Hey Guys,

I have an email into Steve to resolve an issue with my new ZMA amp.  After setting up the ZMA and CSP3 preamp I have a pretty loud, steady crackling noise in both speakers with any volume set past about 15-20%.  It was a bit unnerving hearing this after powering up the amp.  All four bias meters start moving around as well when I push the volume up.

I am hoping this is just a bad set of power tubes, as I'm dreading the thought of having to ship the beast back to Steve for repairs.

Any insights/thoughts from you ZMA owners out there in Decware land?

HK

Thanks Lon, very good suggestion.  Just called and left a voice mail for Steve in case he is in during the weekend.  He does like to talk on the phone.

HK

I will check on this Archie by running my CDP directly to the ZMA.  Sent Steve a video w/ sound to he can diagnose the problem and get back to me.  What service - on a weekend no less.

HK

Archie, ran the CDP directly.  Got a very loud buzzing noise, different sounding from crackling sound (almost sounds like popcorn popping loudly) with the CSP3 hooked up.  All the tubes are properly placed in the right position, I triple checked them before turning on the preamp and amp.

After Steve reviews the video I sent him, I'll sure to get a call.  I still have my 2 watt Zen amp and Eastern Electric preamp if something needs to go back.  At least I'll have music.

BTW, even at relatively low volumes I can tell this amp is going to be something very special when the tubes and caps burn in fully.

HK

Update: It's definitely the amp or amp tubes.  I put my little Decware Zen back into my system with the CSP3 preamp. Everything was quiet as a church mouse.  The CDP and turntable sounded great, they are not the problem.

HK  

Have you tried swapping the input tubes?  On my Copland push-pull, I had a similar issue few months ago.  Even when the volume was turned down all the way to zero, it made this loud crackling noise on one of the channels.  I also thought it was one of the output tubes, but it turned out to be one of the 12BH7's...

HockessinKid,

Way to keep a level head about the whole thing, impressive. I know the wait will be worth it.

JD

Steve and Sarah were as good as it can get with my repair. Heck, it was serendipitous for me. My ZMA came back better than ever (Steve gave me backlit meters, volume pot and new 001 serial number sticker and tweaks). It just needed beefier resistors for the meter's and a three year check up. Mine was the first one shipped, back in mid January, 2014.

Yes, you noticed at low volume how good this Amp is................ . I swear mine did come back to me even better. The check up/adjustments did her good.

Enjoy the journey.  My journey continues with NOS Platinum input and inverter tube rolling. I recently had a Pre in and decided to send back. I love my ZMA sans Pre. CSP3 is awesome though..... .  I had one for 27 months with my ZMA.

Hope it's back soon.   Enjoy.

HK,  So are things good now?

Well Kid, too bad you had to send it in but a cable problem is easily fixed...upgrade your cables  :)

A ZMA deserves some great ones!

My suggestion...start a thread to ask what other ZMA owners use and like. Mark.

PS...Lon and I both use Voodoo interconnects with our Torii's...his top of the line...mine the ones he didn't want and sold...
There may be a couple others who use them on the Forum.  But be warned, they are very expensive even used and they don't come up for resale often.  Believe me, I have been looking since I got the first pairs.

Thanks Lon.  I appreciate your suggestions and insights on cabling.  I will reroute cables to see if this eliminates the problems.  I currently try to keep my IC's perpendicular to my power cords, careful not to overlap them.  I also pulled my source equipment rack out a bit.  The wall immediately behind the rack has an encased, basement steel support pole.  With the IC's in close proximity, maybe the pole was acting as an antenna?

Oh well, I'll get it sorted out.

HK

My ZMA gremlins saga continues.  So, it looks like I have two issues.  First, unshielded IC's from source equipment to my CSP3 preamp are causing some noise.  This is easily remedied with some shielded IC's. Second, a continuous hum from the ZMA amp to my Omega speakers, this with no sources connected.

After trying a myriad of potential fixes for my ZMA amp hum (changed out input & power tubes, power cords, cheater plug, switched cabling, checked electrical outlet polarity, system swapping, etc.), Steve believes there is an intermittent problem with the amp.  It will be heading back to the bench in Peoria, IL for a second time.  If Steve can't repair it, he promised to build me a new one.

It's been frustrating to not find a solution.  The only saving grace is my little Zen amp keeps me in the music.  It may be a couple of weeks or so before I get repairs completed or a new ZMA back into my system.  Until then, happy listening everyone.

HK

Mark,

It's very loud and hum increases intensity with the volume.  

HK

HK...I had a mysterious hum with my ZMA as well.  I recently moved my entire system and it's gone.  

I know I have a ton of noise pollution RFI where I live, because it is amplified by my guitar amps and other audio equipment (powered speakers).  

My hypothesis is that the crazy cable situation I had going on in a tight space behind the system wasn't helping.  I also have a SuperZen amp, and it was impervious.  Not sure exactly what was going on, but it was definitely amp dependent.

