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REVIEW: Sort of Epiphany:  Old ZEN SE84Bs are (Read 5180 times)
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REVIEW: Sort of Epiphany:  Old ZEN SE84Bs are
07/01/07 at 18:55:34
Dear Readers,

I am a long term owner of DECWARE:  SE84A's.  Made in 5/98, Modified by Update Kit 9/99.

Recently removed from a year in storage, no real problems.  One amp had a slight static hum...determine litz ground wire was loose at the input jacks...

Review and Sort of Epiphany.

I have had a lot of time with these and has another person who borrowed them for a while.  We tried every tube imaginable, EL84:  from Telefunken to Mullard to SV83's.  Same for the input tube, even a ECC85 Telefunken.

Here is what we determined, over 10 years the bias switch, while the units were stored got noisy.  We fixed this with a quick shot of Caig Deoxit.  The Best Rectifier was the 6106 Bendix, the best output tubes were the Telefunken EL84s followed by the Mullard with the round hole in them and smooth plates, the Telefunkens were completely smooth plate; then the AGED, 9 years SV83s.  We finally wire them as per the user manual with each as a monoblock.  Series the left right neg/pos and use the remaining opposing + /- as the leads to drive the speakers.

Now you would think that the monoblocking would have sounded better, the room EQ'd and treated to almost flat (Phonics - Mike analyzer 31 band)....BUT, they sounded dry, stale if you will and no width or depth.  Now these are your fathers SE84A-B's brushed aluminum chassis and silver painted power transformers:  SE84A 40 and 37 Serial #.

Nothing was altered in the Power Supply except a nice Black Power Resistor was used across the LCR Caps as provided by DECWARE in 1999.

We went back to just a single SE84B.  Stereo....WOW....amazing.  Why bother with Monoblocks for decreased crosstalk and balance...it actually made the magic disappear...only when we went to a single SE84B in stereo did the magic come back...

The Driver was both a Tjoeb 99' with top DAC Chip and Siemens 7308's, courtesy of Upscale Audio and the infamous ZTPRE, both with and without the ANODE/Cathode Mute Switch - a Mute Resistor; YES we had rebuilt the external power supplies as parts provided by Decware and we paid for...the hum was very annoying.  Once we got rid of the dual mono PS transformers the HUM went away.

Now why this review and why the list of gear.

The speakers were Klipsch Forte II's originals...amazing, now the Epiphany; for grins we replaced the AMP with a vintage 1999 B&K ST1400 - Series II with of all things a 1978 PREOUT Pioneer SA-9500-II...using just that tone supply so we could get the room right...the Tjoeb connected into the AUX and then into the B&K on a separate listening test.

Well, I have to say after a ton of music and days and hours later I really liked the B&K, yes solid state; width of field, tone, bass....the owner and the owner of the ZTPREs and ZenSE84B's was shocked, I mean shocked...

Then as a 3rd test we installed a Antique Sound Lab Tulip with both 45's and a 5R4GYB and 2a3's with a Mullard 5AR4...shocking again...so much so we rated the ZENS last.

So why say all this? Well buyers and users need to know a long term ownership perspective.

We are probably down the list of original buyers and yes we paid full boat retail for the ZTPREs and the SE84A-B's + all parts...probably near $3400.

The gear certainly lasts and Decware support is great, but honestly I think I found better sound.

No we can't try the latest gear, no $...but I will say that the B&K with the Pioneer was a revelation and an epiphany.


ZEN SE84B on it's own with the Tjoeb probably the best but almost passed by the B&K.

As a side note we are keeping the B&K as a backup to the ZENs.  These amps have been stored in 3 storage facilities and around the world...they work no matter what...the loose Ground wire was a gotcha that a scope, speaker and chockstick found.

FWIW and your mileage may vary. These are just opinions and the results of a lot of testing and listening.

Yes we have access to just about any gear and tube combination, but handsdown the ZEN's Contrary to everything you have been told DO PRODUCE BASS...

We found a slight attenuation at 90Hz, but down to 30Hz no issues, remember the Klipsch Forte II was tested by Julian Hirsch and he found them to have the lower measurable bass of any speaker.  We even put them on a pair of old 1956 Jensen triplex - WOW.

I hope someone somewhere finds this both useful and interesting.

I just love that B&K...what an amazing solid state amplifier.

Oh, one last note: Cit II H&K was tested as well as Dyn MKIIIs rebuilt, again the monoblocking and the Citation provided a clean sterile presentation but again lacked the fast lush midrange of the ZENS on the RIGHT - Correct speaker.


PS.  Steve knows exactly which amps these ZENS are. Wink  They have been on original tubes for a long time...almost 10 years.

Not on all day mind you a few years in storage.

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« Last Edit: 07/01/07 at 19:01:59 by johndoe »  
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Re: REVIEW: Sort of Epiphany:  Old ZEN SE84Bs are
Reply #1 - 07/02/07 at 02:18:45

Just for kicks, would you mind mentioning what sort of music was listened to, preferentially? And also, was all the listening from your Tjoeb cd player, or did you also give vinyl a try?


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SE84CS (vcapped), CSP, zbox, Dec685, ZP 1.0, Sota tt/Well-Tempered Arm/V15XMR, Parker 98's, Parker Audio *Power Chords*, cat 6 wires, OSX; a garage sale of other stuff...
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Re: REVIEW: Sort of Epiphany:  Old ZEN SE84Bs
Reply #2 - 07/02/07 at 15:03:46
Senior member,

Glad to.

Just the Tjoeb and an OLD Pioneer TX9500-II Tuner.  No Vinyl.  Belt melted in storage - LONG STORY.

Vinyl would have been a treat, no $ for that.

We listened from a pool of 800 CDs:  Everything from Choral, to Classical Orchestra, Violin Concertos, Organ, Jazz, 50's and smooth, ROCK, Electronic, etc....

This guy has a large CD Collection.

I think Jazz like Miles Davis and Oscar Peterson sounded great.  Also, Classical.

Rock was Awesome, but I am not into ROCK.

I was suprised at the BASS on the ZEN once we had a speaker that could actually produe the bass.

One note the Tjoeb was high output more than 2V - lots of gain...the ZENS never clipped...but again the whole monoblock experience left us puzzled, it was BLAND.

Not sure why, but once we got back on the single ZEN with the shared Channel to channel LOCK Resistor and bypass cap. it seemed to GEL (if you pardon the adjectives).

I hope this is helpful and it's of some interest to someone.

Again, the B&K simply put was amazing and I have to say I honestly really liked it.

It ran warm, Middle/High Class AB but stilll, nice.

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