[Anaxilus]

I think you feel that way w/ the 009 because it actually might even be harder to drive.  The 009 can really transform as well.

 

[kiertijai]

I don't think the SR009 is difficult to drive and the Aristaeus amplifier should do very good job on SR009.
That 's the reason why I may try the 5751 which has less gain (by 1/3)  than the 12AX7 and the Sylvania
gold brand grey plate may be good because of its lushness. I may also try the NOS GEC B759 for 009, but I
will keep that for a while because B759's are more expensive and more difficult to find.
The most difficult phone to drive is the O2mkI and I think it may need the BHSE or DIY T2 to drive effectively.
I will get all the mentioned phones by the middle of next week : HE90, O1, O2mkI, O2mkII, HE60, SR009 and try with the Aristaeus
and DIY T2.  I may also bring those to the second Thai Canjoin meeting during the third week of May in Bangkok along with
the second batch of super7 and Px25 modified Balancing Act.   At that time we should have more info on the Electra and Electra SE.
The Electra SE  design is now completed and its prototype is due at the same time of the production of the Electra standard version.

 

[Maxvla]

i assume your question is pointed at me.

having read the iconic reverance many have for the HE90, and seeing the wacko price they sell for, i'll take the 5th on your question....not wanting to push buttons. i've not heard them so i have no opinion on whether they can justify thier price and reputation.

if, at some point, i actually hear the HE90 and they blow my mind, then i guess i'll have to seriously consider owning them.

If you ever go to a meet where Ray Samuels has a display, he carries a pair with his setup you can ask to listen to. n3rdling also has a pair if you go to some of the California meets.

 

[Anaxilus]

Electra is balanced OTL, SE is hybrid.

 

[Anaxilus]

Quote:

I don't think the SR009 is difficult to drive 

 
Maybe, maybe not.  But the difference in dynamics and character of the 009 from an amp w/ ballz to an amp with less is quite substantial.  The BH is just too thin and slow w/ the 009 for my tastes.  So however anyone would like to explain the difference feel free.  Maybe it's output impedance again, the objective answer to everything.  

 
 

 

[Beefy]

 
Quote:

That 's the reason why I may try the 5751 which has less gain (by 1/3)  than the 12AX7

Gain has NOTHING to do with drive power.

 

[kiertijai]

That 's the reason why I may try the 5751 which has less gain (by 1/3)  than the 12AX7

Gain has NOTHING to do with drive power
 
Thanks for the info.  that makes me more comfortable to use? 
 
Electra is balanced OTL, SE is hybrid.
   Yes I was informed that the Electra is OTL while the Electra SE is TTL

 

[Beefy]

Quote:

that makes me more comfortable to use? 

No, that is not what I am saying at all. You have been advised against the 5751 by spritzer AND justin - you should heed that advice.

 

[kiertijai]

No, that is not what I am saying at all. You have been advised against the 5751 by spritzer AND justin - you should heed that advice
   OK , thanks I will not try the 5751 at present.  According to the previous post I think Justin will go back and try but he does not provide more info.
Again it's quite confusing to me about 5751's use.
   I think my comment about the use of  5751 should not be pursued until we hear more information from Justin.
 
I will try the Mullard 10M with the SR009 later if I want the sound to be more lush.

 

[spritzer]

Changing the JJ input tube is a terrible idea in my book let alone using the 5751.  The JJ was tested recently in that circuit and it has a lot less noise than any of the "nos" tubes measured so why waste money on inferior tubes?  If you choose to roll the driver then you have to adjust the phase splitter and for that you need a signal generator/scope to adjust for equal amplitudes. 
 
I'm glad you guys are liking the Aristaeus though since I'm very close to finishing my own take on the same design.  Different tubes used but otherwise pretty similar. 

 

[pachku]

Looking forward to your impressions -

   
 
Don't know a thing about phase splitters, but I like the sound with the Mazdas better than with the stock JJs, and in my book, that's what counts 

 

[spritzer]

The phase splitter does just that, split the "+" input into "+" and "-" to feed the push pull stages of the amp.  This needs to be adjusted for the amp to be perfectly balanced. 

 

[kiertijai]

I now have tried the Aristaeus with HE90 and SR009.   I did not know that there should be
specific postions of the Siemens ECL86 and JJ ECC83S as I was not informed (although I specifically
asked Justin) about the proper use of the Aristaeus.  I also did not receive the rebiasing tool.  However
the sound from the Aristaeus is fantastic.  I found that changing the JJ to Mazda 12AX7s (not 5751's) helps
tone down the brightness of JJ to my preference.    As Pachku mentioned , with the use of Mazda's the SR009 does
not sound bright even I played the music by Chinese female singer.  The SR009 sounds beautiful and comparable to the HE90
However  I still feel that the HE90 is more engaging , more dynamic and more gentle.  I hope that 's not psychoacoustic
and it cannot be blinded as I can tell the differences of the feeling of the earpads and headbands.  Using the Aristaeus
driving the SR009  may be a little bit underpower in my opinion as I need to increase the volume 1-2 steps (DACT volume atteuator)
more than the HE90.
I have received the DIY T2 from Chinsettawong so I have tried the SR009 with the DIY T2 using the Philips EL34 XF3 + Siemens CCa.
Now it's a perfect match as the DIY T2 drives the SR009 excellently with authority, composure and gentleness .  The SR009 does not sound bright
at all  in this setting (while the previous use with Stax 727A it is more forward and bright).  I am now listening the "Planets" by Gustav
Holst: Zubin Mehta and Los Angeles Philharmonic Orchestra XRCD24 : Jupiter; the bringer of Jollity with great Joy.
Next stop I will try the Philips EL34 metal base + Telefunken CCa (or Valvo CCa pinched waist or Amperex 6922 pinched waist) which
Chinsettawong recommends that those are probably the best

 

[justin w.]

Since this is the thread about building the amps, and they have been built, it would be nice if you could post the impressions in the main forums.  Thanks

 

[kiertijai]

Just a quick note before I will try to post into the main forums after some more critical listening.
I have just tried the GEC B759's which are considered as the Holy Grail of the 12AX7's.  I was highly impressed when
I heard the JJ or Mazda in the Aristaeus with the HE90.   I am really excited and involved when I hear the B759's although they are
not perfectly matched. There is no noise even at high volume.   The sound is fuller, the soundstage is very wide , the mid is very sweet, the dynamic
is the best , there is excellent detail.  The JJ's may seem a little bit bright and the Mazda's may not be as exciting as JJ but the B759's
leave both JJ's  and Mazda's in the dust.  The B759's will stay in the Aristaeus for now and I will try to rebias to get the best out of them.