Just a few pictures to make you guys curious!
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Jan Meier

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Explanation will follow later :)













 
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msjjr

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Ok, I'll bite. What are these?
 
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JMT

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I'll take a guess and say that the first series of pics is a AA version of the Porta Corda (isn't the original 9v?). And the second series of pics is perhaps the next generation Corda...the HA-2?

 
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The Quality Guru

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Very nice Jan! Very, very nice!
 
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Old Pa

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Looks like more caps and how many AA batteries? 1/4"/balanced jacks and a whole bunch of RCA jacks for switching (still only one transformer). Hmm, Jan, what's up?
 
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JMT

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It appears that the Porta Corda has room for 2 AAs. The big brother looks really interesting (amazing how things change when you let all of the .jpg load). Maybe the multiple RCAs are for dual inputs and a line/loop out. The front panel knobs: variable crossfeed, volume, variable gain(?)?

How long do we have to guess before you tell us Jan?
 
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braillediver

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The front looks like input selector, volume and crossfeed.

Looks like he might have made a small pre-amp out of it too with 1 pair of the outputs?

The 1/4 inch jacks are great!

And as a guess the outside RCA's have enough components for a phono stage? Turntable/Corda/Headphones?

Since I don't know I might as well dream.
 
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mmmm.....yummy! good work jan, whatever they turn out to be.
 
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My mind is as sharp as a tack... even at my advanced age.
I just noticed that in the last pic, the two amps are different, aesthetically at least (I first thought they were mirror images). Knobs are different. I wonder if that is the only difference.
 
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The PortaCorda II looks much nicer in black than the old model looked in white. I'm wondering if this model has a current source.

The preamp looks nice (Corda PA-1?). There are six RCA sets on the back. Since the original plan called for one input, one preout and four selections, I'm guessing I failed to convince Jan that a tape-out (unamped passthrough) was worth having.
 
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Jan Meier

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Pffffhhh.......

You guys are fast. So many questions in only a few hours :)

Okay, what you see on the first three pictures is the new version of the PORTA CORDA. Sonically this one is only a minor upgrade of the old version but nonetheless it has some major improvements:

- 50% less current consumption (4 mA!). This little amp works 100 hrs (!!!) on a single 9V battery (no AA's, the battery compartment of the enclosure used fits both)

- Class-A on demand. Two DIL switches at the inside (Switches 1 and 2 at the third picture) allow to set this amp to class-A functionality if an external power supply is used.

- power supply input jack (the left side of picture 3)

- The LED can be switched OFF to save current (switch 3 at the third picture). This gives 120 hrs (!!!!!!) on one single battery

- Improved ergonomy. Volume dial is more easily accessible.

- No standard 9V battery clip as these are quite vulnerable. Now two contact clips at the inside wall of the battery compartment allow you to simply insert the battery.

- Better lookings. But that's just my opinion. you may think otherwise :)

There will be no price increase. This week a sales-action will be started in combination with the Ultrasone HFI-650. Simply keep an eye at Mall-Fi.


The last four pictures show two prototypes of the new CORDA PREHEAD. Of course the final versions will have different, better looking front plates.

Some characteristics: 4 pairs of inputs, one passive bypass, and one pre-out. 15V / 800mA output. Zero Ohm and 120 Ohm output jacks. Gain-switch (2 settings). Stereo and 3 crossfeed levels. Double-regulated power supply with a 25VA transformer, mains filter, and a total capacitance of 44000 uF (!)

This weekend Harald, Duveltje (my girl-friend) and I did some extensive A-B listening tests with different opamps (OPA627, AD825, LM6171) and compared the results to the RKV and the HA-1. A review will be published soon. Right now I'm rearranging the power supply of one of the amps to test the AD8610.

A few impressions:

RKV: Lots of power, deep bass, slightly lacking treble. The best amp for the K1000 we know of.

PREHEAD-OPA627: Smooth, but slightly lacking punch.

PREHEAD-AD825: Very similar to the OPA627 but much cheaper. Hardly possible to distinguish these two opamps.

PREHEAD-LM6171: Punchy and extended in both directions (bass and treble). Care has to be taken to prevent oscillations though. The LM6171 is a true diva. Difficult to tame but if she sings, she sings extremely well :)

CORDA HA-1: SNIFF!!! One simply shouldn't compare a Volkswagen with Rolce Royce or a Ferrari, SNIFF!!!

Cheers,

Jan
 
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Quote:

Originally posted by Jan Meier


CORDA HA-1: SNIFF!!! One simply shouldn't compare a Volkswagen with Rolce Royce or a Ferrari, SNIFF!!!

Cheers,

Jan


Uh oh. That PreHead is gonna be expensive isn't it?
 
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Nick Dangerous

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Very nice work Jan! Thanks for the pics and updates. We are all very eager to try out your creations...
 
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wow! I really do like the new features of the Porta Corda. My major qualm with the old Porta Corda is that the battery drains too fast and clipping occurs. All the new features are excellent!!

so even though the new PC uses much less power it still sounds as good as the old PC running with on a 9v(non class-A mode)?

Is there significant circuit change from the pre-existing Porta Corda to the newer version? If not, is it possible to upgrade on the existing Porta Corda?
 
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