[hubert]

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

 
No, no Teiki arii, never stupid questions on this forum, only stupid answers:
 ONE transformer per WATT, nothing else!  
     

      ONE beer for EACH.

[David Ellis]

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

This is a good question.  I think that larger single transformers have less loss.

I... really don't know.  It seems like dual-transformers are a great marketing tool, and might actually sound better.  My totally unverified hunch is that  a consumers $$ would be better spent on high quality diodes, and power supply capacitors, but... most consumers don't know understand the difference between a .5c diode and a $1 diodes.  Commercial hifi is more about what's "visible" from a marketing perspective.  Explaining dioded ripple/ringinng/recovery to a cosumer would be very wordy and couterproductive from a marketing perspective.
Using dual transformers for "improved stereo separation" is much easier.

BTW, my old Bryston 3B-ST had very pretty dual transfomers, but sounded very poor when compared to a single-transfomer VanAlstene FET-Valve 350.  

Summary... I really don't KNOW if there is a discernable postive impact from dual power supply transfomers, but they sure do look nice    .  This is really a question for somebody like Hugh Dean.  I am sure he has performed this experiment.

Dave

[David Ellis]

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?

My opinion of this amplifier has not changed.  The Ultimate 70 is a dandy amplifier and I recommend it.  Frank uses good quality parts, but avoids the use of very high quality capacitors and such, but doesn't use the really high zoot stuff (i.e. Black Gate).  He also use a relatively plane-jane coupling capacitor.  As noted previously, Mrs. VanAlstine preferred the sound of Sonicaps used in my amplifier.  I must also offer that all of Frank's parts are very closely matched, and he does use 1% mil-spec parts wherever possible.  In this regard, the AVA product is significantly better under the hood than comparable commercial products.

Which SS amplifier you would either recommand to me?  

I recommend a AKSA Nirvana+ 55wpc or 100wpc amp.

Since the 1801 is has a low dcr of 6 ohms, you will be just fine with the 240EX amp.  This is what I'd buy.

Most/many loudspeakers that advertise 8 ohm nominal impedance actually have a much lower true impedance.  The low dcr number (not commonly listed) is the most important factor.  The 1801 is a true 8 ohm nominal loudspeaker, and suffers none of the typical marketing embellishment.
 

besides, the 350EXR uses a 12AX7 tube for each channel: what is your advice about hybrid amplifier?

@ 2 years ago the FET Valve stuff sounded better than the SS stuff.  Recently Frank has changed a few things.  This isn't obvious on his web page.  There is a considerable amount of hyperbole present, that really clouds what changed and what didn't change.  I DO know that all of Franks gear with a tube improved about 1 year ago.  I don't know if this improvement follwed in Frank's non-tube gear.  If the SS gear hasn't really improved, I suggest you get a 350 series amp.  It will sound very good.

I suggest you call Frank, mention my comments, and ask for HIS input on the matter.  Frank is a very honest guy.

[teiki arii]

Thank you very much indeed, Dave...

[rez]

Anyone try one of the amps here: www.audiosector.com?  - including the Patek favorably reviewed @ 6moons?

[rmihai0]

I am looking forward to try a Class A SS amplifier with my Ellis speakers.

I know that Dave liked stuff like Dynaco ST-70 (32W), Golden Tube SE40 (40W) or Jolida 302B (50W). From SS amps Dave says that 55W of AKSA 55N+ is more then enough.

My question to you: did anyone tried a 30W Class A SS amplifier with Ellis speakers?

Would you consider 30W Class A SS enough to power the Ellis speakers? (I have in mind a Pass Aleph 30).

I am NOT listening loud: around an average of 85db @ 7' (2m) distance.

[Greg Erskine]

This is a good question.  I think that larger single transformers have less loss.

Summary... I really don't KNOW if there is a discernable postive impact from dual power supply transfomers, but they sure do look nice  . This is really a question for somebody like Hugh Dean. I am sure he has performed this experiment.

Hi David and others,

Here is a very early review of an 2001 AKSA 55. The interesting point is the initial review is an AKSA 55 with one transformer and the second part with two transformers. Without putting words into Hugh's mouth, I think he agrees with the review and every AKSA I know of since this review has had 2 transformers.

http://www.tnt-audio.com/ampli/aksa_e.html

Personally, I can't confirm the results as I have always used 2 toriods.  

regards

[David Ellis]

My question to you: did anyone tried a 30W Class A SS amplifier with Ellis speakers?

Someone did use a @30wpc Aleph, but this was a few years ago.  I don't remember the customers name, but he conveyed favorable results.  

Rumor is that these amps do indeed sound VERY good, but I haven't heard them.

Dave

[David Ellis]

http://www.tnt-audio.com/ampli/aksa_e.html

Great article... okay then... it appears there is at least 1 solid affirmation for dual power supply transformers.

