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Amp Rolling with Active Jubilees


Ziggurat

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2 hours ago, Panelhead said:

  Please do not laugh. But try 2 Micromega MyAmp integrated amplifiers. Only issue for me is they only have RCA inputs. 

  Doubt if the bass bin needs more than 60 watts. If you do, that is shakin’.

 

I wouldn't laugh... all suggestions are valuable.

 

Having 200+ watts at hand did get me in a frac of hot water with my neighbor five houses down the other night..... 🙂

 

 

 

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7 hours ago, Ziggurat said:

 

I wouldn't laugh... all suggestions are valuable.

 

Having 200+ watts at hand did get me in a frac of hot water with my neighbor five houses down the other night..... 🙂

 

 

 

   Back when I had Altec horns, my nearest neighbor was at least 500’ away. She called at 2:00 am demanding to “TURN IT DOWN. Said her kids were crying. 

   That was with a lowly Carver Cube. Early 80’s. 

   Today I am sure one of those headphone amps or a 45 tube amp would be plenty loud. Seems that 1 watt gets plenty loud.

  The MyAmps surprised me. Purchased one because I always like Micromega products. And Accesories4Less was closing them out at 229.000 USD. 

  Matched up so good with LS II that I ordered a couple more. Tried stereo connection, balanced bridged, currently passive biamp. They are easy to integrate into system with active subs.

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  • 2 weeks later...
4 hours ago, Schu said:

Look for a pair of bel canto class D's... they have a dampening factor >1000

Dammit - a pair of those came up locally last week, "Bel Canto" sounded a bit fruity for me, so I passed.  Hopefully the Bryston's DF of 300 @ 20hz should be sufficient. 

 

4 hours ago, rigma said:

Ziggurat both myself and Mike use Jensen IsoMax transformers  near the input of the of the amp (within a foot) and have no hum.

 

rigma (marion)

Great info - thank you.  I have Deuland resistors arriving with extremely low inductance so I can build build an L-Pad with circa -12db to get the amp idle noise to near zero.  I think I mentioned the cheap resistors I have in there have taken a fraction of 3d effect out, hopefully the Deulands will be better.  Switching to SPDIF (optical) output on my PC has helped - no hard-wire connection to the downstream components.  The PC is the main problem, sending noise back through the AC, and through it's own outputs, it seems.  Time for a Bluesound Node 2i, methinks - get the PC right out of the system.  I will also run a couple of new, filtered lines from my switchbox which should help.  My house is old, and the wiring system is less than ideal.  

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6 hours ago, rigma said:

Ziggurat both myself and Mike [mikeTN] use Jensen IsoMax transformers near the input of the of the amp (within a foot) and have no hum.

 

rigma (marion)

Me, too...  The RCA analog-only connection into the First Watt F3 picks up a fair bit of common mode noise (power line 60/120/180/240 Hz hum).  The ISO-MAX reduces that noise floor at least 20-30 dB in my experience, even though my connecting RCA analog cables are just over 1 ft. in length. The ISO-MAX filter doesn't subjectively affect the sound quality at all.  They're a bit spendy however.  I recommend them highly, nevertheless.

 

All my other connections (i.e., seven other stereo amplifiers) are XLR/balanced and have no issues with noise floor.

 

Chris

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4 hours ago, Chris A said:

Me, too...  The RCA analog-only connection into the First Watt F3 picks up a fair bit of common mode noise (power line 60/120/180/240 Hz hum).  The ISO-MAX reduces that noise floor at least 20-30 dB in my experience, even though my connecting RCA analog cables are just over 1 ft. in length. The ISO-MAX filter doesn't subjectively affect the sound quality at all.  They're a bit spendy however.  I recommend them highly, nevertheless.

 

All my other connections (i.e., seven other stereo amplifiers) are XLR/balanced and have no issues with noise floor.

 

Chris

 Is this what you are referring to team?

Screenshot_20201211-142455_Chrome.jpg

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A quick update.

 

I've picked up the Bryston 7bst monoblocks and set them up to power the Jube bins. They took some time to fully warm up, but once they did, the rewards were very apparent...

 

The bass is now super fast, clean, dry, immediate - free of blurring. Really hearing seperate tones right down to the lower registers.. I even seem to have picked up a few extra hz! (Need to confirm this)

 

Again, the characteristics of these amps are considerably different to the other gear, with the closest comparison being the Macrotech. But the Brystons have an edge over the big Crown in terms of speed and clean edges...

 

I don't envy my neighbors tonight....

20201217_202024.jpg

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One of the things that I found with using the zero-phase crossover approaches is that, even after further FIR filters were applied to my surround array using Dirac, the reduction in phase growth (i.e., lagging phase as the frequency decreases) is flattened back toward zero phase, the perception of bass goes up, rather dramatically in fact.

 

Last year in the K-402-MEH thread, I posted the following figure from a tube amplifier (Mullard ECL86 amplifier, 3 w/channel, apparently single-ended, documented in 1962) that raised my eyebrows a bit:

 

art003gb.jpg

 

Notice how the the phase shift of the amplifier itself adds about 45-60 degrees of phase lead below 175 Hz.  This is probably some part of what you're hearing with your Bryston SS.  If you added FIR filtering to your Jubs using something like rePhase, Dirac, JRiver, etc., you would perceive even more bass response, in my experience, all due to the correcting phase shift back toward zero phase at low frequencies. 

 

Additionally, you'll notice that the phase lag at higher frequencies of this tube amplifier is compensating for some of the typical phase lead that you see above 10 kHz, another interesting effect from tubes. 

 

Now, if you ask me what I actually think about tube amplifiers, you might get a totally different response than you might otherwise think (I don't like them), I do see a couple of reasons why people think they're injecting "magic" into their systems.  They're also injecting something else that isn't magic (soft clipping is typical, especially for very low power SETs, etc.) that I don't care for, and a bunch of other nonlinear stuff that I would prefer not to deal with.  But if you're into "euphonic distortion" of tubes/valves, this is one effect that is no longer in the "magic" pile, something that's easily measurable.

 

Chris

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