[rcag_ils]

of this?
http://cgi.ebay.com/Audio-Van-Alstine-OmegaStar-Amp-Building-Guide-/300502485947?pt=LH_DefaultDomain_0&hash=item45f7580bbb

If not, would it be patent infringement?

I've always wanted to learn how to modified my Omegastar with the Exicon and make it an EX, could you help me if I buy the parts from you Frank, so I don't have to pay this guy $100.00?

[avahifi]

This item certainly is unauthorized.  It probably came from an employee I had to let go a year and a half ago. It is an in-house document for internal use only.

The comments that you can get all necessary parts from us are not true.  We will not supply any AVA parts at all for a pirate amplifier project.

Of course it is for an obsolete design, not applicable to current AVA producton.

Regards,

Frank Van Alstine

[avahifi]

By the way if all you want to do is swap an older AVA amplifier from Hitachi to Exicon power mos-fets, all you need to do is swap the devices and change the gate resistors from 100 ohm to 220 ohm and reset the bias to 75 mA per device.

By the way, rcag_ils, thanks for the heads up.  If you need more help with the Exicon output upgrade, just call me.

Regards,

Frank Van Alstine

[ratso]

i would certainly contact ebay over this - i would imagine they have pretty strict policies about selling stolen goods and it shouldn't be too hard to prove seeing as how you own the company. you could also log into ebay and ask a question about the item which will show up on the bottom of the for sale page. something along the lines of "do i get a cut from this" might be good. 

[bregez]

If we wait long enough there will be a question to the seller that will look simular to the following:
"How much shipping to China?"
Then we all knows what happens from there 

[jtwrace]

The bright side of this is that it appears that Frank documents his builds.  That is very important for the future of unkowns.

[avahifi]

With a bit more research I discovered that my first thoughts are correct, the seller is a fired employee who took the document with him when he left.

I have e-mailed him demanding the return of the document or e-bay will learn he is selling stolen goods.

Fortunately it is for an obsolete product line.

Regards,

Frank Van Alstine

[r1seals]

Well bidding has ended for this.

[satfrat]

Well bidding has ended for this.

What bidding would that be? 0 

[rcag_ils]

Well it was unfair for Frank, but I am glad that it got resolved.

Not too long ago, some guys stole my Sonographe SL-21 speakers picture and put it on Craigslist, Ebay, and some other sites, trying to sell his Synthesis speakers. I emailed to all the sites that he posted the pictures on, his ads was pulled almost immediately. Ebay took some work though, it's hard to email them, I ended up calling Ebay, and they too, pulled his ad.

It's  unethical to sell your employer's work, it's unethical to sell anybody's work. Breges was right, if it fell into the wrong hand, pretty soon, China would dominate the highend audio market.

[rlee8394]

Frank,

By the way if all you want to do is swap an older AVA amplifier from Hitachi to Exicon power mos-fets, all you need to do is swap the devices and change the gate resistors from 100 ohm to 220 ohm and reset the bias to 75 mA per device.

Would that be 75ma per device, or per paralleled complimentary pair of devices per channel? Since the same current flows through each P-channel and N-channel device, wouldn't the current need to be set for an Insight + 440H at 225ma and not 450ma? I don't want anyone to refer to your amplifier comparison grid and see that the number of devices for the Insight+ 440H is 12, forget that's a total for both channels, and then try to set the current to 900ma.

Thanks,
Ron

[rcag_ils]

wouldn't the current need to be set for an Insight + 440H at 225ma and not 450ma?

   ??????

75ma bias current per channel, not per device.

[rlee8394]

rcag_ils,

At the minimum, each channel with have a single pair of devices, one P-Channel and one N-Channel power Mos-Fet that are connected in series, with the output at their junction. The Insight+ 170 and Insight+ 240 are two such amplifiers with a single pair of power Mos-Fets. When you adjust bias current, you are adjusting the current flow through both devices simultaneously. That's why you only pull one of the fuses, either the B+ or the B- fuse and connect your meter in-line to measure the current in the loop. In order to provide more power, designers will parallel additional pairs of devices to handle the extra current needed. This can also be accomplished with the newer double-die devices that Frank uses. When devices are paralleled, they share the current load equally. Therefore, if one has an amp with three sets of power Mos-Fets, six devices in total per channel, the bias current would need to be set at three times the single loop value. So if a single pair is biased at 75ma, then three pairs would need the bias current to be 225ma, which is 75ma per set times three. That way, each set is drawing the required amount of current at idle to eliminate crossover notch distortion. Of course, there is some smaller current needed for the audio boards added to the mix, but that may be accounted for in the original specification.

Hope this helps,
Ron

[rcag_ils]

if one has an amp with three sets of power Mos-Fets, six devices in total per channel, the bias current would need to be set at three times the single loop value. So if a single pair is biased at 75ma, then three pairs would need the bias current to be 225ma, which is 75ma per set times three.

I misread Frank's message "75ma per device", he might have meant 75ma per pair of devices, that would make it 225ma per channel if the amp has 3 pairs of devices. Last time Frank helped me to set a small amp that only has one pair per channel, I seem to remember we set it at 75ma per channel.

[avahifi]

Correct, 75mA per PAIR of devices.

Regards,

Frank