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CA3080 revived
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synchroma



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PostPosted: Sat Dec 07, 2013 6:23 am    Post subject: CA3080 revived Reply with quote  Mark this post and the followings unread

Has anyone else noticed that Rochester Electronics has started making the CA3080 again?

http://www.rocelec.com/search/build/CA3080/ISL/1/contains/

The datasheet says 2013!!!!!!

Very Happy


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Dave Kendall



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PostPosted: Sat Dec 07, 2013 7:03 am    Post subject: Reply with quote  Mark this post and the followings unread

Looks hopeful. Found a post on DIYstompboxes.com about it. Here's an excerpt.

Quote:
I've been in touch with Rochester Electronics about getting some CA3080AE ICs (8 pin DIP).  I called Intersil about this company, and a tech informed me that Intersil sold their remaining wafers and dies for the 3080 series to Rochester, so the parts are completely legit and newly manufactured. Given that every single 3080 that I've bought on ebay has been a fake (or at least not working), Rochester seems like a great alternative for this part. Unfortunately, the minimum order is $250.00. 


Cheers,
Dave

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synchroma



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PostPosted: Sat Dec 07, 2013 7:58 am    Post subject: CA3080 revived Reply with quote  Mark this post and the followings unread

FYI I found out this information through Small Bear Electronics. https://www.smallbearelec.com/home.html

Looking at their stock list (rather than their terrible website) I see they have over 10,000 of the Rochester Electronics CA3080 ICs in stock!

Rochester are making all styles and spec too (Can, Dip, Soic, MIL)

Good news I think.
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Dave Kendall



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PostPosted: Sat Dec 07, 2013 8:00 am    Post subject: Reply with quote  Mark this post and the followings unread

Nice one. I think there'll be a lot of people happy about that. Smile

cheers,
Dave

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davidschwan



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PostPosted: Sat Dec 07, 2013 2:39 pm    Post subject: Reply with quote  Mark this post and the followings unread

At $5.00 a part on the small bear website these are very pricy.
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synchroma



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PostPosted: Sat Dec 07, 2013 4:49 pm    Post subject: Reply with quote  Mark this post and the followings unread

davidschwan wrote:
At $5.00 a part on the small bear website these are very pricy.


Sure, and if you are happy with using the LM13700 there's no need to go back. I think there's a limit to economies of scale here also, since this is probably a niche product now (and we are much of the niche, I suspect).

But, it's a useful part and easy to design with. And better than fakes from Hong Kong.
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elmegil



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PostPosted: Sat Dec 07, 2013 9:17 pm    Post subject: Reply with quote  Mark this post and the followings unread

$5 is a darn good price given how hard it is to find real, working models...

The last batch I bought from Unicorn Electronics was $3.50 apiece, and I had to spend time testing them because the batch I bought from Ebay before that was 25 bad chips for $65. Unfortunately I didn't figure that out until more than a year after I bought them, so....
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synchroma



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PostPosted: Sun Dec 08, 2013 5:55 am    Post subject: Reply with quote  Mark this post and the followings unread

Whoa! They also seem to have scads of CA3280 chips! They are (or were) rare as hen's teeth Smile

http://www.rocelec.com/search/all/CA3280/0/1/contains/

Although since there's no package info, they could just be bare silicon dies. Question
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fluxmonkey



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PostPosted: Sun Dec 08, 2013 7:40 am    Post subject: Reply with quote  Mark this post and the followings unread

davidschwan wrote:
At $5.00 a part on the small bear website these are very pricy.


for production, maybe... and i still wouldn't do a new commercial design around a chip that is end-of-life. but for diy of all the legacy designs that relied on it, $5 is one NY cup of coffee...

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new voodoo



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PostPosted: Sun Dec 15, 2013 8:53 am    Post subject:
Subject description: group buy?
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Id be interested in purchasing, say, 125$ wrth..would anyone else like to go in with me?
Id be PSYCHED to have some ca3080s that I didnt have to test before use..I mean, the time savd, ALONE, might be worth about 100$..well maybe not, but still...
IF ANYONE IS INTERESTED, PM ME AND WE'LL COME UP WITH A PLAN.
(PS-IM IN THE US)

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Zodiak



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PostPosted: Wed Dec 18, 2013 2:13 am    Post subject: Reply with quote  Mark this post and the followings unread

OK sorry for showing my ignorance but how is the 3080 better than the LM13700?
He said knowing full well that has had some of these in his spares box for the past 30 years.

