| Author |
 Topic  |
|
Xin
Moderator
USA
2383 Posts |
 Posted - 05/09/2006 : 11:23:23
|
 
 
Introduction
(scroll down for guide on selection and use, buy them from Cool Stuff)
Since I made the very first truly portable amp, the legendary SuperMini that set up the category, I have been thinking about the issues raised by "portable" restrictions and requirements. Following SuperMini, many manufacturers and DIYers have been trying to make good portable amps, but some of the key issues are still not addressed, such as virtual ground.
In my "-III" amp designs, I used a unique passive third channel to address those issues, with very good results. Now, I move one big step further: adding the 4th channel. I call this new technology that I created: 4-channel technology.
With my 4-channel technology, not only are the left and right channels separated like the dual-mono structure found in high-end home amps, so are the front and end stages, like the pre-power amps found in top-end home systems. These separations ensure the untouched, cleanest sound possible, even at very large signal swings. This is so far the most effective way to produce the best sound.
With the new XIN "-IV" amps, you can enjoy the very best music brought to you by this latest and greatest audio technology, right now. XIN SuperMacro-IV, SuperMini-IV and SuperMicro-IV ultra portable headphone amps all deploy the new 4-channel technology created by Dr. Xin, a former rocket scientist. The sound is extremely clean, sweet and powerful with huge sound stage, to say the least.
Here is the benchmarks:
120 OHM Load
Grado 60 (32 OHM)
HD580 (300 OHM)
The follwoings are all with HD580:
OP275
OPA627 etc.
AD822 etc.
OPA637BP 2x BUF634HiC
You can see all the specs, tonal balance, S/N, dynamic range, THD, IMD and channel separation, are all at the extreme edge, unseen in the past. 4-channel technology does make huge differences!
SuperMini-IV
Under Different Working Voltages
Use different OP-AMPs
You see, SuperMini-IV drive HD580 cans extremely well with just two AAA cells (even without enabling DC-DC boost)!!! 4-Channel technology works!
XIN SuperMicro-IV You see, this yongest sister performs as good as its big brothers, only the distortion is higher - still way lower than other amps and such tube-alike distortion is exactly what tube-lovers are looking for. And please don't forget, she is only 1 oz and she is driving huge HD580 cans with just a single AAA battery!!! 4-channels technology rules!
Beside the 4-channel technology, there are some other changes and improvements in these new generation amps.
SuperMacro-IV: now there are totally 8 sockets for taking any opamps and buffers. Battery contacts are fastened by gold-plated springs, much less contact resistance and far more durable. DC plug no longer cause short to the case.
SuperMacro-LE: a low-voltage version for modern 5.5V OPAMP's.
SuperMini-IV: 3 sockets for taking any dual opamps. Internal charging (yes!), and can be turned off. Engraved case. No longer require regulated DC power. Much better PCB design. Thumberwheel is more hidden, much less chance for accidental volume slip. Jumpers are labeled.
SuperMicro-IV: new tube-alike opamps with built-in buffers. Much better PCB layout. Engraved case.
I'm very sorry that I did not have time to be here when I was thoroughly focused on these new designs. And sorry for the delay if you ordered an amp recently. My goal is always to bring the best sound to you. Here I thank all my friends and customers for helping me and supporting me in all these years, especially Simon and Ron on recent development.
Selection Guide
The SuperMacro-IV is your first choice. It is simply the smallest and thinnest amp offering the best sound and features. So far nothing else in this world can beat it on its size, weight, feature, price and performance.
The default chipset, OPA134 + BUF634, offers the typical and classical BB sound - warm and pleasant. If you like AD sound - analytic and live, you may choose the OP275 chipset. The following pictures show these two configurations. Both sound fantastic with super long battery life - more than 30 hours per charge (based on 1000mAh Ni-MH). Of course, these are just two typical configurations and you may change to pretty much anything you like by yourself, see "User Guide" below for details.
SuperMacro-LE is the low voltage (6V vs. 12V) version of SuperMacro-IV, designed mainly for modern 5.5V OPAMP's. These latest chips usually have very tube-alike sound and are very battery friendly. As these chips cannot work above 5.5V, they cannot be used in SuperMacro-IV. This is why we offer this LE version. Actually any OPAMP's can be used in LE, as long as they can work down to 5V such as OPA627 and BUF634, but Rail-Rail types such as AD8616 and AD8397 etc. are ideal as they can use up all the 5V.
