[David Ellis]

Dan,

I did think about the issue of a "formal" reviewer/spokesperson influence on the crowd.  I am very aware of this.  I think you and I fully agree about these issues.

I have an idea...

I have little interest in public speaking.  Would you like to be the spokesperson next year in the DIY room?     And... perhaps provide your source gear.  

I don't mind doing this, and would be very happy if someone else was... eager.

I'd like to evaluate amplifiers just like we evaluated speakers.

The ultimate purpose of DIY evaluation is twofold - I think.

1.  Feedback for the gear being "audited"

2.  Written conveyance to other folk who were not present.

We do a pretty good job on #1, but a relatively piss-poor job on #2.  

I really don't have the gumption to write reviews on a whole bunch of speakers, and I really should not do this.  I am a manufacturer.  For example... It's not fair/right for me to praise the SEAS H1212 tweeter when George Short's tweeter was among them.  I DO like the SEAS H1212 tweeter easily the best of the $25 crowd, but it's wrong for me to place this in a formal letter.  

I believe I could be very unbiased, but I am sure that questions of self-interest would arise.

We should chat.  I'll send you a private email.

Dave

[hubert]

Hello all,

 I know that you are allways interested about amp comparisons . I have the opportunity to compare my Rogers e40a (double push-pull of 6L6 valves) to the well-appreciated Aksa55n+ (one of the rare french owners is living in Alsace, so thanks to Francis).

Here are my feelings:
Yes, I fully agree that the Aksa is certainly the best solid-state amp I have never listen to (under 2500$ to 3500$) because it is fully detailed, has little/no distortion, has much less "SS harschness", has great dynamic on the full range allowing to give rythm to the music, a well-proportioned image and accurate sound-stages. It seems just to miss a few sub-bass spl.
IMHO, its sound is the perfect example of the typical audioholic (good) view about SS gears.

BUT, and this is VERY obvious, at least compared to the Rogers, the Aksa misses a lot of micro-dynamics and micro-details on the full fr range. All the timbres of instruments or voices are as "cutted-off" and the music flow and thus the emotion suffer from this defect. I.e. on reverberation sounds and decreased harmonic notes, the difference is very striking.
The instruments have no better image or better attacks with the Rogers, but the instruments are more real.
Another difference is in the fact that the Rogers is able to fully fill my  room at low listening level and this please me a lot.
So I would not change my Rogers with this Aksa.

I have a question for Dave and others having made comparisons between valves amps (i.e. tweaked se40 or ultimate70) and this Aksa:
Is your feeling and listening experience the same than mine in this matter of timbres?

Thanks,

 
  Santa Claus will bring me a new cd-player...    

[AKSA]

Bonjour Hubert,

You must have been listening to Francis Muller's AKSA!!  Thank you for your positive comments about the AKSA 55W - I will assume you've listened to some very good, very expensive SS amps!

Your analysis largely comes down to SS versus tubes.  This is often a matter of preference.  The micro-detail you refer to is, in my view, introduced by the vacuum tube as it is a high distortion active component.  This is not to denigrate it, of course, it's just a fact of life.......  There are many people who will listen to nothing but tube amplifiers.

However, the deficiencies you refer to are all addressed when you drive the AKSA with a quality tube preamp, such as my GK1 or Swift.  As Nelson Pass has said, if you want it to sound like a tube, use a tube!

There is something organic, almost human, about a tube.  But these qualities are not easy to achieve in practice because it comes back to tube choice, topology and operating point - many variables.  But a good SS amp can be improved along the lines you describe with a good tube preamp.

While I don't agree with you on the bass performance of the 55W AKSA (which I think is very good), I can say that the 100W is stronger in this area.

It is a credit to David's 1801s that these sonic qualities are laid bare with his excellent design.

Cheers,

Hugh

[hubert]

Hello Hugh,

At the moment I saw an Aksa reply to my tread, I thought...he will kill me , but...no , I'm alive ; thanks Hugh, you seem to be definitely a kindly guy.
Yes, it's Francis Muller who permited me to listen for the first time to one of your products.
First of all I wish to confirm that the 55n+ is really a very good amp, with an incredible price/quality ratio. I listened a few days ago to a well-known british SS pre+amp combo priced close to 6000$ which had this harsh sound I hate.
I want to go a little farther with your comments (IMHO):
 

I will assume you've listened to some very good, very expensive SS amps!

