Coincident Frankenstein mk.2 amps

The Supremes are arriving today.  I wanted to add to my previous post as I was rushing and merely wanted to give an update.  As wonderful as the Dynamo was, the Franks are a huge upgrade.  What stands out the most is the perceived power, but the soundstage is enormous and all the instruments have more weight.  Dynamics are simply amazing.  Stop/starts in music are incredibly sharp and crisp.  Everything comes from a silent, dead black background.  Goosebumps are a regular occurrence.  I wanted to ask if there was a consensus on tubes.  What 300bs and rectifiers are being used?  I had a suggestion for Black Bottle Psvanes from Mr. Blume as well as a Mullard CV 378 rectifier.  I'd love to hear what everyone is using.  Thank you.

I copied @charles1dad and got the Mullard's and eml xls 300bs. Loved that combination. 

tswista,
The following tubes I’ve used and are superb in my Frankensteins.
Elrog, Takatsuki, KR XLS and EML XLS. In terms of sound quality you can’t go wrong with any of them. I’ve settled on the EML XLS. Absolutely reliable, very rugged workhorse type of tube with dynamic and authoritative yet very natural presentation.

As cal says I’m using the Mullard rectifier x the past 4 or 5 years. Excellent sound and no reliability issues.

Do you have any early listening impressions of the Frankenstein and Zu Soul Supremes formed yet?
Charles

@charles1dad Thank you.  In addition to what I described above, I can say that I never thought I could achieve this level of detail, drive, realism.  The sound is incredibly engaging, more so now than ever.  

The Mullard you are using is the CV378?  Mr. Blume wrote in the manual not to try tubes other than the 5u4gb, but he suggested the CV378, so I am a bit confused.  I have also read that the KR tubes were somewhat unreliable.  

The Supremes are amazing.  The DWs could get a bit etched or strained at times.  The Supremes are smooth on the highs, relaxed but extremely detailed.  The sound is fuller and it I feel it is more coherent from top to bottom.  Placement is very important.

What is my goal with replacing the tubes?  I really don't know, but I am always looking to improve the sound.  Being surprised by some new sound is something I enjoy immensely.  

tswista,
I’m using the Mullard CV 378 and as I wrote earlier there haven’t been any performance or reliability concerns. This tube and/or the 5u4gb will serve you very well. .

The KR XLS was loaned to me and as stated had excellent sound quality. I know that some KR tubes have had reliability issues and I don’t know the status of current production. I am not sure if this issue involved the XLS 300b. The early production Elrog 300b which I owned had durability problems (I had 3 pairs fail after only 4 to 5 months of use). Elrog has new ownership x about 2 years and are said to be very reliable now. I hope this is true as it’s a superb sounding tube.

The EML XLS 300b has earned a reputation for extraordinary durability and an exceptionally long lifespan. Some of their earliest versions that have gotten very heavy use are now approaching 40,000 hours without failure. This is an outstanding result. I believe that the Frankenstein can be a bit tough on 300bs but seems to present no challenge/problem for the EML XLS. I tried the EML mesh plate (beautiful sound quality) but it failed after a couple of months. It needs to be used in an amplifier with lower operating points than the Frankensteins.

It makes me happy to know that you’re getting "incredibly engaging" sound quality and realism with your Frankensteins/Soul Supreme pairing. I completely understand how you feel. Amplifiers really thrive with good quality high impedance easy load speakers (As atmosphere has  pointed out numerous times on this forum). Who knows, you may not ever return to the high power amplifier/low impedance difficult load alternative 😊.
Charles