SuperMacro-IV Battery Life (1000mAh):
OPA2134+1xBUF634 50 hrs
OPA275+1xBUF634 70 hrs
OPA627+4xBUF634 25 hrs
AD8620+4xBUF634 35 hrs
SuperMacro-LE Battery life:
AD8616 125 hrs
AD8397 50 hrs
If you want something smaller and thinner, then SuperMini-IV is the favorite. You still get all the features of SuperMacro-IV, including 4 switches (internal though), internal charging (not fast though) and OPAMP rolling (dual only though). With the latest 5.5V boost technology, its 2 AAA cells can power almost any headphones. Its DC jack allows you to use 3-7.5V external power. Battery life is 120 hours for the default tube-alike chipset or 50 hrs if DC-DC boost is enabled.
If you want something even smaller, then the SuperMicro-IV is absolutely the smallest top-end amp currently available in this world. Although it does not have the features and its beautiful case is not so rugged, but it does not lose anything on sound. A single AAA battery powers any headphones for 35 hours, thanking to the same 5.5V boost technology used in SuperMini-IV and the latest amplify chips.
SuperMacro-IV/LE:
3.3"x2.1"x0.9", 6.9 oz (w/batt. 5.7 oz for LE), 8 AAA (4 for LE), over-discharge indicator, 2-hour fast charging, switches for 4 features, auto-off timer, single and dual opamp sockets.
SuperMini-IV:
2.4"x1.9"x0.6", 2.0 oz (w/batt.), 2 AAA, internal charging, 5.5V boost, jumpers for 4 features, dual opamp sockets.
SuperMicro-IV:
2.0"x1.0"x0.7", 1.0 oz (w/batt.), 1 AAA, over-discharge protection, 5.5V boost.
More details can be found in user guide below.
User Guide
All the XIN amps are plug and play, very easy to use. Get a mini-mini interconnect cable, plug its one end into your source (MP3 player, for example) and the other end into amp's "IN" jack. Plug your headphones into the "OUT" jack. That's it.
SuperMacro-IV/LE:
At the left is the power switch: on/auto/off. Its knob is also an indicator for power on (red), power off (dark), external power (green), fast charging (blink green), trickle charging (steady green) and low battery (dark).
Above the power switch is the DC jack. When you use the included AC adapter, set its input voltage to your country (110V or 220V). If you use a 3rd party AC adapter, make sure it is regulated to 15V (7.5V for SuperMacro-LE), center positive.
Fast charging takes about 2 hours, it then turns automatically into trickle charging mode. The amp becomes warm at the end of fast charging, which is normal. You may use any type of AAA batteries, rechargeable or not. If you use non-rechargeable, don't plug in AC/DC power. You can use just AC/DC without any batteries in.
The other 4 switches are for customizing sound. From left to right,BAsIC (old versions are It's ABC):
B, Bass Boost, increase bass by 6 dB.
A, Amplify Gain, raise gain from 3 to 8, good for low-efficient headphones.
I, Output Impedance, add 75 ohm, good for some headphones and turning ER4P into ER4S.
C, Crossfeed (XinFeed), simulate home speakers.
This picture shows the configuration of AD8397 chipset. As AD8397 has built-in buffers, there is no need for external buffers. The left buffer sockets (for 4th channel) is bypassed with a single dummy opamp. The buffer socket for L and R channels are bypassed with a dual dummy opamp (of course you can use two single dummy opamps as well).
This picture shows how to use a dual opamp like OPA2134. Although OPA2134 has enough power to drive some headphones directly, it is still better to use external buffers. 220 ohm resistors are soldered between pin 1 and 4 of BUF634s to set them into Hi-C mode for better performance.
This picture shows how to use single opamps like OPA134. Other parts are the same as above.
This picture shows how to use a dual opamp like OPA2134 and a buffer in the 3rd and 4th channel. BUF634 is not set to Hi-C mode to save battery life, because here it does not swing voltage (your mileage may vary). Almost any dual opamps can be used here, but low power and noise are prefered (such as NJM14558) and some opamps (such as OP275) does give better sound image.
This picture shows how to use HA5002 as buffers. They must be mounted on special adapters as their pin layout are not standard. These adapters also allow you to easily stack up 2x or 3x buffers. Also showing in this picture are the NE5534 marked with big "S" and year of making. Many audiophiles believe that these ancient NE5532/4 made in early 80's are so far the best sounding opamps. With output bypassed (OB) and properly used in a very accurate amp like SuperMacro-IV, nothing else can be even close to their sound.
This picture shows a very expensive setup: 2X stacked buffers (BUF634) in Hi-C mode with OPA637. Such a top-end configuration is only found in few $$$$ home headphone amps and it is unseen in portable amps. OPA637 and 2x buffers drain lots of power which is beyond the capacity of 9V batteries that are used by almost all other portable amps. Thanking to 8 AAA cells that power up SuperMacro-IV, we have plenty of power here and we still get decent 20 hours play per charge (based on standard AAA Ni-MH of 1000 mAh and a full recharge takes only 2 hours). In comparison, 9V batteries can play only 4 hours for such a powerful system.
