The AM Forum

the NE602AN is an excellent way to generate high quality AM ... see Tom's (K1JJ et al) threads for interface info ... the problem is that it is becoming unobtanium with no stock reported by Mouser, Digikey, Newark and MCM ... does anyone know of a source other than the guy on epay?   thanks  73  John

The NE612 is a replacement for NE602.

Bob
wb6kwt

Try here for new old stock IC's:

www.ic2ic.com

The SA602AN replaced the NE602AN

Available at Digikey $2.25 each

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=568-1201-5-ND

You will be very pleased with the results of that circuit, John.

Be prepared to fuss around with the output tuning coil  (T1) to get the best peak output. The turns ratio and tuning is critical to get a good peak to drive the FT-102 or whatever else you desire. 

The carrier level injection shud be played with to get the cleanest and highest audio peaks.  Play with all input levels to get the right mix. (Including T1's adjustments)

I did four FT-102's here and each one took some time. But the results are perfect, like Fabio.

http://www.amwindow.org/tech/htm/602mod.htm

Let us know how you make out with it.

T

  " I did four FT-102's here and each one took some time. But the results are perfect, like Fabio. "

How many bird watts did it put out??

thanks everbody ... looks like many parts in the orient ....ah so ...73 ...John

Another source: NTE7164.

John-

Dan's Small Parts has the original NE602AN for $3.85 each.  Just in case you are a purist. ;)

The orginial NE602 creates a cleaner audio with a wider sound-stage. The highs are more transparent and the lows more resonant. The tessitura is astounding!

I understand the original NE602-B was made in Japanese sanitary napkin white rooms, free of oxygen but laced with inert gases. Platinum pins, bronze encased with rubber shock mounts.  The transparency of the mid-bass must be impeckerable.  There's still a few around if you act NOW.

ok you audio pipsqueaks ... I used to be able to hear, now I don't want to hear about it .... life goes on even if its impeckerable (?) ...all kidding aside, thanks fo the help .... the NE602 has me considering a single band transmitter with the bal mod at op freq ... use K4DPK's vfo stabilizer for no synthesizer/conversion xtals ... just the bal mod followed by linear amps to desired power level ...could be simple ...73 ...John

I guess I'm old school.  I still play with MC-1496 ICs.  Too bad the Plessey chips are long gone, they had some neat ones.  :P

Pete

I have some 602's if you need them . I will find out how many I have and where the hell they are.

G

I have some of the rare Western Electric NE-602s made in the same factory as the 300Bs.  I'm asking $2500 each but will entertain offers.

I found them , They are SA 602's if interested.

thanks G ... I was going to order some ....73 ...John

John ,

Do you want me to send them down? If so,  good in the book?

G

I have an original NOS NE602AN that I'll never use. It's yours if you want it. Just send your address and I'll send it out on Monday.

Ron W8ACR

G and Ron ..... thanks .... I am not sure what my addr shows in QRZ and I've lost my password ...

John Ray
1592 hwy 30 E.
Athens, Tn. 37303

73   John

hi Ron ... got your package today ... are you looking for any parts for your projects? ...73....John

Hi John,

OK glad to hear the package arrived. Gee, I think that thing must have been lying around here for 10 years or more. Hope the silicon hasn't transmogrified into platinum or some other worthless element. I betcha that bugger must have cost at least $1.25 or so. (It wasn't the $2500 Western Electric model)

Seriously though, I bought three of those to build a "QRP Three Bander", a qrp cw transceiver for 18, 21 and 24 MHz. Design by Zach Lau at ARRL. Great little fixed freq transceiver with a DC receiver and using an MRF 237 in the final, about 2 watts output. You can find the schematic in the ARRL book "QRP Classics". Original article appeared in QST October 1989 . The NE602AN is used in the receiver front end. I have one in the rig, and kept two for spares. Now I only have one spare, but I'll probably never use it. Hope it serves you well. If you fry it, let me know and I'll send you the last one.

The only thing I'm lookin for right now is a pair of triode audio driver tubes - 2A3, 6A3, 6A5, or 6B4G. I keep hoping that a pair of these tubes will somehow go unnoticed by the audiophools on EPAY, but wishful thinking. I just can't cough up $50 or more for a pair of these tubes. But I have a good backup plan - triode connected 6F6's. Cost half as much or less, and sound just as good as "real" triodes. With grid bias you can get 12 or 13 watts of audio, with self bias about 8 watts or so.

The best sounding AM rig I ever had was a Globe Champ 175. It had triode connected push pull 6F6's driving push pull parallel triode connected 6L6 modulators through a UTC S9 driver transformer. WRL frequently used triode connected tetrodes in audio circuits. My current AM rig is a Globe King 500 that had been gutted before I got it. (thankfully so for the audio section). I rebuilt the audio section using the same circuit from the Globe Champ 175. 6SJ7 speech amp, 6N7 phase inverter, push pull triode connected 6F6's, UTC S9 driver transformer. Kept the 811A modulators. The audio is apparently real nice according to the reports I get.

Still........I'd like to try a pair of real triodes.

Hope your sandy state audio circuit does the trick. I'll stick with electrons flying off the filament, racing through the ether and crashing into the plate.

73,  Ron W8ACR
Lewistown, MT

thanks again, Ron ... Derb suggested the 12B4 as a low plate resistance driver ... as I recall it has 5 or 6 W plate dissipation .... I have a few garnered from Tek scopes ... would also consider 6AS7/6080 ... very low Rp ...73...John

Another nice triode driver is the 6S4. I used 6S4's for the headphone amp that I built for my buddy - cheap and low Z.

Mike WU2D

Dieter has a supply of 602's an 612's.

http://kitsandparts.com/parts.php

W4RJC suggested Jameco .... ne602an at $1.85 ea .... they have good selection of 'obsolete' parts ...73...John

Here is an interesting tidbit and history of the NE602......

http://soldersmoke.blogspot.com/2009/06/na5n-on-ne602.html (http://soldersmoke.blogspot.com/2009/06/na5n-on-ne602.html)