[BUILD] CAPI LC53A~500 Series~Love Child EQ Kit~Official Support Thread

Just re-read your post so actually let me just confirm this then.

Connect DAW to 500 rack sending 400hz tone from DAW to xlr in
connect card to 500 rack on corresponding xlr input
connect Main pcb to other end of card via ribbon cable with op amp in A1
connect xlr to trs lead (got no tt) to input of daw with plugin to monitor dbu
connect crocodile clip from tip of trs to C on A2
connect crocodile clip from sleeve (or ring?)  to negative side of C2
Switch on
find low point of trim pot

Thanks

Close. The tip will go to the neg side of C2. Connect the sleeve (and possibly ring) to the C socket of A2. Be VERY careful not to short anything out as this can snap off in a split second and short your racks PSU.

What Jeff said - I did C2 cap to tip and C of A2 to the ring (for me this was the way my unbalanced to balanced into the protools worked).  To avoid the leads slipping or shorting as Jeff warns, I used a spare millimax pin in the C socket of A2 and used a small retractable hook/pincer probe lead to connect to this pin and then clipped the alligator to the other end of this lead coming off the millimax pin (same type of lead with the C2 connection).

Just wanted to say thanks for your help.

As you rightly suggested Jeff, It was my DMM - the missus is always telling me not to buy cheap crap. Got a decent one, got some crocodile clips to go in it, switched the jig on , instantly got a reading where the previous DMM was blank, trimmed until the lowest pt before it started to go up again.

Sorted.

I hope.

I was calibrating another 500 series EQ that I just finished.

I measured the love child to compare and I noticed they are +6 dB gain to the signal even in bypass ?

1k tone balanced out of a Scarlett 2i2 @ 0.77 VAC comes back out of the love child at 1.58 VAC.

Is this normal ? anyway to adjust overall gain? or am I measuring wrong somehow?

Hmm, there is something wrong somewhere. I forget the exact amount but they will pass to within 0.3dB or so.

Hmm... ok I will pull them out for service one day soon and take a closer look.

Thanks Jeff

Nevermind... My measuring test rig had a unbalanced cable wired up. Cold to ground causing a 6dB level drop from my scarlet. Im gonna have to pull and recalibrate all my other units now    :

That's vaguely what I thought,6dB differences normally are caused by a balancing/debalancing issue.


Best,


Udo.

Hey guys,

I have a problem with my unit.

On the Low Band, the 400 hz position doesn´t work. The problem only exists the shelf mode, when set to peak, it´s fine.

Does anybody have a suggestion?

DonnieDarko said:

On the Low Band, the 400 hz position doesn´t work. The problem only exists the shelf mode, when set to peak, it´s fine.

Click to expand...

400Hz shelving is only R5 in series with the .575H pin of L1. I would resolder those connections. It can't be an open winding on L1 since it is the closest pin to the "end" or COM pin. All of the LB shelving freq's use the same cap C9 so if the rest of them work fine its not that.

Thanks! I will try that!

Hello,

If the level does not change with the RV1 adjustment, where might the problem be? Is the RV1 bad? I'm using the DAW method with the cable going back to DAW input and the signal is returning and is visible on the meter.

Hey Jeff and Guys,

So I finished building two of these eq's and I noticed two things:

1. I don't hear anything happen when I engage the HPF and LPF on both units.
How is it supposed to respond?
2. On one unit, when the low frequency is set to "bell" the volume acts as a master
volume for the whole signal, disregarding the frequency.  This does not happen when
the band is set to shelf.

Where did I go wrong?
thanks

danielbrecher said:

1. I don't hear anything happen when I engage the HPF and LPF on both units.
How is it supposed to respond?

Click to expand...

The HP is @ 50Hz and the LP is @ 15kHz. Both are 12dB per octave so not super aggressive. Depending on your source and/or monitoring, it may be tough to "hear" these but can easily be measured.

2. On one unit, when the low frequency is set to "bell" the volume acts as a master
volume for the whole signal, disregarding the frequency.  This does not happen when
the band is set to shelf.

Click to expand...

Try the unit without the steel cover in place. Sounds like maybe a lead somewhere is shorting out to the cover which is chassis ground.

Try the unit without the steel cover in place. Sounds like maybe a lead somewhere is shorting out to the cover which is chassis ground.

Click to expand...

This was the problem. Thanks.

Hello!

Just build an LC53A and i´m superhappy about how it came out and sounds! Anyway does anyone know how to modify the HPF, which is 50Hz stock build, to about 80Hz. Without the schematic, all i can see is that C4 is connected to the HFP-switch via the PCB. Maybe another value of that capacitor?

Thanks/bastian

bapa said:

Hello!

Just build an LC53A and i´m superhappy about how it came out and sounds! Anyway does anyone know how to modify the HPF, which is 50Hz stock build, to about 80Hz. Without the schematic, all i can see is that C4 is connected to the HFP-switch via the PCB. Maybe another value of that capacitor?

Thanks/bastian

Click to expand...

I just had a quick look. It depends on how accurate you want to be. You will also have to measure with an analyzer and make a few tweaks. On the CB PCB, I would start by changing C9 from .039uF to .027uF and change C10 from .39uF to .27uF. Run some sweeps and see what you think. If you want the knee to be higher, you could either decrease R2 to 120k and R13 to 12k and/or use .022uF and .22uF for the caps. Either way, I would suggest some experimentation. These changes will be pretty slight IMHO.

Thanks a lot, ended up with .022 and .22uf. Sounds fine to me!!

Any pointers to how these units sounds without actually getting my hands on one?
I connect API with rock and a little aggressive flavour. Is that true for the LC53?
(Myself I'm more into acoustical, soul, classical, maybe vintage pop)

I don't have any DOAs on beforehand. Just ordering 2 unassembled is a bad idea, right?
So, I need assembled to be on the safe side?

gar1731 or gar2520? (no idea)