[cloudbaseracer]

I often see component XYZ can be significantly "improved with an upgraded power supply".  It seems that this area is one of the main ways to get the best out of a system - electronics side of course.  Is this something that you guys have experienced as well?

Does a battery powered system take things to an even higher level?  As with the system integration theme of this circle, does it really just depend on the individual components?  I am sure that someone will say "of course, it is system dependent".  But my question is in regard to the general thoughts and accepted pathologies? Is the lowest hanging fruit a power supply upgrade and is it also the largest jump to be experienced?

James

[Browntrout]

From experience low level components such as phonostages benefit most readily from conversion to battery power supply. To run a full system from batteries takes dedication. As in........scroll down to see battery installation.
http://www.6moons.com/industryfeatures/livingvoice/definitive.html

[cloudbaseracer]

Thanks for that link.  I am not going to put that much money into a battery system so I guess I will never experience "nirvana". 

Any one else have any input on this matter?  I have been instructed to upgrade my Panasonic SA-XR700 instead of a total replacement to new amps.  This is the nature and reason for my post.

James

[cloudbaseracer]

Anyone else have any input?

I am really hoping to get some help on this as I am looking for an upgrade path for my Panasonic receivers. 

Is there a better way to ask this to get the input I need?  OR, a better forum?

Thanks,

James

[Browntrout]

Well if you want to improve the amplifier you can replace the power capacitors with larger faster better sounding caps such as Elna Cerafine or Blackgates with values of about double the capacitance as long as the charge/discharge rates are similar or faster.
  Then a higher quality power transformer could be used next together with higher guage better quality internal and external cabling for the power.
  You can replace all components in the signal path with high quality ones.

[cloudbaseracer]

Well if you want to improve the amplifier you can replace the power capacitors with larger faster better sounding caps such as Elna Cerafine or Blackgates with values of about double the capacitance as long as the charge/discharge rates are similar or faster.
  Then a higher quality power transformer could be used next together with higher guage better quality internal and external cabling for the power.
  You can replace all components in the signal path with high quality ones.

Browntrout,

Thanks for the help.  Am I possibly confused when I use the words power supply in regards to an upgrade of a component?  I have just seen the term (linear power supply)used in relation to Boulder Cable Squeezebox and assumed it was a component issue.  Does the term actually have to do with the supplied power to the overall system?  I am not super technical on these issues.

Thanks,

James

[wilsynet]

I'm only interested in two channel music, so I wouldn't bother upgrading the Panasonic HT receiver as I'd consider it a lost cause (for 2-channel) no matter what you did with it.

What does the rest of your system look like and what's your budget?


 

[cloudbaseracer]

I'm only interested in two channel music, so I wouldn't bother upgrading the Panasonic HT receiver as I'd consider it a lost cause (for 2-channel) no matter what you did with it.

What does the rest of your system look like and what's your budget?

My system is two channel as well.  That is my main concern as my living room will not "allow" more speakers for aesthetic reasons. 

I added my system details in my signature so now you will get an idea of what I am dealing with.  I am concerned about not being able to get the sound I want out of the Pannys even with mods.  Are you familiar with the sound of these running in the all digital mode?  Just curious why you state it will be a 'lost cause"?  Please elaborate.

Essentially, I do volume control on the 2 Panasonics and use the Inday to switch sources.  I realize that a change to different amps will require an actual pre-amp, and higher quality DAC than those in the CDP/Duet AND most importantly a MAJOR UPGRADE to the Behringer.  Evryone states that the DCX is horrible as a DAC.


As for budget-- I don't really have one but I don't want to spend more than I have to.  I had read such great things about the Panasonic amps when ran in digital mode that I thought it was a no brainer.  What I don't want to do is spend 5k on new amps/DAC/pre-amp/Behringer and be where I would be with a somewhat extensive upgrade to the receivers.  The Panasonics have been described to me as a sort of power DAC and the simplicity of this appeals to me. 

Also, I am only using a cheap surge protector and no line conditioning.  Perhaps that is an area I should look into before new amps or modification?

