[ooheadsoo]

I recently bought this amp used off of audiogon.  First, appearances - this amp looks better in person than would seem from the pictures you typically see online.  The faceplate is a nice piece of aluminum, and the lettering and logo are clean.  There's no wow factor, but it's not cheap at all.  Sadly, that isn't the impression that I get from the website.  Hey, the power switch is on the front - nice, since it has tubes and I don't want to keep it on.

The sound is fantastic!  Authoritative bass, dynamics, details, and transparency that I didn't have with my previous amp.  This is a keeper until I decide to get the upgrade to Ultra.  I'm not sure I will ever need a better amp than this unless I find it runs out of steam on my next set of speakers and want higher power.  Better instrument separation.  A more transparent look into the window of music.  I purchased this amp mainly because of the two or three reviews that said it bested the Bob Carver Sunfire amps, amps that I have always admired.  I heard the sunfires make 2" full range speakers play decent hip hop.  Now that was an iron fist - and the AVA 440HC was better?  Then how much better could the 550EX get?  Well, I don't know because I've never had the cash for a sunfire, but this 550EX beats the pants off of my last amplifier.  Given the limitations of my room, this is the best I've heard my system.

[Wayner]

Welcome to the world of AVA.

Wayner

[gjs_cds]

Congratulations on the fantastic acquisition.  Save up a little for a used AVA pre-amp, and you'll be blown away yet again!

/been there, done that.  Although mine was the OmegaStar III HC.  (Now upgraded to the 440EXHC.)
(The AVA amp and pre-amp has been a life decision that I'll never regret.)

[tonyptony]

Another welcome to AVA-land. What tubes are you using right now?

[martyo]

Welcome ooheadsoo-

I'd be a former Carver head: amp, preamp, tape deck, and ALS Platinums(until today when I picked up our HT3's). I don't even consider it in the same class as the AVA gear. Great acquisition. 

[ooheadsoo]

Thanks, guys.  I've read mixed things about the Carver gear, but the Sunfire stuff that I heard first hand was top notch, imo.  This 550EX is absolutely wonderful in my system and I can't wait to get home from work and fire it up every night.  An AVA preamp has been in the back of my mind, but I'm enjoying my McCormack Micro Line Drive in passive mode, currently.  I'm actually looking forward to getting my future speakers because they're much more inefficient than my current ones, and will let me use a larger range on my volume dial.  I don't need any gain.  My only concern would be re: the impedances, but thus far, I don't seem to be losing any high end.  I'd measure it, but I'm lazy.

As for the tubes, I have no idea.  That was my one reservation about getting the hybrid - tubes don't seem to last long in the SoCal summer heat, especially when people are stingy with the air conditioning.  I'm too lazy to tube roll - did I mention that I'm lazy?

[Wayner]

Frank has all kinds of 550's all over the place. The tubes do not work that hard in his circuits. Keep the amp in the open so the heatsinks and vents can do their job and you'll be fine.

Wayner 

[BrianM]

I'm not sure I will ever need a better amp than this

My sentiment exactly!

unless I find it runs out of steam on my next set of speakers and want higher power.

Hm, unless your next set of speakers will be the size of refrigerators I can't see raw power being a big issue. I heard the 550 puts out close to 300 real watts.

I too have tried out a Sunfire amp (250 wpc I think) which I would characterize as not in the same league as the FetValve, particularly if transparency is a big priority.  It was an okay amp, but I'd say the difference was between music needing to find its way through the amp, and the amp not seeming to be in the chain at all.  As for tube life I've had mine on probably an average of 6 hours a day for the past 14 months or so and still going great guns, for whatever that's worth.  Congrats...

Oh, and I'll second saving up for an AVA preamp, maybe even before you upgrade the amp.  In the end your amp is constrained by whatever your preamp is doing, and the AVA preamp is...not constrained.  It's equaled or outperformed just about everything I've compared it to, including units costing 2-3 times as much.

