[bobsilver]

Quote:

I do have cmoyBB with OPA2227. OPA2227 is a 'flat, upfront and a bit warm' sounding opamp to me and it isn't nearly as revealing as AD8620, so I guess it can work out for Grado in some way. Personally, I just don't like OPA2227 that much and never quite care to use Grado with portable amp because of the heavy cable.
 

 
Ah the heavy cable issue.  I agree and solved that.  I have changed cables on all 3 pairs of Grados (60,80 and 225) to a light weight 1/8 " plug cable.  In fact when I sent my 225 in to Grado for repair they also replaced my cable as well at request with a HQ light cable.  Easy to do by the way.
 
And my Senn's I shortened the cable and placed a 1/8" plug on it.  Works great.
 
Hate those heavy cables!  And I do not like being stationary when I have headphones on so this fixed all ills.

 

[bluishgreen]

Quote:

I then asked about Beyer DT880.  (I had been considering buying a pair).  Sound was fantastic with the 250 ohm version he claimed.  So I am taking him at his word and I ordered a pair of Beyers.
 
So my early feedback is this.  The 8620 is bright.  And I suppose any headphones that tend to bump the high end are not going to be a good match.
 
While I was hoping to have 1 amp for all my phones that doesnt seem to be the case.


 

 
 
I'm specifically looking to buy the C421/8620 for my DT880's, which are generally my go-to phones that work well with all music--not necessarily the best with everything, but work extremely well with everything. I've always used my AKG K70*'s for purely acoustic music like classic jazz, classical, or acoustic-only singer-songwriter music, but use the DT880's for everything non-acoustic.  Although, the DT880's are exceptional for acoustic as well--just not near-perfect like the AKGs (conversely, I can't listen to any music with the AKG's if there is a single non-acoustic instrument in it).
 
In any case, my one small complaint with the DT880's is that they are a touch warm--not a lot warm, but this is coming from a person who loves the AKG K70* line, so that should tell you something about my feelings of warmth...with the exception of maybe jazz, which lends itself to a more warm vibe.  I'm perfectly fine with the slight warmth as long as the amp I'm using doesn't add any more warmth, so I'm hoping that the C421/8620 that people see as bright will be a good, balanced pairing for my DT880's (I have the 250ohm, BTW).
 
I recently bought the ibasso D7 DAC/amp--the DAC is exceptional for the price, and the amp is good, but is a tad warm, so I don't really like it with my DT880's.  I do love the D7 with my AKG's, in which the slight warmth from the amp balances the brightness of the AKG's--but the slight warmth of the amp plus the slight warmth of the DT880's is just a bit too much for me.  So in the end, it's all about finding balanced pairings--both with the music style and the amp.
 

 

[PANGES]

Soo.. Has anyone who pre-ordered with the temporary case received an email to get a new case? I followed the link to order the replacement case, but paypal wont let you order anything with a $0.00 value. lol.

 

[syphen606]

I ordered mine.. cost 1 cent!  

 

[F900EX]

I got mine yesterday with the OPA2227.  Out of the box, not bad. And will review it at a later time.  Built very well and solid. 

 

[PANGES]

Quote:

I ordered mine.. cost 1 cent!  

lol Yeah. I email'd John from JDSLabs and had him change the price from $0.00 to $0.01, because paypal wouldn't let me checkout with a $0.00 amount.

 

[kyoshiro]

just ordered another C421 with AD8620! And my newly cased AD8066 will be piggy riding it back with it's new enclosure!

 

[JRoMan]

Got through the new Soul Rebels Brass Band album yesterday with my HD25 and c421(8620). All those horns and not once did I think it harsh or shrill. I really think the amp has smoothed out some.

 

[jseaber]

Quote:

lol Yeah. I email'd John from JDSLabs and had him change the price from $0.00 to $0.01, because paypal wouldn't let me checkout with a $0.00 amount.

We were amazed how quickly everyone responded. About 20 emails came in within minutes of the automated announcement! The PayPal bug was resolved within five minutes.
 
@bobsilver: It's fascinating how closely your opinion of the AD8620 + Grados resemble the e-mails I received from Headfonia. Hope you don't mind if I share part of our discussion from the past weekend:
 
Quote:

Bob,

You're right on. When c421 was first designed, the intention was to offer a single amplifier with zero room for options or customization (AD8620 only).

Mike at Headfonia.com wasn't happy with the AD8620 sample. So we sent an OPA2227 version, which I personally don't enjoy [as much], but Mike was thrilled. The decision to offer multiple opamps was as difficult to us as it is for customers to choose a chip. There was a psychology study years back which confirmed that customer enjoyment actually drops as product options increase. Given a single option, there's nothing to fret over. . . .

