JLM Baby Animal

[wolfgang]

This pcb is for the on/off switch and the power LED.
You dont need this, just wire to your switch and solder a LED (with resistor in series) directly to the switch!

I think you get this pcb only if you order a BA2 or BA4 complete set.

regards
Wolfgang

 

[Osse]

I'm having problems with my BA, the same problem with both of my modules.

I have ONLY hum when I connect the output to the soundcard, and it's constant, just a little lower when I turn the gainknob up. No difference when using pad/phase/phantom or the impedance pot.

there were some resistors left that I didn't know where to place, I look at the PCB and can't find any more place for them to fit.

Another thing: I've not connected the Diodes, and I can't see where they should be connceted, anyone could explain? and what value of resistor in series?

I've taken some pictures, but it's with my mobile cam so they could be better. Hope someone maybe can find the problem, otherwise I will have to get another cam for it.

Thanks!

 

[wolfgang]

Hello!

What Transformer, Opamp and PSU are you using?


The Zener Diodes are only used if your opamp runs on smaller power rails then the PSU is giving you!

If you dont need them then you should put a link between C and E where the BD681 should go when you use the zeners.

Have you measured the voltages on the opamp pins? There is a table on the JLM-site.

Have you jumpered the ratio of your input transformer?


regards,
Wolfgang

 

[Osse]

[quote author="wolfgang"]Hello!

What Transformer, Opamp and PSU are you using?


The Zener Diodes are only used if your opamp runs on smaller power rails then the PSU is giving you!

If you dont need them then you should put a link between C and E where the BD681 should go when you use the zeners.

Have you measured the voltages on the opamp pins? There is a table on the JLM-site.

Have you jumpered the ratio of your input transformer?


regards,
Wolfgang[/quote]

I'm using OEP, OPA2604 and the small PSU

Interesting, i've not put a link between those two. But I cant see the C, it's just E and B and the one in middle with no letter on it. When I look at the wiring overlay it looks like there should be a link between B and the right hole of the Zener, is that right?

2 links, between E and mid of BD681 and between B and right hole of Zener?

Ratio is jumped

Thank you so much for the help!

 

[wolfgang]

Ok, i computer didnt show me your pictures before!

But now i can see that you have to install the 10pin idc socket for the di and then you have to place 2 Jumpers if you dont use a di! How to jumper is showed on the pcb between socket and toggle switch.
Otherwise the opamps never see a signal!

And i see there is no link from CE at the regulator place!

Wolfgang

 

[wolfgang]

If you are using 2604 and the small PSU you dont need zeners.
I also looked the JLM site and didnt find any zener in the shematic nor a place on the PCB.
Also it seems that you have a new revision PCB.

The link af the regulator is between C and E ! Look at the baby animal wiring diagram. it seems your PCB is layed out that way.

But i am pretty shure that the main problem is the idc connector.

Place the two links and then measure the voltage at the opamps BEFORE you insert them!

Hope this helps!

Regards,
Wolfgang

 

[Osse]

Oh damn... looks like I lost one of the 10 pin connectors, can I just insert 2 regular links on those two places?

And I cant flind the "C" that you are talking about, are you talking about one of the three holes on the BD681 now? the left is E, the right is B and the mid is no letter.

It also looks like there is a link between the B letter in the BD681 and the right hole of the Zener, is that right?

Thank you for this m8!

 

[wolfgang]

Sure a "normal" link will do it!!!!

C is the center of the BD681.
There is one more link for phantom powr near the idc socket to do!!!!

for the "B"Link: I cant see that on your picture, but as far as i know if you dont have the regulator installed leave out the zener.
And NO Link is requiered there!

Did one more look at your pictures and there you have installed RZ instead of Rload! You have to change this! you dont need ZobelParts for the OEPs but Rload depending on ratio and if you use impedance pot.
The table on the site says that very well!

regards,
Wolfgang

 

[JLM Audio]

Osse all the info that Wolfgang has given is correct and you will need to do that :grin:

But you also have the output XLR's wired backwards so you are not connecting BA ground to the soundcard ground. Remember XLR's are mirror images of each other. The metal chassis tab is always above pin 1 on chassis mount XLR's.

