Moscode vs. AVA power amps

warnerwh · « **Reply #20 on:** 7 Apr 2007, 10:31 pm »

With my VMPS RM 40s I'm using a Fetvalve 550EXR rev.5. This amp sounds the most clean and natural of any amp I've owned. The cleanliness and accuracy is very unique. The 30 day free trial is worth trying imo for you. This really boils down to personal taste. Considering the cost difference I'd definitely try the AVA amp. Mine is staying put as the synergy with my planar/ribbon sections of my speakers is perfect for me.

This amp is not soft at all. In fact with the stock tubes I didn't care for it and am running Mullards that you can get for about 35 a pair. Overall well worth the money. I've not heard the Moscode so can't comment.

BrianM · « **Reply #21 on:** 2 Jun 2007, 05:31 pm »

Bill-
This may be a dead thread, but I'll chime in anyway. Maybe you've already made your move, but I think you should get the AVA FetValve 350 (not the 550), based on your speakers and room size. I am 100% sure this will be more than enough power, and it's $400 cheaper. If it still turns out not to be enough you can always have it upgraded to the 550 (or return it inside 30 days). Unless you've heard both amps already I wouldn't want to spend $5000 before I'd tried the $1800 amp. An added bonus with the AVA amp is that no tube rolling is necessary, and no power cord swaps (as though that should make a difference on any well-designed amplifier!). Just my opinion.

warnerwh · « **Reply #22 on:** 2 Jun 2007, 07:50 pm »

I will have to disagree that with the AVA amp tube rolling isn't necessary. I don't care for mine with the stock tubes, however with Mullard CV4024s it's perfect. Also these Mullards are very robust and quiet tubes. If I didn't tube roll with my 550 I would have sold it.

BrianM · « **Reply #23 on:** 2 Jun 2007, 08:14 pm »

It looks like you have the previous model 550EXR, which is now called the Ultra, and which for all I know used different tubes, or had other things different about it. What preamp are you using? It seems strange to me that a component would go from not worth keeping to "perfect" with a simple switch like that, but I've never been a tube roller.

tonyptony · « **Reply #24 on:** 2 Jun 2007, 09:06 pm »

Recent EXRs and the Ultra use the same tubes: JJ 12AT7s. I don't know how far back Frank started using JJs but that's what the FetValves are outfitted with at his shop.

I have to agree with warnerwh that even the FetValve can be altered with different tubes. I thought the JJs were okay but felt the extreme low end was not in as good a control as the rest of the range. I also felt the high end was not as extended as I thought it should or could be. The JJ is a good tube but it is known to settle pretty much in as a competent tube that doesn't do much of anything really wrong, but really doesn't shine in any area. In my case I went for the Holy Grail (some would have you believe) of 12AT7 - the Telefunken ECC801s tubes. Spoke with a lot of people before I bought them and was satisfied that they are very well regarded in areas that I wanted improved - more articulate and transparent bass, more extension in the highs, and just gorgeous through and through. I tried Mullards and EIs as well, and while the Mullards were very musical the Teles did the job I wanted done.

BrianM · « **Reply #25 on:** 2 Jun 2007, 09:38 pm »

Is the "ECC801" not to be confused with the "12AT7/ECC81" found in a stock Ultra amp then?

BrianM · « **Reply #26 on:** 2 Jun 2007, 09:41 pm »

Never mind, I didn't read closely enough. Telefunken as opposed to JJ. What exactly is the difference.

BrianM · « **Reply #27 on:** 2 Jun 2007, 09:44 pm »

And, did you adjust the biasing yourself.

WEEZ · « **Reply #28 on:** 2 Jun 2007, 10:22 pm »

There should be no bias adjustment needed just to change 'like' tubes for 'like' tubes.

Different brands of tubes can sound different, and NOS tubes were 'mostly' made better than today's stuff...but changing tubes turning an amp from a 'keeper' to a 'seller' is hard for me to believe.

WEEZ

nicksgem10s · « **Reply #29 on:** 2 Jun 2007, 11:03 pm »

I was under the impression that that new Ultra amps use 6N1p tube.

