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 (http://www.seymourduncan.com/forum/showthread.php?t=245224)
tracked them to the original website
http://retrovalves.com/About.aspx (http://retrovalves.com/About.aspx)
including listed patents involved.
Here is the jet city order page:
http://www.jetcityamplification.com/retrovalves/ (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.
So...what exactly are these? They're not tubes, but they work in place of tubes...maybe a patent search is in order.
http://www.google.com/patents/US7408401?dq=7,408,401+patent&ei=Xc9KUPnMC8ioiQKOnICQCQ (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 (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.
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?
Ah so they do exist... not very impressed by the sound in the demos I heard tho :(
Quote from: alanp on September 08, 2012, 05:19:00 AM
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
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?
$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.
ya i don't see a price either.
Quote
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.
Quote from: mgwhit on September 08, 2012, 04:21:49 PM
$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?
Quote from: mgwhit on September 08, 2012, 04:21:49 PM
Interesting, but I can't think of a single good reason to use one over a $15 Tung Sol.
They glow different colors :)
Quote from: mgwhit on September 08, 2012, 04:21:49 PM
$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!
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! (http://photo.shockya.com/wp-content/uploads/2011/11/deliverance-remake.jpg)
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?
Quote from: lincolnic on September 09, 2012, 03:07:16 AM
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.
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....
So you're saying, Anything is just a hero away from being legendary. It has happened before.
And I did try one of those solid state rectifiers in my silverface Deluxe reverb (frustration because it smoked my last Philips rectifier). It definitely changed the character of the amp at mid to high volume where the tone is. The amp lost lows and mids and maybe highs too. It sounded like it had a cold.
That's my thought as well. I hate to beat the old school drum; sure I'd love to see something new and revolutionary that really delivered, but so far...
Till then, I'll have to stick with cloth covered wire, Vitamin Qs and a few ridiculously expensive 50 year old tubes. IMO, putting a Wattgrinder or Retrovalve into a circuit designed for tubes is the equivalent of putting a New Sensor TS 5881 into a real 58 LP Tweed Twin; It'll work but the two aren't designed to get the most from each other. If the good amps are designed around the charcteristics of the tubes in them; maybe it follows that to get the best out of the SS tube replacements, you'd need a workable circuit designed to best use the unique characteristics of Retrovalves. Maybe then you'd have something. I dunno, just my two cents worth.
Quote from: frankie5fingers on September 09, 2012, 09:25:06 PM
IMO, putting a Wattgrinder or Retrovalve into a circuit designed for tubes is the equivalent of putting a New Sensor TS 5881 into a real 58 LP Tweed Twin; It'll work but the two aren't designed to get the most from each other. If the good amps are designed around the charcteristics of the tubes in them; maybe it follows that to get the best out of the SS tube replacements, you'd need a workable circuit designed to best use the unique characteristics of Retrovalves. Maybe then you'd have something. I dunno, just my two cents worth.
That's actually a very good point. Possibly two very good points.
I wish there was a company in the US that was making tubes. The new JJ factory is really modern and pumps out pretty consistent tubes, when will the price of tubes get high enough that production comes back to our shores?
Quote from: timbo_93631 on September 10, 2012, 04:38:55 AM
I wish there was a company in the US that was making tubes. The new JJ factory is really modern and pumps out pretty consistent tubes, when will the price of tubes get high enough that production comes back to our shores?
I think the real question is, when will environmental controls push tube production out of Eastern Europe?
Jokerx over on FSB has noticed AMT has produced a solid state analogue of a 6L6.
http://www.freestompboxes.org/viewtopic.php?f=28&t=19342 (http://www.freestompboxes.org/viewtopic.php?f=28&t=19342)
There is a link there to the data sheet for the product. very interesting stuff, if they could getmost of the way there, it would be very exciting.
I had not thought of JJ getting shut down. JJ makes no poor tubes. They are good and the price is not excessive for the performance factor. I have JJ 6L6, E34L, KT77, and 6V6, and 6CA7. They are all as good as the competitors.
That is quite a cool concept! Love to hear me one of these in the flesh
The more I think about this concept, the more I believe th only way I would be tempted to use solid state replacements is for them to be significantly cheaper than new production tubes. Which is nowhere near reality.