SuperMini-IV:
Warning: Never plug into the DC jack more than 7.5V! If you use a unregulated 7.5V AC adapter, you are going to burn the amp for sure and it is not covered by warrantee!
Charging takes about 10 to 14 hours. Never charge alkaline batteries! When you turn off the power switch, the batteries will not be charged, but the amp is still powered (on) by the external power.
The 4 pairs of jumpers allow you to customize sound. In the following picture, all the jumpers are at bypass (disabled) position. Refer to above for their meanings.
In this picture, the positions of the jumpers set the Amp gain to 3 (or 8, on old versions) and enable Crossfeed. Impedance is set to low (bypassed) and Bass boost is bypassed (disabled).
This picture shows the configuration of AD8397 chipset. The buffer socket is bypassed with a dummy opamp (dual, not included by default), Note the DC-DC (5.5V) boost jumper is set to "L" (low, 3V) position, because AD8397 performs very well at such low voltage. You may change the two AD8397 with other similar opamps such as AD8656 and AD8616.
This picture shows the configuration of AD822+LMH6643 chipset. You may replace the AD822 with your favorite dual opamps such as AD8620, OPA2134, etc. Note the DC-DC boost jumper is set to high position, because these opamps need 5.5V to perform well.
Please note how these opamps are inserted (the #1 pin). If you insert them upside-down, they won't work and could be damaged.
Tricks and Tweaks
- After the power light goes off, all IV amps can still work for a very long period. Although performance is not guaranteed, the sound is not bad at all and at least you can keep your music going. Don't do this with NiMH batteries though because you are over discharging them and may damage them.
- SuperMacro-IV/LE has an advanced fast charger built in. It works in pulse mode - the best for batteries. There is no any interference from the high-current pulses during charging.
|
Edited by - Xin on 11/27/2008 00:46:45 |
|
|
Jon L
Starting Member
29 Posts |
Posted - 05/09/2006 : 11:34:49
|
Hi, Xin, good to hear from you.
Is there an upgrade path for us SMv3 owners? |
 |
|
|
ArchiMark
Junior Member
USA
171 Posts |
Posted - 05/09/2006 : 12:08:08
|
Sounds great, Xin!
A few questions for you before I place an order please...probably your answers will help some others too...
I have MPIO FL100 and want better sound...
1) Trying to figure out which model amp to order; SuperMacro-IV or SuperMini-IV? What is really difference (other than size) sound-wise?
2) Besides using to drive some headphones, I also would like to sometimes use amp to drive some small portable speakers. Is that OK with your amps?
3) Can you describe a little bit as to what the different options are for that you have listed on your amp order page?
Thanks!
Mark
Mark
Silicone Valley |
|
|
|
Moxwell
Starting Member
7 Posts |
Posted - 05/09/2006 : 12:10:31
|
| Welcome back Dr. Xin! Concerning your new 4 channel technology, I am under the impression that the two output grounds are now isolated from the input grounds, but headphones share a common ground so aren't they coming into contact to each other at the output and so the L&R channels aren't isolated from each other? |
|
|
|
goto2003
Average Member
626 Posts |
Posted - 05/09/2006 : 12:14:37
|
| Cool! From my understanding, headphone cable has ground connected at the plug. Even the amp has seperated output, whenever headphone plugged in, they are connected. In this sense, there's no benefit to seperate output ground from left to right unless one uses Balance Headphone. |
Edited by - goto2003 on 05/09/2006 12:45:50 |
|
|
|
Moxwell
Starting Member
7 Posts |
Posted - 05/09/2006 : 12:50:44
|
"With my 4-channel technology, not only the left and right channels are separated like the dual-mono structure found in high-end amps,"
Ok, so the four channels are L, LG, R, & Rg? If LG and RG are connected at the plug would this still be considered four separate channels? Using the dual mono home amplifier analogy, separate loudspeakers have separate grounds so this isn't a problem with home systems but not the same when using headphones unless you separate the LG and RG.
Sorry, just trying to understand the new technology. |
|
|
|
alanz
Junior Member
134 Posts |
Posted - 05/09/2006 : 17:34:14
|
| Congratulations Xin... I'm very much looking forward to hearing the results of your fine work. |
|
|
|
Xin
Moderator
USA
2383 Posts |
Posted - 05/09/2006 : 18:11:50
|
Thank you guys!
Upgrading issues will be addressed shortly.
SuperMini is always recommended first. It is rugged, very small and thin, fully featured, good price. SuperMicro is for those who really want that. All amps sound almost equally good, so you cannot go wrong with either of them, just pick the features you like. All amps are powerful enough to drive small speakers, but you may need to send the amp back to raise the gain if you'll find it is not loud enough.
You don't have to care about the options if you're not familiar with these stuff. You can always come back later if you're ready for more tweakings and fun.
