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

[Studio Mollan]

Hi,
I'm using these eq:s in a console that already has HP filters and i would like to try and change the one ine the EQ to 300Hz. Also i would like to try and change the LP to 12k. I'm not sure which caps are setting the cutoff FREQ. Can you point me in the right direction Jeff? Also if might need to adjust my new cutoff to taste so a set of numbers to calculate that would be appreciated,
Thanks!
/
Emil

 

[jsteiger]

Hi Emil

C9/R13 and C10/R2 are for the HPF

R7/C4 and R5/C5 are for the LPF.

You can use the calculators here to find your new values. http://sim.okawa-denshi.jp/en/CRhikeisan.htm

IIRC, I followed the bandpass filter from the 550A

 

[kokkobil3]

Dear Jeff and everybody,
built my first one of two, with red dots in.

Everything works right except for a couple of positions:
5k HF peaking seem centered on a 9k area with a sharper q than the other settings.
seems shelving works ok.

400 LF both peaking and shelving doesn't work at all.

any clue for me?

thanks

Raffa

 

[jsteiger]

Everything works right except for a couple of positions:
5k HF peaking seem centered on a 9k area with a sharper q than the other settings.
seems shelving works ok.

Raffa, which 5k. Mid band or high band?

400 LF both peaking and shelving doesn't work at all.

This is a little odd because they are actually completely unrelated. I mean that they do not share any common circuitry. Could it be a bad solder joint(s) problem?

 

[kokkobil3]

Hello Jeff, thanks for the quick reply:
5K high frequency in peaking mode. In shelving seems to be working fine.

Regarding 400... It can be, even if my soldering skills are really improved in the last month.
The only thing shelving and peaking has in common is the frequency selector. I'll start double checking that. Any other clue?
Thanks!
Raffa

 

[jsteiger]

5K high frequency in peaking mode. In shelving seems to be working fine.

So it is the high band control? I asked since 5k peak is also available on the mid band control. After the switch, 5k peak on the high band is C31 in parallel with C32 and then to inductor L4. Since .075H and .0047µF give us 8.5k, my guess is there's a bad solder joint on C31 (.01µF) or its failed open which can be measured if you desolder it. Its prolly a bad solder joint though. I would reflow C31 first.

Regarding 400... It can be, even if my soldering skills are really improved in the last month.
The only thing shelving and peaking has in common is the frequency selector. I'll start double checking that. Any other clue?

Well, the switch is a 2 pole switch. One side for peak and one side for shelving so even though they share the same switch they are not electronically related inside of it. 400 peak on the low band is R10 to C10 to the L2 inductor. I'd reflow those points. 400 shelving is R5 to L1. C9 is the common cap that is between L1 and ground so if the other low shelving bands are fine, it won't be C9.

It probably won't be the inductor(s) for either 400 problem since that tap is closest to the common so if the rest of the pins are OK, chances are that one is too.

 

[kokkobil3]

Solved everything!
tried it on some real audio... wow.
Great!!

Raffaele

 

[Golgoth]

What is the most popular opamp combo on this one?

 

[jsteiger]

What is the most popular opamp combo on this one?

Folks order then all different ways. I don't think there is really a bad choice. Not sure if that is helpful or not.

 

[Golgoth]

It doesn't really help but it confirms I'm going to go for 2520/1731 like in my 28  ;D
Thanks Jeff

 

[rabe]

Hi Jeff,

I botched the building of a DT05 for my LC53A kit.  Is there a way I can purchase just a DT05?

Thanks,
Rob

 

[jsteiger]

I botched the building of a DT05 for my LC53A kit.  Is there a way I can purchase just a DT05?

Yeah man. Just send me an email thru the store.

 

[rabe]

I botched the building of a DT05 for my LC53A kit.  Is there a way I can purchase just a DT05?

Yeah man. Just send me an email thru the store.

Thanks!!!

 

[Golgoth]

Hi,

I am currently gathering tools and informations for my future 53A build. I’d like to get some answers to the questions I have before starting, especially regarding calibration (I hate trimmers!!!).

- First of all my audio installation has -6db inputs. Is it ok to add a plugin to my DAW’s input track before monitoring anything to get unity? I assume it is.

- I will be using the extension test jig and not a special cable, where should I take the measurements to adjust the generator’s output to 1 volt AC?

- Do I really need to monitor the output with both my DAW and a MM? Finding the lowest possible dBu value on the computer screen should be enough, right?

Having two different methods available for calibration got me confused I think…

>>> To the people in Europe and especially France where the Hakko CHP-170 is impossible to find, the Plato 170 is the exact same cutters and is easily findable for 5€ from UE sellers on eBay!

I hope the kit is back in stock soon, I can't wait to get started!  ;D

 

[jsteiger]

I am actually in the midst of building/testing a new updated board layout for LC53A. I had to change some silkscreen things (remove the small arrow) so figured I would make a few layout improvements. One of those things was to change the receiver stage in a way that CMRR cal is no longer required. As soon as I get the build finished and tested, I will post the stock. Hopefully over the next few days. I also made the mounting of the follower's and DTO5's a bit easier.

 

[Golgoth]

That's amazing news Jeff! Will the building process differ a lot from the old version? Chunger's guides are always so helpful...

 

[jsteiger]

That's amazing news Jeff! Will the building process differ a lot from the old version? Chunger's guides are always so helpful...

A few details but mainly on the small end. His work is 2nd to none 

 

[Golgoth]

His work is 2nd to none 

VITAL for beginners like me.

 

[okdaniel]

Can't wait for the stock to come in. I need to build another to make it a stereo pair. I need to change the faceplate knobs on my old one too I guess. It's all about the front panel right?  

Will the new "version" sound at all different? Hoping to get the two as similar as possible. I suppose it might just be a noise floor difference.

 

[jsteiger]

Can't wait for the stock to come in. I need to build another to make it a stereo pair. I need to change the faceplate knobs on my old one too I guess. It's all about the front panel right?

Yes, front panel and knobs. I have Nip-N-Tuck kits posted for all old modules now http://capi-gear.com/catalog/index.php?cPath=209

Will the new "version" sound at all different? Hoping to get the two as similar as possible. I suppose it might just be a noise floor difference.

No, there should be no noticeable difference in sound or function. The noise floor will be the same. Should be nothing to worry about really  I am literally just about to test all of the frequency controls and filters.