Math...
You added 220R in series to the existing 220R... the NEW resistance is 440R.
2.7v / 440ohm = 6.1mA
A little hot, but a lot better than the almost 11mA that you started with. You could continue to tweak it down, but I'd hook things up now and see if everything is working or not first.
You added 220R in series to the existing 220R... the NEW resistance is 440R.
2.7v / 440ohm = 6.1mA
A little hot, but a lot better than the almost 11mA that you started with. You could continue to tweak it down, but I'd hook things up now and see if everything is working or not first.
I really dont know what I started with. Remember, I measured that across R26 that I accidentally added 220 ohms to! Once fixed R26 AND R27, then I measured 2.7 It had been 2.4 originally. Was going to series the extra 220 ohm, but made the R26 mistake. Once corrected, it measured HIGHER than original!
Rereading this, it isnt clear. After fire up post corrected opamp with the standard 220 ohm resistor in place, I got 2.4 across R27. Just like in example in build guide. Attempted to add additional 220 ohm resistor to double resistance and lower 2.4.
Then I messed up and added the 220 ohm resistors to R26. Seeing the voltage go past 10 with variac, i powered down, no smoke, noise sparks nothing.
Then I noticed I had added the extra 220 to R26, and I was measuring across R26 on fireup, not R27.
I then removed the 220 from R26, and added it to R27. Measuring that, I now got the higher than original 2.4, up to 2.7! I must have killed something.
Russellc
Rereading this, it isnt clear. After fire up post corrected opamp with the standard 220 ohm resistor in place, I got 2.4 across R27. Just like in example in build guide. Attempted to add additional 220 ohm resistor to double resistance and lower 2.4.
Then I messed up and added the 220 ohm resistors to R26. Seeing the voltage go past 10 with variac, i powered down, no smoke, noise sparks nothing.
Then I noticed I had added the extra 220 to R26, and I was measuring across R26 on fireup, not R27.
I then removed the 220 from R26, and added it to R27. Measuring that, I now got the higher than original 2.4, up to 2.7! I must have killed something.
Russellc
Last edited:
After a bit of coaching from 6l6, I may be fine here. I guess its time to hook it up and test a bit further. I thought that once the resistance was raised the measured voltage would measure lower. It stays the same, but the resistance is still reducing the current. when it said If you measure within the sweet range you are good to go, so I thought once resistance upped it would measure different. Im reasonably certain this thing will work fine, always the possible hum reduction dance. My Pearl 2 and Salas are very quiet so Im sure this will be fine.
Russellc
Russellc
Last edited:
I suppose it needs to run in a bit. Lots of gain, extremely quiet. I was sure when I got dead silence through headphones I had a problem, but music played. Very quiet. Quite punchy, seems maybe a trace of electronic haze, which is extremely slight, and likely will burn off with a bit of run time.
I assume that since some are rolling opamps that it is either in the signal path or rolling would be of no consequence?
I will give plenty of time for run in and getting use to it before any changes.
Russellc
I assume that since some are rolling opamps that it is either in the signal path or rolling would be of no consequence?
I will give plenty of time for run in and getting use to it before any changes.
Russellc
I want to install a new moving coil cartridge, but after playing with VTA, ( got to love VTA adjustment on the fly) I have this MM Ortofon Super OM30 sounding better than it has any right to. Glad I bought the new body for it, it was well worth the save.
Eventually it will be on a vintage Black Widow on a different table.
Russellc
Eventually it will be on a vintage Black Widow on a different table.
Russellc
Interesting option IIRC, the Black Widow was made when the thought was super low mass tonearms
. In most cases this puts the resonant frequency where yah don't want it, but the OM30 is probably a terrific match for that arm.
Its easier to find for me if you click on the link in post #1. It has you measure resistance (power off) from one box to the other, hopefully zero ohms. Then with umbilical unconnected, checking power supply is around 20 volts, then connected, 20 at the boards. Measure across R27, and adjust as needed.
Go to bottom of post #1, and click on the box on left...it seems to have extra info not found if you go forums, build guides, pearl 3 route.