Coincident Frankenstein mk.2 amps

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

I ordered a pair of Mullard CV378s from Mr. Blume.  For good measure, I also ordered a pair of vintage RCA 5u4gbs.  When I scrape together the funds, I will either order a pair of Psvane Black Bottles or the Acmes, based on his recommendations.  @charles1dad I can tell you right now, that I am never turning back.  This may sound cheesy, but this path that I have finally come across has been a life changing experience when it comes to music reproduction.

@charles1dad  From what I understand, there are not many 6EM/A7 choices around.  I dropped in some NOS GEs and they were SUPER hot on the high end.  Almost unlistenable.  The amp came with RCAs.  Before I order a few backups, I wanted to see if you had anything to add.  Thank you.

tswisla,
My 6EM7 are the original ones that came with the amplifier, GE or RCA. Not exactly sure (I’m currently out of town). Which ever they are they’ve been fine and trouble free. The 6EM7 are very long lasting tubes. Mine are 10 years old. I had them tested about 2 years ago and they still tested as new. tswisla you’ll have no worries with the Frankensteins. They have been rock solid reliable while providing superb sound quality. You have the latest MK III model which is probably even better than my MK II.

At this early stage you have already recognized that the Frankenstein and Soul Supremes are a Splendid pairing. All you have to do is just enjoy your music and connect with it. Your sound will continue to improve as the amplifier’s transformers (and various parts) accumulate hours of use/burn-in. Same process is applicable to the speakers. I strongly suspect that your appreciation of your audio system with  grow as time goes by.
Charles