I am highly recommended OPA627.
See below:
The op-amps used are generally of poor quality, corrupting the analogue signal, having a disastrous effect on the sonic capabilities of the CD player. The effects are a smearing of detail, reduced dynamics, congestion of instruments on complex music passages causing a mass of sound, rather than a spacious, airy, sound stage. The quality of the mid-high frequencies is particularly poor, where the mid-band is brittle and aggressive, and higher frequencies are edgy, cold and fatiguing to listen to.
The following op-amps produce the poorest results; NE5534, NJM2114, NE5532, NJM4558, NJM4560, AD711, AD712, LM833.
The performance of op-amps from different manufacturers varies considerably. Therefore, selecting a single type of op-amp to meet the parameters required for the analogue output stage involved analysing data sheets and conducting many listening tests.
The important parameters for sound quality are high speed (or bandwidth) low THD, fast settling, and low input noise. The most natural and musical sounding were FET-Input types as opposed to bipolar.
Burr Brown OPA 627 BP(single, ceramic) on Browndog adaptor
Price: US$28 each (Total US$56 for 2 singles) Browndog adaptor $5 Total: $61
Comment: Two words sum this chip up........ "absolute class" This is single chip and it was necessary to fit two single channel 627's onto a single to dual Browndog adaptor which Adapts two single-channel DIP-8 op-amps to a dual DIP-8 pinout. These 2 single channel op amps absolutely trounced anything that had gone before them ..... the width of the soundstage, the clarity and the sheer presence make this my choice of op amp for use in the Chiarra without a shadow of a doubt. The sound is just so "clean", so "natural", so "musical" and so "detailed" with the 627's on board. The Burr Brown 627 "is" headphone heaven....... absolute class act.
LM4562(dual, ceramic)
Price: US$30.
Comment : A "Very" revealing chip, sound similar to the OPA627 but puncher around the edges. I found this chip gave out "way" too much information for my liking. It is analytical to the point that certain pieces of music can become impossible to listen to, especially bad recordings, it reproduces every last detail / imperfection with microscopic accuracy which, at times, can be detrimental to the overall enjoyment of the music. For those that love a warts and all insight into the music then this is the star of the show but it may not be to everyone liking. It may be an op amp which can beat OPA627.
Burr Brown OPA2604 (dual, ceramic)
Price: US$10.
Comment: OPA2604 sounded very warm, very laid back and very easy to listen to but slightly veiled in the detail department. "Chocolaty" and "syrupy" though a good easy to listen to Op amp., This may just be what the doctor ordered for those who like a laid back, thick, chocolaty, easy going and easy to listen to sound.
Linear techonolgy LT1057(dual, ceramic)
Price: US$20,
Comment: Without a shadow of a doubt this op amp is the star of the the centry. Easy to listen to, easy to pick out every last detail and ever so natural. There was an ethereal quality to the sound that only ever heard on high quality loudspeaker based systems. It's hard to put what this op amp does into words but listening to the sound with it on board is as close to headphone heaven. Very analytical.
Linear techonolgy LT1028(single, ceramic) on Browndog adaptor
Price: US$15 each (Total US$30 for 2 singles) Browndog adaptor $5 Total: $35
Comment: It provided very similar results to the LT-1057 but each component of the sound was treated to an additional air of realism and effortless delivery that was immediately evident.
Linear techonolgy LT1028(single, metal) on Browndog adaptor
Price: US$25 each (Total US$50 for 2 singles) Browndog adaptor $5 Total: $52
Comment: It provided very similar results to the LT-1028 but the sound is ten times better LT-1028 with their punch , detail , range of frequency ….. especially the naturality.
Analog device AD797 (single, ceramic)
Price: US$25 each (Total US$50 for 2 singles) Browndog adaptor $5 Total: $52
Comment : Smooth, highly analytical, warm, uncoloured, laid back yet all detail is present (and then some) Very electrostatic quality to the sound with that super solid state bass underpinning the proceedings without overwhelming them. Start and stops are followed by an inky black silence and the timbre of the drums is very realistic indeed. Something that is very evident with this op amp is it's inherent ability to provide accurate timing which I really do like! There is no bass overhang, the drums start and stop as they should and, as a result, the timing is pretty much spot on. This is like listening to music with a stethoscope with the metronome ticking away in the background but it also adds a touch of valium to make the experience very bearable and extremely enjoyable.
Analog device DY2000 (dual, ceramic)
Price: US$20
Comment : These chips makes the sound more valve like than the tube sound ever did if that can possibly make any sense! Melodious, slightly laid back and warm yet it brings out every last bit of detail from a recording. Overall a very nice sound. A kind of hybrid valve and solid state mix which gives the best of both worlds. Nice smooth valve like mids and highs with lovely solid state bass oomph . This is the Op amp for those who prefer a valve like sound but would also like a solid state bottom end delivery. With this Op amp you can have your cake and eat it. Smooth as silk.
Analog device DY2000 (dual, metal)
Price: US$35.
Comment : It provided very similar results to the DY2000 ceramic but the sound is ten times better with their punch , detail , range of frequency ….. especially the naturality.
Thank you very much !
Best regards,
Lawrence |
The Zero can function as a DAC, and at the press of a button, switch to headphones. It can't do both at the same time, which, when you think about it, is ok. You can't really listen to both at the same time anyway. 
