[pansixt]

I am hoping some of you on the circle have had the opportunity to compare the Ultravalve amp with the FET Valve 400 or 600R Amps in your system. I was never fortunate enough at the Denver or DC shows to do that comparison in the last couple of years.

In particular, the Ultravalve amp has that alluring golden tube sound.
My question is does the FET Valve R Series come close to that?

I'm currently pushing my Maggie MMG's with my AVA U70 and they sound amazing. But I realize that more power would make them sing to their potential. I have tried some of the best built tube amps at twice the power of my little U70, but to me they don't provide the soundstage and realism and they don't draw me into the music as the little amp that Frank built.

Speaking of Frank, he advises me that I won't be happy driving the Maggies, like I would be with the R series amps.
I just don't want to lose that golden tube sound, and I can't afford a new 400R at the moment but I need to look to the future
when I may.
And yes Frank, I know you have a great return policy.
And BTW my T-8 and Vision EC DAC are the other foundations of my system.

The other option might be to buy SFOX's U70 on the Trading Post and send them both back to Frank to bridge and run the two U70's as mono blocks

James

 

[mresseguie]

PM sent. 

[Ace Deprave]

I'm interested in a comparison between the two also.

[Wayner]

I have 2 Ultravalve amps, the original prototype and probably the 3 or 4th one built. Very capable amplifiers. Please keep in mind that a 30+ watt per channel tube amp is in reality, lots of power. No, not made to drive power hungry Maggies or my Martin Logans, but it will make my Dynaco A25XLs sing with plenty of punch and headroom.

This is a prefect example of how many people ignore the amps power and the speaker's efficiency. They are married and if you strangle the relationship, there will be problems. As an example, I just finished restoring a set of Altec Lansing Valencia speakers for my friend. 3 or 4 watts will put the speakers in your face. With a set of Martin Logan or Maggies, it's barely playing. While the Maggies are mainly a resistive load, the MLs can go down to 1 ohm and that is not good for really any tube amp, especially at even moderate volumes.

So if you want more juice out of your Maggies, the 400 or 600R is the answer.

Wayner

[Vulcan00]

Wayner I agree. I think the OP is interested in the sound coming from the Fet Valve amps, he is wondering if the sound is similar to  the Ultravalve or U70 in general terms? I do not think the fet valve has the generally same sonic signature, to me the Fet Valve is better period.  How you feel?

[I.Greyhound Fan]

PM sent.  I have heard both the UV and the R series amps and they are 2 different flavors, both very good but very different sounding.  The UV is tube sounding and a very nice amp ( I wish I owned one to run with my Monitor Audio Silver speakers) .  The FET's lean more to the SS side.  The FET's are more dynamic and sound great at low volumes.  They are very musical and have a lot of air and transparency.  I own a pair of Magnepan 1.6's and MMG's.  Unless you are doing near field listening, you really need a lot of power and high current to get the most out of Magnepans if you listen at mid to loud volumes.  I run 500wpc at 4 ohms with my 1.6's and almost never come close to using that much power but the music sounds fuller and more dynamic and musical.

[tipatina]

I have a pair of Vandersteen 3A sig speakers which I drive with a Bryston 4BSST using a T8+ preamp. On vinyl my listening level is about 10-11oclock on the T8 and for CD/SACD 9oclock. Clearly more than enough power. Thus I have wondered how either a 400R or an Ultravalve would work in my system. My next upgrade is probably to send my T8+ for the CF upgrade. I assume an upgraded T8+ will be equal to a new CF.

[pansixt]

Thanks to all who have responded thus far. This is some good input derived from varied experience.

Larry, in answer to your question, yes I am running a sub and you're right it does seem to fill out the sound. Surprisingly, the MMG's have some fairly good Bass response considering the popular opinion that they don't.

Vulcan00 you were correct in your conclusion. I really am out for others input on the difference in sound between the two models. I also agree that the R series amps sound wonderful and have heard them driving different speakers since they were introduced, but no Planars.

Wayner. I knew when I bought the MMG's that some Maggies like a lot of power. I didn't ignore that and my system will produce lots of volume. Probably enough for most folks. And I am happy with where it is now. And to your point, since the MMG's are probably not the last Maggies I will own, nor will my listening room remain the same, this is good experience and hasn't cost me great gobs of cash and regardless of how my main system may evolve, I will never part with my U70 amp.

Michael, you and Larry both mentioned upgrading the T-8 and I have thought about that often and will discuss it with Frank. Tipatina you can relate to that.
I have rolled the tubes some. I have some Clear Tops in it now. They are a little bright but sound great and will stay for a while.

James

[I.Greyhound Fan]

James, do you have a friend that has a high powered amp that he can bring over and hook up in your system so you can see how the MMG's respond to higher power and current?  With the higher power, music just fills out, bass is more explosive and deeper, the music is less strained.  Dynamics are markedly improved.

[pansixt]

Larry,

I had jarchers Conrad Johnson M75 A1 after Bill Thalmann did his upgrades. Twice the power of the U70. Shortly after we connected it, Jon brought over some KT120's and swapped out the 6550's. I put about 100 hours on the amp and it sounded awesome. And the MMG's sang. At that same time I had his CJ PV10 Preamp with some Mullard like tubes in it and that combo is hard to beat. At the same time, Jon had my U70 at his house in one of his systems and was impressed.

We also tried his CJ Premiere 11 amp but determined that there was a problem with that amp and he currently has it with Bill to solve a couple of issues. We'll preview it in my system again when it is repaired. But I don't expect as much of the older Glorious Tube Sound from it as the M75 A1 or my U70 for that matter and I am just hooked on that sound.

And I hate to admit it but I had Woodsyi's big Audio Research amp here but managed to have a small fire when it was powered up with a bad tube. After it was fixed I didn't want to try again.

I suppose that my main motive for this topic is just that the Golden Tube Sound is just so alluring. As for the future, who can tell? Tastes change. Systems evolve.

Again thanks for the input from everyone so far.

James

[I.Greyhound Fan]

If you want a real tubey sound then CJ is the way to go.  Especially their older preamps.  The AVA CF preamp is a great sounding preamp as well but not as syrupy as the CJ.   Maggies sound great with tubes, you cant beat the midrange.

By the way, thanks for mentioning Woodsi.  I have to send back some tubes to him.  I have them packaged up and ready to go and I have been so busy at work with the cold and flu season and seeing record numbers in our clinic that I have forgotten about them.