Jan Meier
King Corda
Member of the Trade: Meier Audio
- Joined
- Jun 21, 2001
- Posts
- 854
- Likes
- 182
Dear Headfellows,
The last two months I got several mails from people who had compared the crossfeed functionality of the Headphonia amplifiers to that of the PORTA CORDA. According to them the two filters sound surprisingly similar.
Two weeks ago I was able to organize myself an Headphonia amplifier and opened it to check how crossfeed was implemented. People were found to be right. The crossfeed filter inside the Headphonia is a 1:1 copy of that of the PORTA CORDA amplifiers. Even exactly the same capacitor and resistor values were used.
However, more carefull examination of the amp revealed that the amplification circuitry itself is also an exact copy of my own amp. The same schematics, the same resistor values and exactly the same capacitor values were used. The only difference was found in the brand/model of the capacitors used and in the type of opamp.
Please be aware that the amplification circuitry of the PORTA CORDA is not a trivial one. In many aspects it is very different from standard opamp topologies as used for instance in a CMOY. It is very clear, that the people of Headphonia simply analyzed the circuitry of the PORTA CORDA (which was never made public) and used it for their own products.
This is made even more evident by the fact that they copied two resistors that inside the PORTA CORDA are necessary to lower offset voltages produced by the LM6171 opamp but that are not necessary when FET-opamps are used as inside the Headphonia amp. Actually, in combination with a FET-opamp these resistors even slightly deteriorate sound quality. The schematics were simply copied within fully understanding all its aspects.
Needless to say that I was rather upsett by my findings. I wrote Headphonia a letter and summoned them to stop selling amps and to send me a list of all their sales so as to be able to come to a license agreement. I also asked them for a proof that their company has been legally registered. None of this has happened thus far.
Before I will forward this case to my lawyer I would like to know how many Headphonia amplifiers have been sold thus far. Since I didn’t get the information from Headphonia my request to all Headphonia owners is to send me a short E-mail with your name, the amp-model that you have bought (did it have crossfeed?) as well as the price that you paid for the amp. Please be noted that all names will be kept confidential and will not be forwarded to Headphonia or any other third party. I simply like to get an impression of the size of the “damage”.
I’m aware that my request is a very unusual one. If you feel a certain loyalty towards the people of Headphonia then I understand that you do not like to send me the data. However if you agree with me that their behaviour is below any moral standards, then I will be very happy to receive your mail.
The mail-address: meier-audio@t-online.de
Cheers
Jan
The last two months I got several mails from people who had compared the crossfeed functionality of the Headphonia amplifiers to that of the PORTA CORDA. According to them the two filters sound surprisingly similar.
Two weeks ago I was able to organize myself an Headphonia amplifier and opened it to check how crossfeed was implemented. People were found to be right. The crossfeed filter inside the Headphonia is a 1:1 copy of that of the PORTA CORDA amplifiers. Even exactly the same capacitor and resistor values were used.
However, more carefull examination of the amp revealed that the amplification circuitry itself is also an exact copy of my own amp. The same schematics, the same resistor values and exactly the same capacitor values were used. The only difference was found in the brand/model of the capacitors used and in the type of opamp.
Please be aware that the amplification circuitry of the PORTA CORDA is not a trivial one. In many aspects it is very different from standard opamp topologies as used for instance in a CMOY. It is very clear, that the people of Headphonia simply analyzed the circuitry of the PORTA CORDA (which was never made public) and used it for their own products.
This is made even more evident by the fact that they copied two resistors that inside the PORTA CORDA are necessary to lower offset voltages produced by the LM6171 opamp but that are not necessary when FET-opamps are used as inside the Headphonia amp. Actually, in combination with a FET-opamp these resistors even slightly deteriorate sound quality. The schematics were simply copied within fully understanding all its aspects.
Needless to say that I was rather upsett by my findings. I wrote Headphonia a letter and summoned them to stop selling amps and to send me a list of all their sales so as to be able to come to a license agreement. I also asked them for a proof that their company has been legally registered. None of this has happened thus far.
Before I will forward this case to my lawyer I would like to know how many Headphonia amplifiers have been sold thus far. Since I didn’t get the information from Headphonia my request to all Headphonia owners is to send me a short E-mail with your name, the amp-model that you have bought (did it have crossfeed?) as well as the price that you paid for the amp. Please be noted that all names will be kept confidential and will not be forwarded to Headphonia or any other third party. I simply like to get an impression of the size of the “damage”.
I’m aware that my request is a very unusual one. If you feel a certain loyalty towards the people of Headphonia then I understand that you do not like to send me the data. However if you agree with me that their behaviour is below any moral standards, then I will be very happy to receive your mail.
The mail-address: meier-audio@t-online.de
Cheers
Jan