I’m still Trying to understand the decware mono capabilities.

Can you run two Sarah’s in unbalanced mono and still have it excel with doubling the power? Or is that only for balanaced mono configs is where one would get double power output and 6db gain per channel together with SQ gains?

My unit shipped--no tracking number yet but probably early next week.

Awesome! Now the hard part…::trusting the carrier to not only mishandle it, but also get it to you yesterday lol

Woohoo! Looking forward to your updates!

Listening with about 2.5 hours on the amp now. As this has no Treble Cut Circuit I rolled some tubes to get a mellower tonal balance. I put in a Cunningham Globe Type 80, two RCA 7308s and a National 5963 that Steve had sent with one of my ZROCK2. And I put a Bugle Boy 12AU7 in the ZROCK2.

I feel I can sense the "MiFlex sound" as compared to the Jupiters in the SEWEFUO3s.

Very nice tonal balance now as everything begins the break in process.

Two things I'll note: I have never seen nicer tube sockets. Wow. And the copper transformer end plates are beautiful.

I'll keep posting impressions on this page for a while. No pics though. I"m not a pic person. I don't own a camera though there is one in my flip phone. . . that does not connect to any othere device.

it was operating perfectly and sounded great but I got restless and rolled two other rectifiers in since then. I got the idea to try it from one of Steve's pictures where it seems to me he has a Type 80 globe but it's probably another tube type.

It's going to be hard to find the right combo that will make me not wish I could reach for my treble cut knob. . . but that's just ME.

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IMO a lot is going to depend on what way your 300B tubes go when they break in. Mine started dark and added some high end sparkle with more hours. Other types (in other amps) seem like they start out bright and brittle and mellow out.

Good point. I have no other 300B tube experience to compare and I know that in a few weeks things will begin to be settling in on a direction.

In the meantime I'm just going to keep listening as I do.

I researched the tube going in--I have been all over that website-- and I think it may turn out fine, we'll see. I'll be doing tuning along the way. My audio budget has changed, I won't be buying 300B tubes for a while.

I know, huh. Too expensive to be ripping through too many of those!

I’m glad you guys will be the early adopters. Thanks for taking one for the team!

I don't think it's about the resistor as much as it is current. I have plenty of more compatible rectifiers to try and I'm not in a position to buy more Sophias etc.right now. I'll find just the right one to go forward for now. I'm listening to another RCA 5V4G right now, these are very good tubes. I have to remember that the voltage regulation and output tubes I'm using are all new.

Thanks Tony and Kam. This is a great amp, I can tell that already . . . with 8 hours of play. Starting the seventh hour.

Thank you my friend. I wish today I could fast forward 600 hours or so just for a few hours!

Yes, I remember similar experience with Sophia Electric 274B. Which is why I was so totally surprised that the first thing that happened was an Aqua arced and blew a fuse.

Is yours an Aqua?

I could try it again. If I wanted to risk another Aqua. I don't know. I'm going to ponder it.

Thanks. I may risk another one later.

Thank you. Yes, it seems the Aqua II is a safer choice. And supposedly sounds even better.

Lon,

Glad your are learning your new amp and getting some exciting results so early in burnin. I enjoy your tube experiments.

I thought Steve making those cool/layered and lower value first caps would cause this amp to be notably more flexible in terms of capacitance effecting rectifiers negatively. Not willing to dig through the thread just now to verify, but isn't this what you remember, that the net of those smaller caps was a pretty low value first cap... like a fraction of 47?

If I am remembering this correctly, seems your thought that is it not capacitance that blew the Sophia, and CAJames ideas about 300B current requirements might be worth exploring some. I have not measured current on the 300B I am playing with, and no doubt Steve's circuit is different, but the inrush voltage on mine is about 530 volts, which eases off to the mid to upper mid 400s for B+, and the higher 300s on the 300B plate with the cathode resistor. Just suggesting these big tubes may be different in flexibility for rectifiers than our other amps, even though Steve always seems to give us really good flexibility??? Or maybe it was just coincidentally a weak rectifier... something that seems to be a thread in the past for some Sophia Aqua users.

