[Mozu]

I'd read it before, and felt like I was reading a review of a completely different amp from the one I owned. It makes me wonder if there was something up with some of the early batch AD8620s, as I found the Headfonia review to be spot-on with my experience with it.

 

[jseaber]

Words of caution: It took months to find an honest battery brand. Quite a few vendors claimed 1200, even 1300mAH, but these were nothing more than re-badged 700mAH batteries. One even had its original 700mAH sticker visible beneath a 1200mAH label! The easiest way to spot a deceptive Li-Ion vendor is by comparing widths of batteries marked for use with the same product. A true 1200mAH Li-Ion is something like 2mm thicker than lower capacity batteries.
 
Unless cycled excessively, these should last years. The test iPod on our bench is 4 years old. It gets charged once a week.
 
Don't top off a Li-Ion. Keep it about halfway charged/empty (depending on your mindset) for longest lifespan.
 
Quote:

 


I opened up the C421 and found that it uses an Apple IPOD 4G battery, super easy to find a replacement if it wears out.

 

 

 

[jseaber]

Words of caution: It took months to find an honest battery brand. Quite a few vendors claimed 1200, even 1300mAH, but these were nothing more than re-badged 700mAH batteries. One even had its original 700mAH sticker visible beneath a 1200mAH label! The easiest way to spot a deceptive Li-Ion vendor is by comparing widths of batteries marked for use with the same product. A true 1200mAH Li-Ion is something like 2mm thicker than lower capacity batteries.
 
Unless cycled excessively, these should last years. The test iPod on our bench is 4 years old. It gets charged once a week.
 
Don't top off a Li-Ion. Keep it about halfway charged/empty (depending on your mindset) for longest lifespan.
 
Quote:

 


I opened up the C421 and found that it uses an Apple IPOD 4G battery, super easy to find a replacement if it wears out.

 

 
Only the low gain resistor changed.
 

I'd read it before, and felt like I was reading a review of a completely different amp from the one I owned. It makes me wonder if there was something up with some of the early batch AD8620s, as I found the Headfonia review to be spot-on with my experience with it.

 

 

[Ragno7]

This post is exactly the place I was looking for... Last saturday I ordered my c421/AD8620 ...and... An Ibasso d7.... Still waiting for both to come. I'll be using with my Beyer DT880, my Sennheisser HD518, my M-Audio IE10.

I'm a bit impatient but both seem to arrive on monday, so I'll have to wait.

I was a bit concerned over headfonia's review (i ordered the AD8620 ones), but now that you guys said that staging is better on this opamp I feel relieved, that's what I was aiming at (the ibasso d7 also).

I'll report how I did with both devices once I test them further.

I wonder if the lousy review for the AD8620 in headfonia came because he didn't burn in the device beforehand... Or maybe he did get a lemon after all, or something happened there...

 

[808Ronin]

Quote:

Me and you, mate. I already find myself reaching an opposite conclusion on quite a few Headfonia's past amp review (especially on PA2V2, among others). Guess I'll have to disagree with his finding on AD8620 vs. OPA2227 this time as well. The impression is so different from mine that it makes me wonder if they could have received an lemon unit or not. Maybe we just have too different an interpretation on amp.

+1
 

 

[Mutnat]

Damn, I wish there was some way I could try an 8620 version without having to buy both. 
 
EDIT: anyone in the greater Vancouver BC area with a C421-8620? 

 

[Cassadian]

I would've lent you mine if you were in the Chicago area.  Alas...
 
Quote:

Damn, I wish there was some way I could try an 8620 version without having to buy both. 
 
EDIT: anyone in the greater Vancouver BC area with a C421-8620? 

 

 

[tattare]

Can anyone comment on this with HiFiman's HE-400 or HE-500?

 

[Ultrainferno]

Quote:

Can anyone comment on this with HiFiman's HE-400 or HE-500?

I've got both. I'll try them this weekend and get back to you

 

[tattare]

Ohh word thanks!  Looking forward to your thoughts on it with the HE-400 as im looking for a portable to drive them.
 
Quote:

I've got both. I'll try them this weekend and get back to you

 

 

[jseaber]

Mike's first e-mail to us came no more than 12 hours after he'd received the AD8620 c421. I'm not sure if he tried additional break-in. We were quick to ship out an OPA2227 edition, so maybe he set the AD8620 amp aside...
 
It was no lemon. He de-soldered the AD8620 and soldered in an OPA2227 to compare v1.00 to v1.01. This wasn't mentioned in the review, since the experiment produced no worthwhile discussion.
 
Quote:

I wonder if the lousy review for the AD8620 in headfonia came because he didn't burn in the device beforehand... Or maybe he did get a lemon after all, or something happened there...

 

 

[Terps Fan]

Guys, I'm using the AD8620ARZ and it took my cMoy built by John over the top.  Don't hesitate if your sitting on the fence.

 

[Ultrainferno]

Quote:

Ohh word thanks!  Looking forward to your thoughts on it with the HE-400 as im looking for a portable to drive them.
 


 

I just tried it with both the He-400 en 500 and it drives them both just fine.
The He-400 is the best match in my opinion, it doesn't need a lot of power and it makes it sound just fine. Bass boost on to keep the good bass and normal gain sounds best. With high gain it sounds as if the mids get a nice boost which also is enjoyable but a little to aggressive to my liking
It also drives the He-500 just fine but you don't get out of it what it can do, compared to a full desktop amp, or my fav, a tube amp. It just doesn't sound as smooth and relaxed; I guess I just miss the tube sound but in all objectivity, the C421 does a good job driving the He-500 too, I didn't expect it to do this good. What I'm missing most with the HE-500 and C421 is the bass quality and quantity and the smoothes I so love with this headphones
 
Anyway, for driving the HE-400, which is your main goal, I can only recommend it.
 
Hope this helps

 

[BGRoberts]

Does the opamp in the cMoy from JDS just "pop out" ?
 
Quote:

Guys, I'm using the AD8620ARZ and it took my cMoy built by John over the top.  Don't hesitate if your sitting on the fence.

 

 

[Terps Fan]

Quote:

Does the opamp in the cMoy from JDS just "pop out" ?
 


 

Hi BG.  No, you will need a extraction tool.  I bought mine at Radio Shack for like ten bucks or so.  The optional opanp came in a foil baggy, my heart went into my throat when I saw that I had to do it myself, but it was easy.