[floresjc]

I have 3 different AVA amps, all from the Insight series. I took delivery of them last August and have been pretty happy with them. I have Double 240 and 240/3 driving a Salk SongTower home theater, and a Double 440 driving my HT2-TL's (along with the matching Insight DAC and Preamp).

What I've been considering doing is upgrading the 240 to something with more power, because my SongTowers do home theater and 2 channel. I also have been pondering buying my first piece of tube gear to see what all the rave is about.

One way I could do this is get a Fet Valve Ultra Double 550 (and move the 440 over to the SongTowers), which if I'm not mistaken by all the terminology is a hybrid tube/SS amp that also has the mosfet upgrade. A few things I'm concerned about:

1. Are tubes in an amp like the 550 a high maintenance item? Are they expensive to buy? Is biasing a big deal, I hear that term alot with tubes, or is there something in the tube replacement process I can't do myself?

2. Am I'm going to hear a difference with the hybrid amp being the only tube component in the chain? I don't have the money to upgrade everything, so if there's no difference with the amp, I might just have to save the $2400.

3. Are tube amps noisier than SS amps? My 2 of my AVA amps are dead silent, and one has a quiet hum to it, and they keep the noise floor out of the speakers at idle to a dead minimum.

Thanks for any insights more experienced folks can bring to the discussion. I would like to take the plunge, but I want to make an informed decision knowing what I can and can't expect between the two systems.

Edit: I'd like to also know if they run hot, or are similar in heat output to the SS amps.

[ArthurDent]

I'm sure you'll get some other, more expert, input on this particular topic, but fwiw -

1) No, but for the year & a half I've been running it I don't have that many hours on it. I don't recall that Frank's manual noted any need to check the biasing, though I'll go back and re-read. I think Frank, Dean, Larry, or Wayner should be the experts on that. As to tube replacement, follow recommended procedures, and shouldn't be a problem. I've changed one tube in my T-8, no particular problem. Have the 6CG7 Mazdas on order to start some rolling in the T-8 & Ultra Pre, and am looking forward to checking things out.

2) I'd say 'Yes'. I started with a Halfer to Omega upgrade, then to Insight, and op amp upgrade myself, that was driving the combo 2 channel/HT. I heard a difference with the T-8 pre when I moved the 250 to my office system, and inserted a std Ultra 550. In my case (though not the only 'tube' piece in the chain, Ultra Pre, & Insight DAC) each step up in the AVA lines has provided more detail, more refinement, smoother, quicker response, with a more detailed soundstage. Granted a fair bit depends on the recording, or soundtrack, but I have no doubt you'll hear a difference. Aside, I'm driving std Song Towers with the 550 for the 2 ch & front HT, I'd think you'll be happy using either the 440 or 550 with either the STs or the HT2-TLs.

3) I'd probably say a qualified 'yes', but only when there's no source playing and you have your ear close to the speakers in my system.

Seems to me martyo, and maybe a couple others have experience with the Dbl 550, it's an upgrade that's on my wish list, so they can probably speak to that best. Heat-wise, there's probably a little more with the 550 vs the 250 (260). The combo system is on an open shelf system similar to Frank's, the office with the 250 is in a cabinet. Haven't had any problems in either case.

Bottom line, not that there aren't alternatives as noted my many more knowledgeable than myself, I can't imagine you'd be disappointed in any way. Then again kind of depends on expectations,  ymmv.

Office system - Insight '260' with Burr Brown, T-8 pre, Ultra DAC, Dahlquist DCM-7s
2 ch/HT system - FET Valve Ultra 550, Ultra pre, Insight DAC with Burr Brown, Omega 240/3 driving C/LR/RR, std STs, Song Center, & SS Is.

[tonyptony]

I have 3 different AVA amps, all from the Insight series. I took delivery of them last August and have been pretty happy with them. I have Double 240 and 240/3 driving a Salk SongTower home theater, and a Double 440 driving my HT2-TL's (along with the matching Insight DAC and Preamp).

What I've been considering doing is upgrading the 240 to something with more power, because my SongTowers do home theater and 2 channel. I also have been pondering buying my first piece of tube gear to see what all the rave is about.

