[tangent]

I would expect better battery life than that, JMT. I have an AD8620-based META42 here drawing about 12 mA. For a single 9V alkaline battery drawn down to 6V, you would expect 30-40 hours. This is without current sources, high-efficiency LED, single EL2001s on the outputs and vgnd.

Obviously I haven't tried to 'marathon' an AD8620 1x9V META42 yet, so I may be full of crap.

 

[JMT]

Quote:

For a single 9V alkaline battery drawn down to 6V, you would expect 30-40 hours. This is without current sources, high-efficiency LED, single EL2001s on the outputs and vgnd.

Like I said, I haven't kept track, plus I changed the batteries even though they really didn't need to be. My travel amp has stacked output and ground buffers and current souce.

 

[KurtW]

HappymaN, the AD8620 is not compatible with the Corda's +/-15 volt supplies, but I plan to try the AD845 sometime soon.

 

[tangent]

Quote:

My travel amp has stacked output and ground buffers and current souce.

That would make draw more like 20 mA, so 30 hours would be the absolute max. You could probably still hit 20 hours easily with that config.

 

[HappymaN]

Quote:

Originally posted by KurtW HappymaN, the AD8620 is not compatible with the Corda's +/-15 volt supplies, but I plan to try the AD845 sometime soon.

Thanks for the info. Let me know how the AD845 sounds when you get around to it.

 

[taoster]

KurtW,

How do you think the Porta Corda with the cascode current source mod compare with the other portable META42 configurations?

 

[KurtW]

In comparing the PC with current sources to a META42 with the 8620 and double buffers, I preferred the META, being smoother and having better bass.

 

[taoster]

Quote:

Originally posted by KurtW In comparing the PC with current sources to a META42 with the 8620 and double buffers, I preferred the META, being smoother and having better bass.

Wow, I'd love to hear the META42.

I am really enjoying the sound of the PCorda already. I love the fact i can just plug it into my 24V supply at work for a very noticeable improvement.

 

[kelly]

Quote:

Originally posted by KurtW In comparing the PC with current sources to a META42 with the 8620 and double buffers, I preferred the META, being smoother and having better bass.

I was surprised by how smooth Kurt's modded Porta Corda was, even if it was a bit lacking in detail compared to the META. I remember thinking at the time that it was really nice for something running on batteries and small, but not as good as my memory of the Cosmic and its bag of batteries. I'm trying to secure an audition of Kurt's portable META42. I'll let you guys know what I think, though of course I won't have a Cosmic or Porta Corda to AB it with.

 

[taoster]

Quote:

Originally posted by kelly I was surprised by how smooth Kurt's modded Porta Corda was, even if it was a bit lacking in detail compared to the META. I remember thinking at the time that it was really nice for something running on batteries and small, but not as good as my memory of the Cosmic and its bag of batteries. I'm trying to secure an audition of Kurt's portable META42. I'll let you guys know what I think, though of course I won't have a Cosmic or Porta Corda to AB it with.

I'll be looking forward to that review! The Porta Corda sure does a fine job with a single 9V battery but have you heard it with a custom battery pack consisting of 3 9V batteries?

 

[Taphil]

I've been A/B-ing the AD845 and AD8620 yesterday and today. I can confirm what Tangent said. The highs are crisper with the AD8620. It's "unveiled" but not at all bright, harsh, or grainy. However, I never had a problem with the highs on the AD845.

My main reason for switching to the AD8620 was to get better bass. The AD823 was definitely muddy or uncontrolled (relatively, of course) but it had a nice impact or presence in the music, so I switched that out to the AD845 shortly after Tangent built me the amp. The bass/lows on the AD845 was MUCH more detailed and clear, and overall it was a lot "faster" (which I suppose contributes to its improved clarity and detail). I liked it a lot, but it slightly lacked the impact of the AD823. I'm not sure how to describe it, but the lows with the AD845 were deep and clear, but they kind of reduced the overall power of the lows in the music and made it sound somewhat dull. So I wanted the lows to have a stronger presence in the music while still remaining clear and precise, and thus I ordered the AD8620 with Tangent's advice. I'm now finding that the AD8620 does indeed provide exactly that.

 

[purk]

Taphill,
Will u recommend the AD8620 to the AD845 then? Is that the case, i think I should really try the AD8620. I hope you can write more b/w the two op-amp. Thanks.

Purk

 

[Taphil]

I'm no amp expert, but yes, to my ears, the 8620 sounds better in all aspects. The clarity or openness of the highs is very apparent over the AD845. But I'm most pleased by the enhancement of the lows. I'm using the HD600+stock cable btw.

Switching the opamp was just a matter of buying the chip from Tangent mounted on the Browndog adapter and putting it into the socket. There was no risk involved and I had nothing but $16 to lose, so I just gave it a shot and it worked out well.

 

[kelly]

Quote:

Originally posted by taoster I'll be looking forward to that review! The Porta Corda sure does a fine job with a single 9V battery but have you heard it with a custom battery pack consisting of 3 9V batteries?

My KurtW/META42 audition didn't happen. HeadWired wasn't feeling well on Friday. Hopefully I'll still get to hear one eventually.

I've only heard the Porta Corda twice -- once at WOH tour and only very briefly since I had bigger fish to fry, and once to hear KurtW's modded Porta Corda extremely briefly when I met him one day. Thus, I don't really have much of an opinion on them and tend to trust what Kurt tells me about them.