[tonyptony]

I've decided to start a new thread to focus on this new topic, instead of tacking it on to one or the other of my other posts.

So I finally have had a couple of days to play with my new (used) 550EXR. The current tale...

Now from my other posts let me bring everyone up to date by saying that I decided to replace not only my Bedini 803 amp, but also my Bedini pre. I fell into a fabulous opportunity on a new-in-box Pass X1 at an unbelievable price, so I bought it. I had been running it with my 803 until the FetValve showed up. The preamp is very nice. Again, speakers are Shahinian Diapasons.

Well, I'm not sure what to say. The soundstage is about 1000 times better than the 803. Deeper, wider. The body of the music is also more natural. I was shocked to find that the low end is quicker and deeper than my 803. That really made me scratch my head. The 803 is a great amp: a brute force bipolar design with a very high Class A bias. I thought it had great low end (I've compared it to well regarded, more "popular" amps), but the FetValve bested it.

Although now we come to the interesting part. While the 803, by comaprison, has a much "flatter" soundstage it also has a level of transparency and extension in the upper frequencies that the FetValve could not seem to match. This had me confused. I thought that with a tube front end and an overall super wide bandwidth design the FetValve would trounce the 803 in this very area, but the upper registers seemed a bit attenuated by comparison. It was always my feeling that the 803 does not "push" the high end. It provides a very balanced presentation.

The original owner switched out the JJ tubes from the 550 and replaced them with EIs. I asked him about this and he said that he liked the EIs better. He also noted that he was a fan of the SET type tube sound.

He did provide the old JJ tubes, but I had also ordered from Frank a brand new set of JJs, on the off chance that one or more of the tubes might get damaged in shipment of the amp.

So I put the new JJs in the amp, let it cook for about an hour.

I know I've heard that the FetValve is supposed to be relatively immune to tube changes, but what I heard coming out was noticeably different, and better. The EIs leaned toward a thicker, more prominent lower half of the frequency spectrum. It was not as transparent or as well balanced as the JJ tubes, IMO. The soundstage and all other aspects that were good in the EI configuration were matched by the JJ tubes in my system, with the added benefit of a more balanced frequency presentation and improved transparency.

As for the extreme high end? Better than the EIs by far. As good as my old 803? That's a hard question to answer now. With the EI tubes the answer was no. I'm now playing a brand new pair of tubes, but even fresh out of the box the high end is more open, but different. It may have something to do with the improved depth of the soundstage. Like I said earlier, the 803 had a somewhat "flat" presentation. In that respect it makes the high frequencies stand out more than they should, maybe. But things like triangles and flutes are typically set toward the mid or at the back of an orchestra. And that's where the FetValve puts them. My brain is telling me what I'm hearing seems more "right" (I go to a lot of musical events during the season), but I'm missing being able to pick out the details from those higher frequency instruments. No, that's wrong. The details are there, but are set further back.

I'm a little confused right now, but with the new tubes in place I did something I hadn't done in a long time. I sat through an entire CD. Even when I first got the FetValve I didn't do that with the EI tubes in place.

How long do new tubes take to break in with a FetValve?

Update to the update:

Thinking that I was not sure what the Pass X1 might be doing to the overall sound, I put my old Bedini preamp back into the mix. Sure enough the soundstage flattened again, as it did with the amp (family sound?). Still musical in most senses, but the music picked up a "mechanical" quality. The Pass X1 was definitely not affecting any part of the high end, and is clearly more musical and open compared to the old preamp. Needless to say my dear old preamp was removed from the system.

Picking up on the characteristics that were present with the old preamp, it strengthened my original thought that the high end cues I was getting with the old gear may actually have been a result of a flatter soundstage. The high end is still there with the new gear, but presented in a different way. There is no doubt that the whole thing is more enjoyable.

[avahifi]

Thanks so much for the time you have spent writing a careful observation of your impressions of the Fet Valve 550EXR amplifier you have purchased used.

I am glad the new JJ ECC81 tubes are helpful.  We thought they would be.

Now if you were to think about upgrading the amplifier to a Fet Valve Ultra 550 ($399) you would really hear some more nice things, like increased dynamics, the feeling that a bit of "darkness" was removed from the music, and a bit more realist "sparkle" revealed in the high range.

Adding the new black/gold Ultra faceplate is a $100 extra cost option for better sound yet.

It will be more useful than further tube rolling or buying high priced cables.

Frank Van Alstine

[tonyptony]

Frank, as you know I was considering having this 550EXR sent directly to you from the original owner. I decided not to for a few reasons:

1) I was dying to hear it, and

2) I wanted it in hand to get my new equipment arrangement off the ground, and

2) I'm a conservative person by nature, and wasn't sure how I felt about being one of the first ones out of the box with the new Ultra design

I have every intention of carefully evaluating the reactions and reviews of the Ultra (can you at least tell us when the review will be out?   ). I suspect if your tease so far is on the mark (as I expect it is), I will be sending it off to you at some point.

What should I expect in the way of tube break in time with these new JJs?

BTW, I'm even listening to my FM tuner again   Haven't done that in years.

[ricmon]

I'm not a tube roller, but I'm getting some good sound using Siemens Tri Mica's in the 550 EXR.  However, I must admit that I retubed the TR7 and 550EXR at the same time.  None the less the whole system performes better than it did with the stock (JJ's) tubes (at least to my ears and or taste).  And welcome to the AVA fold.

[tonyptony]

Thanks ricmon. I'm as happy as can be. Please give us a sense of how you'd characterize the difference with the Siemens tubes.