Lang PEQ-2A clone...RESURRECTED

[PRR]

> power supply: would one of these 50V toroidals work?

Real question: how do you re-create the magic EQ inductors?

The rest of it is high-class BS. Simple booster, simple PS, beefy interface transformers.... the magic is in the passive EQ and the many-tap inductors.

 

[damnyankee]

> power supply: would one of these 50V toroidals work?

Real question: how do you re-create the magic EQ inductors?

The rest of it is high-class BS. Simple booster, simple PS, beefy interface transformers.... the magic is in the passive EQ and the many-tap inductors.

See, that's what I thought - those Freed network "inductors" are the heart of that EQ.  I don't know much about inductors but is it possible to substitute multiple inductors for the frequencies in lieu of the Freed Network multi-tap inductors?

I emailed ETC yesterday (they acquired Freed) to see if they have any info/build sheets on the transformers and EQ inductors.  If I don't hear from them in the next couple of days, I'll call them.

DY

 

[ruffrecords]

Is it just me or does the block diagram of the Lang PEQ-2A bear an uncanny resemblance to that of a Pultec EQP-1A ???

Cheers

Ian

 

[PRR]

I've been assuming the Lang is a carry-on of the Pultec, no substantial difference except bottled versus canned amplification.

I was wrong about inductors. Assuming Gyraf's plan is correct for Pultec and Lang, inductors are used only for the treble ringiness, only 100mH 100mH 47mH and 22mH inductors needed, and you can score these >30mA <100 ohm many-mH inductors at DigiKey (et al) for 20 bucks.
http://www.gyraf.dk/gy_pd/pultec/pultech.gif

And it appears the worst switch is 2 pole 6 throw, available in the $2 switches.

In fact a modern-studio work-alike could be built with a wall-wart, a 5532, and $30-$40 of switches, caps, and coils. (No, it won't "sound alike" until you collect or fab the heavy faceplate and fist-size knobs.)


DN7752-ND 4590R-107K INDUCTOR HIGH CURRENT 100000UH 4590R API Delevan Inc 100mH 90mA 60mA - - ±10% - 76 Ohm Max - - Axial  Through Hole  $2.87 

M8337-ND 5900-104-RC CHOKE RF HI CURR 100000UH .065A 5900 JW Miller A Bourns Company 100mH 65mA 81mA - Ferrite Core ±10% - 89.7 Ohm Max - - Axial  Through Hole  $2.03

 

[damnyankee]

PRR:

I'm a simple man with a simple mind.  Are you saying we can clone the Lang?

DY

 

[emrr]

Can clone the pultec, can clone the Lang.  No prob. 

 

[strangeandbouncy]

Hi,



  Lang PEQ1 is tube, I think . . . .



   ANdyP

 

[damnyankee]

Hi,



  Lang PEQ1 is tube, I think . . . .



   ANdyP

Yes, I believe you're correct.  PEQ1 is tube and has round knobs.  PEQ2 is SS with tear drop knobs.  It appears the Lang also has 20Hz and 20kHz frequency points

 

[Biasrocks]

The sweetest 20kHz ever!

 

[damnyankee]

Hi All,

I want to try to breadboard one of these.  Does anyone have an image of one of these with her top off?

In particular, a snapshot of the EQ Network with caps/values would be ideal.  I've seen the hand-drawn schemo of the cap values floating around in here but me thinks given the voltage ratings, those are for the original vacuum tubed Lang PEQ1 and I don't know if there's a difference between the toob and solid state versions.

Thanks in advance!!!

DY

 

[Biasrocks]

I can take some inside pics, but the EQ network is sealed in wax.

Mark

 

[damnyankee]

I can take some inside pics, but the EQ network is sealed in wax.

Mark

Thank you in advance for letting us peak under the hood, Mark! 

DY

 

[creal]

nice post.
I also interested by this eq.
But we need to find the toroidal inductor.
Anyone have an idea for this part?

 

[damnyankee]

Would I be correct to assume we'll need individual inductors as the Freed is no longer available?  If so, the question is what mH and what capacitors.  Given the frequency range, they are likely different than the Pultecs, yes?

 

[strangeandbouncy]

Hi Mark,



   . . . . and possibly the fattest bottom too, methinks . . . . so tight on Kicks


  Kindest regards

 

[creal]

Would I be correct to assume we'll need individual inductors as the Freed is no longer available?  If so, the question is what mH and what capacitors.  Given the frequency range, they are likely different than the Pultecs, yes?

for the filter and the amp, we have all what needed here

Maybe it's possible to make a groupbuy for the custom inductors

 

[damnyankee]

Could these work for the inductors?  (thanks, PRR!)

http://www.delevan.com/seriesPDFs/4590.pdf

If so, can we wire in series to create the uH values we need?
(i.e., 2 x 15uH for the 30uH value, 15uH + 33uH for the 48uH value, 68uH + 27uH for the 95uH value, etc?)

DY

 

[mitsos]

That should work.

FWIW, I am working on a quote for a toroidal inductor for the enhanced pultec. The problem is we have to get a large number (~100). I am pretty sure this one can also be made, after all it´s the same technology, but we'd have to have a certain minimum number.  Depending on price, I can try to see if we can do half pultec and half lang, if enough people are interested in each.

so I guess maybe I´ll post a feeler with a poll?

 

[strangeandbouncy]

Hi Guys,



      Am I right in thinking that that schemo of the makup amp is seriously flawed . . . . .

 

[creal]

That should work.
FWIW, I am working on a quote for a toroidal inductor for the enhanced pultec. The problem is we have to get a large number (~100). I am pretty sure this one can also be made, after all it´s the same technology, but we'd have to have a certain minimum number.  Depending on price, I can try to see if we can do half pultec and half lang, if enough people are interested in each.
so I guess maybe I´ll post a feeler with a poll?

great idea, Dimitri
I'm in for two Lang