[xrk971]

I only was hoping Wima's kick in above 6k or so for the treble. You want to wire caps in parallel for them to sum up. They decrease in value when in series, like resistors decrease when in parallel. I think 1uF Wima's and 3200 Hz doe 30ohm cans is fine. It wa small a tradeoff of compactness. Some people like using 50uF film caps. look up motor run caps. You can get oil filled film caps 50uF for cheap. They sound nice too but are the size of car spark coil.

 

[stellarelephant]

Cool. I think I'll try playing around with the different combos, throwing in 1uF, 2.2uF, and 4.4uF (2x paralleled 2.2uF) to see how they affect the sound. Vocals tend to have quite a bit of info around the 2kHz region... it'll be interesting to see if dropping the "crossover point" (bad analogy, I now know) below this region yields significant differences to my ears. Vocals are what I always tend to listen to most when judging realism and transparency for any sound system.

 

[Hutnicks]

I only was hoping Wima's kick in above 6k or so for the treble. You want to wire caps in parallel for them to sum up. They decrease in value when in series, like resistors decrease when in parallel. I think 1uF Wima's and 3200 Hz doe 30ohm cans is fine. It wa small a tradeoff of compactness. Some people like using 50uF film caps.

look up motor run caps. You can get oil filled film caps 50uF for cheap. They sound nice too but are the size of car spark coil.

Pair em up with wire wound resistors and you have a backpackable solution. Cooling then becomes a moot point.

 

[stellarelephant]

Rofl

 

[xrk971]

Pair em up with wire wound resistors and you have a backpackable solution. Cooling then becomes a moot point.

What are you talking about? The amp already fits in a pocket and has no cooling issues with metal thin film SMT resistors.

 

[stellarelephant]

He was riffing off your motor run caps joke

 

[stellarelephant]

Wow. I love this amp. After a ton of experimentation, I've found a killer output capacitor combo to match my 50 ohm Sennheiser 598 headphones.

Bass has excellent weight and texture. Mids are rich and electrifying. Vocals are wonderfully engaging--right in my face--in a beautiful, hyper-real way that is totally addictive. Treble is not quite as transparent nor as extended as the Class D amp circuits I am used to, but treble detail is still magically present, with a gorgeous euphonic sparkle. Overall the sound is full-bodied, detailed, attention-grabbing, and just downright sweet. ...And mine isn't even entirely soldered together yet, let alone burned in!

Everything else sounds boring now. X, you've made a true believer out of me. SE Class A magic is real.

I am using 470uF Nichicon AK series electrolytic output caps with 2.2uF WIMA film bypass. Try it...you'll like it.

 

[gikigill]

Anyone selling a fully built unit?

 

[xrk971]

Fully built with matched FETs and tested and burned in pocket class A headamps are $199:
 
http://www.ebay.com/itm/-/222413187019? 

 

[bogde]

it was a good day today. i managed to fix my first board and finished building the second one, plus managed to install one of the boards in an altoids tin. everything worked out better than i expected. this amp sounds great and can power my dt990 pro just fine, not to mention the hd598cs. i'm yet to test it with my other cans but i don't expect any issues. thanks @stellarelephant for bring this up here on head-fi!

 

 

 

 

[stellarelephant]

Congrats Bodge! I was wondering how you were coming along with your build(s). What did you have to fix on your first board?

Your soldering work looks better than mine! Have you done a lot of DIY before?

I love the sound this amp lends to my (open) 598 SE cans...I've never heard the Closed CS version but I hope you are getting some of the same awesome synergy I am! I am subbing a different output cap combo as described above, which really brought vocals to life for me.

I'll be interested to hear your impressions of the sound, and I'm especially curious about whether you'll notice any burn-in.

Cheers!

 

[bogde]

Congrats Bodge! I was wondering how you were coming along with your build(s). What did you have to fix on your first board?

Your soldering work looks better than mine! Have you done a lot of DIY before?

I love the sound this amp lends to my (open) 598 SE cans...I've never heard the Closed CS version but I hope you are getting some of the same awesome synergy I am! I am subbing a different output cap combo as described above, which really brought vocals to life for me.

I'll be interested to hear your impressions of the sound, and I'm especially curious about whether you'll notice any burn-in.

Cheers!

thanks! one of the mosfets was defective, apparently, i just replaced it and then it worked like a charm. 
 
you did a great job with your build actually, having in mind you only used a soldering iron. i used a cheap hot air soldering station (gordak 952) and i it was a lot easier. i've done some soldering before, but i wouldn't say i'm very experienced.
 
i joined GB2 and i can't wait to get two new boards to play with, i plan to experiment with different caps, just like you did. i just tried my ma900 with this amp and it's a great pairing. i'll let you know if i notice any burn-in. cheers!

 

[xrk971]

Bogde,
So glad it was all fixed and sounding nice now!  Congratulations.
 
Great soldering skills by the way - you look like a pro.
 

 

 

[bogde]

  Bogde,
So glad it was all fixed and sounding nice now!  Congratulations.
 
Great soldering skills by the way - you look like a pro.
 

 

thanks! in fairness, that's a picture of the second board, the first one looks messier. i'm happy with both though. eva cassidy sounds simply stunning through this amp into my ma900.

 

[stellarelephant]

Just ordered components for a rechargeable battery setup for my Pocket Class A.
 
The setup will go like this:
1) Apple USB Wall Charger, 5V, 1A (I already own this)
2) iFlash Micro USB Splitter Cable ($8 on Amazon)
3) 2x OKCell 800mAh LiPo USB-charging Batteries ($12 on AliExpress)

I really like the idea of being able to charge without taking the batteries out of the tin.  If I punch two extra holes in the side of the tin, I'll be able to plug the micro USB cables in there.  I am not positive if the green charge indicator lights glow only during charging, or also during use, but I may also drill some tiny holes in the tin next to the indicator lights on one cell, so that they will be visible from the outside.
 
I read an Amazon review of these batteries wherein the buyer stated that the actual capacity of the cells is closer to 400mAh.  I'll still be satisfied with around 3 hours of listening time, if this is the case.  On the other hand, if the advertised capacity of 800mAh is true, then I could get over 5 hours of operation.  They are advertised as reaching full charge in 1.5 hours via the internal charging circuit.  My 1 Amp Apple charger should provide almost enough current for maximum speed charging.  I calculate that if the cells are really 800mAh each, it should take 1.92 hours to charge them both fully.  Not bad.