Having built Pearl, Pearl 2, and now Pearl 3, I think that yes, this is genuinely the best so far. Amazing phonostage, you will love it.
😎
I've PM'd Wayne, who has kindly offered to send me a second board - looking forward to building Pearl 3.
It appears he didn't receive my first PM, and not sure he received my reply to his PM, so hopefully he checks this thread and goes to his messages.
It appears he didn't receive my first PM, and not sure he received my reply to his PM, so hopefully he checks this thread and goes to his messages.
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Single chassis prototype is singing. This is in a linestage chassis that is temporarily being repurposed for this test. Sounds great so far! I’ll move these boards to a 2 box setup next. First I need to finalize a couple of details with Gianluca.
Raw PSU rails are about +/- 22V
This setup is using a Shelter 901 MC set at 100R. High gain. And the first record Tasmanian NWOTHM / Doom band The Wizar’d.
Raw PSU rails are about +/- 22V
This setup is using a Shelter 901 MC set at 100R. High gain. And the first record Tasmanian NWOTHM / Doom band The Wizar’d.
Attachments
My Pearl 3 prototype was 0.026 V with 2sk170GR, in the simulation with LSK170A it was a bit lower @2.5mA This coincides with the optimal current through the ZTX851 for lowest noise (per AoE) of 10mA.
I won't build a Pearl 3 until the boards are generally available through the store, so no listening tests until after Christmas!
Remember that before the cap multiplier, the LM7815,7915 have 10uF on the input and output. The 7915's probably draw only 10mA.
Those 7915 I have (vintage Nat Semi) measure less noise voltage than that spec'd in the TI data-sheet, but this may be anomalous.
@DualTriode
I have two built, one with 2SK209GR, they are reading 0.018v across the 10R resistors.
The 2nd has 2SK370 and they are measuring 0.030v across the 10R.
On the bench they both sound the same.
I have two built, one with 2SK209GR, they are reading 0.018v across the 10R resistors.
The 2nd has 2SK370 and they are measuring 0.030v across the 10R.
On the bench they both sound the same.
Small thing to note, probably only of note to those of us fetishists who enjoy measuring things. In Groner's ULN amplifier article in Linear Audio he suggests that when the JFET runs cooler, it also runs quieter. Next thing you know we will be using liquid helium to cool them in a Dewar flask.
There are particular ones just for that, also nitrogen does not count, does it?
I think that Scott Wurcer mentioned that there were diminishing returns to going below a certain temperature, but I will let you solid-state physicists figure that out and report back. I had a lovely undergrad summer doing that stuff, but the memories are lost to the mists of time!
Hi Wayne,
As a suggestion, on Sam Groner’s LNA, he put down a dummy sot23 footprint and bias resistors so that you could match the specified bf862 jfet devices. Instructions were to Populate your regulator test area only, test/select jfets using DMM and tweezers, finish populating.
Just a minor pcb rev for a lot of convenience in selecting the jfets
Rick
As a suggestion, on Sam Groner’s LNA, he put down a dummy sot23 footprint and bias resistors so that you could match the specified bf862 jfet devices. Instructions were to Populate your regulator test area only, test/select jfets using DMM and tweezers, finish populating.
Just a minor pcb rev for a lot of convenience in selecting the jfets
Rick
Well, the only answer is build both—and more. Two arms, preferably 4, over 2 tables. (I have built both versions of FSP.)
Well this is my first step into hifi diy.... so probably more will come... 😂
I was thinking 3 diy tube guitar amps was enough, so lets try something different. Im a little sensitive to diy addiction 🙄😂
If you gonna build the pearl 3 i will be curious about what you think in comparison with the FSP 😉
I was thinking 3 diy tube guitar amps was enough, so lets try something different. Im a little sensitive to diy addiction 🙄😂
If you gonna build the pearl 3 i will be curious about what you think in comparison with the FSP 😉
In the "Pearl Domain" the P3 is likely to be easier to build. Folks had some issues with the P-Channel mosfet in the final stage of the P2 -- static sensitive.
The power supply for the P3 is probably a bit easier to source.
Hello PEARL 3 -phono-pre-freaks,
still some work left... 😳
Getting closer with my PEARL 3 - project.
A few OPAmp-leftovers from M2X and DRV134 and THAT 1646 - audiolinedrivers... Hmmm!
What's going on here?
Cheers
Dirk 😉
still some work left... 😳
Getting closer with my PEARL 3 - project.
A few OPAmp-leftovers from M2X and DRV134 and THAT 1646 - audiolinedrivers... Hmmm!
What's going on here?
Cheers
Dirk 😉
