Power to your digital amp

geofstro · « **on:** 3 Nov 2004, 01:29 pm »

Guys, I'm starting this thread in the hope that it could become a repository of information on the best way to get power to your digital amp.

It's clear from the tomes here on the JVC's and other low cost digital wonders, that their biggest limiting factors are their power supplies and susceptability to EMI/RFI. Both of which have lead most of us to look for solutions.

Actually I'm starting this thread for a selfish reason. Somewhere in one of these tomes someone kindly advised me on a good power conditioner to use and I've lost track of it. Anyway I think it could be useful to many of us to have a central place to gather this information.

My suggestions to kick it off is that it could include the following:

1/ Replacement power cord(what do you use/ how did you do it?)
2/ Any form of power conditioning used between the digital amp and the AC outlet.
3/ Any transformer, voltage regulator/isolation transformer used between the AC outlet and the amp.
4/ Filters employed on other AC outlets that seem to have improved the system in which the digital amp is being used.
5/ Any other methods of reducing EMI/RFI that have worked for you.
6/ Use of alternative power than the AC outlet, such as batteries. Or piles as they're called over here. Hope you don't have too many

In otherwords any additions/changes to just sticking the stock PC of your Digital amp into the AC outlet.

Any takers?

tianguis · « **Reply #1 on:** 3 Nov 2004, 02:44 pm »

geofstro:
Yesterday, I finished the first stage of upgrades to a Panasonic XR50. Most of your questions apply.
1. I installed a Furutech IEC receptacle, wired to the board with VH Audio cryoed 12AWG wire (shielded), which I also used to make a PC with Wattgate plugs.
2. I use a Transcendent Sound Balanced Power Supply. I've run the Panny direct to the mains for comparison. The BPS is a huge improvement.
3. Above
4. I use large Bybees on both output legs of the BPS, which I use to power all my audio equipment.
5. I live in the RFI capitol of the US, NYC. I have no issues with RFI, although I used to when using a 47 Labs Gaincard. IC's are the main culprit. I use VH Audio Pulsar cryo for both digital (> 1.5 m. long) and analog IC's, all with Eichman bullets. I've also tried Stillpoints ERS shielding on the Panny and can't hear any difference.
6. I've used external SLA battery power with the Sonic Impact T-Amp. It provides more punch than the internal batteries and is far more listenable than wall wart power.
I also changed the binding posts, removing some of the spring-clip junk that was there. I bi-amp, so have two sets. I also wired the outputs directly to the amp board with VH Audio cryoed hook-up wire.
The recent mods have made a HUGE difference, way more than I expected. Bass extension has improved dramatically, as well as becoming faster and tighter when driving Hammer Super 12's or noRh 4.0's. I haven't measured it yet. It's now much more detailed and crisp. I intend to do some cap changes as soon as I have the time, or can live without it for a bit!

Regards,
Larry Welsh

geofstro · « **Reply #2 on:** 3 Nov 2004, 02:49 pm »

Great feedback tianguis,

I've been looking into the issue of balanced power and most of the units are at the $2000 range, so your balanced conditioner seems like really good value.

For those of us here in Europe, though, or anywhere else that already has a balanced ac line I don't think there would be any advantage.

We Europeans are already getting the benefit of balanced power for free

(I think)

geoff

tianguis · « **Reply #3 on:** 3 Nov 2004, 03:32 pm »

Geoff:
Yup, I think you have balanced power. However, a BPS offers the benefit of isolation, which shouldn't be overlooked. Proper isolation reduces mains "hash" considerably. The Bybees virtually eliminate it.

Regards,
Larry Welsh

geofstro · « **Reply #4 on:** 3 Nov 2004, 03:59 pm »

OK, wouldn't a simple isolation transformer do the same thing though?

I agree the Bybees definitely sound like a good idea.

Thanks again

geoff

tianguis · « **Reply #5 on:** 3 Nov 2004, 04:31 pm »

Geoff:
Isolation is a good thing. In addition, BPS's offer filtering of one sort or another, which helps.

LW

cryotweaks · « **Reply #6 on:** 3 Nov 2004, 05:13 pm »

I know someone in the industry who is really up to speed on this. He owns a Sony ES unit with their proprietary digital amplifier, but his experiences should be valid here. He is fanatical about power conditioning, and below is what he uses.

1. Balanced power 3.0 (one small and one large xformer in one chassis)
2. UPS/voltage stabilizer like this one

In addtition, he really likes the Apogee Big Ben reclocking/upsampling unit. In fact he ownd TWO of these and runs the digital signal through both before conversion into analog.

Personally, I think battery power would be the ultimate, and with the efficiency of digital gear, it is becoming a possibility.

Cheers!

[/url]

Dmason · « **Reply #7 on:** 3 Nov 2004, 06:46 pm »

I think balanced power would be about the best bet investment for good quality power. I was using a medical equipment power regenerator and this seemed to be the ultimate, although it used an unethical amount of AC, and would be prohibitive to purchase for home audio use. PS Audio makes some and they can be had on Audiogon. Apart from that, the Transcendent BPS comes in a kit form which is extremely cost effective relative to what is out there.

I have replaced the power cord on each digital amp I have owned, Carver ZR, Panny 45, Teac, and now the JVC F10. I believe this change makes the biggest single difference, when used with decent power conditioning. The regenerator went back and I was left with a Monster 3500, which also does a good job. I know very little about this product except that this series seems to have a good reputation for design and effectiveness.

With the Teac, I addressed the Tripath RFI/EMI issue by lining the case with two layers of Al foil. This made a good difference as well. I think the Teac is the best overall candidate for optimizing.