Thanks,

James

[Occam]

James,

I'm curious as to why you're using 2 Panasonic SA-XR700s to bi-amp, as Panasonic gives you ways to bi-amp/tri-amp with a single SA-XR700 using the normally unused amplifier channels when set up for stereo use. A Google search on 'Panasonic SA-XR700 bi-amp' will give you lots of hits, and more specifically, pgs 20 & 36 of the operating instructions manual walks you through the set up. (the manual is on-line as a PDF and will come up in the Google search).
Using 2 separate receivers might well offer benefits by not taxing the power supplies on the 2 receivers as much as in a single receiver providing bi-amp duties.

As to upgrades, I am rather partial to power conditioning.  I've never met a switching/digital amp that hasn't benefited tremendously from a series mode power conditioner, the only type capable of providing isolation between components. Actually, The Behringer and transport will also benefit substantially given their switching supplies.
Something like the Audience Adept Response 6 [Ar6] would be ideal, as it provides independent conditioning and isolation for each of its 6 outlets. But given that it retails for probably more than the total of all your electroninics, it doesn't make a lots of sense, unless you could find it heavily discounted on the used market.
If you are into DIY, and know how to work safely with potentially lethal AC voltages, you could build an individual Felix [do a search in the Lab Circle on 'felix', and you'll find the project] for each component, inexpensively.

FWIW,
Paul

[wilsynet]

A cursory search for the Panasonic SA-X700 doesn't turn up anything audiophile related.  I've yet to be impressed by music coming from a HT receiver (or processor even), what's special about this one?  Can someone send me links to reviews?

Also, what does it mean to be in all digital mode?
 

[Browntrout]

The power supply of a amplifier is a term used to denote the part of the circuit which changes the mains voltage to the correct voltage for the amplifier circuits to operate at.
  The construction and design of the power supply has a large determining factor in the speed and dynamics of the amplifier as the amplifying part of the circuit requires it to supply power as fast as possiblr and in sufficient quantity.
  A hometheatre amp usually uses multiple amplifier modules drawn from one large power supply circuit and is part of the reason they tend to be laking compared to dedicated stereo amps. However as you are using two and each only in stereo you should in theory already have 'ample' capability in the power supply section of each as it was designed to be sufficent for 5.1? so should be cruising in stereo or mono.
  If I was trying to improve sound quality I would think about removing the unused amplifier modules to reduce noise but this is most likely not going to make a huge difference and knowing how mentally complicated those such things tend to be would probably stop it from working all together unless it was built in a completely moduler fashion.

[konut]

What is it about your present system that you are not happy with? Noise? Dynamics? Soundstage? Tone? Identify the major flaw you are trying to address.

[cloudbaseracer]

Paul,

I am running each of the receivers in their "Advanced Dual Amp" mode which actually uses 3 amps to drive each speaker.  Very confusing nomenclature but after reading the manual several times I am convinced that this is the configuration and is what I am doing.  Page 39 of the manual shows this under the Advanced Dual Amp - Stereo Playback.  So, since the CS2's required must be bi-amped- I should be getting 3 amps from one receiver for the Left High frequency and 3 amps for the Right High Frequency.  The same is true for the other amp with is driving the Low Frequency, right and left, each with 3 amps.  Clear as mud I know!! 

Are there other companies that make a series mode power conditioner? I know the Adept stuff is highly regarded but, as you mention, seems a bit overkill price wise.

Wilsynet,

A few posts;
http://www.avsforum.com/avs-vb/archive/index.php/t-600778.html. 

http://www.avsforum.com/avs-vb/showthread.php?t=988505

http://www.avsforum.com/avs-vb/showthread.php?t=745662

Some of these are dealing with the previous versions of this receiver but I wanted the most current technology so I went with the current model.  A lot of the guys are really interested in the HT aspect but many consider the amp to be great for 2 channel.

Maybe someone else can chime in on the All Digital aspect of the Panasonic/Equibit Technology?

Browntrout,

See above description of Triple Amp Mode.  I am using all the amps in each unit. 

