MASS-Kobo Headphone Amp. model404

[wazzupi]

Dynamics technicalities wider staging are all improved

 

[Bax1020]

Dynamics technicalities wider staging are all improved

Thank you for your reply

 

[fabio19]

I have put my Mass Kobo 428 amp up for sale if anyone should be interested...... Thank you .

 

[Puroplatino]

I have put my Mass Kobo 428 amp up for sale if anyone should be interested...... Thank you .

Is this the one that has the XLR in front? Forgive me I get the models confused.

 

[fabio19]

 

[subguy812]

Is this the one that has the XLR in front? Forgive me I get the models confused.

I think it is similar to the 475, but the 475 is a newer model

 

[eskamobob1]

I think it is similar to the 475, but the 475 is a newer model

424 - XLR output
428 - 4.4mm output
475 - Identical to 428 but with USB-C power bypass instead of micro-USB

 

[Objedych]

Good day everyone!
I decided to make a little tuning on my Mass Kobo 428 and replaced all the op amps. In the original there were 4 x JRC 5532 - not bad, but outdated in their characteristics.
After installing the replacement panels DIP8, I tried several different op amps and settled on the following option:
Preamp - dual discrete op amp Sparkos SS3602 x 2
Output stage - dual (single x 2) JFET op amp OPA828 x 2
The sound is simply unrecognizable! )

P.S. micro-usb connector was replaced with usb-c.

 

[tassardar]

Just to check, when you guys use with really sensitive IEM (above 110 db/mw) types, when connected to a DAP, do you hear the capacitive screen noise?

 

[tassardar]

Posted a review for the 475 for those that are interested to know more!

https://www.head-fi.org/showcase/mass-kobo-475.27025/reviews#review-32950

 

[Nostoi]

Posted a review for the 475 for those that are interested to know more!

https://www.head-fi.org/showcase/mass-kobo-475.27025/reviews#review-32950

Nice review, though laid back/relaxed signature? I would describe it as the very opposite - namely, forward and incisive. Laid back is not something I'd ever associate with the Mass Kobo house sound, especially the 428/475...

 

[tassardar]

Nice review, though laid back/relaxed signature? I would describe it as the very opposite - namely, forward and incisive. Laid back is not something I'd ever associate with the Mass Kobo house sound, especially the 428/475...

This is actually in comparison with many amplifiers. I have quite a few and everything I compared to have a slightly more forward sound. It's just on a very small amount and noticeable only in a AB comparison as what I wrote in the review. If you don't compare directly, it will sound just fine really.

 

[kajetanjazz]

Good day everyone!
I decided to make a little tuning on my Mass Kobo 428 and replaced all the op amps

Hi, I sent you a PM a few days ago. Would like to do the same kinda mod and I have some questions

 

[kajetanjazz]

Alright! The mod of Mass Kobo is completed, moreover.. documented on YouTube My friend (audio reviewer and fresh YouTuber) has done an amazing job and now the op-amps are swappable in the MK 428/475 - those two “models” are exactly the same, just different usb connector. If you could give Michal’s channel some love, will be highly appreciated

For start we’ve immediately put Sparkos SS3602 in preamp stage and Muses02 in output stage. Mass Kobo has a new sound to it - I’d say it’s become meatier, namely bass is stronger and tighter and the signature has slightly more body. As for soundstage, details, etc. I’ll have to wait to receive stock JRC5532 back to compare more directly (it was 2 weeks break in between hearing MK). I will be writing conclusions after those direct comparisons with stock and some other opamps

Here are some photos when I took it apart. Easy enough for anyone, but complex enough to be satisfying as well!

 

[YakAttack99]

Alright! The mod of Mass Kobo is completed, moreover.. documented on YouTube My friend (audio reviewer and fresh YouTuber) has done an amazing job and now the op-amps are swappable in the MK 428/475 - those two “models” are exactly the same, just different usb connector. If you could give Michal’s channel some love, will be highly appreciated

For start we’ve immediately put Sparkos SS3602 in preamp stage and Muses02 in output stage. Mass Kobo has a new sound to it - I’d say it’s become meatier, namely bass is stronger and tighter and the signature has slightly more body. As for soundstage, details, etc. I’ll have to wait to receive stock JRC5532 back to compare more directly (it was 2 weeks break in between hearing MK). I will be writing conclusions after those direct comparisons with stock and some other opamps

Here are some photos when I took it apart. Easy enough for anyone, but complex enough to be satisfying as well!

Great video! If someone else has modded one of these portable amps, maybe they can shed some light on the changes the mod made? Big or small, I’m interested to know how much the signature changes with op amp swap.