AphileEarlyAdopter · « **Reply #8 on:** 3 Nov 2004, 08:11 pm »

I am using Blue Circle Music ring 1200 balanced power conditioner with my Panny XR50. The Music Ring has a VHAudio Flavor 2 power cord and the Panny a Empirical Audio older-model Magnum power cord. The wall socket has been replaced with a cryoed Hospital Grade outlet.
Power cord and Balanced power conditioner made a qualitative difference. Almost from mundane to close to fine sound.

Occam · « **Reply #9 on:** 3 Nov 2004, 08:26 pm »

Quote from: geofstro

We Europeans are already getting the benefit of balanced power for free (I think)
geoff

Are you sure? While your mains voltage is 220-240v (or whatever you EU folks have decided is your 'harmonized' voltage) this is not, I believe, two antiphase AC rails. It is not balanced. Though the higher mains does have benefits in and of itself, less current draw.

geofstro · « **Reply #10 on:** 4 Nov 2004, 11:48 am »

Thanks Occam,

So it seems from your post and Larry's there may still be benefit to us Europeans in Balanced conditioning.

I'm learning a lot here. Keep 'em coming.

geoff

lcrim · « **Reply #11 on:** 5 Nov 2004, 05:34 pm »

Last night I opened the Teac and found that the supplied power cable is wound around a circular magnet before connecting to the circuit board which presumably mounts the power supply.
My plan was to replace the power cord w/ one that is shielded and is bit larger guage wire. Some questions:
1. Keep the magnet or not?
2. Attach the pc shield to the Teac chassis?
3. Recommendation for a good but cheap and widely available three prong male plug (and a good but cheap and widely available cable for that matter.
TIA

mcgsxr · « **Reply #12 on:** 5 Nov 2004, 05:41 pm »

Good questions all.

If you go over to the Bolder Circle, and find the post there by Wayne, showing the interior of the Teac he modded for me, it shows that the circular "thing" is gone.

I am building a DIY power cord for this device, using Belden 83802, and a hospital grade 3 prong male end from Hubbell - here is a link to a similar one from Marinco.

http://www.takefiveaudio.com/belden_83802.htm
http://www.takefiveaudio.com/marinco%208215t.htm

mark in Canada

Occam · « **Reply #13 on:** 5 Nov 2004, 06:16 pm »

Lcrim,

Its not a magnet. It is a toroidal core (probably a ferrite, possibly and iron core) that forms [most likely] a CMC (common mode choke). Its principal purpose is to filter the crap generated by the swiitching power supply and to prevent it from polluting the powerline, FCC sec 15, etc...

geofstro · « **Reply #14 on:** 5 Nov 2004, 07:47 pm »

Although these things are reputedly susceptible to RFI/EMI, they ain't got nothing on my Fi X in that regard. For the first time last night I hooked up my FI X to my main system and got the local radio (or maybe TV) station loud enough for me to make out every word they were saying when I wasn't playing my own choice through the system, and loud enough to be instrusive on quiet passages.

Now I'm desperately seeking a way to eliminate RFI. Preferably cost effectively and without any detrimental filtration effects.

If anyone has any advice on this, I'll be very grateful .

geoff

lcrim · « **Reply #15 on:** 6 Nov 2004, 04:30 pm »

geoff:
I have turned systems into radio's a few times. I resolved the problem in the most recent edition by moving things around. Something in the chain acts as a receptor for a specific wavelength of radio signals. I moved a power supply for a phono section and a power supply for a TT to as far away from the amp as their connections would comfortably allow. This solved it in this case but I've read of people pulling their hair out because of this problem. It generally seems to affect a gain section but I'm reaching here. Good luck.

So, should I keep the toroidal thingy or not?

geofstro · « **Reply #16 on:** 7 Nov 2004, 10:58 am »

Larry,

Thanks for the encouragement. I was getting to the hair pulling out stage yesterday, so I went and got it cut

Moving things around is one thing I haven't tried. I'll give it a go.

Sorry I can't answer your question on the toroids, hope someone else can.

geoff

GBB · « **Reply #17 on:** 7 Nov 2004, 01:12 pm »

Geoff,
You need to do a bit of detective work to see where the RFI is entering the amp. It could be entering from the power lines, from the cable connecting the preamp, or the speaker cables.

So I'd suggest the following:

--- see if the interference disappears if the amp is used without the preamp connected. If you still have interference then its either the speaker cables or the AC

--- If the preamp cable test doesn't show a problem, see if the speaker cables are an issue. Try running with very short speaker cables and/or a different set of speakers. Obviously this requires moves the speakers very close to the amp. If this doesn't change the problem then the likely source of the problem is RF on the AC power.

The best solution is some sort of ferrite clamp on the AC line.

Hope this is understandable.

---Gary

geofstro · « **Reply #18 on:** 7 Nov 2004, 01:19 pm »

Thanks

With the preamp disconnected I couldn't detect it at first; but when I listened some more I could just detect it, so I guess that means it's entering through either the AC line or the speakers cables and is being exacerbated when the preamp and other components are also connected.

I'm going to try those ferrite clamps or chokes.

Cheers

geoff

GBB · « **Reply #19 on:** 7 Nov 2004, 01:23 pm »

Or its coming from multiple sources.

What sort of cables are you using from preamp to amp? Are they shielded? I live in a relatively quiet area so I can use whatever cables I want but friends in NYC sometimes have trouble if their cables aren't shield.

Also, how are you handling grounding on your system?

---Gary