Konut,

I think I am just looking to get a little more resolution at higher volume levels.  It seems to me that my sound gets a little muddied or constricted when I crank it up.  I think the sound stage is very good with pin-point accuracy and width. Tone appears good but to me is hard to judge.  Maybe the word is control?  I just feel the mid, to mid base gets a little congested.  Is that a sign of inadequate power?


Thanks Guys,

James

[konut]

Konut,

I think I am just looking to get a little more resolution at higher volume levels.  It seems to me that my sound gets a little muddied or constricted when I crank it up.  I think the sound stage is very good with pin-point accuracy and width. Tone appears good but to me is hard to judge.  Maybe the word is control?  I just feel the mid, to mid base gets a little congested.  Is that a sign of inadequate power?


Thanks Guys,

James

Hi James
        I looked up the specs on the Panny and found this;
100 watts x 7 into 6 ohms at 0.9% THD
Your instincts are correct. Mid and mid-bass is where the meat of the frequency spectrum is and the demands on your amp get insistant. At higher SPLs you are running out of 'gas' in this range. While power conditioning might get you a modicum of control back at these frequencies and SPLs, there is no substitute for massive, clean power to bring things back into control. Perhaps all you need is larger amps for the mid-bass.

[cloudbaseracer]

Hmmmmm,  that sounds like I am onto a completely different set-up then.  One in which I have 2 new amps, a preamp and a DAC. 

I know of no high power amps that will accept a digital signal.  I wonder if the Triple amp thing is just a gimmick?  I believe that not all "watts" are created equal but one would think that if the receiver truly puts 3 amps into one channel (one of 4 in my case) then there should be some type of increased power synergy?  Unfortunately, I have not found any data that suggests what power one may expect to see in this configuration.

James

[cloudbaseracer]

Also, what does it mean to be in all digital mode?

From: http://www.diyaudio.com/forums/archive/index.php/t-7754.html

For those not familiar, TI's digital amps are basically class D PWM amplifier output stages.

Conventional Class D amps start with an analog signal and then modulate it into PWM by a comparator that's also being fed a triangle wave running at the carrier frequency (usually at 100KHz to 1MHz). Most Class D amps require feedback for stability, and this imposes some pretty serious gain-bandwidth limitations. This is why present-day use is primarily on subwoofers (bandwidth can be limited), car audio (higher distortion of outputs is tolerated by the market), or headphones (gain is limited).

TI's digital amps use a technology called Equibit that was developed by Tocatta Industries and was first commercially offered by TacT.

Equibit is a direct digital modulation technique that converts a standard digital audio PCM data stream into PWM.

Before Equibit, there was a limitation to achieving a direct PCM to PWM conversion: for sixteen bit audio data (not to even mention 24bit), the variation in duty cycle of the PWM wave would have required a carrier frequency up in the GHz range. This isn't practical for today's output devices to handle.

Equibit gets around the carrier frequency limitation by skewing the relative turn-on and turn-off timing of the upper and lower transistors of the output H bridge. This allows much finer resolution than could be achieved by the duty cycle varying at multiples of the carrier cycle alone. (Equibit typically runs at a 384KHz carrier).

Equibit modulation runs completely open loop, with no feedback. This avoids the bandwidth problems of most Class D, but it makes the quality of the power supply very important.
In a way, an Equibit amplifier could be compared to a high power DAC. To continue the analogy, the amp's power supply could be compared to a DAC's voltage reference.

Advantages of Equibit:
Efficiency comparable to conventional Class D (80% to 95%).
Preserves audio in digital format until the last possible moment.
Because there are no low level analog signals, there is also no amplification of low level noise.
PWM has no zero-crossing distortion (Class A is the only other type that can make this claim).
Exceptionally high damping factor. If the crossover is done digitally, with a separate amp for each driver, any back EMF is shunted directly to the power supply.

I'm just about finished with my first digital amp board layout. I'm starting with the TAS5012 modlulator chip combined with a TAS 5110DAD integrated output chip (50W into 6 Ohms). This is TI's highest performance combination that doesn't use a discrete output section. I figured that it would be the easiest way to get some direct hands-on experience with this technology. I'm also basically copying the layout of their 5100EVM board to use as a starting point.

