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