Yes, Goldmund, Ayre, Plinius and on, all high-end stuff, all tooooo expensive... to follow my points of view on my life

Your analysis largely comes down to SS versus tubes

yes, I know, but I don't like this kind of "audioholic chat matter" because I listened at least to one SS gear which did absolutely not sound as a SS gear, none as a valve:
http://www.neodio-hifi.com/en/technology.php
Unfortunately, if it didn't have the lacks of both SS and valves, it didn't have any superiority

The micro-detail you refer to is, in my view, introduced by the vacuum tube as it is a high distortion active component

How could distortion create a such obvious part of what makes the great numbers of harmonics of a musical instrument timbre?

However, the deficiencies you refer to are all addressed when you drive the AKSA with a quality tube preamp, such as my GK1 or Swift.

Regarding that Francis added a simple 10Ko potentiometer to the amp, is it possible that this component ate the micro-details and micro-dynamics? (please comment seriously your answer because it is the most important question for me in this thread)

While I don't agree with you on the bass performance of the 55W AKSA (which I think is very good), I can say that the 100W is stronger in this area.

Yes, it is quite possible that the Rogers has to much spl in this area (sub-bass) but this fact allow me to listen to it during a part of the night in a very confortable way; IYO, is your 100w able to give me more pleasure at low level than the 55w?

Thanks for your next answer, and sorry for my bad english, now I go  
Regards,

[David Ellis]

Hubert,

I do agree with your assertions regarding the AKSA, and would place it easily in the $3k+ zone.

There are soo many issues here.  As a preface, when I write about quality, I also listen to the micro deatail.  This is the layering of low level instruments and harmonics in the music.  I seek quality in this realm too.  And, the amp must obviously maintain a lack of grit, and very good dynamics.  

I don't believe this is a simple tubes versus SS issue.  Certainly the AKSA was marginally superior to my modified Jolida 302 and therfore the AKSA sounded significantly better than my unmodified Jolida 302.  However, I favored a the VanAlstine Ultimate 70 over the AKSA for the precise reasons you mention.  The inner detail was quite impressive.  Both of these tube amplifiers are a push-pull EL34 design.  However, 1 is better than the other.  

I do understand that these amplifiers are both variations of a Williamson design, but there ARE differences in sound quality.  I cannot attribute these differences to typology or parts quality, but I suspect the latter is significant.  I believe the VanAlstine parts are very tightly matched and of better general quality.  

I haven't heard the bass from your Rogers amp, but I did find the AKSA bass very solid - certainly no problems here.  

Rather than cite my opinion on the matter of tubes versus solid state, I'll offer a quote.  This comes from, "Modern High End Valve Amplifiers" by Menno van der Veen, page 3.  

"The biggest difference between valves and transistors in their distortion behavior.  If we compare amplifier specifications, the distortion produced by a valve amplifier at full power will be in the range of a few percent, while transistor amplifiers distort less than a tenth or even hundreth of a percent in a comparable situation.  These figures corroborate the marketing claims that transistors are much "cleaner" than valves.  But is that really true?  Out of consideration for our neigbors, we do not always listen to music at full power and deafening volume levels.  In fact, the typical music program has a low level, with occasional high power peaks;  the average power level is not more than a few watts.  Now the good thing about valve amplifiers is that the lower the volume, the lower the disortion.  For transistor amplifiers the opposite is true... ""Generaly speaking, valve amplifiers handle small signals with teh utmost care, while tramsistor amplifiers amplifiers  are much more 'rough and tumble'."

Following this quote, I offer my belief on this matter.  There are huge differences in design, quality control, and quality components applied in both SS and tube amplifiers.  I believe these matters are much more important than the issue of Tubes versus SS.  Currently, I am using a killer good 40wpc tube amplifier with 6L6 tubes in a single ended configuration.  

Eventually, I'll likely try some some SE Triode stuff with the correct speaker.  I believe there are significant synergy issues here.  Bad synergy will result in bad results.  No feedback amplifiers subjected to poor loudspeaker impedance curves and low sensitivity is an obvious disaster.  Higher loudspeaker senstivity and a very flat impedance curve is extremely critical - I think.

Great discussion.

Dave

[hubert]

Dave,

I haven't heard the bass from your Rogers amp, but I did find the AKSA bass very solid - certainly no problems here.

Yes, I agree about AKSAs strong and tight bass; I spoke about SUB-bass from the AKSA which  IMO are slightly lean comparing to it's bass-range and comparing to the Rogers; I am far to say the Rogers is the better integrated in the world but I believe too that one of the superiorities of high-end stuff lies in the extension of the bass-range. This greatly enhances the perception of the size of the place of recording and also  
increases my pleasure of listening with low level. When I compared pem's upgraded Jolida 302 to the Rogers, sub-bass extension was the main difference.

"Generaly speaking, valve amplifiers handle small signals with teh utmost care, while tramsistor amplifiers amplifiers are much more 'rough and tumble'."

I am currently looking for SS diy or kit having this quality, and will let you know if I succeed.