 
Extra choices are probably not so bad in the audio world. The focus with c421 was to build a seriously portable amp: comfortable form factor, easy recharging, but still super capable of cleanly driving most headphones. That much was accomplished. The circuits were stable and benchmarked well. About a year into development, beta testers were happy with the AD8620. So it was fairly disappointing when our first AD8620 samples received wildly mixed reviews. Thus, we scrapped the single-configuration goal. Opamp options were the only way to please everyone, short of cancelling the project and starting over.
 
It's been asked repeatedly which chip to choose. Fairly simple:
 

1. If you can't decide, choose the OPA2227. Statistically, this chip receives higher satisfaction. And it's cheaper.
2. If you've tried the AD8620 before and enjoyed it, choose the AD8620. Some find it more enjoyable than the OPA2227, but not everyone. Riskier.

 

[kyoshiro]

does that make my AD8066 the rare breed? lol

 

[jseaber]

Quote:

does that make my AD8066 the rare breed? lol

< 3% chose AD8066 from the first batch. Some chips get no attention!

 

[flu_fighter]

Quote:

< 3% chose AD8066 from the first batch. Some chips get no attention!

I guess I am in that 3% as well. I was actually hoping for a AD827/AD847 version, would be better is AD825 could be used, but AD825 only comes in single channel versions.

 

[mm1434]

So John, the question is - after listening to the 8620 for a while - Hypothetically, if a person decided that they really enjoyed the other chip better - would there be an option to send it back to be swapped?  I do not want to put you on the spot, but after a week or so of listening back and forth to the c421 and my cMoy, it may come down to liking one better than the other sound wise.  Form factor, power and everything else the c421 is much better so I'd want my fav chip in the c421.
 
If that isn't possible, no big deal but it would be nice to know if I had the option - shipping back and forth being my responsibility of course since you and I actually had this conversation via email before it was shipped and I said go with the 8620!
 
Honestly - the 8620 has settled down from my first impressions - so over a short period of time I may find that I like it (for example, I'm liking it more today than I did yesterday...)

 

[2000impreza]

Op-amps is a fairly interesting topic. My first C421 came with the AD8066. That same C421 was later replaced by John due to charging issues. The replacement C421 came with AD8620. Honestly, I could not hear any difference between AD8066 and AD8620. I actually thought the replacement had the AD8066 until I pulled the PCB and seen the AD8620 in place. I also did a blind test between OPA2227 and AD8620 in a custom CMOY I built using JDS PCB and failed at identifying any difference. Perhaps my ears are not trained enough to hear subtle difference between all three op-amps.

 

[bobsilver]

Quote:

We were amazed how quickly everyone responded. About 20 emails came in within minutes of the automated announcement! The PayPal bug was resolved within five minutes.
 
@bobsilver: It's fascinating how closely your opinion of the AD8620 + Grados resemble the e-mails I received from Headfonia. Hope you don't mind if I share part of our discussion from the past weekend:
 
 
Extra choices are probably not so bad in the audio world. The focus with c421 was to build a seriously portable amp: comfortable form factor, easy recharging, but still super capable of cleanly driving most headphones. That much was accomplished. The circuits were stable and benchmarked well. About a year into development, beta testers were happy with the AD8620. So it was fairly disappointing when our first AD8620 samples received wildly mixed reviews. Thus, we scrapped the single-configuration goal. Opamp options were the only way to please everyone, short of cancelling the project and starting over.
 
It's been asked repeatedly which chip to choose. Fairly simple:
 

1. If you can't decide, choose the OPA2227. Statistically, this chip receives higher satisfaction. And it's cheaper.
2. If you've tried the AD8620 before and enjoyed it, choose the AD8620. Some find it more enjoyable than the OPA2227, but not everyone. Riskier.

 
 
In my experience with the 8620 421 now with about 30 hours of burn in it is this.  With my Senns 650 the sound is amazing now.   It is a kind of take your breath away experience with the detail subtlies and a very 3 demensional sound.  It also EXTREMELY smooth with no harshness at all.  I am loving the experience.  I did an AB comparison with my ATHM50 and Cmoy 227 yesterday versus the 421/Senn 650.  It is a night and day difference.  The sound of the 421/650 sounds almost real and lifelike.  The Cmoy/ATHM50 was good but synthetic in comparision. Now I know that a these headphones are dramatically different  but I had been living with them both for the past month or so and had been doing a swap and enjoying both.  Now I have no desire to listen to anything but my Senns and the 421.  I did order a pair of Beyer 880 (per John's comment that the 8620 works great with them) but more from a point of something different as opposed to better then my Senn 650.
 
So IMHO I would suggest to anyone buying this amp is this.  If your headphones are anything like Grados or AT ATHM50 which I would describe as somewhat bright you wont be happy with the 8620.  It is a not a good match.  But if you are using Senns or headphones that sound like them then the 8620 will take you to new level.
 
And let me add I listen to acoustic jazz mostly.  Very little rock.  Nothing electronic.  I like classic jazz and have been listening to recent recordings as my basis for my opinion.  I am very happy with this match.
 
Bob