Official Lang PEQ-2 thread

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Hi,

When I click on the schematic link, all I get is a tiny picture...

Cheers

Nice one Pat.  8)

If I can help out in any way let, I'd be happy too.

Mark

good job. Guys I have used the lang's before and they were very nice...

Pucho,

  I used to own a pair myself. Why oh why did `i have to let them go? Pllease please please can we work out what the heck is inside those things? `I wand a pair more than anything else right now! Better than Pultecs for me, - and that is saying a lot!

  Kindest regards,


    ANdyP

i am keeping an eye out for the input transformer on evilbay,

i bet they use the same C core for the input transformer since the can is the came.

those boards look super easy!  the transistors might be hard to find, maybe just match the hfe with some low noise units,

i had a sh*t load of Lang pics at my site, maybe i backed them up somewhere,

i thought i saw a Lang with an API module instead of the pc board?

was that a custom mod or a real product?

we could do the same since the API parts are already fabbed around here, i'm jus sayin...

jh 990, api, melcor, valley people, it's all good,

drpat said:

Thanks Biasrocks.

Can you put a meter on the HF boost switch and check the capacitance of each position? I've already done so on both of my PEQ-2A's, but I'd like to have an extra set of figures to calculate the inductor values, before I draw up a filter section for it. You'll need to disconnect the non-wiper connection on the bandwidth pot to do so, 'cause it will affect the reading.

Click to expand...

When I get a couple of hours I'll take her out and get the measurements for you.

Mark

that freed output would drop right in the API, more flavor than the quad filar API output, maybe.

Is Freed still around?  If not, did someone buy them?  If so, perhaps we could still obtain documentation on those filter can models.

Anyone know?  ???

JC

Hey Pat  , if it helps
I have a bunch of cards very close to the LLA-4 amp cards I can donate for experimentation .
edge connectors and all .
They came from a old gatley mixer .
If it helps .
gary

do you have an inductance meter?

you might try putting it across the LC filters just for the heck of it.

ah, heck.

what about an MRI?

take it to sutter health and demand an x ray,

LOL! Now that's funny CJ!

Errr, is that really possible ???

hey, did you try measuring the capacitance thru the inductor?

that might give you a ball park figure.

so to reverse this, you pick a band, say 1 K, then build a 1 K filter, hook it in series,

then you inject a signal and see if the voltage gets split exactly between the two filter sections.

if you are sure of the center freq of the original 1 k band, you adjust the reactance of the circuit.

if you are two low, you increase then size of the inductor and drop the cap, etc, until it matches.

can you measure the dims on the PC board?

howabout the chassis?

i could use an end mill, say 1/16" , to cut a nice clean hole in the top of the filter cans,

drain the wax, look inside, fill it with wax and solder the lid back on, a little bondo and paint,

i'm jus sayin,

i just tried measuring an inductor with a cap in series, and it works, no problem.

you just have to keep the cap out of the circuit by increasing the frequency of the L bridge.

we could sweep it on the Gen Rad 650 which has an external Osc. input connector,

you plot L at 10 kc, 1 kc, 500 cps and 100 cps then connect the dots for the mid band, 

then, once you know the inductor, the rest is cake. or papa roach, i hate cake, rip off junkies,  ;D

hey, is the front panel steel or Al?

thanks!

thanks for the info.

so we need

1) mechanical drawings
2) BOM
3)PC Board fab
4)pwr supply fab

(or combine both)

5) filter section reverse job
6)input transformer reverse job

ok, go!