[tonyptony]

I've been a very happy owner of a Bedini 803 amp for many years. For those who are not familiar with it, it is a bipolar 250Wpc amp that works beautifully with Shahinian speakers. Smooth, open, quick, with a natural presentation that does not get there by sounding "warm" or "round" or "slow". For various reasons it is time for me to consider replacing it.

I have a friend who used to own a Bedini 150/150 - not as musical as my 803 but pretty darned good. A number of years ago he looked for a replacement and happened upon the AVA FetValve HC series. He bought one and has been happy as a clam ever since.

The thing is our systems are slightly different. I'm using a Bedini preamp that I do not want to replace if I don't have to (again a bipolar job). I'm looking for something of value that is at least as good as my 803. Sonically my amp does nothing wrong - and with a pair of Shahinian Diapasons I can get a good sense of what an amp will do from the very bottom to the very top. It gives me powerful, controlled lows, a very good (okay, maybe not great) midrange, and about the best high end I've heard from a SS amp. But overall it's the realistic musical quality that gets me.

The kicker is that the replacement amp must be capable of being run by long, single ended ICs - on the order of 25 feet. This is the configuration I have to live with now. And this is where my Bedini has let me down; it's just too unstable with long interconnects. So I'm wondering if the Omegastar can get me what I need, or if a FetValve will get me there. I hesitate a bit becuase I've never been the biggest fan of FETs. The FET amps I've heard over the years have sounded veiled and slow - yes, the standard song I'm sure others have sung.

BTW, the output stage of my preamp is an emitter-follower (okay, I'm an engineer).

[TheChairGuy]

Tony,

I won't hold it gainst you that you're an engineer  

I know Dick Shahinian has loved Bedini's for 20 years...he did when I met him, his wife and son so many years ago in NY.

Frank can certainly fill your engineer soul with the electrical realities of what he does....but the lowly $899 OmegaStar 240ex amp I recently bought is, easily, the most competent amp I've owned.  My list is a long, tho not particularly noteworthy assemblage of amps over the years, but this is just a darn good one. You might want to wander over to critics Circle to see my recent (what turned out to be , rave) review of it...it might give a good idea what you're getting into. 'Tis  shame there aren't more reviews out there on AVA amps - they are just fair value and built with utter competence in mind. Subjectivity, in terms of sound, that's wholly up to the end user of course.

It does need time to break in...Frank seems reticent to tell folks that in his marketing verbage for fear that he'd be thrown of the secret society of engineers   But, I have no such problem in telling you this.

[tonyptony]

ChairGuy, I actually have already read that review (g)! Yes, I've known Dick for on to 20 years myself. I used to live in Nassau County (before moving here to South Jersey). I spent many happy days at the factory talking about anything from music to cheese to beer. We still communicate regularly; he is a dear friend.

I agree with you about Dick's love for these unappreciated amps. But the time has come for me to move on to something that will work in my new environment. Unfortunately I can't afford a Plinius (Dick's alternate pick). OTOH, over the years I've heard a lot of amps from the likes of Rowland, VAC, Krell, Muse, Musical Fidelity, Naim... it's a long list. I've come to the conclusion that among these well known brands there are only a very few that will outdo an 803, and doing it comes at a significantly higher price.

[lonewolfny42]

tonyptony:

Sonically my amp does nothing wrong - and with a pair of Shahinian Diapasons I can get a good sense of what an amp will do from the very bottom to the very top.

Reminded me of an article I read at Stereophile about those speakers....

http://stereophile.com/floorloudspeakers/593shahinian/  ...it's rather long...and old, and a few reviewers listened to the speakers. I have not heard these speakers.[/list:u]

Chris[/list:u]

[tonyptony]

Reminded me of an article I read at Stereophile about those speakers....[/list]

Chris[/list:u]

Yeah, I remember when that article came out. There's a lot of history behind that article. I don't want to dig up old issues, so I'll just say I strongly disagree with Atkinson's - sorry, JGH's - review.

[TheChairGuy]

ChairGuy, I actually have already read that review (g)! Yes, I've known Dick for on to 20 years myself. I used to live in Nassau County (before moving here to South Jersey). I spent many happy days at the factory talking about anything from music to cheese to beer. We still communicate regularly; he is a dear friend.

Hey, me, too...born in Flushing; raised in Syosset, NY.  I never made it out to Dick's place in Suffolk, tho (Nesconset, is it?)

[avahifi]

I think you would be really happy with a Fet Valve Ultra 350 amplifier.  It has a 1 meg ohm input impedence and could care less about the length or the interconnect to it or the output impedence of the preamp driving it.

It certainly does not sound like a "mosfet" amplifier as designed by anyone else and should be a great step up from the Bedini for you.