Currently, I am using a killer good 40wpc tube amplifier with 6L6 tubes in a single ended configuration.

killer good, certainly... but   how could a 6L6 SE config become 40watts if in Absolute Maximum Operating Conditions the Power out of a 6L6 is 11watts? Where am I wrong?
 
 

[Brad]

It could be parallel single-ended instead of push-pull

[David Ellis]

how could a 6L6 SE config become 40watts if in Absolute Maximum Operating Conditions the Power out of a 6L6 is 11watts? Where am I wrong

There are 3 output 6L6 tubes per channel.  Also, the RCA tube receiving manual suggests 11 watts, but the output could be 15 watts per channel.  Hence, the 40wpc rating is close.

I am currently looking for SS diy or kit having this quality, and will let you know if I succeed.

I... belive the odds of finding a better SS amplifier than the AKSA are very sliim.  The AKSA is extremely good.

The only other possibility might be an older Nelson Pass Aleph amplifier.  There aare projects for these amplifiers, but the commercial/used units sell for @$1500.  With some high quality DIY parts under the hood these amplifiers might be very good.  A fellow DIY guy who has owned many VERY expensive commercial amps (i.e. Rowland, Levinson etc.) said the Aleph amps are on par with the very best.

Hubert, for now, I do recommend a modified Golden Tube SE40 from Jeff Glowacki at soniccraft.  It has the exact sonic characteristics you describe in the Rogers and even uses the same output tubes.  The finished SE40 will cost @$1600-$2000.  But.... unfortunately, the wall-outlet power requirements might be very different.  Do you guys use 220v on your side of the pond?

Dave

[Watson]

Dave, could you comment a bit more about the advantages of the Golden Tube over the Ultimate 70?  Is it just the lean bass that's an issue with the Ultimate 70?  Are the midrange and highs similar?  If a person were to use it with a separate powered subwoofer, would the lean bass be less of an issue?

[David Ellis]

Dave, could you comment a bit more about the advantages of the Golden Tube over the Ultimate 70?

I will again comment.  The SE40 sounded quite bad before modification.  The sound was on par with a very mediocre consumer grade amplifier.  After amplification, the SE40 had the following characteristics when compared to the Ultimate 70.

1.  More low level detail.

2.  Less grunge.

3.  Equal dynamics.

4.  More "appealing" bass.

Are the midrange and highs similar?

They are "similar" in tonal character, but the SE40 is better.  If you require more prose, please explain exactly what subjective comments you seek.

If a person were to use it with a separate powered subwoofer, would the lean bass be less of an issue?

No.

The Ultimate 70 has a very lean and accurate sounding bass.  It's not "full" sounding.  It's lean and crisp.  This is not an issue of frequency response.

I recently read this is rooted in output transformer characteristics.  Output transformers with high inductance will produce less distortion than transformers with less inductance.  (van der Veen, p.90).  Strangely, having MORE distortion via the transfomer might actually sound better.  The author suggested this is true for most listeners.  

Dave

[hubert]

Brad,
You were right

Dave,

I... belive the odds of finding a better SS amplifier than the AKSA are very sliim. The AKSA is extremely good.

Dave, please comment:
Do the Golden Tube SE40 have
- equal macro-dynamics than the Aksa55n+ in term of tightness, speed, impacts of transients?
- equal perceived spl in SUB-bass range than the Aksa? (as previously said I find the sub-bass of the Aksa too lean -even if tight- comparing to it's bass-range)

Do you guys use 220v on your side of the pond?

Unfortunately, yes.

Thanks,
 

[David Ellis]

Do the Golden Tube SE40 have
- equal macro-dynamics than the Aksa55n+ in term of tightness, speed, impacts of transients?

Equal...No.  The Golden Tube is superior in terms of tightness, speed, impacts of transients.

- equal perceived spl in SUB-bass range than the Aksa? (as previously said I find the sub-bass of the Aksa too lean -even if tight- comparing to it's bass-range)

What do you mean by "sub-bass"?  Are you referring to bass in the 20hz zone?

Either way, I found the bass of both amps very good.  I am really not to particular about a certain flavor of bass.  I found the AKSA tighter and leaner than the Golden Tube, but the difference wasn't very significant.

Dave

[hubert]

Hello Dave,

The Golden Tube is superior in terms of tightness, speed, impacts of transients.

    That's very astonishing   ; the Rogers is slightly less dynamic than the AKSA, thus it gives a less focused - materialized sound.

What do you mean by "sub-bass"? Are you referring to bass in the 20hz zone?

Yes, frequencies below 50-60hz; we use "sub" as "below" like in the word "subway".
Thanks for your comments,
 

[David Ellis]

thus it gives a less focused - materialized sound.

