Great news! Yes, the lead bender is one of those things that is indispensable once you use it.
🙂
🙂
It sure does save time and make for prettier builds. Don't know why I don't use mine more often!
I'm bending leads by sheer will
who needs tool for that?
who needs tool for that?
Now I learned a new brand of TT (EMT):
https://www.hedonic.store/i/Qx3WHSgAA?lang=en
Yes, I am concentrated very much in the moment to prepare my setup of J112 on bread board (I think it is called?) with 9V battery and 220R to check if current is within spec......for the opamp bias.
Next "ODC thread" will be about matching the PP output stage transistors to avoid any DC on output (there was a member in a previous post asking if anybody had experienced DC at output.....and I think no answer to that). My OCD is concerned about IronPre which is DC-coupled......and "magnetizing" of the Cinemags caused by DC. But that is next thread.......which I can't think about in the moment. I also need to check first if IronPre really are pure DC-coupled....
https://www.hedonic.store/i/Qx3WHSgAA?lang=en
Yes, I am concentrated very much in the moment to prepare my setup of J112 on bread board (I think it is called?) with 9V battery and 220R to check if current is within spec......for the opamp bias.
Next "ODC thread" will be about matching the PP output stage transistors to avoid any DC on output (there was a member in a previous post asking if anybody had experienced DC at output.....and I think no answer to that). My OCD is concerned about IronPre which is DC-coupled......and "magnetizing" of the Cinemags caused by DC. But that is next thread.......which I can't think about in the moment. I also need to check first if IronPre really are pure DC-coupled....
1. Temporarily install a nonpolar, AC coupling capacitor at the output, thereby guaranteeing zero millivolts of DC output
2. Rent a strip chart recorder plus compatible preamp, which lets you plot DC millivolts on the strip chart.
3. Measure the DC output before ("upstream of") the nonpolar capacitor and plot it on the strip chart recorder.
4. Run this gear for 5 to 14 days and carefully save the strip chart paper output. Play music as you normally would.
5. Analyze the paper charts, looking to find the peak DC output and the average DC output, upstream of the nonpolar capacitor.
6. Decide whether the measured DC output is low enough to make you happy. If so, remove the temporary AC coupling capacitor.
7. Return the chart recorder and pay the rental fees.
2. Rent a strip chart recorder plus compatible preamp, which lets you plot DC millivolts on the strip chart.
3. Measure the DC output before ("upstream of") the nonpolar capacitor and plot it on the strip chart recorder.
4. Run this gear for 5 to 14 days and carefully save the strip chart paper output. Play music as you normally would.
5. Analyze the paper charts, looking to find the peak DC output and the average DC output, upstream of the nonpolar capacitor.
6. Decide whether the measured DC output is low enough to make you happy. If so, remove the temporary AC coupling capacitor.
7. Return the chart recorder and pay the rental fees.
Yes, but there are no modern solutions which stores the millivolts in digital format?
A digital millivolt meter with a logging functionality (probably expensive)?
I may also wait to see if others have same concerns (I guess some will use the IronPre as preamp) and what they conclude...... 🙂
It was just that I have 4 x NPN and 4 x PNP of the Toshiba output transistors (and those from the kit).......so why not try to do the best match. I know there can be some unbalance during warm-up that can cause some higher DC-offsets. I can switch on the P3 first to warm that up and after that turn on the IronPre 🙂
But it already seems that I should not be concerned.......if I read "between the lines"........ 🙂
A digital millivolt meter with a logging functionality (probably expensive)?
I may also wait to see if others have same concerns (I guess some will use the IronPre as preamp) and what they conclude...... 🙂
It was just that I have 4 x NPN and 4 x PNP of the Toshiba output transistors (and those from the kit).......so why not try to do the best match. I know there can be some unbalance during warm-up that can cause some higher DC-offsets. I can switch on the P3 first to warm that up and after that turn on the IronPre 🙂
But it already seems that I should not be concerned.......if I read "between the lines"........ 🙂
As there has been no mention of the output pair needing matching, and there’s no output capacitor, it’s almost like there’s already a mechanism to keep output DC zeroed…
You are 80% there.
While you have the DCA75 out on your bench put a resistor in between the DCA75 and the J112 Source pin and run the test again. The Idss will be reduced because of the added resistor.
Find the resistor value that gives you about 4ma use that value resistor for your P3 PCB R27.
Thanks DT
Hi,
I got my precious blue bag 😍
And the umbilical psu is under way - a good start in the new year 🙂
I got my precious blue bag 😍
And the umbilical psu is under way - a good start in the new year 🙂
Feeling lucky tonight. Would that be the negative feedback loop here that zeroes DC offset?