YESSS I was just going to say...you can't say you're a real DIY Audio geek until you have an oscilloscope hooked up to your main system! Props, MR! 😉
thank you Mr. MR 🙂
may I ask where are big JBLs, I remember you had on some older pics?
I guess I’m not a real DIYer since I don’t have a scope I my system. I think a will breakout the multimeter and put it next to my amp.
Very nice, and agree the look of the ACP+ looks great on the board. I’m really thinking about building the ACP+ myself. I just have most of the parts for the BA-3.
By the way what speakers are those?
Very nice, and agree the look of the ACP+ looks great on the board. I’m really thinking about building the ACP+ myself. I just have most of the parts for the BA-3.
By the way what speakers are those?
Love your system Mr. Rothacher! Can you please give some info regarding the super tweeter (with horns) on the top of the cabs? Thanks!
Hello experts!
I still have not found the problem with my ACP+. I suspected my DIY speakers to be the problem but figured out when I connect my Dragonfly directly to the ACA monos without ACP+, the harshness is absolutely gone. Already swapped one of the resistors as suggested by one of you but that did not do the trick. Here is a photo, maybe someone can detect a problem. Happy to provide values if needed.
I still have not found the problem with my ACP+. I suspected my DIY speakers to be the problem but figured out when I connect my Dragonfly directly to the ACA monos without ACP+, the harshness is absolutely gone. Already swapped one of the resistors as suggested by one of you but that did not do the trick. Here is a photo, maybe someone can detect a problem. Happy to provide values if needed.
Those are just Fostex 025H30 and horns HP around 5500 Hz with a cap and L-Pad. Nothing on the woofer. 🙂
Can the Toshiba 2SJ74 Lab Matched quad To 0.03mA / 4mV (4.0mA Range), sold by punkydawgs, be used without any problems? Would the Toshiba 2SJ74 GR also be suitable? If I buy 10 units, will it be difficult to find 2 pairs combined? What happens if the pair is not perfectly matched?
From: https://www.firstwatt.com/pdf/art_acp.pdf
"Q1, Q2 JFETS ARE MATCHED WITHIN 1 MA IDss"
Each JFET operates at 5mA.
The J113 (Q3) CCS controls the overall total current of 10mA.
"Q1, Q2 JFETS ARE MATCHED WITHIN 1 MA IDss"
Each JFET operates at 5mA.
The J113 (Q3) CCS controls the overall total current of 10mA.
They are waiting for you at the coast.
Papa likes giving gifts, and making people happy
ZM likes when Papa is happy
To be clear, you are "matching" Q3 against the value of R4 to create the CCS value. That is, you use a value of R4 (which may or may not be 125R as in the article) to match Q3 in order to draw 10mA.
--Tom
The question was about Q1/Q2 (LSJ74)matching and my post was in response to that.