Time to clarify a few things again.
Based on several comments it is clear to me that there are many poorly understood / misconceived ideas.
1. Cavalli's NDA
- back in November 2010, several people who had been involved in various prototyping efforts with Cavalli signed an NDA +
- this document not only limited our discussion of the design elements of Cavalli Audio but also restricted the use of the builds for personal use only. Never to be sold, not to be used to promote Cavalli Audio and to remain the property of Cavalli Audio where Alex had the right to request we send him completed amps should he deem it necessary.
I hope that closes the argument that Cavalli was providing "DIY" boards to some people for the purposes of shilling or possible sale for profit. In most cases I even etched my own prototype boards.
2. My role in Cavalli Audio - this subject is bound to rear itself again and I do not want to be held ransom. I had stated earlier that Alex had approached me to be a part of Cavalli Audio. Some of you may know that I am a pediatric medical geneticist, some not. It is not really relevant other than to say that my professional life is fairly full and I have a family to balance along the way. I was thus unable to commit to his offer but have always helped him where I can and at this time ( for the past 2 -3 weeks, as Brian Kurtz is stepping out), I am helping him field e-mail queries regarding the amplifiers as I have the technical knowledge of the circuit and I enjoy the communication. It is not a chore and my reward is knowing that I have helped a friend try and make a success of something that is dear to him. I did not announce myself as an MOT as I did not consider myself as such but I did send Jude a pm regarding this matter and was happy to oblige whatever he decided it should be. I am not a shill for Cavalli, I do like his amps, always have. This does not mean that I do not like any other amps. I am not particularly fond of Woo as they sound too "tubey" for me , I really liked the Pico but it doesn't like orthos very much. I have only ever heard the G-lite and that would not be a fair evaluation of KG's amps. I did try and build a dynalo way back when but that power supply was not much fun and I gave up. I won't list the amps that I do like but I can assure you there are many and they originate from the normal contenders, DocB, Millet, Uthus ..... If you need even further transparency, I signed an NDA with Audeze way back too , I was never actually involved in any of the development and did not benefit from this financially but when we initially communicated , they were interested in exploring different ideas. Hell, before that I even offered Fang free advice to sort his first ortho as I didn't care who was doing it, I just knew how to fix it.
3. Cavalli's clandetsine development .......
Marc mentioned ( iirc ) a few pages ago "remember digi" . I know I have told this story to a few people who have asked over the years but perhaps it is time for all to hear it publicly.
Digi01 was a member of the forums on Headwize. When Alex, Mark and Bill ( runeight , mains_hum & batman) developed the SOHA , digi hijacked the process and started producing boards for sale through his website. The initial design was meant to be modular so that it could be "upgraded" as builder expertise improved. ie started off as a low voltage hybrid with an opamp on the output. Upgrade psu, change out output buffer and you have a very different amp = you get the picture. Well the process was interrupted when digi arrived offering boards. The team ( CLP ) were not happy about the change in direction but worked with digi to make boards that would work and this became the SOHA , but it left an aftermath and the overall experience was not pleasant.
If the story ended there it would have been a nonentity. When Cavalli and Tom (snoopy) started to finalize the work on the embedded hybrid, digi reappeared and simply stated that he would be making boards available. The animosity at that point was high and I mediated an agreement between Alex and Digi which allowed the design process to be completed and digi supplied the first batch of boards to Jeff Rossell who was going to be selling the kits.
It was this ineterruption of the design process and threat of an incomplete product release that drove Alex to move further project development off of the public forums. It appeared as though he was excluding most of the collective inteligence which is the power of open source design. Alex knew this and he mentioned his discontent on more than one occassion to me but he strongly suspected that digi would repeat this behaviour again. Funny thing is that it didn't matter who supplied boards , if digi had just waited for the process to be complete or offering to supply pcb's at the end of the design, it might have worked out for all.
A quick search found this EHHA layout , I do not have the url for his project site and really can't be bothered searching for it but it is proof enough that what I say is true.
I can assure you that there was no "cloak and dagger" operation, and it was truly unfortunate that it went that way.
4. Abe was a clever man when he said " You can fool all the people some of the time, and some of the people all the time, but you cannot fool all the people all the time."
Pete is quite right of course when he said that a 6922 should never be operated below 70volts on the plate, in fact 90-100 is optimal for this tube to keep it operating in a linear fashion. Alex knows this and that is why he designed the EHHA around the 6GM8 which is a military spec space charge tube developed for field radio communication. It operates at 27-30V on the plates and has surprisingly good specs. People use 6922 tubes in the amp because they "work" but the kit is sold with a pair of 6GM8 because this is the design. Many people forget that tube amps are generally designed to operate optimally with a single tube type ( in a specified position ). We all love tube rolling and thus many circuits are a little lax to enable a reasonable range of good operating points for several tube types. BUT you will hear some designers say that it is better to optimise a circuit for a single tube as you will then get the most out of that tube. This is what Alex achieved with the LF - it runs dual rails for this purpose : quote from LF webpage "Separate HV and LV Regulated Rails for the Tubes and Transistors" . I am familiar with the LF schematic and I can assure you that it is not an EHHA. The tubes operate at an optimal 90-100V , it has a relatively low gain and thus limited feedback. This has been posted previously by Alex and thus I am not revealing any trade secrets here.
Thanks to the voices of reason. I will most likely not post on this matter again, it is getting late and I have probably said more than I intended