[martyo]

As for the tubes, I have no idea.  That was my one reservation about getting the hybrid - tubes don't seem to last long in the SoCal summer heat, especially when people are stingy with the air conditioning.  I'm too lazy to tube roll - did I mention that I'm lazy?

I believe almost all 550 owners run them with the stock JJ tubes. They last 2-3000 hrs and are only $30 for a matched pair, you can even get them from Frank.

[tonyptony]

As for the tubes, I have no idea.  That was my one reservation about getting the hybrid - tubes don't seem to last long in the SoCal summer heat, especially when people are stingy with the air conditioning.  I'm too lazy to tube roll - did I mention that I'm lazy?

I believe almost all 550 owners run them with the stock JJ tubes. They last 2-3000 hrs and are only $30 for a matched pair, you can even get them from Frank.

True Marty, true. But I would maybe say the JJs are the best value tube for the EXR... not necessarily the best. It's largely system and taste dependent as we know, but I have tried some tubes that I wound up liking better than the JJs. So there is room for experimentation if someone has a hankerin' for it. 

As for having enough juice, my speakers drop down to a hair above 2 Ohms at one point (in the frequency range) and average about 4 Ohms. When it was still an EXR - and now that I'm running an Ultra - I have never even been given a hint of the amp running out of steam or range.

[ooheadsoo]

My speakers only dip down to 8 ohms, so I'm a tad concerned about how much power the amp puts out.  Everyone says the speakers will show any compression upstream.

[gjs_cds]

My speakers only dip down to 8 ohms, so I'm a tad concerned about how much power the amp puts out.  Everyone says the speakers will show any compression upstream.

A few things:
1.  As a speakerbuilder, I can pretty much guarantee you that your speakers do *not* "only dip down to 8 ohms".  More than likely, they represent a nominal 8 ohm load (averaged over the frequency spectrum).  Impedance is a function of the driver (and subsequently the frequency).

2.  I'm not even sure what you mean by speakers showing compression upstream.  The fact that the 550EX *can* put out vast amounts of wattage doesn't mean that it *has to*.  Chances are--if you are listening at sane listening levels, the amp is only putting out 1 to 2 watts at the most (depending on speaker efficiency). 

[Brett Buck]

A few things:
1.  As a speakerbuilder, I can pretty much guarantee you that your speakers "only dip down to 8 ohms".  More than likely, they represent a nominal 8 ohm load (averaged over the frequency spectrum).  Impedance is a function of the driver (and subsequently the frequency).

   Did you leave out a word here?  I don't think I understand your first sentence.

2.  I'm not even sure what you mean by speakers showing compression upstream.  The fact that the 550EX *can* put out vast amounts of wattage doesn't mean that it *has to*.  Chances are--if you are listening at sane listening levels, the amp is only putting out 1 to 2 watts at the most (depending on speaker efficiency). 

   I agree that, 10 ohms or 2 ohms, a 550 EXR is going to provide sufficient power for any plausible application!

     Brett

[Zheeeem]

I'm too lazy to tube roll - did I mention that I'm lazy?

Ahhhhh.  A man after my own heart.

Congrats on the amp.  I have a 350 EXR which is fine for my needs.  Frank's hybrids only use the small tubes, so they don't overheat rooms.

Not sure what else you have, except the preamp.  McCormack makes decent gear, so it's not really clear that a new AVA preamp is your best next step.  My personal favourite of Frank's lineup is the Ultra DAC.  But again, not knowing what you're using as a source(s) or speakers....

[ooheadsoo]

I will be using SP Tech Timepieces.  My current speakers are diy sp tech av-2.  My dac is a NOS dddac1543 with 8 chips in parallel.

I like that you guys are confident about the amp.  I'm more concerned with instantaneous power for peaks in the signal than I am with rms power, but there's no specification I know of for that.

[martyo]

I like that you guys are confident about the amp.  I'm more concerned with instantaneous power for peaks in the signal than I am with rms power, but there's no specification I know of for that.

You certainly won't be disappointed in that area. It would be another area that the 550 excells in. Trust us, dynamics, quickness, both strengths of the gear.