SuperDual from Xin Feng
Apr 2, 2004 at 1:29 AM Thread Starter Post #1 of 34

bobjew

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Received another version of the SuperDual prototype from Xin yesterday. This one has basically the same appearance as the first prototype. The only external differences are minor. All the jacks and plugs are in the same place as the last proto unit.

One nice addition is that the switches are marked (see photo). The case on this one is also the Serpac with hand-cut openings for the various openings and switches; not the final manufactured case from Serpac. I'm going to ask him also to mark which side is input and output as well as this is my biggest faux pas with this amp- which side to plug the source and phones into.

The switches are also new, they have a kind of non-slip texture molded onto their front surfaces which presumably make them easier for your fingers to contact.

As before, there is the two digital up and down volume buttons far left and the row of three switches in the center. All the switches are two position- left/off- right/ on. The switch marked "X" is for the Xinfeed(crossfeed) "P"- power, "B", Bass boost.

This unit does not have the auto detect, sleep timer or Ety4p-s adapter. These items will be standard on the production model. I am not sure of the timings on the auto detect and sleep timer, but I think the auto detect will automatically shut the amp off in about 2 minutes the sleep timer about 90 mins.

The new feature to the SD is the Bass boost. It is a circuit similar to the one in the PPA. A steep rise at about 50hz going up +15db. Way too much. The boost sounds really big, fat and artificial. I would think this is too much even for Techno fans. Xin will be dropping this down to around 10 db; he says its an easy adjustment. The standard Bass on this amp is more than sufficent for me.

I got about 6 hours listening last night and a couple today as well as going back and forth a little between the old proto and new. Xin has been working on the sound as he puts it,"tweaking and listening, listening and tweaking" for the last few weeks.

It shows. This amp uses the AD8620 opamp and it really sounds good. The SDII proto is significantly more refined sounding than the first and puts it way beyond any other Mini amp. I would say it puts it into the Maxed Out META or Pocket Reference class. I lacks only in some transparency and layering/size of the soundstage.

The Bass control without boost is excellent. I am using Ety4s' and Bass is tight, deep and fast. Midrange has been improved greatly, nicely presented, transparent, with good separation and range. This amp sounds best to me with a Straightwire mini to RCA (with Radio shack RCA-mini adapter). The highs have much better detail and separation than before. This SD tends toward being warm and is a great match for Ety's.

I went a little nuts trying different cables last night. (I liked the absuridty of it all) From a Homegrown Silver braid to the Straightwire to a DIYcable "Superlative" to a VD Reference to VD Nites.

I will continue to burn-in this amp for a few days more- it sounded very good right out of the bag. I expect it to open and bloom even more in the next few days.
 
Apr 2, 2004 at 1:36 AM Post #3 of 34
anyone know when this is going to be available? I've been looking at portable headphone amps and this looks like the one I would like to have.
 
Apr 2, 2004 at 1:37 AM Post #4 of 34
Quote:

Originally posted by bobjew
One nice addition is that the switches are marked (see photo).


Yes we'd love photos. Thanks for the insight on an anticipated amp!
 
Apr 2, 2004 at 1:48 AM Post #6 of 34
Xin says the battery will last 15 hours, I will do a timing within the next few days. According to my last timing on the previous proto, this is probably a very close.

The production SD should be available next week
 
Apr 2, 2004 at 2:06 AM Post #7 of 34
Damn you, Bob
biggrin.gif
! You got your new SD prototype before me again. I need to check the mail and see if USPS got it to the DC-area today.

I have been getting 13-18 hours on the old prototype BEFORE Xin made the adjustments and optimizations.

To correct bob on one item, Xin told me a few days ago that the current release date for the SuperDual is now May 1, 2004. The optimizations and tweaks made to the board over the past few weeks has pushed the date back a bit. The final change that is being made to the Dual is the 3-poisition Power switch, which will be offered in two versions. One is On/Auto-Off (90 mins)/Off, and the other is a springloaded switch that is Off/Auto-off (90 mins)/Reset timer (spring loaded portion).
 
Apr 2, 2004 at 2:17 AM Post #8 of 34
Thanks for the picture, we appreciate it greatly.
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Apr 2, 2004 at 2:30 AM Post #9 of 34
Any word on pricing yet ?
 
Apr 2, 2004 at 2:36 AM Post #10 of 34
Pricing should be in the same range as the SuperMicro plus/minus a few dollars. Check out the Cool Talk forums over at Xin's website (www.fixup.net) for the most current updates on release and pricing. I believe he posted there a few days ago with pricing info..
 
Apr 2, 2004 at 3:09 AM Post #12 of 34
cmascatello:

April fools!?! Yes, you're right about the release date, I was thinking the beginning of the wrong month. Hey, good to hear from you. I think I must just live closer than you. In an email from Xin last night, he said "So quick?" Feel free to jump into this as soon as you get yours; we were going to do this one together right? I will PM you.

Bob

oddball:
You're most welcome
 
Apr 2, 2004 at 4:42 AM Post #14 of 34
Dr. Xin's place is in Davis right? Berkeley is definitely closer than the DC area.
 
Apr 2, 2004 at 4:58 AM Post #15 of 34
Guess what came today? It is always nice when I brave the cold rain here in DC and have a sweet surprise waiting for me in the mail or package storage. Yesterday is was the CD3000s and today the SuperDual.

I am giving the Dual a bit of burn-in tonight while I head to bed and will give it its first audition tomorrow evening. I am curious to see how the bass boost sounds with the E5 -- I am guessing that it is going to be way too strong if the ER-4 sounded over-cooked.

Xin sent me a red version this time and I have since pulled the PCB out of the new one and swapped it with the old PCB in my previous Blue case. I like the look of the blue more than the red. The only quirk I have now is that the LED on the new PCB is red and "clashes" with the blue case (the PCBs for the blue cases carry blue LEDs)
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