Can you bring your amp to a friends place to see if the problem still exists there?

Sounds like your issue is worse than mine, but I feel your pain...

Dave

I am pleased to be able to say that I have found the problem with the amp and less pleased to admit I didn't find it during the original QC process and the second QC process when it came back. Turns out we omitted the bridging capacitor/resistor that connects the audio ground to earth ground. Just goes to show that when you're obsessed with finding something wrong with something it seldom occurs to you to look for what is not there.

Since the audio ground and earth ground are bridged together through the test equipment the missing parts would have non consequence during the QC process.  When these two missing parts are installed, I always check them to be sure they work correctly, but when they're not there and the amp still reads hum at -72.4dB...

This is a classic example of how I have learned literally everything I actually know. It's amazing how well memory works when large sums of money are involved.

Anyway, we'll get the amp back in the mail this week so you can finally start enjoying it.

Thanks,

Steve

Yay!  I have a quiet ZMA now.  Have just begun the burn in process -  5 hours on, 5 hours off for a few days.  Sounds great right out of the shipping crate.

HK

That's good news HKid....I can't imagine being without my Zen amp for weeks at a time. Enjoy!

So the ZMA with stock tubes has sufficiently settled in and for the last couple of weeks I've been auditioning some of Dave Cahoon's (Zenwave Audio) IC's with my system.

Here are my impressions:  The ZMA is an exceptional, musically satisfying amplifier.  It is absolutely quiet in my system, has perfect tonality to my ears, and creates an insanely accurate 3D soundstage driving my Omega Super Alnico High Output speakers.  

The sound from my speakers really opened up when I replaced my Reality Cables with Zenwave's offerings (D3 & D4 interconnects and SMSG speaker cables).   I can just hear so deeply into the music now.  It appears that the ZMA benefits from the best cables you can throw into the mix.

It's difficult for me to put the sound characteristics of the Mystery amplifier into words.  But to me what best describes this amp is the immersive listening experience you'll enjoy with decent source equipment and speakers.  You simply get lost in the music.  And after all isn't that what this hobby journey is all about?

This amplifier was a early retirement gift to myself.  Having worked in the non-profit conservation arena throughout my career, I just count my blessings people like Steve Deckert make such wonderful audio products that most folks can afford.  Sonic nirvana awaits - thanks Steve.

HK

HK,
Glad to hear all worked out with the ZMA.  I knew it would. When you have a product predicated on quality built by a company with a genuine desire to serve the customer, there really is no other outcome - other than good.  

I have the exact same speaker & amp combo as you and having about a month on my new Omega SAHO's with the ZMA, I couldn't be more pleased.  I still have and use my Monoliths and they are phenomenal with the ZMA as well.  They are serving a new purpose now and fulfilling it well!  The ZMA is magical.  And with the right combination of speakers and allied components, I can't believe that I don't have the best that can be - at least for my preferences.  Real, musical, dynamic... are the best three words I can come up with.  

I recently added a ZSB switch box to allow me to go direct from source to ZMA.  I previously ran everything through my Decware Ultra pre-amp but always wondered what it would be like to go direct.  I am very pleased so far.  But in all honesty, I have not truly decided which I prefer.  Now I tubed the hell out of both, and did so to achieve a synergy that I believe is the very reason why I am not quite certain - yet- which I prefer.  I purchased (8) Reflektor "Holy Grail" '75 input tubes.  I put a matched quad in the ZMA.  I then put a matched pair on the "mains" pre-amp section of the Ultra and another matched pair on the "mixed" section of the Ultra since the mains are routed through the mixed sections tubes to add some additional "tube love" as Steve puts it for 2-channel listening.  Those eight 1975 Reflektors, working in harmony between my Ultra and ZMA, is something special.  I get the benefit of riding the gain, but with a set of tubes that are perfectly matched between the Ultra and ZMA.  Had I not tube rolled in this manner, I am not sure my results would have been what they are.  I also put some Gold Lion KT66's in the ZMA and a PSVANE 275B in the Ultra.  Beautiful sound.  

I am actually hoping that I will like the direct to ZMA at least as much as the Ultra in between, since it is a simpler path and one that doesn't require the powering up of an ungodly amount of tubes just for 2-channel listening.  
The ZMA is the "bees knees" (and I have a Torii MK IV and had a Torii Jr.)  and I am so pleased with the sound the ZMA is able to create with Loius' SAHO's.  For now... I am perfectly content.  

As far as the "heavy lifting," the ZMA/Omega combo is a match made in heaven.  Now I can fine tune as needed with IC's, source components, etc.  As you know - or soon will know - you are never really "there."  It is always inspiring to once "be there."  But, it is that journey that we all enjoy so much.  So, I hope I never quite get there because the pursuit is too much fun. I am ok with 99.99%.  That 0.01% is enough to keep me motivated to continue on

Enjoy your most wonderful speaker & amp combination!