retrovalves

[atreidesheir]

Has anyone had any experience with retrovalves distributed by Jet City amps.

Saw them in a review here
http://www.seymourduncan.com/forum/showthread.php?t=245224
tracked them to the original website
http://retrovalves.com/About.aspx
including listed patents involved.

Here is the jet city order page:
http://www.jetcityamplification.com/retrovalves/

Has anyone had any experience or heard them?  how do they sound?
Any idea what is inside?
Just curious about an intresting item.

[lincolnic]

So...what exactly are these? They're not tubes, but they work in place of tubes...maybe a patent search is in order.

[JakeFuzz]

http://www.google.com/patents/US7408401?dq=7,408,401+patent&ei=Xc9KUPnMC8ioiQKOnICQCQ

http://www.google.com/patents?id=ezOzAAAAEBAJ&printsec=frontcover&dq=7,482,863+patent&source=bl&ots=t6fzgpagMi&sig=Y1yJnVkgzsYJBSNUcciTLchDv9k&hl=en&sa=X&ei=zM9KUICkF8qniAKdnIGwDQ&ved=0CDEQ6AEwAA

Very interesting.

EDIT: Of course the patent is vague enough to cover a wide variety of possible devices and not divulge any specifics. My guess is it is a high voltage MOSFET operating in the ohmic region with power regulation and filtering circuitry to get it to sound and act like a 12ax7.

[alanp]

I'd love to hear an expert's opinion on them -- if you loaded an amp up with them, would the lack of current drawn on the heaters mean that heater voltage would rise?

[nzCdog]

Ah so they do exist...  not very impressed by the sound in the demos I heard tho

would the lack of current drawn on the heaters mean that heater voltage would rise?

Shouldn't do... Voltage usually comes from a PT secondary as a product of the turns ratio, so it would remain constant

[sgmezei]

They sound like a transistor-esque replacement. I don't have too much faith about the sound vs. real tubes but I would pick some up as spares for the gig bag. Never know when you might need them. Then again, you could just have real tubes as back-ups. Maybe someone has tried them?

Anyone seen a price for these?

[mgwhit]

$35 a pop or $99 for a 3 pack at the Jet City site store.  Interesting, but I can't think of a single good reason to use one over a $15 Tung Sol.

[stecykmi]

ya i don't see a price either.

EDIT: Of course the patent is vague enough to cover a wide variety of possible devices and not divulge any specifics. My guess is it is a high voltage MOSFET operating in the ohmic region with power regulation and filtering circuitry to get it to sound and act like a 12ax7.

this is probably a pretty good guess.

[stecykmi]

$35 a pop or $99 for a 3 pack at the Jet City site store.  Interesting, but I can't think of a single good reason to use one over a $15 Tung Sol.

if you have too much money?

[slimtriggers]

  Interesting, but I can't think of a single good reason to use one over a $15 Tung Sol.

They glow different colors 

[sgmezei]

$35 a pop or $99 for a 3 pack at the Jet City site store.  Interesting, but I can't think of a single good reason to use one over a $15 Tung Sol.

I agree!

[atreidesheir]

The review on the seymour duncan forum said the power tubes run cooler with the retrovalves loaded.  I cannot find any reference to a user opening one up, but someone said they heard (right) it was an opamp implementation, but Mosfet seems more likely.

Interesting,
But they sure are purty! 

[lincolnic]

I'm too tired right now to read through those patents, but the second one mentions DSP and converters - I'm guessing something digital is going on inside those guys. Maybe some custom DSP chips?

[JakeFuzz]

I'm too tired right now to read through those patents, but the second one mentions DSP and converters - I'm guessing something digital is going on inside those guys. Maybe some custom DSP chips?

Could be but they usually include that stuff to cover their bases for future infringement purposes. They always say things like "the VTRD could incorporate an ADC and a DAC...". It is possible and it would probably make matching the response to a real 12ax7 easier. My guess is it is probably pretty easy and way cheaper to do it with just a simple analog gain stage. Also getting the input level into the ADC correctly would be a challenge especially for cascaded stages considering the high voltage swing of the MOSFET.

[frankie5fingers]

SS tube replacements have been around for a while, right?  Wattgrinder or Tonegrinder (something like that) was a player at the '09 NAMM show.  Those were a lot more spendy - over $100.00 IIRC.  I found them muddy and thin, and these demos sound pretty similar.  What's the difference between a SS rectifier and a tube rectifier?  Although the rec isn't a "tone" tube per se', I'll bet the same Principal applies.
Even though I don't care for 'em, I'm glad t see resources being spent to develop a viable alternative. It's obvious that new materials, stricter manufacturing regs, and a dramatically smaller market prevent turning out tubes with the tone and lifespan of their predecessors, maybe the money is better spent on a completely different solution.  Who knows;  maybe 50 years from now people will be paying 500 Spacebucks for NOS Retrovalves....