[justin w.]

2020 Update: upgraded Aristaeus power cable now available. See this post for details: Post #119

The enclosure parts for the Aristaeus electrostatic amp arrived back from the metal finisher today. I'll have to laser engrave them, and then can start assembling the amps.

This batch is sold out, but I will have a few more available in Q2 of this year.

 

[n3rdling]

Can't wait

 

[kiertijai]

Me too,
@Justin : I am ready for the remaining payment especially after
this weekend (Chinese New Year) when I receive the red envelope
from the relatives.

 

[Mossback]

Great news, thanks Justin.
 
can't wait to get both the BHSE and the Aristaeus.

 

[kiertijai]

@Justin,  Can we use the 12AT7 or 12AU7 instead of the 12AX7 or 5751 for the Aristaeus?

 

[kevin gilmore]

The front end circuit has local feedback, and the phase splitter has values
designed for a 12ax7.  The 12au7 is going to have less gain and the
phase splitter will be off in one direction, and the 12au7 has too much
gain so the phase splitter will be off in the other direction. So unless
you want to mess with swapping out parts, use the tube the circuit
was designed for.

 

[kiertijai]

Dear Kevin,   Thanks for the info.  I think the 12AX7 is the tubes and the 5751 should be OK too , is that correct?

 

[spritzer]

The circuit was designed to use ECC83/12AX7 so use that and only that.  The 5751 is not the same tube and doesn't have the same specs. 

 

[HeadphoneAddict]

Quote:

The circuit was designed to use ECC83/12AX7 so use that and only that.  The 5751 is not the same tube and doesn't have the same specs. 

I thought the biggest difference was the lower gain of the 5751, but in return they give better micro-detail and transparency than a typical 12AX7.  I know in my ZDT Craig says the 5751 are interchangeable with the 12AX7, but says the amp is not biased right for the 12AU7.

 

[kiertijai]

I am a little bit confused here because before this blog was moved from the Headamp BHSE several
members suggested about the 5751's especially the Sylvania's gold brand black plate or grey plate gold pin.
I think Justin also saw that but he did not comment that the 5751's can not be used.  We all know that the 5751's
may have less gain but less noise , better microdetail and transparency as said by HeadphoneAddict

 

[kevin gilmore]

I'm pretty sure there is enough adjustment range on the phase splitter to work with a 5751.
But it is going to require adjustment when you switch to that tube. This is not an open loop
amplifier and the changes in the input tube are going to make far less difference than
in other amplifiers.

 

[justin w.]

Quote:

I am a little bit confused here because before this blog was moved from the Headamp BHSE several
members suggested about the 5751's especially the Sylvania's gold brand black plate or grey plate gold pin.
I think Justin also saw that but he did not comment that the 5751's can not be used.  We all know that the 5751's
may have less gain but less noise , better microdetail and transparency as said by HeadphoneAddict

someone had sent me a 5751 years ago to test in the Aristaeus and it actually had more noise than the new production JJ 12AX7 i am using.  the specs of the tubes 50 years ago really don't apply anymore.  sorry i don't remember if there were other issues with that particular tube in this circuit, i would have to look at it again.

 

[spritzer]

The 5751 does indeed have lower mu than the ECC83 but there are other differences needed to bypass the ECC83 patent.  Same story as with the 6CA7 vs. EL34, similar but not the same. Now the mu is a critical factor in any electrostatic amp so the front end of the amp would have to be adjusted and you need proper measurement equipment to do so. 

 

[n3rdling]

I love being a non tube roller.  Life is much simpler.

 

[kiertijai]

@Kevin, Spritzer, Justin : Thanks for the info.  Like n3rdling said I love being a non tube roller.  Life is much simpler.
I may go with his direction but I need to manage the 5751's that I have, I may ask my Thai friend to do the job for me.
Life is definitely harder  and more expensive but may be more fun