It is big and open with a huge sound state, lots of detail and resolution, but no glare or grain at all.  Bass control and power is excellent, and the dynamics will knock you out of your chair (even a Chairguy chair).

Remember we do have a 30 day satisfaction guarantee.

Frank Van Alstine

[tonyptony]

Thanks Frank. While my AVA owning friend has been a tube guy for quite some time (he drives it with a beautiful Quicksilver preamp), I have been careful about getting into tubes. I don't have a "tube roller" mentality. What kind of tubes do the Fet Valves use and what is their average life while in use? And is it a design that benefits from tube rolling? (knowing you only by reputation and what I've heard from my friend, I suspect the answer to the last is "no")

[skrivis]

Thanks Frank. While my AVA owning friend has been a tube guy for quite some time (he drives it with a beautiful Quicksilver preamp), I have been careful about getting into tubes. I don't have a "tube roller" mentality. What kind of tubes do the Fet Valves use and what is their average life while in use? And is it a design that benefits from tube rolling? (knowing you only by reputation and what I've heard from my friend, I suspect the answer to the last is "no")

The problem I have with tube-rolling is that you don't usually know what you're actually doing. Are the new tubes higher-gain in the circuit? Lower? What about noise or microphonics?

If Frank were to say," I have here a tested pair of Brand ___ tubes that are closely matched and have higher gain than our normal stock tubes," I'd probably go for some tube-rolling.

Other than that, Frank has already selected the best tubes he can get for a reasonable price and in reasonable quantities. There probably isn't anyone else out there that has Frank's baseline data and can say, "Yes, these tubes are "better" than what AVA provides as stock."

I have a bunch of NOS Mullard tubes that were extremely high-quality and very expensive ~40 years ago. I no longer have my Hickok tube tester, so I can't even begin to speculate or measure how good they are today or how they compare to the tubes that come stock with AVA gear.

Tube-rolling becomes kind of a crap-shoot without objective measurements, and you're just as likely to harm performance as to improve it.

I won't say it's wrong to swap tubes, and you probably won't hurt anything (don't do it in an AVA hybrid amp though!), but I do question whether it's worthwhile in most cases.

I think Frank has stated that, all else being equal, higher-gain tubes than stock in his circuits will increase performance. Lower-gain tubes will decrease performance, and probably give you more of that "tube" sound. Still, there's probably room for some subjectivity in this, so feel free to swap tubes. You might just get lucky and find the best sound for you!

[avahifi]

Why tubes?  Because they provide a 200 volt overload capability in summing an input and feedback signal.  All other things being nearly equal, a solid state circuit has about a 0.2 volt overload capability under the same conditions.  If you can then use the tube properly, such as in our patented transimpedance circuit, the overall musical benefits are pretty obvious.

Tube rolling?  skrivis covered that very well indeed.

Frank Van Alstine

[tonyptony]

Oh, I have no fundamental issue with tubes, Frank. I've heard a few tube devices over the years that sounded very fine indeed. In your Fet Valve design what is the expected useful life of the tubes?

[guest1632]

I've been a very happy owner of a Bedini 803 amp for many years. For those who are not familiar with it, it is a bipolar 250Wpc amp that works beautifully with Shahinian speakers. Smooth, open, quick, with a natural presentation that does not get there by sounding "warm" or "round" or "slow". For various reasons it is time for me to consider replacing it.

I have a friend who used to own a Bedini 150/150 - not as musical as my 803 but pretty darned good. A number of years ago he looked for a replacement a ...

Hi, In the early 80's I had the pleasure of spending some time with John Bedini. To this day, I wish I'd never let go of my A25. Anyway, when I lost touch with him he had developed an amp using only diodes, and no transistors. The bass was extremely tight and fast. Don't know whatever happened to them. His preamps were completely mono. Have you contacted Gary to see what could be done to resolve your current problems?

Ray

[tonyptony]

Oh, I've spoken many times to both John and Gary. John concedes that the 803 input stage is not designed for long IC runs, although he did say that the best bet would be a low capacitance coaxial design with an impedance on the order of 60 ohms. Well, I tried a straight stick coaxial 75 ohm cable with a capacitance of 16 pf/ft and still had problems. Much as I love this amp I don't know honestly if it's worth it.

[skrivis]

Oh, I've spoken many times to both John and Gary. John concedes that the 803 input stage is not designed for long IC runs, although he did say that the best bet would be a low capacitance coaxial design with an impedance on the order of 60 ohms. Well, I tried a straight stick coaxial 75 ohm cable with a capacitance of 16 pf/ft and still had problems. Much as I love this amp I don't know honestly if it's worth it.

