Thinking about matching Jfets Q1-Q4, given Idds and transconductance aka Yfs within close ranges, is it preferable to match transconductance more tightly, or Idss?
Presumably R4-R7 could be tweaked to achieve identical bias in Q1-Q4?
Presumably R4-R7 could be tweaked to achieve identical bias in Q1-Q4?
Idss. You want to make sure you don't have one that’s significantly more than the rest and it takes all the current.
That said, they are good enough right off the reel that nobody is having any issues and quite a number have been built as were into this project about one year now.
Matching will make something that’s good a little bit better, so let us know how it goes!
That said, they are good enough right off the reel that nobody is having any issues and quite a number have been built as were into this project about one year now.
Matching will make something that’s good a little bit better, so let us know how it goes!
@Giallograle: Check out my post 4222 above; here you will see the difference between 10 2sK209s pulled right off the strip and ten others matched using Idss. A rather large difference. Have done this matching on the BA2018 preamp (by 6L6's recco) and found a significant improvement.
Here are some areas in which the P3's sound can be improved (or altered to your taste):
1. OpAmp selection
2. Setting your cartridge for correct/preferred resistive and capacitance loading
3. Improving PSU with either dual supplies or improved DC creation
4. Matching the 2SK209s
5. Setting resistor values to 0.1%
6. Fine-tuning R27 so it operates within range and so this value is matched from one board to the other
7. Improving various board components
Likely, there are even more ways. The good news is that the phono pre is superb in its stock form.
Here are some areas in which the P3's sound can be improved (or altered to your taste):
1. OpAmp selection
2. Setting your cartridge for correct/preferred resistive and capacitance loading
3. Improving PSU with either dual supplies or improved DC creation
4. Matching the 2SK209s
5. Setting resistor values to 0.1%
6. Fine-tuning R27 so it operates within range and so this value is matched from one board to the other
7. Improving various board components
Likely, there are even more ways. The good news is that the phono pre is superb in its stock form.
Okay. I've finally installed the new regulators on the right channel and have biased R27 to 4mA.
I've searched and haven't found specific descriptions of how to accurately set the cartridge loading. Any recommendations on dip switch settings will be appreciated. My F-9E specs are as follows:
I've searched and haven't found specific descriptions of how to accurately set the cartridge loading. Any recommendations on dip switch settings will be appreciated. My F-9E specs are as follows:
This says 100k for the F9-F; just an Internet source:
https://www.vinylengine.com/cartridge_reviews.php?make=Grace&model=F-9
https://www.vinylengine.com/cartridge_reviews.php?make=Grace&model=F-9
Wow! I knew it was going to be good. I had no idea it would be this good!
Thanks Wayne, for this incredible design! The bottom end seems tighter and better balanced than my Pearl 2. I never did switch the phase on the P2 however, maybe that's in part why. The sound stage is the best I've heard from vinyl in a long time. The detail on Smith & Mudd's Blue River is unbelievable!!!
Also, thanks to 6L6 and Olen and the others who guided me along the way.
I can see it's going to be a long night spinning vinyl! 🙂
Thanks Wayne, for this incredible design! The bottom end seems tighter and better balanced than my Pearl 2. I never did switch the phase on the P2 however, maybe that's in part why. The sound stage is the best I've heard from vinyl in a long time. The detail on Smith & Mudd's Blue River is unbelievable!!!
Also, thanks to 6L6 and Olen and the others who guided me along the way.
I can see it's going to be a long night spinning vinyl! 🙂
Last edited:
Why is there more noise with a balanced cartridge? Isn't the point of using balanced electronics to lower the noise?
I was looking at the photos of the boards on the ordering page along with the description of the boards where it list the size. The power board is listed as being square but it obviously isn't in the photos. Also the phono board doesn't look to scale either. And the hammond chassis listed will in no way fit 2 phono boards. Whats the real correct size for the boards so I can order chassis before my kit arrives?
A question concerning the chassis set listed for $250 euros. So is this the same enclosure that sells for 53 and change? So the extra money is for the machining on the back panel and the silk screening? A 150 euro delta for the pair for the back panel machining? Is this correct? So a person could buy 2 of the unmachined chassis for 106 and change and then put the holes in themselves and be set? Just making sure I have this correct.
the board sizes are noted on the Pearl 3 page.
the square board doesn't look square because of the angle of the photo... perspective. but it's square.
the square board doesn't look square because of the angle of the photo... perspective. but it's square.
Unless one channel is reversed in relation to the other one it won't make a bit of difference will it?. So your speaker cone moves in first instead of out when its going back and forth thousands of times a second what possible difference could there be? If I am wrong please enlighten me. I can't imagine it mattering.
Some people claim to be able to hear absolute phase. I highly doubt I would, But it can't hurt either to do it the "right" way.