Search found 139 matches

by juniorhifikit
Tue Apr 30, 2013 8:45 am
Forum: Pro Audio Design
Topic: Boosting signal generator or op amp outputs to >+30 dBu
Replies: 77
Views: 96355

Re: Boosting signal generator or op amp outputs to >+30 dBu

Well, I for one, am still following this thread with great interest and appreciate all of the input and background from all camps. My silence stems from the fact that I can't add anything useful. Please continue!
by juniorhifikit
Thu Apr 25, 2013 3:03 pm
Forum: Pro Audio Design
Topic: Boosting signal generator or op amp outputs to >+30 dBu
Replies: 77
Views: 96355

Re: Signal generator output ranges

Thanks Wayne! Another nice tool for the tool kit.
by juniorhifikit
Sat Mar 30, 2013 9:54 am
Forum: Pro Audio Design
Topic: Boosting signal generator or op amp outputs to >+30 dBu
Replies: 77
Views: 96355

Re: Signal generator output ranges

Did you by chance do any distortion measurements? Unfortunately no. I was just looking at my scope for clipping. I did do a full 20Hz - 20KHz sweep though. I don't really have anything official for distortion measurements other than RMAA through my converters, which wasn't really practical in this ...
by juniorhifikit
Fri Mar 29, 2013 8:02 pm
Forum: Pro Audio Design
Topic: Boosting signal generator or op amp outputs to >+30 dBu
Replies: 77
Views: 96355

Re: Signal generator output ranges

Just wanted to report back on where I ended up on this topic. My maximum supply voltage for my test was +/- 35V, and the swinging op amp couldn't get my output close enough to the rails to approach +30dBu. I ended up breadboarding a booster circuit using the LTC6090 on an adaptor board (it's SOIC), ...
by juniorhifikit
Mon Mar 18, 2013 10:17 am
Forum: Pro Audio Design
Topic: Boosting signal generator or op amp outputs to >+30 dBu
Replies: 77
Views: 96355

Re: Signal generator output ranges

30dBu is 34.64Vp. And you'll need a Vcc/Vee that's at least 3-5V higher on each polarity to get 35Vp output. With a bootstrap transistor maybe 6-10V per polarity. The 40-45V rails I mentioned earlier aren't that unrealistic. The LTC6090 doesn't have that great of distortion vs. frequency performanc...
by juniorhifikit
Mon Mar 18, 2013 12:00 am
Forum: Pro Audio Design
Topic: Boosting signal generator or op amp outputs to >+30 dBu
Replies: 77
Views: 96355

Re: Signal generator output ranges

Well, I'm not going to be driving a speaker, just a high impedance op amp input.
by juniorhifikit
Sat Mar 16, 2013 10:27 pm
Forum: Pro Audio Design
Topic: Boosting signal generator or op amp outputs to >+30 dBu
Replies: 77
Views: 96355

Re: Signal generator output ranges

mediatechnology wrote:
I think you'll need +/-45V to get to +30 dBu.
Haven't got that much available. It's kind of a one-off test situation, so I'm not going to build a separate power supply just for this. I did order some samples of the LTC6090 though...
by juniorhifikit
Sat Mar 16, 2013 7:10 pm
Forum: Pro Audio Design
Topic: Boosting signal generator or op amp outputs to >+30 dBu
Replies: 77
Views: 96355

Re: Signal generator output ranges

I breadboarded it using NTE375 & NTE398 transistors (all I had available). With +/-35 on the transistors, and an equal 10K/10K voltage divider, I had around +/-16.5V on the op amp rails. I could only get about 26.7dBu output before it does this: [img]deleted[/img] And the rails do this: [img]deleted...
by juniorhifikit
Tue Mar 12, 2013 2:08 pm
Forum: Pro Audio Design
Topic: Boosting signal generator or op amp outputs to >+30 dBu
Replies: 77
Views: 96355

Re: Signal generator output ranges

mediatechnology wrote:The 140V P-P LTC6090 is interesting: http://www.linear.com/docs/42316
Wow, and under $6. Too bad it's not stocked at Digikey
by juniorhifikit
Mon Mar 11, 2013 9:01 pm
Forum: Pro Audio Design
Topic: Boosting signal generator or op amp outputs to >+30 dBu
Replies: 77
Views: 96355

Re: Signal generator output ranges

Scott: Your re-posted sch looks fine though you'll probably want to add a Cc and Cfb around the 5534 That's one of those things I'm always too lazy to draw in when scratching on a napkin, as I think of it as a given. But thanks for reminding me. One additional thing you can do is bypass the 5534 di...