Another option might be one of Frank's preamps that would be better able to drive a long IC. There is also a line driver (http://www.avahifi.com/root/equipment/buffered_line_driver/index.htm), but I think you would want to spend the extra $100 and get a full preamp, or even build a kit preamp for the same price as the assembled line driver. I have an OmegaStar SL preamp that I built as a kit and I'm very pleased with it. It's a $5K preamp for $0.5K

Still, it sounds like you want to keep your current preamp, so maybe the power amp is your best bet.

[tonyptony]

Well, part of my problem is that I'm being told it's my amp, so I have to believe that. The amp has a 50K ohm input impedance, which may explain the problem. I don't know if that's considered marginal for long ICs.

[guest1632]

Well, part of my problem is that I'm being told it's my amp, so I have to believe that. The amp has a 50K ohm input impedance, which may explain the problem. I don't know if that's considered marginal for long ICs.

Hi Tony,

Well how long are your present IC's. It's gonna be a tough decission. I am considering Frank's stuff. There are other vendors here on the circle. You might wantta ask them about the length of IC's for there stuff. It does seem if Frank's amps will do the job for you, then you should consider them. I don't think you will go wrong in purchasing one, whether it is the Omegastar or the FETValve.

Ray

[tonyptony]

My current IC is only 1 meter, but I can't keep my configuration this way. I will be going to 25 foot ICs between the preamp and amp. Frank said earlier in this thread that the Fet Valve is capable of handling long runs, but I didn't say at that point how long it was going to be.

[guest1632]

My current IC is only 1 meter, but I can't keep my configuration this way. I will be going to 25 foot ICs between the preamp and amp. Frank said earlier in this thread that the Fet Valve is capable of handling long runs, but I didn't say at that point how long it was going to be.

Well, you ought to give Frank a call, or wait and see if he says anything about length.

Ray

[avahifi]

A 25 foot long interconnect set is no problem for an OmegaStar or Ultra series hybrid preamplifier.

However - - - - - -

In general think about this.

A power amplifier is a load driving device.  It cares not one whit how long the speaker wires are as long as they are not braded wires (which trade off a capacitive load for an inductive load and are the same as tying a big capacitor across the amplifier output terminals - bad news - even to the point of making some poorly designed amplifiers oscillate) or the runs are picking up too much RFI  (you are hearing your local radio station thru the speakers even when everything is turned off --- fixable by twisting the speaker wires about three turns per foot with an electrical drill).

The preamplifier is NOT a load driving device, note that some output tubes can only put out 5 - 10 milliamps of current before they saturate, and some output ICs are worse than that.  The interconnect cable is a terrible load for the preamp, and the longer the cable is the worse the load is.

So please, please, please think with me.  Since the amplifier is a load driving device by design and does not care how long a resonalbe speaker wire is, and since the preamp is not a load driving device and a long interconnect cable can make its performance suffer, then why not simplify your life and your equipment's and use as short an interconnect cable as practical, and then speaker wires as long as needed to "bridge the gap"?  Yes I know all about the audiophlake descriptions that short speaker wire and long interconnectrs sound better, but this flys in the face of all rationality.  Will a short speaker wire and long interconnect cable setup change the sound of your system.  It most like will do that, but never never for the better.

Again an OmegaStar or Ultra premp will drive these long cables just fine, as we built gobs of extra drive current into them to make up for what we consider system setup errors. But why not just do it right in the first place.

Frank Van Alstine

[tonyptony]

Frank, I want to tread very carefully in my response to your post. I do not want to get into an audiophile pi$$ing contest. In my particular case it is primarily a matter of economics and feasibility WRT my living space. If you are familiar with the Diapasons you will know they work best with two separate speaker cable runs per channel, as each channel is a mid/high frequency module and a low end dual woofer cabinet. Living space problems aside (although they make this a non-starter from the get go), I know what kind of speaker cables work best with these speakers (both top and bottom), and frankly I'd rather not lay out the cash for 4 runs at approximately 35 feet each. Given that I have not yet found an IC that works it's not clear that I'd be able to afford whatever solves that problem (I appreciate the irony here). I'll put my cards on the table - I'm willing to go up to about $1K for a pair of ICs if they can get the job done. Going the speaker cable route would put me into a price range where I'd consider solving the problem by just getting a newer amp. No, I don't believe in buying megabuck cables just becuase people say so; if I was that kind of audiophool I'd have dropped Shahinian and Bedini a LONG time ago. But I do know that matching cables to a system is no different than any other component.

(sound of me falling on the floor as somebody pulls away the soapbox)

That's about it. I believe my biggest problem here is that my current amp has a fairly low input impedance (50K ohms) for this kind of scenario. So I either get something like an AudioHarmony or HRS to buffer it, or bite the bullet and consider a newer amp.