MASS-Kobo Headphone Amp. model404
Feb 8, 2015 at 7:54 AM Thread Starter Post #1 of 197

seeteeyou

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https://www.facebook.com/MASSkobo/posts/749982861745578
http://www.masskobo.com/e/sale-e/m404.htm
http://www.masskobo.com/j/sale-j/m404.htm
 
This amplifier provides you with the highest sound also by Balance Headphone.
 
The sound is similar to model394 or model395 since those use similar circuit and same part as model394 and model395.
 
<Specifications>
 
Model : Stereo headphone amp
Input : φ3.5 TRS x 1(Unbalance) , φ2.5 TRRS x 1(Balance)
Output : φ3.5 TRS x 1 (Unbalance for Dinamic HP) , φ2.5 TRRS x 1(Balance for BA IEM) , XLR4 x 1(Balance for Dinamic HP)
Frequency Characteristics : 20Hz - 20kHz (-1dB)
Battery : AA Alkaline or Rechargable Battery x 6
Size : 113mmW x 155mmD x 40mmH

 
Six AA batteries required, that's gotta be powerful enough to drive pretty hungry cans. Could it be a serious rival to the upcoming portable amp from Cavalli Audio?
 
Feb 9, 2015 at 11:52 PM Post #2 of 197
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Cases look good
 
https://www.facebook.com/photo.php?fbid=762329940510870
 

 
I'm getting some LiFePO4 AA batteries with constant 1.5V output
 
http://item.taobao.com/item.htm?id=39871207392
 
Many owners of Sony PCM-D100 tried them with great results.
 
Feb 10, 2015 at 7:15 AM Post #3 of 197
It's looks good
But the price is too expensive


And the link of the battery is not LiFePO4. It is a battery which can keeps 1.5V normally. If you want to try LiFePO4, "coolook" or "coolworld" maybe your favor.
 
Feb 10, 2015 at 9:07 AM Post #4 of 197
Oops, that's my fault and I stand corrected since KENTLI should be LiPo or LIP batteries.
 
They're actually making 3.2V ones with whopping 1,500 mAh but not exactly sure about how trustworthy that rating would be
 
http://www.ebay.com/itm/2pcs-ETINESAN-1500MAH-3-2v-14500-AA-rechargable-battery-w-dummy-14500-Charger-/390980052915
 
It's just too risky for an amp like this and I'll have to constantly remind myself about this
 
http://www.ebay.com/itm/4-3-2V-LiFePO4-AA-rechargeable-battery-w-4-Dummy-Cells-Conduct-Electric-Current-/151337010425
 
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PowerGenix also made something called NiZn with 2,500 mAh @ 1.6V
 
http://item.taobao.com/item.htm?id=22306552883
 
Obviously LiFePO4 should be the lightest ones with 3 real batteries plus 3 dummy ones.
 

 
Rudi tried so many amps out there and he seemed to like both desktop/portable ones from Masuda-san
 
http://www.head-fi.org/t/711879/mass-ko-bo-394-new-high-end-amp-for-power-hungry-headphone-like-abyss-1266
 
I was so intrigued when he talked about something portable yet powerful enough to drive Abyss with authority. A beast like that does come with a price and it could be worth the difference if the balanced output were even better than the single-ended ones from Hugo.
 
Feb 11, 2015 at 5:24 AM Post #5 of 197
Thank you Frankie to post This New balance Amp Mass Ko Bo 404

Now on Mass Ko Bo website got Promotion For ¥130.000 Yen For 10 units first Batch .

I have the desktop full balance amp :

Mass Ko Bo 394

And The portabkle Amp :

Mass Ko Bo 395

I am waiting to get My Mass Ko Bo 404 full balance portable amp

According to Masuda San This New balance amp Mass Ko Bo 404 is Power full , It can drive Abyss 1266
 
Feb 12, 2015 at 10:18 PM Post #6 of 197
I love my 395. Very revealing amp for detail and clarity. Very impressive. I would consider this amp is on the bright side of character. Not overly bright. Its just neutral kinda amp. i do wish it has a slightly warmer tone on its performance. So that will be heavenly matched for my grado cans.
 