 

[Osse]

Wtf...

 

[Osse]

wtf...

 

[Osse]

It told me it didn't work to post, but it did... Sorry for quadpost :shock:

 

[Osse]

Hello again! troubleshooting is going along, but I've got some new questions :grin:

Now I've done as you told me, but when I check the voltages I get some really strange voltages:

(1 st op-amp is closest to Transformer)

on PCB#1:
1 st OP-amp: (in+ 23,8), (in- 17,5) (Out 17,0)
2 st OP-amp: (in+ 23,6), (in- 2,7) (Out 2,7)
The rest of the places seem to be good.

PCB#2:
1 st OP-amp: (in+ 23,7), (in- 17,2) (Out 16,5 )
2 st OP-amp: (in+ 23,7), (in- 2,2) (Out 2,2)
The rest seems to be fine.

According to the Wiring overlay it should be +24 on all of the Op-amp spots, anyone have any idea what's up with my unit? :shock:

It also looks like the voltage is dropping all the time when I have the multimeter on on the in- and out on the FIRST op amp on both PCB's, to be restored after I remove the multimeter, the other ones isn't reacting like this, is this normal?

 

[Osse]

No one with a clue? :roll:

 

[Osse]

Still need some advice on this one.

How do I get upp the voltages to the level it should be?

Thank you!

 

[mfdu]

dude, i had strange volktages on my opamp 'out' pins, too.

only on one unit - the other one was working fine.

so i swapped opamps, and the problem swapped across too!!!

so the problem was actually the opamp, not the BA board.

as a side note, god-damn Fabio 2520 and BFB opamps - they took 18 months to arrive, and i've got one working out of 6 bloody opamps!!!!!!

 

[Osse]

I guess that aint my problem, as the voltages is strange even with the OP-amps not fitted.

 

[Purusha]

[quote author="Purusha"] HAVE A PROBLEM I CAN'T SOLVE ON MY OWN

One of my BAs with 1:4 + 99V + 1:1:1 doesn't work anymore.
There is almost no sound coming through, just a lot of noise.
I noticed the noise increases when I turn my variable impedance
knob CW. Otherwise the V seem to be correct and Opamp works OK.

Any suggestions? [/quote]

[quote author="JLM Audio"]
If the noise goes up when the impedance and/or the gain control are turned up all the electronics is working fine. And the fact you can hear a slight bit of signal it sounds like you have one open leg of the balanced input signal. First thing with a ohmmeter check that you can see the JLM14 input which should be about 20ohms with the 48v off, pad off measured between the input XLR pins 2 & 3. IF not check the wiring from the input XLR to the +/- in on the BA PCB. The next set of contacts in the balanced line are the IDC10 socket. So if there is a DI plugged in remove it and place the 2 jumpers in the IDC10 header. IF this fixes the mic pre the switch in the DI socket is open circuit. The signal then goes to the pad switch and then the phase switch. You should be able to measure the JLM14 input of 20ohms on the top to legs of the phase switch. If you cannot measure the 20ohm here go straight to the red and green wires on the JLM14 and see if you see 20ohm between them.
[/quote]

Hi Joe,

I did what you suggested but the problem remains the same even without the DI.
I see 29ohms on all places you mentioned. Any further suggestions what to measure?
I also hear a constant hi pitch klick in same intervals.

 

[Purusha]

This is weird, I stuffed another PCB and replaced the "not" working PCB.
Used same Opamp, In and OUT trafo but the problem remains the same.
I bypassed the 1:1:1 trafo and replaced the volume pot but still no luck.
Changed the opamp, no luck either. Checked the wires twice....

Can the problem be in the 1:4 trafo? This is the only thing I didn't replace yet.

 

[Purusha]

Hello, I wonder if anyone built a BA with L31267 and LO1166 iron so far?

I would like to try it out, buy I am not so good with the part values if there is any need to change anything to make it work.