For headphone amps, there two types of dual-mono: 1) Input and output jacks are separated. This requires specially cabled headphones. HD580, for example, can use such special cable. 2) Input and output jacks are not separated. This is most popular as it does not require special headphones/cable. If you really want true dual-mono, you can use two XIN amps, one for L and one for R. |
|
|
|
Moxwell
Starting Member
7 Posts |
Posted - 05/09/2006 : 18:32:22
|
quote:
Originally posted by Xin
For headphone amps, there two types of dual-mono: 1) Input and output jacks are separated. This requires specially cabled headphones. HD580, for example, can use such special cable. 2) Input and output jacks are not separated. This is most popular as it does not require special headphones/cable. If you really want true dual-mono, you can use two XIN amps, one for L and one for R.
Thanks for the explanation Xin, but I am still not clear on the four channels. To have four channels I would think that you would need separate LG and RG but from your explanation, that is not the case here, or am I missing something? To get true separate RG and LG (and true four channels) I would need two amplifiers?
|
|
|
|
goto2003
Average Member
626 Posts |
Posted - 05/09/2006 : 18:57:28
|
| I think Dr. Xin has explained it - "With my 4-channel technology, not only the left and right channels are separated like the dual-mono structure found in high-end amps, so are the front and end stages" L, R, Front ground for OP/BUF, & End ground for headphone. |
Edited by - goto2003 on 05/09/2006 19:45:05 |
|
|
|
HiFlight
Average Member
USA
826 Posts |
Posted - 05/09/2006 : 19:16:11
|
Moxwell...
Without knowing the circuit layout, I am guessing that the isolation is more in the DC voltages, (power supplies, biasing, etc.) rather than only the signal path itself. I am sure that Dr Xin will clarify these circuitry questions as time passes, but I can attest to the fact that the active 3rd channel (as evaluated in one of the prototypes) notably improved the soundstage, imaging, and detail from previous versions.
It would probably have been difficult to detect the differences without comparing them directly, side by side at the same volume settings thru the same phones. I spent quite some time doing this with a variety of different opamps.
Ron Kerlin
Ft Myers, FL, USA
iAudio X5L, iRiver H120,
SMIIIv.8, Mini3, ER4P, ER6i, EM3, UM2, AH-D6, HD650/Equinox, Ultrasone 2500, AKG501, B&O A8, KSC-35 |
|
|
|
Xin
Moderator
USA
2383 Posts |
Posted - 05/09/2006 : 21:37:32
|
Moxwell, forgive me that I cannot post on public the technical details. It is not very complicated to understand, but it did took me 4 years to figure it out. The Earth turns around Sun, how simple was that; but human used to believe it the other way, not long ago.
Although all the "-IV" amps deploy the same 4-channel tech, there are some differences in each amp's implementation. What you see from the SuperMini-IV's pictures, do not all apply to SuperMacro-IV and SuperMicro-IV. |
|
|
|
Zoide
Starting Member
26 Posts |
Posted - 05/09/2006 : 21:46:58
|
Hi Dr. Xin,
Will there be an upgrade option for owners of previous SuperMacro's?
Thanks, and congratulations on your new creation! |
|
|
|
Xin
Moderator
USA
2383 Posts |
Posted - 05/09/2006 : 22:49:54
|
I'm still thinking about the details of upgrading. SuperMicro cannot be upgraded and re-use of the case makes no sense. SuperMini may be (or not) be upgraded with an add-on board. V6 of SuperMacro can be easily upgraded by replacing the bottom board, or adding a module and some simple modifications. Other earlier version may (or may not) add an upgrade module plus some modification. These upgradings (if poosible) cannot get all the benifit, but should get the key 4-channel technology.
Meanwhile, we should first wait and see people's impressions. |
|
|
|
fongalv
Starting Member
28 Posts |
Posted - 05/09/2006 : 23:32:06
|
congratulations on yet another "breakthrough" Xin!
yesyes...Im also awaiting some impressions form the few who has gotten the SMIV...
some quick questions tho, from previous mods Ive seen, most of them have added more caps to "improve" the sound but now I see that you have choosen to use just one cap, and yet even lowering the capacitance to 1000uF?
"SuperMacro-IV: now there are totally 8 sockets for taking any opamps and buffers"
I see 6?
on the products page I see that you have removed the "maxout" option and in its stead changed it to opa627? does this got anything to do with the new channel design?
I would very much like to upgrade my v6.
thanks for all the work again!
|
|
|
|
GaZoh
Starting Member
Japan
2 Posts |
Posted - 05/10/2006 : 07:10:09
|
Congratulations Dr.Xin!
I am looking forward to "Up-grade Pass".o(^-^)o
In "SuperMacro-IV", is there a gain for which "OPA637" can be used?
|
|
|
|
Topic |
|
|
|
New XIN amps with 4-channel technology
Topic Locked
