Wyloch
100+ Head-Fier
- Joined
- Jan 1, 2005
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Sick of the CMOY, not enough cash for a PIMETA, so going with the A47. I'm following the plans here:
http://www.feistworks.com/ben/a47/default.asp
Questions:
1. The diagram says to use a OPA2227 for each channel - is that interchangable (same pinout) with the OPA2134 (which I hear is superior)?
2. I'm somewhat new to the three-pin TLE device. In the power supply circuit diagram, it seems to have four connections, not three: 1, 2, 3, and 8 which goes to cap C5. What's the story on that?
3. I assume D1 is a diode - what's it for?
4. And perhaps most important: I am going to be using this with my Senn HD270s, which an impedance of 64 ohms. This is speced for 32-50 ohms. Which resistors can I adjust to make it more suitable to my headphones, and what values?
5. Are R3 and R4 on the audio circuit diagram 47 ohms or 47 kohms?
Also, regarding the basic idea of the amp: from what I see, it uses two dual amps, and basically amplifies each signal twice by running through both channels in the opamps, correct?
Thanks all for your time.
http://www.feistworks.com/ben/a47/default.asp
Questions:
1. The diagram says to use a OPA2227 for each channel - is that interchangable (same pinout) with the OPA2134 (which I hear is superior)?
2. I'm somewhat new to the three-pin TLE device. In the power supply circuit diagram, it seems to have four connections, not three: 1, 2, 3, and 8 which goes to cap C5. What's the story on that?
3. I assume D1 is a diode - what's it for?
4. And perhaps most important: I am going to be using this with my Senn HD270s, which an impedance of 64 ohms. This is speced for 32-50 ohms. Which resistors can I adjust to make it more suitable to my headphones, and what values?
5. Are R3 and R4 on the audio circuit diagram 47 ohms or 47 kohms?
Also, regarding the basic idea of the amp: from what I see, it uses two dual amps, and basically amplifies each signal twice by running through both channels in the opamps, correct?
Thanks all for your time.