Forums - Tube rolling in SE84UFO25?

CAJames Seasoned Member "I've run every red light on memory lane." Posts: 2866	Re: Tube rolling in SE84UFO25? Reply #50 - 11/06/25 at 02:44:51 I actually like the GZ33 rectifier better than the GZ34, and last time I looked it was less expensive. But that was a while ago.
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Lon Seasoned Member "Love without guts is worthless!" Philip K. Dick Posts: 26845	Re: Tube rolling in SE84UFO25? Reply #51 - 11/06/25 at 07:45:50 It should, I don't think they were manufactured when I had a ZP3 years ago.
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Bluzrover

Senior Member

Posts: 51

Re: Tube rolling in SE84UFO25?
Reply #52 - 11/06/25 at 13:47:19

You’re right James, the GZ33 is about half, if not more, than the GZ34s I’ve found. I see a couple of the metal base GZ34s on eBay, all used, at a price I’m not willing to pay, especially with the “no returns” disclaimer.

What fascinates me about this hobby is how many options there are, but also how many folks continue down the path of experimentation even after they find something they really love!

Thanks for the replies gents!

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Sean

Seasoned Member

Posts: 386

Re: Tube rolling in SE84UFO25?
Reply #53 - 11/06/25 at 20:16:50

Upon CAJAmes recommendation awhile ago I picked up two GZ33's. I prefer the GZ33 in my ZP3 and GZ32 in the CSP and UFO25. The 32's bring just the right amount of bottom end for me. Another great tube if you need more low end is the 5v4, I've got RCAs and a Mullard. IMO, I'd give the RCA a slight advantage, the extra cost of the Mullard seems to be for the name only and not performance.

Honestly, one of the better sounding rectifiers I've used in the UFO25 was a Cryotone 5ar4. However, two of them went out to pasture on start up. Great sound while they lasted but I wouldn't buy another as there are more reliable options out there.

If you really want a good read, check out this super long thread. Warning: it's dated and some stuff you could have had for $30 back then is gone or very pricey but well worth skimming or deep reading.
https://www.head-fi.org/threads/dubstep-girls-massive-5ar4-5r4-5u4g-rectifier-re...

As for the other tubes I run these in my UFO25:
Sylvania OB3, Cryotone EL84, and an Holland made Amperex 7308.

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Bluzrover

Senior Member

Posts: 51

Re: Tube rolling in SE84UFO25?
Reply #54 - Yesterday at 15:45:33

Thanks for that Sean. That is a great read and, yes, amazing how much more expensive those tubes have become. Lots of food for thought, that’s for sure! I appreciate those of you have experimented with many of these tubes and are willing to share your experience. I’m not rich, but I’m willing to pay a premium for something that is going to make a big, positive difference, in the audio performance of this beautiful amp.

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Lon

Seasoned Member

"Love without
guts is
worthless!"
Philip K. Dick

Posts: 26845

Re: Tube rolling in SE84UFO25?
Reply #55 - Yesterday at 15:51:23

It's such a risky business as tubes sound different in different amps with different cabling and other factors, rooms treated or untreated, and according to differing individual tastes.

For instance I have 5V4 and similar British rectifiers that seemed great in one amp and turgid in another. I have found real synergy and reliability with Chinese rectifiers that were not available when I first started on this journey twenty-seven years or so ago when i then thought Chinese rectifiers were just awful and undependable. And I have found tubes such as Cryotone that are adored to be not to my taste at all.

And EVERY tube matters in this resolving and revealing components that Decware makes! I have had to find just the right signal, driver, rectifier, output AND voltage regulation tube . . . all influence the others and finding just the right ones is harder than Goldilock porridge picking.

I'm glad that now that my wife and I are both retired and not bringing in a lot of money to dispose of that I have found the right tubes for my systems and have a stock on hand. The exploration is fun. . . but finding just the right complements of tubes is even more fun, and letting them all season in and give their all gives great listening satisfaction.

Enjoy the hunt. . .if hunting is your thing! I hope all of us find just the right tubes for our systems. . . it takes luck and some skill.

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HR-1,ZBIT,ZROCK3,SEWE300B; Rega RP3 all GrooveTracer mods;PSAudio:PST+DSD, DAC Mk II,NPC,PowerBases,AC-12 pwr cbls, Reference spkrcbls; Mapleshade SamsonV3;VeraFi Audio cpts VooDoo:Cremona+Amati interconnects;Stack EQ; headphones:Sennheiser HD800S,ZMF Ori,Oppo PM1

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CAJames

Seasoned Member

"I've run every
red light on memory
lane."

Posts: 2866

Re: Tube rolling in SE84UFO25?
Reply #56 - Yesterday at 17:46:51

Quote:

Posted by: Bluzrover Posted on: Today at 07:45:33

...amazing how much more expensive those tubes have become...

The thing is people have been saying this every year for forever. 30ish years ago, in the early days of the internet I bought a bunch of lightly used Amperex 7308s for 10 dollars each, and at the time people thought that was "ridiculous." My advice to anyone who is #tubecurious, has been to get your tubes now because they will only cost more, and likely be of more dubious quality in, the future.

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[Volumio | Jay's CDT2 MRK3] -> Denafrips Terminator 2 + Gaia
Sumiko Pearwood -> Mapleknoll Athena -> Luxman SUT -> Mapletree Phono 3E
STR-1002 -> Woo WA22 -> 2x UFO25s, balanced monos
Omega SAM , Hifiman Arya, Audeze LCD-XC

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Sean

Seasoned Member

Posts: 386

Re: Tube rolling in SE84UFO25?
Reply #57 - Yesterday at 18:43:44

I should have added this to previous post...

Check out Will's posts here, he is vastly knowledgable and his posts are incredibly well thought out.

Also, when I got my first Decware amp I went haphazardly buying many different tubes. Some were great, a few were not. It really helped me to just put whatever tubes in and listen. Just listen. Take notes if that helps. Throw a bunch of different genres or styles of music at it, even stuff you're not really into. I found this to really help get an idea of strengths and weaknesses. Change ONE tube (or pair for outputs) at a time. Just ONE at a time. Compare/contrast each step. With infinite possibilities it really helped me focus on changes and how certain tubes interacted with other. It's a blessing how different tubes can change the sound in Decware products, but it can also be a curse! Force the patience and there are great rewards.

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Technics 1210G, Phasemation PP-500, ZMC2, ZP3, CSP2+, UFO25, Tekton Pendragon

Denafrips Ares 15, Mac Mini, Roon

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Bluzrover

Senior Member

Posts: 51

Re: Tube rolling in SE84UFO25?
Reply #58 - Today at 14:19:24

@CAJames, I hear you and appreciate your sentiment. I think that’s my sense of urgency here, both with starting the tube rolling experience, but also the exploration of the Decware tube amplifier world. I recognize that the number of these NOS tubes is finite and becoming harder and harder to find. And I’m late to the game. So paying a premium for a tube that many covet is understandable, it’s the way the market works.

@Sean, that makes a lot of sense and because I’ve become more and more forgetful these days, I’m definitely going to start a notebook. I have an eclectic collection of albums and, in my limited time thus far, have found that some albums are better sources for sonic exploration than others. I’m also learning that not all recordings are even close to equal. Clearly, in my youth I wasn’t quite as discerning, or aware. Great suggestions!

Again, you guys rock! I have been thrilled with the UFO25 thus far and anxiously, and somewhat impatiently, looking forward to further exploration.

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