IJR's 2254/33609!

[rafafredd]

so, it will come sometime, I hope. I´ll wait patiently, because this one is really interesting. Might be expensive also

 

[rich]

I once had a 2254 in my studio another engineer brought over and it knocked me over, I can't even imagine a better sounding compressor existing although I never heard a fairchild. 5K though yikes!!!

 

[aurt]

A week or two ago I was mucking around with diode bridges for limiting and got to wondering what the advantages, disadvantages, or characteristics would be depending on what type of diodes one used, schottky on up to blue leds. Anyone have a clue for me?

 

[Rob Flinn]

Igor

I`m looking at your board & wondering whether it would be possible to substitute the 10468 transformer with another 31267, but reverse wired, like when they use it as a mic transformer. Or would that not work in this circuit ?
I say this because I happen to have 4 31267.

 

[rafafredd]

Use one winding only, when substituting the 10468 for the 31267. Yiu should wire it backwards, but just one winding. Not in series, and not in parallel...

 

[Rob Flinn]

Rafa

Thats what I figured, just trying to work out if there would be any issues using it that way for this application.

 

[rafafredd]

I think you should be fine.

 

[Rob Flinn]

Having studied the diagram that Igor sent me I have come to the conclusion that it is not possible to use the 31267 in the postion of the 10468 in this circuit.

The 10468 has its primary`s wired in series & the centre point is taken to ground via a resistor. When reversing the 31267 for use as a 10468 only one of the primary`s is used, therefore the centre tap is not there to be used.

 

[vladi]

?????????????????????

 

[rafafredd]

Yes, it´s really not connected as in the mic input. So, maybe it won´t be possible to use the 31267.

 

[tonymite]

I am half way ( mu tech cousin... is) half way thrtu building one of ijr's carnations but we have no pot / variable resistor values since they are not specified on the schematic. Any help much appreciated.
If anyone has transormers relevant to this project for sale ... also interested .. i have the input tx's ... i need the rest.

 

[Rob Flinn]

If you go here you will find a diagram which has some of the pot values & hook up info

http://www.geocities.com/igor_jazz/225433609.html

Other values I think you can pull off the diagrams at Dan Alexanders page. The side chain is very similar to the 33609.

 

[Tekay]

Just found a wrong value fault in the 33609 manual regarding the Compressor Recovery switch.
The 6k8 resistor shall be 24k not 6k8 as shown in the EX20236 drawing!
With 6k8 the fastest recovery will be around 25mS!

 

[Rob Flinn]

Tekay

Do you have acopy of the manual that is in digital form that you could email me ? Or anyone else for that matter ?

Also

does anyone know which caps are tantulum. The 33uF & 100uF radials are the ones I`m looking at in particularthat are in the side chain.

 

[Tekay]

All timing caps are tantalums, the 10uF connected to the recoveryswitches and the 47uF mounted on the recovery switches. I can check the manuals tomorrow, only have them in paper form!

 

[Tekay]

More from an original 33609C manual.
Diodbridge D14-17.Selected 1N4148 diode low FV (low forward voltage?) Newer version ( with BA640 outputstage) used selected 1N4153 or ZDX1R dual diodes
C13, C14 10uF / 25V tant. (timing)
47uF / 16V tants mounted on recovery switches.
All other caps are electrolytics, no more notes about selected transistors, fets or diodes exept for the D14-17

2264 used tants for all of the polarized caps except for power filtering, BA440 output cap and neg input cap (gainsetting).
Fet was a dual fet E410 or E413
Bridge was a BAX52 bridge rectifier.

 

[gyraf]

Thanks, Thomas!

very, very good info indeed!

Jakob E.

 

[Rob Flinn]

Thanks for the info Tekay.

Does the manual have any info on how to match the diodes & adjust the preset pots ?

 

[Tekay]

I have the test procedur manual for the 33609, I'll see if there's any info about the settings there!

 

[Rob Flinn]

Tekay

One other thing that I thought about:

On Kev`s website (I think) there is a picture of the inside of a 33609. In this picture there seems to be at least 10 Tantulum capacitors. Maybe its a different revision to the manual that you have ?

Am I getting different models confused here ?