Below is from the AVA website

"With a lot of work, testing, and listening, we have been able to engineer a very useful upgrade to these products. The 6N1P tube has substantially higher current drive and linearity than our current 12AT7 tube in line applications. Redesigning our circuits to use this tube makes a really nice musical improvement in all the applicable products.

What you hear is significantly better dynamics, resolution, and range. Along with that comes an even sweeter, more open, and more musical extreme top end. We think this new upgrade will make you very happy."

I have only heard the current AVA Ultra amp, preamp, and DAC and they are incredible and one of the best values I have ever come across in audio.

tonyptony · « **Reply #30 on:** 2 Jun 2007, 11:29 pm »

Nick, I think the 6N1P change is only (so far) for the Ultra preamp. The FetValve Ultra still uses the 12AT7/ECC81.

Brian, the ECC801s is a triple mica tube. The difference between it and the JJ is pretty substantial, just as the difference between a JJ and a nice Mullard. Which one anyone would prefer is up to them. In the case of JJ vs. Tele, the Tele is more articulate, more transparent, and more extended at both ends without losing any beauty or liquidity. It was the right change for me. They're ungodly expensive (I was a bit lucky in getting a pair for a slightly less than ungodly price). I sent them in to Frank with my EXR when he upgraded it to an Ultra. He did the biasing.

Weez, I'm not the one who made claim that the FetValve was no keeper with JJ tubes. I was happy as a pig in sh!t with my FetValve even with the stock JJs. With the ECC801s I'm a pig that died and went to sh!t heaven!

BrianM · « **Reply #31 on:** 2 Jun 2007, 11:32 pm »

The 6N1P tube upgrade applies to the Ultra and T8 preamps and the Ultra DAC, not the FetValve amplifiers. It did require significant rebiasing, incidentally, and was not a "rolling upgrade."

Anyone who has only heard the FetValve without an AVA pre should consider trying the pre. What you hear may surprise you! In retrospect, my 350 made my previous preamp sound both better and worse; it created a much better soundstage and image than my previous amp, but it also exposed more of the shortcomings of my preamp. Switching to an AVA pre was definitely a wow.

BrianM · « **Reply #32 on:** 2 Jun 2007, 11:34 pm »

Thanks for clearing that up, tonypony. So how much do they cost? And what did Frank charge you for rebiasing the amp?

warnerwh · « **Reply #33 on:** 3 Jun 2007, 02:17 am »

Quote from: WEEZ on 2 Jun 2007, 10:22 pm

There should be no bias adjustment needed just to change 'like' tubes for 'like' tubes.

Different brands of tubes can sound different, and NOS tubes were 'mostly' made better than today's stuff...but changing tubes turning an amp from a 'keeper' to a 'seller' is hard for me to believe.

WEEZ

The reason I said it went from Keeper to Seller was because a while back I put in the JJs to see what they sounded like and couldn't stand it. The Mullards on the planar/ribbon section of my speakers has good synergy. I may have put it too strongly but after last time I put in the JJs I couldn't get them out fast enough. This is on a 550EXR rev 5. I am also something of a perfectionist.

tonyptony · « **Reply #34 on:** 3 Jun 2007, 02:22 am »

Since the Teles are no longer made (as you may or may not know) you can only get them NOS or used. If you're lucky on eBay you can get a NOS pair for less than $200. I got a decently matched NOS pair from a private sale (not eBay) for less than $200, although reputable on line dealers are usually selling them for way above $200. That's the unfortunate part about these tubes; they've gotten such a cult reputation that the price is pretty much a rip off, no two ways about it. Supply and demand coupled with exaggerated cult status.

I'd recommend doing a bunch of research to try and get a sense of what some of the other 12AT7/ECC81/ECC801 tubes (and their variants) are like. My apologies if you know this already. Decide which ones sound like they might do what you'd like, and then start with the cheaper ones. I tried EIs and Mullards (as I said earlier) along with Sylvanias and Raytheons. What I found gratifying was that much (but not all) of what I read on the Audioasylum Tube asylum about these different tubes was borne out in my listening tests. That and talking to some on line sellers helped me in my investigations.