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analog_backlash



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PostPosted: Wed Dec 18, 2013 4:27 am    Post subject: Reply with quote  Mark this post and the followings unread

I'm with you there Zodiak. I have some old CA3080s as spares for my ancient kit synth (ETI Transcendent 2000). The only reason I can see for using the old IC is if you have a PCB specifically designed for it. It's not difficult to redesign a circuit to use the LM13700 instead. I thought the there was an e-m thread on this, but all I can find is this:

http://electro-music.com/forum/post-181680.html

This doesn't go into much detail, really.

I'm sure someone will now tell me why the CA3080 is superior Laughing

Gary
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piedwagtail



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PostPosted: Wed Dec 18, 2013 8:50 am    Post subject: Reply with quote  Mark this post and the followings unread

Footprint!

I recently couldn't fit a 13700 on a packed 100x50mm pcb, a free VCA would have been available but the 3080 works fine.

it gives better balance, with silkier treble and firmer bass and increased soundstage;why with this chip it's much closer to being inside the bass drum right at the beater....etc


R
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analog_backlash



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PostPosted: Wed Dec 18, 2013 8:58 am    Post subject: Reply with quote  Mark this post and the followings unread

piedwagtail wrote:
Footprint!

I recently couldn't fit a 13700 on a packed 100x50mm pcb, a free VCA would have been available but the 3080 works fine.


That's true - I've never been any good at producing small PCBs anyway! As for the sound quality, my ears can't detect much difference (but my ears aren't that good either).

Gary

P.S. I was born and brought up in your neck of the woods (Bethnal Green). It's all changed now, I know...
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new voodoo



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PostPosted: Wed Dec 18, 2013 1:17 pm    Post subject: Reply with quote  Mark this post and the followings unread

i think it sounds better and, cause i suppose i dnt know enough, I have sme circs I like to use fr various things which use it and i dont know how to change them to NOT use it..plus its not like the lm13700 is .50 cents a piece or anything. the places i get them theyre both more than a couple bucks and id RATHER, if it was possible, pay about what something like a 324 costs but thats not going to happen i guess
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synchroma



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PostPosted: Fri Dec 27, 2013 3:51 pm    Post subject: Reply with quote  Mark this post and the followings unread

New Voodoo: I'm up for going in with you on a bulk purchase Smile but I'm in UK so you'd probably have to send then to me when you get them - I.e. it'd probably have to be a single delivery to you from Rochester Electronics. Do you have a paypal account? I can share my spam-attractor email: loneshark@hotmail.com so post here if you reply and I'll check it. I'm a bit reluctant to put my main email address etc on a public forum.

I need to generate some cash for my real project, so I'm looking to build some simple-ish synths to sell while I finish my prototype. CA3080s are perfect for that, as I already build a working synth around them.

Piedwagtail: we should get together for a beer sometime. I'm in brixton. Question

Happy festive whatever!
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roglok



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PostPosted: Sun Dec 29, 2013 4:17 pm    Post subject: Reply with quote  Mark this post and the followings unread

new voodoo wrote:
i think it sounds better


that's surprising. the LM13600/LM13700 is basically two 3080 plus some buffers and linearization diodes:

Quote:
The schematic part was easy. Just used the 3080 exactly. There were 16 pins, so we could just mirror the layout to do a stereo. That left 3 extra pins per channel. The simplest buffer was a darlington which needed two pins per channel. There were complaints about high levels in input signal generated too much distortion in the 3080. That could be addressed by connecting the left over pin to predistortion diodes.


full story here: http://www.idea2ic.com/LM13700.html
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analog_backlash



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PostPosted: Sun Dec 29, 2013 5:30 pm    Post subject: Reply with quote  Mark this post and the followings unread

roglok wrote:
that's surprising. the LM13600/LM13700 is basically two 3080 plus some buffers and linearization diodes...

I was going to say that (having already read the article in your link), but I know that people have their own ideas about components that you can't talk them out of (e.g. the tropical fish capacitors beloved of guitar effects fanatics).

Gary
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roglok



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PostPosted: Mon Dec 30, 2013 12:14 pm    Post subject: Reply with quote  Mark this post and the followings unread

analog_backlash wrote:
roglok wrote:
that's surprising. the LM13600/LM13700 is basically two 3080 plus some buffers and linearization diodes...

