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AUDIO FORUMS >> General Discussion and Support >> early Decware opt's as in pre ufo
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Message started by Kahuna Jack on 08/17/23 at 00:40:57

Title: early Decware opt's as in pre ufo
Post by Kahuna Jack on 08/17/23 at 00:40:57

Ive poked around a bit but havent really found anything substantial on the subject. Google searches just bring up a bunch of negative posts regarding physical size .

and maybe Steve's the only one with accurate descriptive words of wisdom.

what could one get excited about pre UFO opt's ? collectability ? a warmer yet less detailed sound??? that kind of stuff.

there's gotta be some gold in that silver lining someplace. people prefer different sounds for various reasons

The classified section with a pair of early Rachels for sale got me thinking about this and I didnt want to intrude on the sales thread.

Title: Re: early Decware opt's as in pre ufo
Post by Lon on 08/17/23 at 01:42:41

There's a good bit of dissing and disinformation about Decware transformers out there.

I think one good source of info from Steve is on pages 10 and 11 of this Decware manual:

https://manualzz.com/doc/37360919/decware-se84ufo-owner-s-manual

Title: Re: early Decware opt's as in pre ufo
Post by CAJames on 08/17/23 at 14:59:08

I guess to me the biggest reason to be excited about pre-UFO amps is they can be upgraded to a current UFO amp.

I don't have any personal experience with any of the old amps, and certainly some people prefer the aesthetics of the white amps. But I've read many many post from people over the years being happy with the updates/upgrades Steve has made to the SE84 amps and I can't remember a single one regretting them.

Title: Re: early Decware opt's as in pre ufo
Post by Kamran on 08/17/23 at 16:47:35

What CAJames said. I was recently going through some old threads including when the UFO was launched and the feedback was almost unanimously positive. I dig the white aesthetic.

The only other mod that seemed to rival the UFO in popularity (or perhaps even more popular) was the Christmas Come Early mod. I had to reacquaint myself with it after Harley mentioned it in his Torii MKV review.

Title: Re: early Decware opt's as in pre ufo
Post by Steve Deckert on 08/17/23 at 17:02:16

The quality of the steel that makes up the core and the number of laminations is what determines the size of an output transformer for a given power level. It is a 2 watt amp. What 2 watt amplifiers are out there being compared to a Zen amp? Even the original Decware transformers were make from US grain-oriented silicon steel with lots of laminations. To put this in context, a low grade steel used to make a transformer core would be a fraction of the cost and usually over double the size to achieve the same power level at the same bandwidth. So when you see amps with great big output transformers it could easily mean they are lower quality. Many audiophiles are programmed that bigger is always better.

Title: Re: early Decware opt's as in pre ufo
Post by Kahuna Jack on 08/17/23 at 17:24:21

" I guess to me the biggest reason to be excited about pre-UFO amps is they can be upgraded to a current UFO amp."

Understood fully. But there's also a rich history of people "modding/upgrading" things only to rediscover the magic of original components years later.

part of this curiosity is that there are a few older Decware amps available locally and a 'shootout' comparison is poking me.

Title: Re: early Decware opt's as in pre ufo
Post by Kahuna Jack on 08/17/23 at 17:29:28

"Even the original Decware transformers were make from US grain-oriented silicon steel with lots of laminations" says Steve.

see? that's a seed. Just need some soil, a pot and some water .

Title: Re: early Decware opt's as in pre ufo
Post by Lon on 08/17/23 at 17:40:03

I dig the white chassis plate as well. But my new favorite is the SEWE300B color. Gorgeous in person.

Title: Re: early Decware opt's as in pre ufo
Post by Dominick on 08/17/23 at 18:15:45

I run a pair of SE84C+ white amps in a mono configuration. One amp has been fully upgraded with the UFO and 25th Anniversary mods, and the other one is still bone stock. I plan to send in the aforementioned amp for the full upgrades at the end of the summer.

The short answer … they are different in several ways. There is way more detail with the Miflex caps, and in the bass region the UFO amp is tighter. Also…to match the volume levels… the stock amp needs to be set a bit higher than the UFO amp.

IMHO…once you hear a UFO amp…I don’t think you would want to go back to a pre UFO amp in a side by side comparison. But in their own right….the SE84C+ and the CKC models are great sounding.

Dom

Title: Re: early Decware opt's as in pre ufo
Post by Kahuna Jack on 08/17/23 at 18:49:52

"IMHO…once you hear a UFO amp…I don’t think you would want to go back to a pre UFO amp in a side by side comparison."

Valid point of view . BUT ??? do you know how many guitar amp techs in the 70s 80s even 90s ripped out perfectly healthy Mullards , Brimars , small bottle RCA 6L6's in amps just to 'freshn' up' the amp with a nice new set of new 'pick your country' made tubes? Sure there were some decent current tubes but check prices today to determine what people consider to be 'holy grail'

What if someday?.... people covet early white or gray Decware amplifiers for 'that sound' . Nothing wrong with having multiple choices in listening tools.