One way I could do this is get a Fet Valve Ultra Double 550 (and move the 440 over to the SongTowers), which if I'm not mistaken by all the terminology is a hybrid tube/SS amp that also has the mosfet upgrade. A few things I'm concerned about:

1. Are tubes in an amp like the 550 a high maintenance item? Are they expensive to buy? Is biasing a big deal, I hear that term alot with tubes, or is there something in the tube replacement process I can't do myself?

The way the 12AT7 tubes are used in the FetValve places very little stress on them. On top of that the AT7 is a typically long lived tube. Reports are on the order of up to 10,000 hours in a use like this. Of course that's probably under optimal circumstances. Still, it should be possible to get several thousand hours out of the tubes.

As to expensive, that depends on what you tube you wind up using. While the stock tubes are quite nice, using different tubes will produce a slightly different sound out of a FetValve (don't hit me Frank!). AT7s run anywhere from $10-20 a pair to $200-300 a pair, but - and this is very important - just because it's expensive doesn't mean you will like it in your application! I've found over the years that there's often no right or wrong with tubes. In many cases it's whatever creates the kind of sound that works well in your system. I know this sounds like it's leaving you in a sea of uncertainty, but here and on other sites (most especially the Tubes forum on AA) there is a wealth of knowledge on the sound character of various tubes. But if you tread into these waters you may have to try a pair or two before you find the best for your system. Don't let that discourage you!

Frank does not recommend do it yourself biasing on the FetValve. Biasing, in general, can be very dangerous with the voltages involved.

2. Am I'm going to hear a difference with the hybrid amp being the only tube component in the chain?

I'd think so. I did. But that's a hard question to answer for someone else.

3. Are tube amps noisier than SS amps? My 2 of my AVA amps are dead silent, and one has a quiet hum to it, and they keep the noise floor out of the speakers at idle to a dead minimum.

Mmm, a lot of this depends on how efficient your speakers are and how close you sit. In general I'd say the FetValve seems no noisier than many SS amps I've had in my system, meaning less than any pure tube amp I've used. It's quiet.

Edit: I'd like to also know if they run hot, or are similar in heat output to the SS amps.

IMO similar to a high bias SS amp of similar power. You shouldn't burn yourself touching the heatsinks

[Rocket]

Hi,

I guess if you have the money to spend you might as well do the upgrade.

However, the songtowers are rated at 88db and the 240 is a 120 watt (8ohm) speaker which should provide plenty of power to drive them.  The 440 is 220 watts per channel and from all I have read should have plenty of available power for your ht2tl's.  I currently have ht2's and use a Son of Ampzilla amp that is rated at 120 watts per channel with very good results.  In fact at one stage I was using an 88 watt per channel amplifier with them with good results.

What are you trying to achieve?  Better clarity?  Deeper bass?

I've wasted a ton of money over the years making sideways improvements in my system.

Just my take on your idea  .

Regards

Rod

[floresjc]

Well, more than anything I'm curious about experiencing the tube sound longer term than a 20 minute demo could give me. If you saw my house, I have pieces of audio systems laying everywhere, I still have 5 channel Rocket system in storage, an Outlaw 1070 receiver laying around. Since my 2.1 Klipsch system for my computer is pretty much dead, I'll probably end up using 2 channels of the Rocket and that 1070 on the computer, if I get a new amp, I'll shove the 240 over to the computer as well since the 1070 is only 65wpc. My father works out of the home quite a bit, and he has expressed interest in buying at least an amp from me to pair with the Rockets or some new SongBirds for his office, somewhat subsidizing the upgrade.

I'm quite happy with the solid state gear I bought from Frank, with the kinds of load the HT2 and SongTowers present, there's probably no real need for more power. But I do have a little cash burning a hole in my pocket from tax returns, and I had been considering getting a high power amp for the SongTowers via Audiogon (something like the A21) or making my first foray into tubes. Since I've been real impressed with AVA, I'm leaning the tube route. Perhaps the "most difference" would come from a tube pre, but I don't have near as much need for another preamp as opposed to an amp in my home. I suppose I could always trade up my Insight EC.

[avahifi]

Just to remind you the new "+" upgrade to both the Insight solid state and Ultra hybrid amplifiers makes a big improvement in musicality, especially at the top end and with space and involvement.  The cost is $100 per channel and a quick turn around.  Return shipping is $40.

I suggest you start with the "+" upgrade to one of your Insight amps and see if that does not take care of your needs for now.

