ch1n4
100+ Head-Fier
- Joined
- Oct 21, 2011
- Posts
- 148
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- 22
Last month, i bought one from Amazon Japan; so i think i am qualified to post my own experience and impression with this wonderful little gadget:
First, let's talk about its build quality; i think it is built like a tank with all aluminum body and polished front panel; however the four screws left on the top metal cover are eyesore but according to the owners of the original model A4, their presence may faciliate the replacement of OPAMP, which i have found is not so for A4-BL; more on that later.
Second, about its sound qualtity: i have some highly sensitive IEMs and some high and low impedance cans to pair with my A4-BL; and they pair well; the sum up, the sound of A4-BL is very neutral, resolving and spacious, not colored, more like FOSTEX adopting a reference tuning on this one, which may displease some audiophiles who have preference for a very colored sound and find the sound of A4-BL a little boring; it is noteworthy that i have only listened to the SE and have not tried the BAL OUT, which may be more powerful and euphonic judgding from the specs (300MW BAL vs 150MW SE); having read the A4 thread, i am very intrigued to try OPAMP rolling on A4-BL but my attempts to do so failed because this required the complete disasembly of the entire metiallic enclosure, taking out of the PCB and even the removal of the potentiometer, which is very tricky; however I do have a careful look at the internal PCB layout and find it quite different from that of the original A4 because FOSTEX does adopt a TRUE balanced design on this one. First I see three NJR2114Ds and two OPA2134PAs soldered onto the right corner of the PCB with a replaceable DIP version of OPA2134PA on a DIP socket, which i think is right located at the gain stage of the PCB. In addtion, what makes me think this is a truly balanced design is that channel imbalance issue frequently found on non-balanced amps is non-existent on this one. On top of that, the new type of capacictors touted by FOSTEX in its ads are actually NICHICON FG series and I do see two or three MUSES-series capacitors.
I think what i need to do now is to find a pair of balanced headphones to see how it pairs with A4-BL; i eye for BEYER T5P 2nd GEN, but boy, what a hefty price to pay! my wallet is crying.
thanks for your impressions. Did you test it with high impedance phones? I am wondering if it could drive a Sennheiser HD 600/650 in balanced mode.
is it already available outside japan? couldn't find any reviews...