I am having fun with my now pretty old 300B, gradually tuning out its, for me, somewhat slowish/darkish euphonic qualities, making them less apparent with more resolution and speed, but still present. I get the sonic interest in the type though... pretty compelling that big tube sound!

I am blown away how loud it plays compared to my Torii. What is up with that? I mean it is not as loud before notable distortion, but feeling (not measured) close to the Torii here, and supposedly less than half the wattage. Could this be a big SE tube thing?

Do you have thoughts about how different rectifier electrical values can effect a 300B tube lifetime?


EDIT: assuming the 300B cathode has a correct voltage?

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I'm happy to make something up .

I think the big factor in power tube lifetime is the operating point, how many watts the tube dissipates without any signal. That is usually set by the designer based on an assumed B+, but the actually B+ is going to be determined by the voltage sag of the rectifier. The more sag, the lower the actual B+ so the lower the operating point and (in theory) the longer the tube life. That also impacts how the tube sounds and probably varies (maybe considerably) from rectifier to rectifier even of the same type. I don't think the typical datasheet values like max plate voltage and DC current have a direct impact on power tube life, or at least not an important one compared to the variations in the 300B tubes themselves. That is assuming the operating specs of the amp are within the operating specs of the rectifier. If you exceed the limits of the rectifier that's much more of a problem for the rectifier than the power tubes.

This is all very much JMO/FWIW and all that.

Yes, I'm much happier to have just one fuse. When the rectifier went down it blew a fuse, when I popped out the fuse holder it is like those I am used to seeing in the Decware components, an active fuse and a spare in a holder, the exact same fuse holder as in the other Decware components I have. (With the exception of the ZTPRE and ZLC, both of which have two large fuses . . . I'm using two Purple in ZTPR right now and two Blue in the ZLC). I've asked Steve about the fuse/fuses here, as the product page, the manual and some posts here mention two active fuses.

I just put one of my "younger" 6085 in the input spot and am liking what that is bringing. Gave me a dash of warm smoothness as well as a bit more of a 3D image. I am not surprised--these tubes amaze me, I have six in my ZTPRE.

Junker, I guess you are using the newer one now?

Lon,

Is that a Holland Phillips E80CC/6085? If so, I get how that could ease you closer to your preferences. The ones I have are full, rich, and resolving throughout, but I tend so far to find them a little too warm/full for my tastes while highly apprenticing the quality. I have been liking some Mullard made E180CCs in my setup more off and on, in the ZR2, though probably not as completely a great tube.

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I think it is very real, but also out of your control. The designer chooses the operating point and your choice of tubes only changes that on the margin. The good news is it isn't an issue for any reasonable commercial product. An amp that operates outside the 300B (or any power tube or transistor) comfort zone is likely going to be highly distorted and almost certainly sound terrible. So long as your amp sounds good you're OK.

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Is the guy the designer/builder of the amp? I suspect it is much more because the 5U4G is the burliest of the common rectifiers and the least likely to fail on powerup, like Lon's 274B. Same reason Steve supplies the 5U4G with Sarah. Some designers are also very, how would you say it, proprietary, about their amps and feel like they should be operated just so. But you understand the risks and should feel free to make your own decisions.

Hey Junker,

Sorry, I was meaning which Sophia are you using. In my "new" 300B this is first time I have fully appreciated what I guess is the right hand version of the Sophia Aqua 274B in your pic. This amp has a 50 uF Wima Film cap for the rectifier, and those earlier, tubes I bought several years ago so far are working fine.

I am not using a 274B Will. I will not have my Sarah for a considerable time, and my Shindo Apetite is not tube rectified. The First Watt SIT-4 is solid-state.

Kamran above in post #1020 cited that the original Aqua was improved in 2016 to support a 47uF capacitor / in-rush current.

Hey Junker,

Oh, I understand... sorry I did not get that before. Yes I am pretty sure mine are the same design type as those Kamran is talking about, the version before the more recent 274B Aqua IIs, but having been modified from original 274B perimeters to supposedly tolerate 47uF caps. This tube has had some folks captivated, and some disgusted for costing as much as it did, and not lasting very long in some Decware amps with 47uF rectifier caps. I wonder if the new Aqua II that is supposed to be higher current as well will solve this thing of some being fine and others not so.