[senny-ftw]

Hi,

I'd like to know how Dr Meier's Porta Corda MkIII-USB compares with Headroom's Total Bithead sound-wise and if it works well with HD600s. I'd also welcome alternative suggestions for portable/smallish amps with USB DAC (yes, I'll stay WELL AWAY from the Corda clones

) - about $600 max with shipping to UK. Must match HD600 and MacBook Pro.

I'm very happy with the TB as a device but it's not powerful enough for my HD600s. I'm not willing to lug two boxes around (Headroom micro DAC+amp) and the desktop with DAC is out of price range.

Thanks for any suggestions.

 

[senny-ftw]

...

Buy it anyway

 

[mrarroyo]

The Porta Corda MkIII is a beautiful sounding amp, sounds as good as amps costing far more.

 

[GreatDane]

YES! just buy it, you won't regret it. Listening to Redbook CD using the DAC sounds very good to me. This amp works great with my HD 650 sounding better than one might expect.

I don't use USB power because I use mine as part of my home rig for full-time computer listening use. From what I remember it does have pretty good power from USB but I can't test that because I don't have my Senn cable now. I use a 30 volt power supply which make the amp very powerful. Darth Beyers stand to attention with this setup.

 

[senny-ftw]

Thanks! From the specs it looks just what I want...

I've sent my order request to Dr M

 

[PeterDLai]

Does anybody know how the Meier-Audio PORTA CORDA MkIII-USB would compare to an HPDAC?

 

[saint.panda]

One huge advantage of the Bithead is that it can be powered via USB. The HPDAC sounds slightly more refined than the Bithead, but it can only be used via USB. Since I'm only using it for laptop-fi, that's perfectly fine with me. So the Bithead really is the most convenient solution as it also works as a normal amp on batteries. It doesn't charge batteries however. And I'm not sure how it compares to the Porta Corda MKIII in terms of sound quality.

 

[dsavitsk]

Quote:

Originally Posted by PeterDLai /img/forum/go_quote.gif Does anybody know how the Meier-Audio PORTA CORDA MkIII-USB would compare to an HPDAC?

Well, one you can get, and one you can't

But, beyond that, the porta corda seems to use a monolithic TI usb dac chip. The hpdac uses a usb to i2s converter and a NOS dac (TDA1543) and a passive IV.

The Meier seems to need a battery or an external power supply while the hpdac is usb powered and uses a dc-dc boost converter to get to about 9V to work with.

The Meier uses 2 6171 mono opamps. The hpdac generally uses 2 6172 stereo opamps (or you could choose you own), using both sides of one for voltage gain, and one side of the other as a rail splitter (the Meier uses a tle2426) and the other side as a ground driver.

The Meier has a much beefier power supply. The hpdac's cap bank is pretty small so as not to stress the usb supply or the dc-dc converter.

The Meier has crossfeed while the designer of the hpdac does not like any more caps in the signal path than are necessary and believes that the "benefit" of crossfeed is more that it softens the harsh edges of solid state gear by running the signal through a filter than anything else. But, is willing to believe that he is incorrect in this assumption.

The Meier is in a plastic case, while the hpdac was designed for an ugly aluminum one. The hpdac is generally a little less expensive, but does not come with any real support.

The hpdac schematic is publicly available.

But, I can't offer any real comparison of sound as I have never heard a Meier amp and generally don't use any commercial gear -- I make my own. The last commercial amp I listened to was a Melos SHA-1 which now has a place of honor gathering dust on the shelf in my closet.

Also, to answer the original question, I think the hpdac is probably not ideal with Senn phones. It was really designed with Grados in mind.

-d

 

[iancraig10]

The PORTA CORDA MkIII has a beautiful midrange. Plenty of presence and clarity. The only thing that I dislike about it is the tiny volume control which doesn't allow for easy slight trimming of the volume.

Compared to a Go-Vibe (for instance) it gives the impression of more weight, retaining a great deal of clarity and plenty of presence. Some may find it a bit warm sounding for the Senn 600/650.

Ian

 

[GreatDane]

Quote:

Originally Posted by dsavitsk /img/forum/go_quote.gif The Meier seems to need a battery or an external power supply while the hpdac is usb powered and uses a dc-dc boost converter to get to about 9V to work with.

The Porta Corda MkIII-USB can be powered by the 5 volt USB power which also uses boost for about 10 volts.

When USB is connected, the 9 volt battery is overridden.

 

[senny-ftw]

One new MKIII-USB on its way from Germany this afternoon

I'm looking forward to hearing the HD600 properly powered...

 

[GreatDane]

Quote:

Originally Posted by senny-ftw /img/forum/go_quote.gif One new MKIII-USB on its way from Germany this afternoon I'm looking forward to hearing the HD600 properly powered...

Congrats.

Please do comment on your experience with your new amp after you've had a few days with it.

 

[itsborken]

Great Dane, have any model number/vendor for that power supply you are using (or ones that you looked at)? I've had it for about a month, like the output for work but don't want to risk frying it with the wrong PS.

Thanks in advance,
John

 

[GreatDane]

Quote:

Originally Posted by itsborken /img/forum/go_quote.gif Great Dane, have any model number/vendor for that power supply you are using (or ones that you looked at)? I've had it for about a month, like the output for work but don't want to risk frying it with the wrong PS. Thanks in advance, John

Hi John,

The AC adapter that I'm using is this one from Radio Shack. I'm sure you can find a suitable adapter for less money on-line but I didn't search around. I wanted to try it so I took the quick route. If you do decide to try the RS adapter you'll need to bring the amp with you so that you can choose the correct size plug...I forget the size.

I did send Dr. Meier the same link as above so that he could approve(which he did) before I began using the 30 volt selection, I had been using the lower voltage.

I've been using the 30 volts for a couple months and mine hasn't exploded yet

.

 

[senny-ftw]

Please do comment on your experience with your new amp after you've had a few days with it.

Will do. I've got some MS-1s coming (bought them for my mum to use with my old iPod - gives me an excuse to try the grado/alessandro sound!)... I'll also try the super.fi 5 pro, which although not needing much power, seem to be extremely revealing of source/DAC quality...