I was going to say that (having already read the article in your link), but I know that people have their own ideas about components that you can't talk them out of (e.g. the tropical fish capacitors beloved of guitar effects fanatics).

Gary


yeah, that's probably true. but then again those same people will likely hear differences between a 1975 RCA TO-78, a 1991 Harris CDIP and a 2013 Rochester PDIP.

i could just as well say the LM13700 sounds better than the Rochester CA3080 because it's wrapped in ceramics, not plastic... Shocked
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Dave Kendall



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PostPosted: Tue Dec 31, 2013 11:27 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi.

Something for the melting pot. . . this link within the main body of the earlier link explains exactly what the difference between the LM13600 and 13700 is, namely that the buffers are slightly different designs. As they (and the diode bias pin ) do not need to be used, what you're left with is two 3080s in a 16-pin DIP package.

If a LM13x00 is "piggy-backed" onto an existing PCB that was designed for a 3080, there is a small possibility of interference or other artifacts because of flying wires etc. that *may* change the sound, but that's far from certain. Manufacturing and spec tolerances in the surrounding components are probably more likely to have an effect.

Designing any new PCB to use LM13X00 from the ground up avoids this, and can have benefits when more than one OTA is used in a design, as the two halves will be quite well matched.

cheers,
Dave

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synchroma



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PostPosted: Wed Jan 01, 2014 5:15 pm    Post subject: Reply with quote  Mark this post and the followings unread

It's amazing that Don Sauer implies that they were just mucking around in the lab. And it's become a primary method of analog synthesizer building.

Does anyone know who that mythical "trainee mask designer" was?

There is probably a lot of hokum about the 3080, but having a single chip package often makes PCB layouts easier. They can be single-sided rather than double, but of course this is only of interest to small guys like me, who align their DS board by hand when exposing, rather than big corps.
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new voodoo



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PostPosted: Wed Jan 15, 2014 6:51 pm    Post subject: Reply with quote  Mark this post and the followings unread

[quote="roglok"]
new voodoo wrote:
i think it sounds better

that's surprising. the LM13600/LM13700 is basically two 3080 plus some buffers and linearization diodes:
l

U realize that IS a difference, right?
When youre talking about simple and small things, simple and small things--like footprint, or signal path or a single component or composition, etc DO make a difference.
Ive seen a single diode's composition make the difference in a fuzz pedal, and im certainly not alone (w ppl paying MUCH more for germanium PNPs when newer ones seem to have very similar specs, n more for original chips than coolaudios, or more for vacuum tubes or argue that metasonix' filters ALWAYS sound different, etc)..


But its always easier to say or imply something deleterious than attempt to see things frm another point of view...so why not imply im inventing an opinion from ignorance?

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synchroma



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PostPosted: Thu Jan 16, 2014 4:19 am    Post subject: Reply with quote  Mark this post and the followings unread

new voodoo wrote:
When youre talking about simple and small things, simple and small things--like footprint, or signal path or a single component or composition, etc DO make a difference.


I'm inclined to agree.
I think where the confusion comes is largely down to how we learn about electronics. The two ICs may do the same thing in theory, but how they do it is another matter. Every component in a circuit does something, and the character of a circuit's unique sound may well be down to "theoretical imperfections" in the ICs or the design - a factor exemplified by Tim Stinchcombe's modelling of the TB-303 filter. His discovery of an extra 6 poles and zeroes in the 4-pole filter's economical design led to a more accurate model of the filter.

But still, my main reason for wanting CA3080s is the simplicity of designing with the form factor - inputs on the opposite side to outputs! I recently made single-sided boards for the Thomas Henry VCA and VCO-1, whereas my OSCar filter clone needs a 2-sided board which is much more hassle to solder NOT Cool
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synchroma



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PostPosted: Fri Jan 17, 2014 4:24 pm    Post subject: Reply with quote  Mark this post and the followings unread

FYI

I spoke to Rochester Electronics today. The CA3080AE ICs are $2.50 each, so the minimum order of $250 gets you 100 chips.

Also they have the masks, and they are not made from old wafers. They are newly fabricated silicon, not just repackaged old stuff.
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davidschwan



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PostPosted: Sat Jan 18, 2014 8:49 pm    Post subject: Reply with quote  Mark this post and the followings unread

At $2.50 per part I'll order some. The real cost is much lower if the volume is good, the test costs are probably the big item.
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