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So, to those of you who attended RMAF 2011, did you come away with a more thorough understanding of what has happened with the jh-3a since last year? I would assume this was the first opportunity for most of you to talk with Jerry face to face since the last Canjam. I'm very curious to hear what Jerry's insights are on this situation.
This is my first of two posts on the subject. The second one will be linked here once I finished writing it, because it will take a lot of effort on my part to recapture hours worth of conversation and comparative testing he and I have conducted with the gear I've brought. It will also outline the technical differences between the old and new design specifically how the crossover is implemented.
Bottom line is this: I have returned the old amp and my shells. The amp will be replaced and the shells modified and tuned to the new amp this week. JHA now has 100 amps ready to go as soon as Tuesday. Jerry will spend most of today fine tuning the DSP programming as a result of our little session and primarily listening to the new amp using the HM-801 as a source via a mini-to-mini cable (the HM-801 has no digital coax output, unfortunately). The HM-801 had the same 24/96 FLACs I had on the iPod Touch/CLAS combo I had been using as the source to feed the old amp.
Because the only shells tuned to the new amp were demo shells, I will not post any impressions here. Not because they didn't sound good, but they are not equivalents to custom shells. So, Jerry had offered to build the new amp, rebuild my own shells and tune them using the tweaked version of the DSP microcode he's working on today.
What we have discovered is that the revised analog input stage now works so well that the HM-801 24/96 analog output using its dual PCM-1704UK DACs simply outperforms the iPod Touch/CLAS combo using SPDIF out from the CLAS. This was not the case with the old amp. We have used only high-res material, and I have not compared it to Redbook stuff, where the iPod/CLAS combo could still perform very well.
The amp gain structure is now totally silent, as promised. Battery performance has remained the same for this version, about 6+ hours of continuous playback. It currently cannot be charged via USB wall charger while being fed via SPDIF in, but it can if analog line-input is being used. The battery life is roughly equal of that the HM-801 is capable of with the balanced amp module, which Jerry had intently listened to using his own JH16 custom shells as a basis of comparison. The battery life can be substantially increased with relatively modest effort for those who will want this, but Jerry has flatly declined to hold back shipping the amps out any longer, which is I think the right call considering the circumstances. There are always things you can improve on a design and it is an iterative process, which in this case will depend on market acceptance of the current batch.
The other major change is that the B/M button now functions differently. In the old amp, it has completely turned off the bass amp. In the new one it merely drops it back to a near-linear dB level, perhaps a 3dB bump at 50Hz. This will be useful for pro use, such as live performing artists and recording engineers, but most of us, listeners will want to leave it engaged, as before.
Once I receive my new amp, I will post sonic impressions. My plan for mobile use--assuming I will be satisfied with the final outcome of the sound signature--is to revert back to my WhipMOD/Fat Boy LOD combo. For desktop use, I will be able to use my MBP/Amarra 2.3/Cynosure/Sonicweld Diverter HR/Coax SPDIF input and play high-res up to 24/96. This is why my CLAS and iPod Touch is now up in the F/S forum. I'm hoping to find eventually a comparatively sized DAP with 24/96 playback, 32GB swappable storage and SPDIF output to reevaluate digital a go with the JH-3A down the road. The HM-801 would be an option using Line-Out, but the it has a bigger chassis so it would be challenging to stack them together.
I will work on the second post later this afternoon and will update this one with the link.
Here is the second post URL:
http://www.head-fi.org/t/576238/jh-audio-jh-3a-3-way-dsp-amplifier-crossover-design-changes#post_7828889
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Update from JHA RE: the content of this post and the preorder batch of amps.
All of the prep we had done building all of the earpieces for the 2.0 amp have to be cut open and reworked. This is time consuming and we will be completing the work as quickly as possible. We have completed the composer file and waiting for the binary file to be emailed to us to write the 1st chips.