Title: Re: early Decware opt's as in pre ufo
Post by Kahuna Jack on 08/17/23 at 18:51:27

" But in their own right….the SE84C+ and the CKC models are great sounding"

bingo !

Title: Re: early Decware opt's as in pre ufo
Post by MikeinMontana on 08/17/23 at 19:40:43

..'Many audiophiles are programmed that bigger is always better." Well, hope my way better half never says that to me! [smiley=beer.gif] All the best everyone~ Mike

Title: Re: early Decware opt's as in pre ufo
Post by Dominick on 08/17/23 at 22:39:42

Kahuna Jack…so here’s where it goes a bit deeper to another level. I run both amps with the matched tubes. Matched vs non matched…that’s a separate topic….and CAJAMES says it best.

What I’m hearing by comparison is primarily a difference under the hood with different capacitors and the 25th Anniversay mods. What Steve does when you upgrade the amps….he gives you back the stock caps. So…if I wanted the original sound of the amp as Steve designed it back when it was originally released…. I could in fact bring it back to stock.

I feel that the upgraded amp is more resolving and allows more of the finer detail to come through.

The full upgrade that includes the UFO transformers, the capacitor upgrade, and the 25th Anniversay bypass mods, with a new tube set that’s mandatory if you do the warranty transfer is not cheap… it’s upwards of like $1000 dollars. So keep that in mind.

Dom

Title: Re: early Decware opt's as in pre ufo
Post by Kahuna Jack on 08/18/23 at 16:36:08

Dominick "Matched vs non matched…that’s a separate topic"

are you talking tubes themselves unmatched? or mono blocks with different transformers.

Larger often does seem to be better but smaller has been catching up for awhile now. In a collection of vintage tube amplifiers that sat in my shop ( early 90's ) there were a pair of immaculate pristine Fisher el84 monoblocks ( model 20? 30? ) just sitting there with factory paper tags on them,fully loaded with the stock bugle boys etc etc... not a single person ever asked about them as they were fixated on all the big boys ( 275's , Citation II's , Quads etc ) . I think today that may be a different story.

Title: Re: early Decware opt's as in pre ufo
Post by Dominick on 08/18/23 at 17:35:16

Jack,

Sorry….should have been more clear. I was referring to running matched tubes in my monoblocks in the previous post. Right now I have the UFO transformers in one amp, and the stock transformers in the other amp. I’ll be doing the full upgrades to the stock amp soon so they both match internally.

Dom

Title: Re: early Decware opt's as in pre ufo
Post by Rap on 10/26/23 at 21:08:15

Was nothing wrong with original OPT´s but many were and are running them in parallel mono and then there is the matching impedance to speakers to take into account... The original OPT´s were designed for lower impedance speakers so finding a good match was not easy. They could drive just about anything at 9.8k impedance but when doubled in mono that drops to 4.9k which is still a bit short of the 3-3.3k that is optimal for a 8ohm speaker to produce low-end.

Title: Re: early Decware opt's as in pre ufo
Post by Lon on 10/26/23 at 21:42:49

Mike: you two are a nice looking, happy looking pair. Cheers!

Title: Re: early Decware opt's as in pre ufo
Post by Steve Deckert on 10/28/23 at 17:24:25

The original Decware output transformers were and are premium made from OFC on grain-oriented silicon steel cores made in the USA. These premium cores and the fact that the amplifier is designed for 2 watts is why they appear small to so many audiophiles.

Non-grain oriented low grade steel would require nearly double the laminations (size) to achieve the same bandwidth without hysteresis losses which is also known as 'saturation'.

The difference between original Decware transformers, which by the way are proprietary, and the newer UFO transformers is in the interleaving. Increased interleaving gave even wider bandwidth and flatter response.

The original transformers came in 9800 - 6 ohm which would drive nearly a dead short since 9800 is almost 3 times higher than needed for the output tube and speaker impedance is reflected backwards through the transformer to the plate of the tube, so as impedance dropped so did the primary impedance of the transformer which allowed the tube to couple more power to the speaker. Additionally these transformers also came in 3300 - 6 which maximized power into higher impedances. The amplifiers were ordered with either one or the other.

When bridged into the mono, the output transformer secondaries are wired in series on a Zen Triode amplifier. This raises the secondary to 12 ohms which now operates with dual primaries and dual cores. Because a 6 ohm speaker is 1/2 of 12 ohms, each output tube would see a reflected impedance of 1/2 the primary impedance, except there are now two primaries, each taking half the load - same thing as they saw prior to the amplifier being bridged.

The UFO transformers feature a secondary tap that allows us to have both HI and LO impedance speakers at the flip of a switch.

Title: Re: early Decware opt's as in pre ufo
Post by Kahuna Jack on 10/28/23 at 21:01:22

Im hoping those older opt's dont get tossed. Maybe Steve you have a secret vault of them waiting for the day people crave some OG Decware butter on their pancakes : )