Feb 12, 2015 at 11:39 PM Post #7 of 197
I'm glad that wiring scheme for 2.5-mm TRRS jacks of model404 will be changed to accomodate existing cables designed for AK240:
 
R- R+ L+ L-
 
Fortunately my e-mail should be sent to Masuda-san before the design was finalized. I'll have some fun with quad-stack like this:
 
Source > Hugo > Aclear Porta NXT-2AK > MASS-Kobo model404
 

 
Looks like this is the best connector for balanced interconnects going between NXT-2AK and model404
 
http://ns-t.com/products/trans/nsit47.html
 
Feb 27, 2015 at 11:14 PM Post #8 of 197
We're almost there, external 5V DC power via USB port was shown and we could add a high quality linear power supply such as Hydra ZPM from Audiobyte
 
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https://fbcdn-sphotos-f-a.akamaihd.net/hphotos-ak-xap1/t31.0-8/10841799_770721569671707_2711970247509824092_o.jpg
 
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https://scontent-sin.xx.fbcdn.net/hphotos-xfp1/t31.0-8/11004562_768476083229589_2776808965567364255_o.jpg
 

 
Another choice for clean 5V DC power in a portable package
 
http://global.rakuten.com/en/store/ratoc/item/ralextpw01/
http://www.amazon.co.jp/ラトックシステム-USB外部電源供給アダプタ-RAL-EXTPW01/dp/B0043BX072
 
Similar one for desktop rigs
 
http://global.rakuten.com/en/store/ratoc/item/ralps0514/
http://www.amazon.co.jp/ラトックシステム-DC-5V電源ユニット-RAL-PS0514/dp/B005GRGY3Y
 
Pangea Audio IEC C7 Adapter
 
http://www.audioadvisor.com/prodinfo.asp?number=PGC7ADP
http://www.amazon.com/Pangea-IEC-C7-Adapter-Cryogenically-Treated/dp/B003K1GXY8
 
Mar 2, 2015 at 11:53 AM Post #10 of 197
Maybe stuff like K3003 or Piano Forte could be some exceptions? They do scale with amplification and shine with desktop rigs
 
http://www.head-fi.org/t/613641/final-audio-design-impressions-and-discussion-thread/2115#post_9503355
 
Special discounts for the very first lot should be over, I was able to score one myself
 
https://twitter.com/MASSkobo/status/572425983480864768
https://www.facebook.com/MASSkobo/posts/772002632876934
 
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Mar 14, 2015 at 1:14 PM Post #13 of 197
Not sure if that were shipped yet, let's wait for some impressions in the near future.
 
Pin outs were changed to fit A&K so Masuda-san scratched those labels off the faceplates, basically it's looking like this
 
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Balanced interconnects are definitely required, there are quite a few connectors to choose from. First one is from Eidolic
 
http://www.doublehelixcables.com/store/index.php?main_page=product_info&cPath=18&products_id=166
http://www.norneaudio.com/litzheim/Furutech-Valab-Oyaide-Shure-Denon-diy-headphone-cable-connector/Astell-Kern-2-5-mm-4-pole-balanced-trrs-eidolic-hi-fi-headphone-portable-diy-connectors
 
Then we've got this one from VentureCraft
 
http://www.amazon.co.jp/VentureCraft-BP-254S-オーディオプラグ-2-5mm4極プラグ-シルバー/dp/B00MI9J9NA
http://www.amazon.co.jp/VentureCraft-BP-254B-オーディオプラグ-2-5mm4極プラグ-ブラック/dp/B00MI9XDR8
 
Another one from Nakamura
 
http://ns-t.com/products/trans/nsit47.html
 
Finally this one is from Ranko
 
http://item.taobao.com/item.htm?id=41685401546
http://item.taobao.com/item.htm?id=41762598423
http://www.ebay.com/itm/Original-Ranko-Acoustics-REP-1050-4P-Rhodium-Plated-2-5mm-TRRS-Stereo-Plug/321674461535
 

 
Besides AK240, of course we could also connect something like Cypher Labs AlgoRhythm Solo -dB or iBasso DB2 as well. That should look just like this
 
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Mar 27, 2015 at 7:49 AM Post #14 of 197
First units to be delivered to two lucky customers in Japan, the rest should be shipped to international customers by the end of this month
 
https://www.facebook.com/photo.php?fbid=785687798175084
 
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