Best regards,

Frank Van Alstine

[Vulcan00]

I have a question considering I now have a Ultra EC pre and I am considering the FetValve 550.
My question concerns the Bias issue. I am aware that with pure tube amp bias is adjusted when changing tubes and as playing time occurs. I really had not thought about bias with tube rolling in pre-amps and the hybrid power amps. How is tube bias handled in tube pre-amps and hybrid power amps when changing tubes or for normal playing time adjustments?

[avahifi]

There are no bias adjustments needed for any AVA hybrid or pure tube preamplifier.

For our hybrid amplifiers, bias adjustment is only recommended if you change brands of tubes (ECC81/12AT7 types). We consider the bias setting to be semi-permanent after it has been built and passed final testing here. No adjustments should be required during the life of the original tubes and they normally last for years in this circuit.  The adjustment procedure is not easy and not recommended unless you are an experienced electronic tech. However we will tell you how to do it if you really want to try making the adjustments.

Regards,

Frank Van Alstine

[Nuance]

I am interested in the Fet Valve Ultra 550+ or 350+ amplifier.  I saw someone mentioned the tubes should last 10,000 hours, which is pretty amazing.  Will they slowly decrease in sound quality like most tubes, though, or should they sound the same at 5000 hours as they did at 100 hours?

Frank, how often would you recommend the Fet Valve series amps be sent in to have the tubes checked, re-biased or replaced?

[avahifi]

Regarding tube life in our hybrid amplifiers, it appears to be very long.

We sell very few replacement tubes for the amps, most being "just in case" purchase decisions, not due to sonic degradation.

We see one of our very old hybrids show up for service or as a trade up once in a while.  In general the original tubes are still just fine, even in units built 15 years ago.  With these, the major reason for a tube replacement is that the ones we have available and use now are simply better than those from years ago.  Of course this does not include new old stock super premium and high priced Telefunkens and the like, but even those do not make much of a sonic difference with AVA hybrid amps, the tubes just do not have to work very hard.

The tubes have regulated heater supplies and regulated B+ supplies, independent regulated supplies for each plate of each tube and that is doubled up for each channel too.  They are not driven hard like output tubes and with any luck should last for years.

Thanks for your interest.

Remember that if you are not sure you need the extra power of the 550, then start with the 350 and save some money.  We have a standard policy that a Ultra+ 350 can be returned and upgraded to an Ultra+ 550 for simply the difference in price, as long as they are in current production.

Best regards,

Frank Van Alstine

[Nuance]

Frank,

Thank you - that was just the information I was looking for.  My speakers are the SongTower RT's, so the 350+ would probably be perfect for my needs.  Will you be bringing any of the Fet Valve amplifiers to RMAF this year?

[avahifi]

Yes, we will be sharing a display with Jim Salk at RMAF again this fall and will have a full line of AVA electronics there for you to see and listen too, including the Ultra+ hybrid amp and more.

Best regards,

Frank Van Alstine

[Nuance]

Sounds great, Frank.  I'll be there!

[Art_Chicago]

wow, seems like Nuance has converted to the AVA amps! Hope we can see a nice write-up about picking the best amp 

[ArthurDent]

Hmmm. " ....., but this needs to be my permanent amp for a good 10 years.  If I used the words "tide me over" ......"  Don't worry we won't tell. 

Give them a listen Nuance, I don't think you will be disappointed in anyway. They aren't everyone's cup of tea, but what is, particularly in such a personal endeavor as stereo. 

[Nuance]

Hehe, I may be convert folks; we'll know in a couple months.    I will keep you guys posted.

[martyo]

Hey Nuance,

Next time I'm headed up to my brother-in-laws in Grafton I'll PM you to see how your schedule is. I can bring a Double 550+ and/or T8+, and/or Ultra DAC and you can listen on your set if you like.   

[Nuance]

Hey Nuance,

Next time I'm headed up to my brother-in-laws in Grafton I'll PM you to see how your schedule is. I can bring a Double 550+ and/or T8+, and/or Ultra DAC and you can listen on your set if you like.   

Niiiiiiiiiice!  That would be amazing, martyo!  Thank you. 

[ArthurDent]

Niiiiiiiiiice!  That would be amazing, martyo!  Thank you. 

He is indeed a gentleman of the highest quality.