I believe the quality of the power supply is the fundamental issue that will determine the quality of the overall amp. At least in the audio band, the PSRR is essentially non-existant. What is less clear to me is how critical ultra-sonic noise will be. I'm laying out my board in a way that I can experiement with a lot of different power supply topologies (everything from linear regulators and off-line switchers to a stack of gel-cells). I anticipate quite a few months of power supply experimentation once I get the first prototype up and running. I also want to experiment with varying the supply level for volume control (to preserve dynamic range) vs simple digital attenuation (it seems to me that 24bit data with 72bit processing should be pretty good by itself).

The TAS5015 chip looks like it will be pretty tricky to use. It requires the designer to discretely build all of the protection circuitry around the output stage.

The Panasonic SA-XR10 (AV receiver) is the first commercial product that I've seen to use a TI Equibit chip. I haven't heard one, but I did buy the service manual which has the schematic. It's using a single switching supply for all five channels. Depending on how good the supplies bandwidth is, I've wondered if it has any cross-talk issues (at least it has a good separation spec with a 1KHz test tone, but it'd be interesting to 'listen' to the supply with another amp coupled to its rails by some caps while real music is going through it (one of my preferred methods for evaluating supplies)).

There's a new chip, the TAS5182 (not sampling yet), that still accomodates a discrete output section (up to 100W), while providing all of the protection and sensing functions needed. It may not quite match the TAS5015's potential, but I think ease of use will make the TAS5182 the chip of choice for most designers interested in high performance.

Anyway, I think that Equibit is one of the most promising things to come along in digital audio. TacT appears to have done some great stuff with it on the high end (I haven't heard a TacT amp myself). We'll have to see how good it can be on a more practical cost level.

Regards,
Brian.:cubist:

There is an extensive discussion relating to the Texas Instruments Equibit amps on the above mentioned forum.

James

[Browntrout]

Hello, so could you try one amp for the tweeter and four for the woofer on each side? Or two for the tweeter and four for the woofer?
  Having three for tweeter and three for the woofer seems to be an inappropriate use of amps in that the sound would benefit from the woofer getting the larger portion of the available power. Is it possible to try this? Or would you end up with unequal gain?

[cloudbaseracer]

Hello, so could you try one amp for the tweeter and four for the woofer on each side? Or two for the tweeter and four for the woofer?
  Having three for tweeter and three for the woofer seems to be an inappropriate use of amps in that the sound would benefit from the woofer getting the larger portion of the available power. Is it possible to try this? Or would you end up with unequal gain?

I do not know how I would do this because the receiver has 3 different modes.  It can have one amp, 2 amps or three amps per channel but I cannot put one amp to one channel and a different number (2,3 or all remaining) to the other channel.  This is because these are internal settings that are selected through a menu and not simply a wiring issue. 

That would be a good idea if it were feasible.

[cloudbaseracer]

Hi James
        I looked up the specs on the Panny and found this;
100 watts x 7 into 6 ohms at 0.9% THD
Your instincts are correct. Mid and mid-bass is where the meat of the frequency spectrum is and the demands on your amp get insistant. At higher SPLs you are running out of 'gas' in this range. While power conditioning might get you a modicum of control back at these frequencies and SPLs, there is no substitute for massive, clean power to bring things back into control. Perhaps all you need is larger amps for the mid-bass.

I just remembered that the Lyngdorf and the Tact amplifiers seem to use the same full digital amplification set-up.  Some of their amps have room correction in addition.

What I don't know is what power rating I am actually getting through the 3 amp per channel setup.  OR, whether there is a great difference between the Panasonic and the other two manufactures?

[konut]

Those were the amps that I had in mind. Another tack would be to buy an additional SA-X700 and just use it for the mid-bass. This way you relieve the present amps of additional load, to the power supply, and dedicate the separate Pannys' supply to the mid-bass giving additional headroom. Weather this achieves the required clearing of congestion, at high SPLs, is debatable. The other concern is an overall control of volume.

Actually I admire your setup for its simplicity re direct digital to power conversion and lack of preamp. It would be great if you could find a way to maintain that.