...This is getting into audiophile language that I really don't understand or wish to engage  

The 40hz bass from the Golden Tube on Piano keys and Bass guitar strings sound slightly more full, and the AKSA sounds slightly more lean.  The differences are minor IMO.

Dave

[Rocket]

Hi Hubert,

When you listened to the aksa did you use a good quality preamp? or was a volume pot built into the aksa?

I've used the aksa direct i.e. without preamp and it never sounds as good when i am using my tube preamp.

Perhaps that could explain why you didn't like the aksa that much.  I don't own an aksa at the moment and i'm not being defensive at all but it does make a difference to the sound quality using a good preamp.

Regards

Rod

[hubert]

Hello,
Dave,

Quote:
thus it gives a less focused - materialized sound.
 


...This is getting into audiophile language that I really don't understand or wish to engage

I understand your point of view but IMO, using an audiophile language for me is necessary if I want to give an impression of listening by clarifying all characters; i.e. if I say : this piano sounds much more like a piano, it could be about it's size, or it's timbre, or it's fondamental note attack and on... Generally the piano on the Rogers is better timbred but it's size and notes attack are better on the Aksa; Thus I (Hubert) could say the piano sounds better like a piano because timbres are what I prefer to get a certain reality,  while others prefer to privilege attacks and size of the instrument.
However, if all characters of the sound are better when listening on one gear vs another, thus no need to precise things.

Rod,

When you listened to the aksa did you use a good quality preamp? or was a volume pot built into the aksa?

A 10Kohms Blue Alps.
About this matter, one electronic engineer said me that a pot cannot eat informations, only eventually reduce the dynamics.
Also, Francis said me he used the Aksa with 2 good pre-amps: no improvement about micro-details/dynamics, thus it seems not to be the solution for what I'm looking for.

I've used the aksa direct i.e. without preamp and it never sounds as good when i am using my tube preamp.

Could you comment a little more about the differences?

Thanks,
 

[gonefishin]

Hi guys...I'll try not to get too involved in the Ellis speaker discussion (seeing as I don't have a pair).  But as some have mentioned to regard the preamp when talking about amplifier/loudspeaker interaction.  Which is certainly a good idea.  

   But also don't forget the other components too...such as CD players and DACs.  If they're stock or modified it certainly doesn't matter.  They can not only shape the tone and timbre...but also give you a different presentation in soundstage and/or imaging...along with differences in depth, layering and dynamics as well.  

  Aside from changing DAC's...a change in input/driver tubes, power output tubes, rectifier tubes...room treatments or positioning can also change much of what's heard.  Any one of these could give you such a difference in tone, stage, response, dynamics and presentaion to change your conclusions.  

    This is why for me personally...I've enjoyed talking about varying components at times...but have always been leery...when I could change one element in the "system" which could lead to such a different result.

   This holds true for any component in any system.  You really do need to treat the system as such.  Because a change in the room...loudspeaker...amplifier...preamp ...source (dac, TT) could change the sound and presentation so much.

    g'day

    dan

[David Ellis]

Generally the piano on the Rogers is better timbred but it's size and notes attack are better on the Aksa; Thus I (Hubert) could say the piano sounds better like a piano because timbres are what I prefer to get a certain reality,

I (Dave) would generally agree with this commentary.  I will also add that we have a full upright piano in our living room that is also the home for my stereo.  As such, my ear is fairly keen to the sound of the piano in my listening room.  In this regard, I am a simple guy.  The Golden Tube SE40 makes the piano sound more like a piano.

Dave

[David Ellis]

Hi guys...I'll try not to get too involved in the Ellis speaker discussion (seeing as I don't have a pair). But as some have mentioned to regard the preamp when talking about amplifier/loudspeaker interaction. Which is certainly a good idea.

Good stuff Dan.  Please do contribute.

Dave

[teiki arii]

Hello Dave,
As you know, I am to make up my mind about a not DIY power amplifier for my Ellis 1801b by January-February 2006, since I have a Cayin SC-6LS. I would like to know as you were "impressed with the AVA's quality of parts under the hood" if you changed your mind about this amplifier? I didn't get so many comments about this amplifier and none serious with Ellis 1801b. Which SS amplifier you would either recommand to me?
About AVA, I hesitate between Fet Valve 350EXR Amplifier and OmegaStar 260EXH Amplifier. Which one do you think is the best one for my -your - loudspeakers?
besides, the 350EXR uses a 12AX7 tube for each channel: what is your advice about hybrid amplifier?
Best regards, thank you for answering,
teiki.

PS: a stupid question? Is it better to have one transformer for a stereo amp or one transformer for each channel?