Old or fake chips? See pics.

[Kevin Mitchell]

Hey gang. I've purchased a couple of 3046 transistor arrays that has me on the fence on whether they're old or fake. I wanted to show these to the forum before I find out as I don't have a circuit I can drop these into yet. I haven't come across ICs that look this old yet and had me laughing when I opened the package. Looking up images of these chips I've only seen one with similar branding but not quite the same.

I've bought them from a reputable electronics dealer and was a bit shocked to see these.

[duck_arse]

I'd say legit, old, ceramic package. possibly mil-spec, certainly better than the plastic dips. that is what they used to look like.

[whisper the suppliers name?]

[bluebunny]

They're ceramic packages.  Tonnes of mojo!   

(Ducky's answer got there first, but he's waaaay further east than me...)

[Kevin Mitchell]

Haha thanks guys. I asked one of my coworkers who used to repair vintage arcade machines. He agrees that they are NOS. You can find what I suspect to be newer ones for a few pennies less elsewhere like SB.

*whispers* jameco

[antonis]

*whispers* jameco

So, you think that anyone aged like Stephen can hear it..??

[Kevin Mitchell]

*whispers* jameco

So, you think that anyone aged like Stephen can hear it..??

It wasn't until now that I acknowledge I may be the youngest frequent poster on the forum

[anotherjim]

I think they look legit. And old NOS. 1974 dates.

[Kevin Mitchell]

Thanks! Well now I'm optimistic. I did a test on them last night with the diode function on my MM. The pins seem to make sense with the datasheet so I know it's not a blank or alternative wafer in there.

74 you say? That seems about right from the information I've dug up. Fairchild must have been one of the original manufactures of this chip.

[Rob Strand]

Fairchild must have been one of the original manufactures of this chip.

Maybe RCA , perhaps 1970/1971 but I'm not sure about the year.


EDIT:
Here, mid 1970, printed page 5, fig 5
https://www.americanradiohistory.com/ARCHIVE-RCA/RCA-Engineer/1970-08-09.pdf

[PRR]

Agree: stone-age digi-chips, and Jameco would be the place they have been hiding.

> Here, mid 1970

WOW! Note the OTA description with background thinking and much data. Compare the elegant no-resistor design with the clunky opamps and resistor-ridden audio amp in the same issue.

[duck_arse]

MY EARS!

antonis, I asked whisper for a reason ......

I had the "f" next the datecode as the Fairchild logo, suggesting fairchild manufacture.

[Rob Strand]

WOW! Note the OTA description with background thinking and much data. Compare the elegant no-resistor design with the clunky opamps and resistor-ridden audio amp in the same issue.

I have some recollection that the first OTA was conceived in 1969 and that was improved soon after; probably 1970 as per that article.   

The RCA guys don't get much credit in historical articles but I read that stuff and they clearly seemed to be on the ball about the future.  They also seem to be clear thinkers.  Sure some of the designs are just discrete designs put on chip but that *was* the period where things turned into what they are today.

[italianguy63]

Hey @Kevin.. what are you using these chips in?  Curious.

MC

[anotherjim]

Looks like a Fairchild "F" to me too. There were other F's, in particular, the European brand  Ferranti...

However, the Fairchild F is slightly stylized while Ferranti used a standard plain font and if space permitted, wrote their name in full.

Date codes of YY/WW where its the last 2 digits of the year followed by the business week number is very commonly used. It's the same system used on USA made guitar control pots which is so helpful to date an instrument by. It only gets more difficult for small parts where there isn't room for much text.

You will come across awkward ones with 4 digit type numbers and either that or the date code could read either way.

Those 3046 transistor arrays are a vintage synth speciality since the matched and thermally coupled BJT's can make for accurate and stable circuits. As it's an obsolete part, I wouldn't use one if discrete modern BJT's can equally do the job.

[Rob Strand]

However, the Fairchild F is slightly stylized while Ferranti used a standard plain font and if space permitted, wrote their name in full.

There's no doubt those units are Fairchild.

Those 3046 transistor arrays are a vintage synth speciality since the matched and thermally coupled BJT's can make for accurate and stable circuits. As it's an obsolete part, I wouldn't use one if discrete modern BJT's can equally do the job.

The Intersil datasheet for the CA3046 points to a new version (HFA3046?, HAF3046?) which I believe is a faster version.

[Kevin Mitchell]

Hey @Kevin.. what are you using these chips in?  Curious.

MC

There's two things I plan to do with these. One is the Retro Fuzz and the other is for the VCO board of my Model D clone. They used these in the 2nd version in the early 70s.

[amptramp]

You just hit the motherlode here.

What can you do with four transistors?  Use one as a temperature sensor, another as a heater and the remaining two as a Fuzz Face with thermostatic control so the unit sounds the same in the Yukon in winter and in Phoenix in the summer.  You would use an op amp with a Zener to act as a driver for the heater transistor and compare the sensor transistor Vbe to a dropped Zener value.  The high thermal conductivity of the ceramic package guarantees all transistors to be at nearly the same temperature.

If you are into synthesizers, the same thermal conductivity would help logarithm circuits used for translating control voltages into pitch values.  There are some avid synth builders who would buy you out in an instant.

The ceramic package was standard for military electronics because it was hermetically sealed and had better thermal conductivity than epoxy packages.

[Kevin Mitchell]

MY EARS!

antonis, I asked whisper for a reason ......

Haha! I edited the post for discretion. Also I didn't want the market to get whiped out before I snag a few more 

[Kevin Mitchell]

You just hit the motherlode here.

What can you do with four transistors?  Use one as a temperature sensor, another as a heater and the remaining two as a Fuzz Face with thermostatic control so the unit sounds the same in the Yukon in winter and in Phoenix in the summer.  You would use an op amp with a Zener to act as a driver for the heater transistor and compare the sensor transistor Vbe to a dropped Zener value.  The high thermal conductivity of the ceramic package guarantees all transistors to be at nearly the same temperature.

If you are into synthesizers, the same thermal conductivity would help logarithm circuits used for translating control voltages into pitch values.  There are some avid synth builders who would buy you out in an instant.

The ceramic package was standard for military electronics because it was hermetically sealed and had better thermal conductivity than epoxy packages.

Great info! Considering the temperature stability needed for the VCO design I now understand how the ceramic package is much preferred.

I went from thinking I got ripped off to learning I hit the jackpot.

[greaser_au]

You just hit the motherlode here.

What can you do with four transistors?  Use one as a temperature sensor, another as a heater and the remaining two as a Fuzz Face with thermostatic control so the unit sounds the same in the Yukon in winter and in Phoenix in the summer.  You would use an op amp with a Zener to act as a driver for the heater transistor and compare the sensor transistor Vbe to a dropped Zener value.  The high thermal conductivity of the ceramic package guarantees all transistors to be at nearly the same temperature.

I got howled down for a very similar suggestion several years ago... 

davidt