I will be careful to state that the differences are smaller, in general, on Frank's amps than in other tube amps that I've heard in tube rolling experiments. But if that small change is what you're looking for (blanket assumption that the rest of one's system is up to it) then it can be found even in a FetValve design.

Frank did not charge extra for biasing with these tubes. Since they were the ones that I was using in my EXR5 when I sent it in for the upgrade it was just part of the process.

zybar · « **Reply #35 on:** 3 Jun 2007, 06:39 pm »

I recently was able to listen to the latest AVA Fet Valve Ultra 550 with the stock tubes.

I directly compared it to my Moscode 401HR (which has NOS Siemens Greyplate CCA's from the 1950's plus a Black Sand Silver Ref Mk V power cord) in my system which I know very well. Outside of making sure the hi-pass filters were set properly for the AVA amp, nothing else changed. For all of my critical listening I made sure I level matched and listened to the same songs at the same SPL level.

I don't have time to give a full review right now, but thought I would give a few teaser comments...

Build Quality/Ergonomics

Not really any type of fair comparison in this area - big advantage goes to the Moscode.

The Moscode not only looks better, it is built better and is designed in a way that is easy to use. Binding posts, tube access, and the ability to use aftermarket power cords all are in the Moscode's favor.

Sound Quality

In my full review, I will give details on the test tracks I used as well as be more granular in my comments.

Bass

The AVA amp was able to rock and had a small edge in the area of sheer dynamics. While everything was tight and fast with the AVA amp, it wasn't able to resolve as much detail and texture as the Moscode. The AVA amp also didn't capture the body of the instruments as well as the Moscode. Were these night and day differences? NO! So I would call this area a draw or a slight nod to the AVA amp.

Midrange

The AVA amp didn't have the same clarity, detail, texture, and presence as the Moscode. At times (especially at higher volume levels) the AVA amp sounded a little congested and compressed. Voices and instruments weren't as holographic and 3D like with the AVA amp as they were with the Moscode. The differences in this area were more pronounced and obvious than the bass area.

Highs

This area was also pretty close between the amps, but the same general theme of the AVA not quite having the same level of detail, texture, etc... came into play.

Soundstage

I felt that the Moscode's soundstage was deeper and wider, with a little more concrete placement of people and instruments.

Overall enjoyment

Probably no surprise that I wanted to listen to my system more with the Moscode in place. However, I did really enjoy the AVA amp. The AVA amp has a very musical presentation that doesn't really do anything wrong and does many things right. If not directly compared to an amp costing more than twice its price (I know price isn't always an indicator of performance), I am not so sure how readily apparent it's shortcomings would be. I now can say from first hand experience that the AVA amp is a very good performer and an excellent value.

Stay tuned for the full review...

George

Papajin · « **Reply #36 on:** 3 Jun 2007, 07:04 pm »

George,

Interesting read so far! Just wanted to make a quick comment on your mini review; Under midrange, I found it to be somewhat unclear what you were saying. Specifically the sentence "Voices and instruments weren't as holographic and 3D like with the AVA amp.", I wonder if you meant to say "Moscode" at the end there instead of "AVA amp"?

zybar · « **Reply #37 on:** 3 Jun 2007, 07:07 pm »

Quote from: Papajin on 3 Jun 2007, 07:04 pm

George,

Interesting read so far! Just wanted to make a quick comment on your mini review; Under midrange, I found it to be somewhat unclear what you were saying. Specifically the sentence "Voices and instruments weren't as holographic and 3D like with the AVA amp.", I wonder if you meant to say "Moscode" at the end there instead of "AVA amp"?

Just made a change to hopefully make things clear.

The Moscode amp was superior to the AVA amp in all areas of the midrange.

George

Papajin · « **Reply #38 on:** 3 Jun 2007, 07:10 pm »

George,

Much clearer! Thanks!

Wayner · « **Reply #39 on:** 3 Jun 2007, 09:22 pm »

Zybar,

What speakers did you use?

W