The begin of the end

[kagliostro]

The begin of the end 


http://www.jetcityamplification.com/#!retrovalves/ctjr


they also look bad outside




and inside more




K

[PRR]

> RetroValves are so cool and advanced, they’re protected by US patents: 7,286,060; 7,408,401; and 7,482,863

http://www.google.com/patents/US7286060
A vacuum tube replacement device includes an indicator. The indicator can be arranged to provide audible and/or visual indication of system performance, function, status, or any other desired indication. The vacuum tube replacement device is pin-for-pin compatible with standard vacuum tube circuit pin configurations. The replacement device may be a solid-state tube emulator device, a traditional glass envelope vacuum tube device, or some other hybrid device. The visual indicator is equally useful for non-vacuum tube replacement devices such as audio amplifier circuits.
http://patentimages.storage.googleapis.com/pdfs/US7286060.pdf
43 Claims relating to LEDs in tube-like products. Seems to have thought of everything: if the toilet backs-up it can send a code over the filament lines to some unspecified central point.

http://www.google.com/patents/US7408401
A system is provided for a solid-state implementation of a vacuum tube replacement device. The system may derive power from a target amplifier filament supply. The system may include active or passive functions for noise reduction, voltage isolation, servo biasing, and other functions. The vacuum tube replacement device is pin-for-pin compatible with standard vacuum tube circuit pin configurations. The vacuum tube replacement device system architecture is equally useful for non-vacuum tube systems such as audio amplifier circuits.
http://patentimages.storage.googleapis.com/pdfs/US7408401.pdf
An "everything patent" for tube replacement.

https://www.google.com/patents/US7482863
Methods are provided for solid-state implementation of a vacuum tube replacement device that supplements the functional performance of the target replacement device, i.e., a traditional glass vacuum tube. Example functions may include OEM or user adjustable parameters such as gain and/or frequency response (e.g. transfer function), current and/or voltage saturation thresholds, bias condition, input and/or output impedance, linear-to-non-linear transfer function(s) (e.g. soft clipping parameters), power dissipation, communication protocols, and audio/visual indication parameters such as signal limiting detection, safety, stress, or wear-out conditions, and tube emulation model type to name a few. The methods presented for the vacuum tube replacement device system(s) are equally useful for non-vacuum tube systems such as audio amplifier circuits.
https://patentimages.storage.googleapis.com/pdfs/US7482863.pdf
More of the above. Concepts appear to be very ordinary (may be unique in context of a "vacuum tube replacement device"). You will not learn how to build your own 12AX7 from these patents.

[PRR]

Jetcity RV3B12 3-Pack Analog Vacuum Tube By Roberts Retrovalve - Blue
by Jet City Amplification
Price:    $99.90 & FREE Shipping.
Only 4 left in stock.
http://www.amazon.com/Jetcity-RV3B12-3-Pack-Roberts-Retrovalve/dp/B0091X0LWY

Three "tubes" for a hundred bucks is hardly going to kill the demand for $12-$20 real-tubes from Russian or Chinese sources. Other Amazon sellers offer 3-packs of real tubes for $30-$40. So for $99 you could buy NINE bottles to swap for tone or in case of failure.

Compared to long-sleep Golden Age tubes, these plastic "tubes" are a lot cheaper.

______________________________________

More data on Mr Roberts' page:
http://www.robertsaudiotech.com/designs/retrovalve.php

[HotBluePlates]

I guess the modern patent examiner never heard of the Fetron.

Sure the device replaces a vacuum tube with something which should be less expensive. Except it's not. And they picked the tube that is the most prevalent, but also which lasts the longest in use (at least decades, often even if you leave the equipment on 24/7).

I am starting to think modern patents are like modern copyrights: anyone can get a patent/copyright on anything... whether it's enforceable depends on who's got more money for the court battle.

[PRR]

> examiner never heard of the Fetron.

Appears to be cited by applicant.

US3742261   Oct 6, 1971   Jun 26, 1973   Teledyne Inc   Solid state vacuum tube replacement

The Roberts patent(s) don't Claim the basic idea of a sand-state tube. They cover an amazing array of improvements on that idea.