I have question about the output stage amp. Is it possible to use it in other projects as well like in a line preamp? Or is there a better schematic available for that using TTC004B and TTA004B?
What is the gain for this and do I need to add some other parts to work? What would be maximum input mV and output V? Can I replace J112 with another JFET like JFE150?
What is the gain for this and do I need to add some other parts to work? What would be maximum input mV and output V? Can I replace J112 with another JFET like JFE150?
The output stage has no (voltage) gain.
The combination of Q9 and R27 can be replaced by any stabile current source.
The combination of Q9 and R27 can be replaced by any stabile current source.
Yes. Wayne’s BA2018 linestage. It comes with the A004/C004 outputs in the kit as an option. Sounds wonderful!!
https://diyaudiostore.com/collectio...r-gain-front-end/products/waynes-ba18-pre-amp
Pearl 3 are back in stock. There are only a few remaining of this batch.
There will be more, I promise.
There will be more, I promise.
How about also including the op-amp and feedback loop that controls the DC in the output?
Thanks DT
Thanks Jim! Snagged one. Can't wait to build it for a vinyl loving buddy. (reads weird after typing it but, eh, that's life)
The P3 continues to amaze me. It is such a great phono stage. Currently listening to the Garden State soundtrack on vinyl and it’s putting a big grin on my face. 
Yeah! I just got one too! Thanks, Everyone for putting this together. That's my quota of good luck for the year. I'll have to rely on skill from here on out...
Let's hope my Dad will, too! 😀
Would you guys like to see a video tutorial on how to solder the SMD parts?
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Seems that my Pearl-3 has finally left the customs warehouse and should arrive within a few days.
I plan on using it with a Rega Excact pickup. Advertised output level from Rega pickups are above avarage for MM.
I have two questions, one related to the circuit and one to the build guide.
1 - Power led: The build guide states "any colour, but blue prefered". Any reason for the blue/cyan preference?
2 - The feedback network of U1a when used at low MM gain is rather low impedance with R22 at 220ohm and R8 at10 ohms. Is this not rather low impedance load for op-amp U1a or am i missing something?
I plan on using it with a Rega Excact pickup. Advertised output level from Rega pickups are above avarage for MM.
I have two questions, one related to the circuit and one to the build guide.
1 - Power led: The build guide states "any colour, but blue prefered". Any reason for the blue/cyan preference?
2 - The feedback network of U1a when used at low MM gain is rather low impedance with R22 at 220ohm and R8 at10 ohms. Is this not rather low impedance load for op-amp U1a or am i missing something?
Me neither
It is a really good question! I presume that while it is a pretty big load for an opamp, with the voltage levels at this circuit node being still very low, opamps won't have problems driving it. Best to ask the Wizard's Assistant though @wayne
@Alpha6230, I have been checking in daily. Given how fast the 1st batch went and 6L6's talk of a limited number of kits that magically appeared, I wasn't taking chances. I happened to check in on this thread after getting done at the gym, saw the update from Jim that was 37minutes old. So there I was sitting in the parking lot, 20 degrees F, in sweaty gym clothes entering CC info into my phone. I felt like I was back in college trying to buy concert tickets.
Edit: I did not receive a notification from the store either.
Edit: I did not receive a notification from the store either.
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Same. They must be sending notifications based on when everyone registered for notifications. I need to finish several other projects, anyway. This will be my third phono amp project and I anticipate one of the other amps will go up for sale after this is completed.
Cheers,
Chris
I don't know if notifications are going out. I never received one. Just checked in on this thread a little after Jim posted the store was in stock.
@LJT - blue/cyan is one I will always put in build docs because Pass Labs traditionally uses blue. And as best as I can tell Nelson bought a few million LEDs that are a light shade of blue that isn’t currently on the market. Believe me, I have tried to find a match to my D1 Dac and a factory FW F3. I found a Cyan that I like. It is close enough for me.
So feel free to pick any color you like. Or try a color changing LED if you’re feeling particularly wild.
So feel free to pick any color you like. Or try a color changing LED if you’re feeling particularly wild.
With low gain for a mm cartridge driving 220 Ohms only requires about 500 uA’s.
The measurements looked okay at these levels and gain settings.
Maybe op amp rolling will have some effect here.
The measurements looked okay at these levels and gain settings.
Maybe op amp rolling will have some effect here.