RC1556NB equivalent

Anyone? I can't even find a complete datasheet for the RC1556NB. It's made by Raytheon. That much I know.

Perhaps any of you American GDIY:ers have it or know of a modern/available equivalent.

I'm working on a Tore Seem TSLR-12 console, with I3000 channel strips (schematic in tech section) and have to replace several of these=confirmed faulty.

http://pdf.datasheetcatalog.com/datasheets/208/440281_DS.pdf

Google found it

JR

https://www.tedss.com/2028022351


I've seen this guy's store on Ebay with 100% feedback.....Maybe a reputable source???

JohnRoberts said:

http://pdf.datasheetcatalog.com/datasheets/208/440281_DS.pdf

Google found it

JR

Click to expand...

Thanks JR! I actually googled, a lot (to no avail).

scott2000 said:

https://www.tedss.com/2028022351


I've seen this guy's store on Ebay with 100% feedback.....Maybe a reputable source???

Click to expand...

I'll check it out! Thanks Scott!

Conviction said:

Anyone? I can't even find a complete datasheet for the RC1556NB. It's made by Raytheon.  That much I know.

Perhaps any of you American GDIY:ers have it or know of a modern/available equivalent.

I'm working on a Tore Seem TSLR-12 console, with I3000 channel strips (schematic in tech section) and have to replace several of these=confirmed faulty.

All the best,
Olle

Click to expand...

If anyone has successfully substituted the RC1556NB with a modern equivalent, please chime in.
Thanks!

I looked at the I3000 tech docs and it says RC4559 not 1556. 

1556 is a single opamp and 4559 is a dual opamp.  RC4559s are a select RC4558 I believe.  Higher slew  2v/ and lower noise version.  Lots of amps could replace that.  Just make sure your power supply can handle the current of whatever your new chip is and decide on how much you want to spend per dual opamp.   

Also IC3 is penciled in 5532.  That would be my first choice actually.

fazer said:

Also IC3 is penciled in 5532.  That would be my first choice actually.

Click to expand...

Thanks a lot for your input fazer! Strangely, the schematic doesn't match most l3000 channel strips still in circulation. Might be a matter of different revisions. And perhaps opamp availability?

The twelve boards in my console each have four 4558. If they're equivalent to 4559 (selected?) I guess there's nothing wrong there.

The 1556 is a bit of a mystery then and I still need to find an equivalent. I believe it drives the output (I'll confirm IC numbers tomorrow).

Conviction said:

Thanks a lot for your input fazer! Strangely, the schematic doesn't match most l3000 channel strips still in circulation. Might be a matter of different revisions. And perhaps opamp availability?

The twelve boards in my console each have four 4558. If they're equivalent to 4559 (selected?) I guess there's nothing wrong there.

The 1556 is a bit of a mystery then and I still need to find an equivalent. I believe it drives the output (I'll confirm IC numbers tomorrow).

Click to expand...

In consoles it is pretty common to mix different op amps in a single design based on what they are doing...

Op amps that can drive low Z (like 553x) often end up in output sockets, op amps working into high impedance can use Bifet  technology, and general purpose op amps (like for meters and blinking LEDs) can get away with cheaper than dirt 455x.**

You need to look at the schematic and figure out what the op amp in each socket is doing to determine what substitute may be appropriate.

JR

**For modest signal level (like -10dBV), modest gain,  and modest slew rate, the 455x can be OK, I used truckloads of 4560s back in the day.

For future reference:

On early Tore Seem I3000 channel strips, there is indeed a RC1556NB driving the output transformer. Turns out a LM741 does the job perfectly.

Conviction said:

For future reference:

On early Tore Seem I3000 channel strips, there is indeed a RC1556NB driving the output transformer. Turns out a LM741 does the job perfectly.

Click to expand...

741 is the equivalent of a wheelbarrow compared to a 5534 that would be a BMW.
It is faster, less noisy, has less distortion and what's more important for driving a xfmr, it has much more output capability.
Note that 5534 needs a compensation cap (33pF) between pins 5 and 8. Easy to add.

Abbey, I'm not referring to a 5534, but a 741 in place of a 1556. The question originally got confused because fazer didn't read my post (4 years ago).

Conviction said:

Abbey, I'm not referring to a 5534, but a 741 in place of a 1556. The question originally got confused because fazer didn't read my post (4 years ago).

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You misunderstand me.
You wrote; "Turns out a LM741 does the job perfectly"
I just say that a 741 is a poor choice in this position and that a 5534 is much better.

Ok, noted!

But looking at the datasheets, I'd say LM741 is a worthy drop-in replacement for the hard-to-source 1556.
They're both ancient, I know, but that's beside the point. They perform equally well (into a 600 ohm load) in the I3001 circuit.

Am I missing something?

Conviction said:

They perform equally well (into a 600 ohm load) in the I3001 circuit.

Am I missing something?

Click to expand...

You probably haven't had the opportunity to hear the difference between a 741 and a 5534.
I would say the 1556 and 741 work equally bad, compared to a 5534.
Now maybe the rest of the circuit is also restricting performance.

I actually haven't! Not in a A/B test anyway. I'm not sure I would even hear a difference. The later channel revisions make use of a 4559 in the same position, which is close to a 5532, right?

Still: If anyone is looking for a drop-in replacement for the 1556, a 741 does the job equally good (or equally bad) in this circuit. Wheel-barrow style. I'm OK with that.

... but I'd like to say thanks for the much valuable input Abbey. As always.

Conviction said:

4559 in the same position, which is close to a 5532, right?

Click to expand...

Not really. 4559 is an improved 4558, which is an improved 741.
The 4559 is slightly inferior in almost every respect, in particular it does not have the drive capability of the 5532, which can make a significant difference when driving a xfmr.

Hello,

the 741 isn´t a good solution due the slew induced distorsion made by this ic.
Walt Jung´s book show this.

Best regards!
jokeramik