Putting a Jung-Didden SR in front of a MC7n15 regulator is like taking a shower and then putting on streaky underwear. Of course it will be "obviated"!
Then there should be no reason to measure, unless the pre matched ones are mixed up
they sent SK170 in your kit? I will have to open mine up and take a look, was thinking the supplied smd in that position?
@maxellfullmon, not sure who has built the Pearl 3 with LSK170 in the forum. You can use the search function to check, look at who has built the kit with 2SK170’s or better yet ask for Wayne’s comments.
I have been working with 2SK170’s but have not gotten to the point of testing the boards. The largest question for me was the impact of a high output levels of the matched jfet’s and if the high jfet Idss in this circuit caused a change in any other parts. In my case, I am changing the R4-7 resistors from 10R to 22R to adjust for my matched set with an Idss of 8.9mA.
From what I can tell in your case, you have two matched sets of (4) LSK170’s. Depending on the differences in the Idss of the two set’s, you may need to adjust R4-7 values for each channel. As was commented in a previous reply, the matched sets should have a stated Idss written on the bag the jfet’s were shipped in or on a sticker on the jfet or measure the levels yourself.
I have been working with 2SK170’s but have not gotten to the point of testing the boards. The largest question for me was the impact of a high output levels of the matched jfet’s and if the high jfet Idss in this circuit caused a change in any other parts. In my case, I am changing the R4-7 resistors from 10R to 22R to adjust for my matched set with an Idss of 8.9mA.
From what I can tell in your case, you have two matched sets of (4) LSK170’s. Depending on the differences in the Idss of the two set’s, you may need to adjust R4-7 values for each channel. As was commented in a previous reply, the matched sets should have a stated Idss written on the bag the jfet’s were shipped in or on a sticker on the jfet or measure the levels yourself.
I guess I'll just get some more 2SK209's. I was just trying to avoid making another order. Shipping sucks for these small orders.
Thanks
Thanks
I have used matched quads of 2SK170 ...early in this thread I posted that the noise level confirms Wayne's estimate in the original schematic.
I have a lot of matched leftover 2SK209´s from my 3 Pearl3 builds. You can "gift" me whatever you want and pay for the stamp.
Just PM me 😉
I used matched 2SK170's with Idss around 9 mA. I lowered R1 to 412R to keep the voltages around Q5 as they should be.
For dual mono PSU you'll probably want two separate AC mains fuses, two separate EMI filters, two separate power transformers, and two enclosures made of ferromagnetic material such as steel. Be sure the entire stereo ensemble makes a single "star" connection to the Protective Earth terminal of the 3-wire AC mains cord.
You'll also have to own the decision (and make the decision) whether to connect the two "grounds" from the two mono channels, or to leave them independent and unconnected. And if "yes connected", at how many different positions will you connect those grounds together, and where should those connections be? At the input RCA jacks? At the output RCA jacks? From one Pearl3 circuit board "ground" to the other Pearl3 circuit board "ground"? Where on the circuit boards?
It will give you lots of opportunities to express your individuality.
You'll also have to own the decision (and make the decision) whether to connect the two "grounds" from the two mono channels, or to leave them independent and unconnected. And if "yes connected", at how many different positions will you connect those grounds together, and where should those connections be? At the input RCA jacks? At the output RCA jacks? From one Pearl3 circuit board "ground" to the other Pearl3 circuit board "ground"? Where on the circuit boards?
It will give you lots of opportunities to express your individuality.
The long wait is finally over: the Pearl 3 chassis is now back in stock! Grab yours 🙂 https://modushop.biz/site/index.php?route=product/product&product_id=971
I just ordered one of these to properly house mine. Finding a chassis used to be difficult but not with Gianluca around.
That would be dependent on any difficulties a user has (or not) with operating a screwdriver…