JLM AUDIO

Hi!

My BA is working wonderfully. But as always I'm curious to try knew things. I've built a little card that fits two single OP:s and connects the pins to the dual OP socket. The OP:s that I would like to try runs at a maximum of 32v. I've installed the regulator and I use 30v zener diodes. My question is: Are there any drawbacks on using an OP that runs on lower voltage like 30v compared to the OPA2604 that runs on 48v? (Like limited headroom or more distortion or noise). Should I be aware of other incompatibility problems using an unspecified OP?

Best regards,
Jon

jonte-72 wrote:Hi!

My BA is working wonderfully. But as always I'm curious to try knew things. I've built a little card that fits two single OP:s and connects the pins to the dual OP socket. The OP:s that I would like to try runs at a maximum of 32v. I've installed the regulator and I use 30v zener diodes. My question is: Are there any drawbacks on using an OP that runs on lower voltage like 30v compared to the OPA2604 that runs on 48v? (Like limited headroom or more distortion or noise).

Headroom will be reduced a couple of dB.

Should I be aware of other incompatibility problems using an unspecified OP?

A lot of single opamps need a external compensation cap fitted between 2 pins when running between unity gain and a certain low gain figure. The NE5534 is one of these opamps.

Where as the dual versions are internally compensated already like the NE5532. So read the single opamps data sheets carefully.

If you still are not sure just let me know the opamp type and I will be able to let you know what it needs to work.

Thanks for the info!

The OP:s are Burr Brown OPA627s. It seems that they are Unity Gain stable, so perhaps I would be fine. I misread the specs. Actually the OP can take +-18v supply voltage so I suppose a 33v zener will be the best choice?

I would be great if you foresee any trouble using these. Also, do you think they will be fine in the Hybrid as well?

Here's a pic of my adapter: I' afraid this will make a fine GPS or 3G antenna . I have a metal case. Will I be fine then?
And please give me a note if I'm close to being banned from the JLM support

/Cheers Jon

jonte-72 wrote:Thanks for the info!

The OP:s are Burr Brown OPA627s. It seems that they are Unity Gain stable, so perhaps I would be fine. I misread the specs. Actually the OP can take +-18v supply voltage so I suppose a 33v zener will be the best choice?

33v zener gives you roughly 32v = +/-16v. So a 36v zener will give you roughly 35v = +/-17.5v so would be the best headroom wise.

I would be great if you foresee any trouble using these. Also, do you think they will be fine in the Hybrid as well?

One could be wired to match the hybrid. The second servo opamp could be left off as servo is of no use in the BA BAD.

Here's a pic of my adapter:

Homemade adapter.jpg

I' afraid this will make a fine GPS or 3G antenna . I have a metal case. Will I be fine then?

The only thing to watch with most of the OPA opamp series is that they oscillate easily if there is any wire or PCB track distance between there power pins and the power supply decoupling caps. So on your adaptor it would be best to have a 0.1uF to 1uF mono ceramic mounted between the opamp power pins 4 & 7 in the socket.

And please give me a note if I'm close to being banned from the JLM support

/Cheers Jon

Your not even close Good questions like above are always welcome.

Thank you so much for your advice!

This too is working beautifully.

Cheers,
Jon

sorry for hijacking, but Joe would it be possible that you put the PDF's for the Baby Animal circuit diagram back online, the PDF's on the following links are not showing up (Safari webbrowser on Macintosh):

http://www.jlmaudio.com/Baby%20Animal%2 ... ircuit.pdf
http://www.jlmaudio.com/Baby%20Animal%2 ... PA2604.pdf
http://www.jlmaudio.com/Baby%20Animal%2 ... %2048v.pdf

thanks!

martthie_08 wrote:sorry for hijacking, but Joe would it be possible that you put the PDF's for the Baby Animal circuit diagram back online, the PDF's on the following links are not showing up (Safari webbrowser on Macintosh):

http://www.jlmaudio.com/Baby%20Animal%2 ... ircuit.pdf
http://www.jlmaudio.com/Baby%20Animal%2 ... PA2604.pdf
http://www.jlmaudio.com/Baby%20Animal%2 ... %2048v.pdf

thanks!

All PDF have been updated to the latest Adobe so we could lock and watermark them from being modified due to other companies stealing our designs and modifying the PDF. Download the latest Adobe reader and the PDF will work fine.

ok, thanks for the info, I was wondering why some would open (like the dual BA pdf) and others would not. But Acrobat Reader opens them all. It is a shame that people are misusing your schematics, btw. your PCB layouts are a work of art, keep up the great work!!