Federal Limiter AM864 thread

[NewYorkDave]

No, dude, that's -6dBM max INPUT. That doesn't tell you what the headroom is. But anyway...

FWIW, the input transformer is Langevin # TF-132B (150/600: 60K p-p grids), same as in the 5116-B preamp. The output xfmr is TF-322-B, 10KCT:600/150 with tertiary feedback winding (ratio of feedback winding not given), +40dBM max level.

But let's not sidetrack this thread. I'm all up for a Leveline thread if anyone's interested enough to start one.

[Joechris]

Well, I have startet to collect parts to build the federal compressor.
I will try to use NYDs altec mods on the front , with a stepped switch insted
of the doubble pot, and a 500 ohm to ballance the input tubes.
I will try the lundahl 1689 as the output transformer.
 I was wondering if its posible to shorten the release time a bit by lowering the value of the 1 meg resistor??  And does anybody know how many milliamps the meter is??

please
jo

[tk@halmi]

I got most parts now, except resistors, from Antique Electronic Supply.
I have decided on using the Hamond T269EX for power transformer (no 5V tap) so I will be replacing the tube rectumfier with a HFA08TA60C dual diode. This means I will be adding a 1k 2W resistor and an extra buffer capacitor to the power supply to drop the voltage approximately where it would be with lower seconday voltage and the tube rectumfire.
For choke I picked the Hammond T155J at AES. They also have all the potentiometers including a 1K 5W pot for the "current control".
Now I just need to order the resistors from Digikey and off we go building...

Cheers,
Tamas

[cannikin]

Never mind  :grin:

[cannikin]

:grin:

[tk@halmi]

Thanks for researching it David. Those are nice transformers indeed. I would have to sell a kidney to pay for them though...
(The UD$ is weak. The exchange rate from GBP is pretty much 1:2.)

[audioforge]

this power traffo could be good for the am864 anda bit cheaper than the sowter.ref :4N1241  
http://www.amplimo.nl/index.html?lang=en-uk&target=d22.html
data: http://www.amplimo.nl/download/4N1241.pdf

[Rob Flinn]

(The UD$ is weak. The exchange rate from GBP is pretty much 1:2.)

Yes!    :razz:

[toilet tunes]

hello i could not find this in the search. my federal is distorting as the gian reduction kicks in im going to 2 have some techs give it a cap job but was told that while it needed it .that may not fix the problem. could some one point me in the right direction. all ive done so far is the gssl and thank u all for that. these are the same techs that sortof walked me through the ssl how ever im afraid of the tube stuff till i learn more.

[toilet tunes]

well the tubes all checked out and no cold solder joints so

[cannikin]

Did you just get this unit?  was it working fine then one day it just started distorting when compressing?

What is the position of limit compress POT.  when you rotate it does the distortion increase/decrease?

Check the connections to the tube behind the Meter (V4) .. that is your compression tube. (I think).

Follow the circuit according to the schematic... make sure the values of the resistors and caps are correct.  

Look for new parts.. known as Modifications that aren't in the schematic.

if its an original unit ...My guess...

Old, bad caps - especially C4 ( the can), old Potentiometers, Old Tubes.

Have you modified the Unit, replaced anything?

[toilet tunes]

thank u for getting back to me. I got it off of ebay like this there is one mod someone put an unbalanced output jack on the front. The meter indicates compresson im still trying to get used to the back settings terms(curret threshhold) if you dial it back where there is no compresson its pretty clean. other than that this thing is like a fuzz box.   the pots seem pretty tore up lots of niose. thank you for the starting point :grin:

[cannikin]

edit

[cannikin]

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=122-330


The Choke

[audioforge]

original choke is 15H 300ohm. 20ma is too small...
NYD allready give you the info:
"Besides, filter chokes are not hard to find; Hammond makes ones that are reasonably priced. The value is right there on the schematic: 15H. The Hammond 158L, at about 17 bucks, looks like a suitable part. It's rated for 75mA and its DC resistance is 400 ohms. "
btw i pm you about the sowter traffos did you had my message?
audioforge

[cannikin]

Here is the Choke... Thanks NYD

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=122-330

I got your message audioforge.. reply on its way

[tk@halmi]

Those Edcor people have a 180V-0-180V power transformer for less than $40, darn close to 175V-0-175V.
http://www.edcorusa.com/classx/power/xpwr/Xpwr105.htm
No 5V tap, but a 2A filament transformer can be had for $10. I will ask them how much it would be to make a transformer to the original specs.

Anyone has a copy of the manual to share?

Cheers,
Tamas

[cannikin]

I will ask them how much it would be to make a transformer to the original specs.

That would be great.  Any word on this, T?

The other option that I was thinking of was getting a 270-0-270 50mA 6.3V@2Amp/5V@2Amp.  then knocking down the voltage with some power resistors... it would be a waste but figured.. it might come down to it.

[NewYorkDave]

If you're buying a transformer, why buy the wrong one and waste power in resistors, when the right one wouldn't cost any more or be any harder to find?

if you MUST use a 270-0-270 transformer, consider a choke-input supply instead of a cap input. As a bonus, you'll get better regulation, which is good for a compressor.

[cannikin]

:sam: