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Amp Rolling with Active Jubilees


Ziggurat

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The only thing I say say for sure is that @mikebse2a3 (MikeTN) pretty strongly recommended the much more expensive ISO-Max, and when I found the loose cash to lay on it, bought it, and ultimately inserted it between the Xilica and the First Watt F3, the common mode noise (power noise) decreased from 20-30 dB--with no other artifacts.  You'd have to ask Mike what the tradeoffs are with these kind of devices since this really isn't in my comfort zone.  Mike has a pretty good background in that area, IIRC.

 

Chris

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5 hours ago, Chris A said:

The only thing I say say for sure is that @mikebse2a3 (MikeTN) pretty strongly recommended the much more expensive ISO-Max, and when I found the loose cash to lay on it, bought it, and ultimately inserted it between the Xilica and the First Watt F3, the common mode noise (power noise) decreased from 20-30 dB--with no other artifacts.  You'd have to ask Mike what the tradeoffs are with these kind of devices since this really isn't in my comfort zone.  Mike has a pretty good background in that area, IIRC.

 

Chris

 

 

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The trouble with the cheap($12.95) transformer type isolators is while they may help with the ground loop noise to some degree the signal integrity is very likely to suffer in bandwidth and added distortions.  

 

You simply can’t manufacture wide bandwidth high quality transformers for this purpose and sell it for $12.95..!!!  

 

It’s also very important for signal integrity and noise suppression that the design includes additional components as seen in the Jensen ISO-MAX units.

 

In some situations like going from Pro-Level signals to Consumer Level signals that a reduction in gain of about -14db is very beneficial at noise reduction for the system.

 

 

Examples: Here is the Jensen ISO-MAX  PC-2XR which offers a 4:1 transformer giving the often needed -14db gain reduction in some systems.

 

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Example #2: Jensen ISO-MAX  PI-2XX

This unit uses a 1:1 ratio transformer and can be configured if needed with RCA Single Ended Output if desired as well which will give more signal output for amplifiers with low input sensitivity for example like the First Watt F3 I have.

 

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miketn

 

 

 

 

 

 

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On 12/18/2020 at 1:54 AM, Ziggurat said:

I FOUND THE SOURCE OF MY HUM!

Joy of joys, and after just spending $200 on Deuland kitted L-pads. Idiot.

 

The USB cable between the Xilica and computer.... always plugged in so I can make Xilica adjustments.... unplugged, BINGO, DEAD SILENT amps. Very very happy to have finally worked it out. 

 

Seems silly, but I'd tried turning the computer and the xilica off individually and together, and not had any improvement - as such I never thought to try disconnecting them...

 

Anyone looking for a hot deal on 2x 5r7 and 2x 3r Deuland Silver Graphite cast resistors? 🙂

   Glad to see you solved your hum issue.  I recently had a similar experience.  I also run an active multi-amp system (using LaScala bass binds, ZXPC top horns and a MiniDPS4x10).  I had hum issues from day one.  Sometimes it was bearable, sometimes it ruined the experience.  I chased this down for years.  Swapped amps and cables, etc.  Was able to make some improvement, but it never went away.  I just kinda figured this was an unavoidable characteristic of running a complex, multi-component system with high efficiency speakers.

   I did notice, however, that the hum usually got worse when I turned my projector on to watch a movie.  Sometimes dramatically worse.  So I decided to buy another power conditioner just for the projector.  I already had a OneAC unit that I bough off of eBay powering my pre-amp and front-end components, so I decided to get another for the projector.  Being hospital cast-offs, they are cheap enough (~$50 each).  Lo and behold, when I plugged the projector in to the dedicated power conditioner, the hum vanished!  Not only did it vanish when the projector was on, but it was gone when the projector was off too!  The projector was creating a ground loop with the audio components, even when it was powered off!

   I now enjoy a nearly noise-less system.  You can hear just a touch of tube buzz coming from the HF horns if you stick your ear up to them.  Nearly silent from the couch.  I probably spent over $1000 swapping out components, trying to trace the noise, when all I needed was a $50 power conditioner!

 

 

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3 hours ago, Coytee said:

 

It's possible that the infrasonic waves.....  you know....  assist them when they need it.

 

Mere speculation on my part of course. :blink2:

 

Well, all my subs are on tables or the like.  I  figure that if I keep the deep bass to myself, it will be appreciated.

 

Oh, now I get it.  You're referring to the Brown Note, from South Park, of course.  I'd be doing them a favour in that case.

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