NelsonVandal
1000+ Head-Fier
- Joined
- Aug 27, 2006
- Posts
- 1,023
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- 11
I just got my boards from GoldPhoenix in China. 11 boards for 129 USD incl shipment to Sweden. From gerbers to delivery in one week, that's fast. I also got very fast replies via e-mail. I've seen nicer boards, but they're OK.
It's intended for (semi)portable use in a Hammond 1455J1201 with 8 AAA batteries. When powered by wallwart the supply is regulated to 15 V.
I choose a folded casode input/diamond buffer output design because I like Analogs AD829, AD797, ADA4841 and ADA4899. LT1469 is also claimed to sound good. It simulates very well and seems stable in LTSpice. "All" good discrete DIY headphone amps seem to be symmetrical, so I thought I'd try something totally different, but it would have been safer to go for something like a Gilmore lite clone.
Folded cascode headphone amplifier eSnips Folder
You're welcome to comment on how to make it better. The VR (offset trimpot) will be something like 500R and RH/RI 68R instead for more precision, otherwise I think this will be it to start with. The 22 uF input capacitor is just to simulate the DAP. The amp is DC-coupled. Everything is star grounded. The two ground planes are used as shield.
I wonder if 2SK170GR is OK (diff pair), or should I get 2SK170BL instead? Can I parallel two GR's?
Is anyone willing to help me with measurements, oscilloscope and distortion analysis?
Anyone willing to take a risk and buy a board?
It's intended for (semi)portable use in a Hammond 1455J1201 with 8 AAA batteries. When powered by wallwart the supply is regulated to 15 V.
I choose a folded casode input/diamond buffer output design because I like Analogs AD829, AD797, ADA4841 and ADA4899. LT1469 is also claimed to sound good. It simulates very well and seems stable in LTSpice. "All" good discrete DIY headphone amps seem to be symmetrical, so I thought I'd try something totally different, but it would have been safer to go for something like a Gilmore lite clone.
Folded cascode headphone amplifier eSnips Folder
You're welcome to comment on how to make it better. The VR (offset trimpot) will be something like 500R and RH/RI 68R instead for more precision, otherwise I think this will be it to start with. The 22 uF input capacitor is just to simulate the DAP. The amp is DC-coupled. Everything is star grounded. The two ground planes are used as shield.
I wonder if 2SK170GR is OK (diff pair), or should I get 2SK170BL instead? Can I parallel two GR's?
Is anyone willing to help me with measurements, oscilloscope and distortion analysis?
Anyone willing to take a risk and buy a board?