Dave
[/quote]

[hubert]

Hello Dave and all,

Bellow is a copy of a mail I sended to Francis, a crazy electronic tweaker friend of mine, to Matt (machmat) who selled me 8 west-cap NOS paper in oil to replace the poor MKT on the signal path of my Rogers e40a and to Pierre-Etienne.
Now I know how important is to place good stuff under the wood:


Hello Francis and Matt,

As promised, here are my first impressions about my upgraded roro; Matt, as previously said, Francis made not only the replacement of the 8 mkt placed on the signal path with your west-caps but also improved the signal path with some silver/copper/teflon wiring and by suppressing the balance, changed diodes with hyper fast soft recovery and added some bypass (the original mkt) on the chemical capacitors of the power supply; To finish, he regulated the bias; that's said, let's go:
First of all, the Rogers remains...the Rogers, even if only 10 hours of burn in: it means that, i.e., it remains totaly different from the Aska 55w nirvana+. Its frequency range remains "physiological" with slightly too much spl in sub-bass, a slightly backward mid and (very slightly) too much top hights.
Also, it keeps this "airy sound", not only in trebles but in upper-mid and in low-mid;
Also, it keeps the same timbres (harmonics structure) than before, at the except of trebles which are a lot more neutral.
To summerize: it remains a valve amp, with the common characters mainly attributed to valves (and that's what I love, haha).
Now, the differences:
- less distortions on the total range and particularly on trebles: no fatigue at all, no more harsh sounds; bad cds remain bad but...less bad.
- dynamics are slightly better, transients, attacks are now distributed on the full range, not only on upper frequencies as before. Bass and sub-bass are tighter.
- image: size of instruments are the same but are better differenciated one to the other.                
- soundstages: they are larger, particularly in the width; i.e., on some modern musics like world/electroacoustic, with a lot of phase effects and on, I fall completely in a much bigger volume/area: that's very enjoying for me.
Now, the most astonishing:
I listened (and am currently listening) to my old Micromega optic bit-stream because my couple of Goldmund are in the shop to be selled. Thus, I let you understand how all the above described feelings certainly will be enhanced by listening to my next (very good, haha) source (Vecteur L4.2); Pierre-Etienne knows exactly what I mean, isn't it P-E?

Francis: Thank you very much given me your time and your perfect working.
Matt: your west-caps work very well. Please, let me know if once burned-in, caps will give another sound, thanks.
Pierre-Etienne, your tweaked joli-jolida is currently very sad, it wants to be a tweaked roro, haha (perhaps in a second life...)

All IMHO and with humour (P-E)

Cheers,

[teiki arii]

Hi Hubert,
you are very lucky to get this amazing Francis! We were talking pem and I about your tweak. I am sure it will be better again in some hundreds hours....  

[hubert]

Yes teiki arii,

 Francis is a very kindly guy and it's practical for me that he lives with 15 kms at home.
About breaking in, Matt mailed me this, :
 

They certainly will need about 100 hours of breaking in. What mostly
happens is that especially the mid clear up and get cleaner, also the stage
will get more stable, first hours it always is everywhere (floating around
in space) and after some time it finally gets focus. Bass gets more precise
and also high frequencies will be more clear.

 

[teiki arii]

I found the Amp that works fine with my Cayin CDT-17A CDP and "my" Ellis 1801b Stand-floor: an Accuphase E-212 with XLR plugs...So I shunt the single-ended AOP on each channel. I changed OPA604AP for OPA627BP and I am very glad with that system: terrific!
Best regards,
Teiki.

Another configuration that it works very well and less expensive, the pem's: Vecteur L4.2, Jolida JD-302B, Ellis 1801b bookshelf...

http://www.accuphase.com/e-212_e1.htm

[David Ellis]

I changed OPA604AP for OPA627BP

Smart move!  The OPA627BP is a darn good opamp.  

Unfortunately, my CD player uses a difet, so the OPA627(A or B) simply won't work.

Dave

[teiki arii]

Unfortunately, my CD player uses a difet, so the OPA627(A or B) simply won't work.

Let you try the AD843JNZ, and listen...  

[David Ellis]

Let you try the AD843JNZ, and listen...  

I ordered a couple of them from DigiKey.  I'll post my comments in a few weeks.  They were more expensive than the BB2604 so maybe the AD843JNZ are actually better.  I also have some LM opamps that I need to try.  

Thanks for the tip.

[nai02fungoid]

Luxman R117, Luxman LX104 or a Linn Klassik.  All work great.  Only problem is when the CD has really low bass.  The woofer looks like it is going to come right out but it doesn't.  Might need to add a sub at some point to get the full deal.

[teiki arii]

Let you try the AD843JNZ, and listen...  

I ordered a couple of them from DigiKey.  I'll post my comments in a few weeks.  They were more expensive than the BB2604 so maybe the AD843JNZ are actually better.  I also have some LM opamps that I need to try.  
Thanks for the tip.

I tried OPA134, AD845, AD847 and AD843...AD OPA are a little rough but "timbres" are very nice...but less "musical" than BB...IMHO.  

[David Ellis]

Luxman R117, Luxman LX104 or a Linn Klassik. All work great. Only problem is when the CD has really low bass. The woofer looks like it is going to come right out but it doesn't. Might need to add a sub at some point to get the full deal.

It's not the amplifier, it's the recording.  I have a choral/pipe organ piece of music that does this too.  The frequencies are probably in the 20s.  The woofer oscillates, but it doesn't cause any problems.  The music sounds wonderful.  

But... yes, a good sealed subwoofer would deal with these frequencies much better.

Dave

[avahifi]

If an AD847 worked, then I suggest you try an AD817.  This device has a much larger output section die and thus has less thermal modulation feedback at low frequencies.

Thermal modulation feedback in an IC is when the output (current gain) section generates heat driving a load, especially at low frequencies, and because the tiny bits in an IC are very closely physically coupled, this heat is then fed back into the front end (voltage gain section) and this modifies its linearity.  This is a very undesirable thermal feedback loop that screws up bass performance in particular.

Frank Van Alstine