal pre's as my very first DIY project so go easy guys

I have managed to finish everything exept the wiring to the power switch and the power adaptor socket. Could some kind soul please show me a picture of how it works or maybe a diagram.

At this stage I have just hooked 1 pre up with a 1:4 and a 99v. I have attached the pos and neg to the PCB and am wondering where the pos and neg go as there are no markings I can see on the power switch.

There are 6 prongs on the power switch. Do I run pos and neg from pre to 2 prongs ,pos and neg from power socket to 2 prongs and , pos and neg to the green LED?

What side do the red and black go?

What is the config on the rear power socket. There are 3 prongs. Do I bridge something?

Also What is the right orientation for the red LED's that ge attached to the Phantom legs?

Thanks for your patience

 

[nick96]

Guys I have some pics to show you where I am at. How do I attach them?

Cheers

 

[3nity]

Does anybody here already tried the BA with some melcor 1731?
i'm willing to try given that i have few boards...
any comments?

 

[craigmorris74]

There was some discussion about whether using Yamaha NE80200 opamp with the BA was feasible, a problem being the power requirement of the opamp. Have these been tested in the circuit?

Craig

 

[mattmoogus]

We havnt tested the Yamaha amps in the BA because theyre actually too big to fit. Youd have to mount half the parts on the other side of the board to get one in there so basically theyre not compatible, unfortunately!

There is a guy here who is building some 99V MB PCBs with the Yamaha amps and transformers on them however. I wonder how hes going...


M@

 

[3nity]

but how about Melcor 1731??

 

[mattmoogus]

Well it should work with the correct reg parts in place to drop the rail to 30v. I think someone has mentioned trying one in this thread already, lowfreq perhaps?


M@

 

[Purusha]

Hey Joe,

have you got the money for my big order yet? :shock: :roll: :grin: