Jump to content
IGNORED

Pace Car Killer Mods


Thomas J
 Share

Recommended Posts

Ok, further to my adventures in audio nervosa tweakdom, I today finished hotrodding the Pace Car I use with my Wadia iPod transport. Here's what I did: I ordered several shunt modules from Paul Hynes + one serial supply. For the shunt modules I purchased separate R-core transformers. I installed all in an aluminum box. I then removed the Pace Car from its box, snipped the supply leads to the Superclock 4, and removed the 7805 and 7809 regulators. I then wired a 12V Hynes shunt to the Superclock, wired 9V and 5V shunts to the 78XX regulator inputs, and wired the remaining 12V serial supply to the 12V input to the Pace Car (I'm actually not sure this is even needed, but I don't know the Pace Car circuit).

 

So all in all, four Hynes supplies powering the Pace Car! Total cost was something of the order of 4 x $175 for the supplies + 3 x $40 for the transformers = $820.

 

My god! What a ~ s-w-e-e-t ~ upgrade! I have to say, this Pace Car is one remarkable machine. I'm speechless. No grating digititis whatever, just soft, detailed, analogue-killing sound. I can hear the difference here as I type, one floor down. I'm now going to walk back upstairs and retrieve my jaw from the floor.

 

My hat's off to Steve. I think I need some new words to describe the sound this little box is producing. Like realitytone, or instrumentdelineation. High and previously unheard-by-me levels of both.

 

Link to comment
Share on other sites

My girlfriend just listened to the upgrade. It's an upgrade to her stereo, actually. The stereo is in her painting room and she listens to it almost daily. (Well, it is *her* stereo, but I put it together, including modded every component from power conditioner to Wadia thingy to amp to speakers to ... Pace Car.)

 

Her response was, "I can't believe how clear it is. Do you think the people who mix music intend all the instruments and singers to sound so separate?"

 

; )

 

I'm still speechless. This little box is now 6 upgrades better (8?) than my Weiss firewire getup, and 5 upgrades better (7?) than my Playback Designs MPD-5. Dave Clark, you reading this?

 

Link to comment
Share on other sites

I did (12V LiFePO4). It works well, though I'm unsure for my own listening which I preferred (the quiet battery was was probably noisified by the noisy regulators it was feeding). Because I need to keep this stereo relatively user friendly for my girlfriend, I've gone the plug-n-play approach and didn't give the battery a fair shake.

 

You know, the absolute killer mod would be to replace all 78XX regulators and other supplies with battery power only. No regulation, just oh so silent battery power.

 

On the other hand, these Hynes supplies are quite something.

 

Link to comment
Share on other sites

I've seen those charts and don't believe them, particularly the ALW chart. Notice the way-big 50Hz spikes. Ask yourself where those could possibly have come from. Read this for a different point of view:

 

http://www.diyhifi.org/forums/viewtopic.php?f=2&t=1816

 

I like carlosfm's comments on the ALW chart:

 

"Ted, that graph of battery noise measurement from ALW should be kicked out of the internet once and for all.

It has some years and until today he didn't explain how come that battery has 50Hz hum."

 

One paper listed in the DIYHiFi thread measures battery noise at the order of -180 to -205dB.

 

Link to comment
Share on other sites

My girlfriend noticed how the sound seemed to shift on this modification toward the midrange. She's right about the perceived effect, and I think what she's hearing is a combination of tighter bass (gone is the wool) and cleaner high frequencies (gone is the sibilance and HF fizzle). The latter effect is quite noticeable and renders the sound more realistic, with vocals taking centre stage, as they should. I've personally never heard HFs in the real, in both quality and content, like I hear them in almost every stereo I've heard. Well, this modification has walked a good mile toward rendering digital HFs very natural indeed. And this is but 16/44.1!

 

Link to comment
Share on other sites

I can vouch for the Paul Hynes power supply... not for the Pacecar but with the Altmann attraction DAC. I used a RedTop car battery previously but recently changed to a Paul Hynes regulator with a transformer rectified via Black Gates capacitors. Tonality, resolution and smoothness have definitely improved (in my system).

 

Kamil

Link to comment
Share on other sites

Thomas, what is the Pace Car? From what I read on the website, it sounds like its an external master clock, is that correct?

 

Gary

 

Intel NUC NUC8i7BEH Roon Server running Audio Linux in RAM -> Sonore UltraRendu (Roon Endpoint) -> Uptone ISO Regen -> Singxer SU-1 KTE -> Holo Audio Spring Level 3 DAC -> Nord One UP Monoblocks -> Spendor LS3/5as | Music controlled via iPad (Power Conditioning: Audience adeptResponse aR12).  Twitter: @hirezaudio

Link to comment
Share on other sites

I'm certainly enamoured with these supplies myself, Kamil, though I haven't much directly compared them to battery supplies. The overall difference they've made to this little Pace Car is nothing short of remarkable. I don't mean that lightly as I've been in this game for 30 years and know the incremental nature of typical audio improvements. I mean, $800 thereabouts, a little time, solder and wire + a few bolts has caused this little box to jump head and shoulders beyond my Playback Designs unit.

 

I'd love to add a few Hynes supplies to the Lyngdorf amp doing amp duties in this system.

 

Link to comment
Share on other sites

Actually, I should be clear about what I actually changed that caused the improvement. Before placing the Pace Car in this box, it was already being powered by two Hynes supplies, one on the Superclock, the other as the main 12V input. I thus merely added two other Hynes supplies to replace the 7805 and 7809 regulators on the internal circuitry. Those are evidently critical regulators.

 

Link to comment
Share on other sites

Another PSU Addon which is reported to give almost as good results as the Paul Hynes Regulators, is a design published in ETI International many years ago by the late John Linsley Hood. Typical specs. were given as 4uV noise , and an impedance below .02 ohms over the range 500HZ to 30KHZ, and < 0.1 ohm over the range 35HZ to 300KHZ. Back then, low ESR capacitors were not not used, and using modern low ESR capacitors, these figures are much improved. The design is non voltage specific, and dual rail versions can be constructed. It has essentially 2 sections, which are a capacitance multiplier with a simulated capacitance of approx. 0.5Farad, and a "ripple eater" section which opposes noise/ ripple on the output, with a correction ripple. The JLH PSU Addon is FAR less costly to construct, and can be used with currents in excess of 600mA, and voltage rails >55V with suitable transistors, and capacitor rating selection.

 

SandyK

 

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

Link to comment
Share on other sites

Hi Sandy, I don't think that supply can really compete with the Hynes supplies. Here are his specs:

 

Specifications - error amplifier used in shunt regulator :- slew rate 5,000 volts per microsecond, gain bandwidth product 1 GHz, rise time < 1 nanosecond, settling time < 10 nanoseconds and wideband noise 2 nanovolts root HZ. Regulator output impedance is less than 0.001 ohm and the power supply line rejection ratio is 110 dB from DC to 200 KHz.

 

Perhaps of equal importance, the supplies I installed are shunt supplies, which are evidently better suited than linear supplies to powering digital circuits.

 

Link to comment
Share on other sites

The JLHs have been extensively used by quite a few people in the last year or so,(>120) and have been judged to sound ALMOST as good as the Paul Hynes regulators when used with the +5v and higher voltage rails of the Twisted pear Buffalo 32 S DAC. Not everybody can afford to splash around that kind of money for Paul Hynes regulators, where the cost of the regulators alone, can exceed the cost of the rest of the whole project.

Please note that I have no financial involvement with anything to do with the JLH. I have been using them for many years with all of my gear, and substantially upgraded the original design for use by fellow DIYers.

 

SandyK

 

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

Link to comment
Share on other sites

Hi Sandy, I appreciate your perspective, though would add that "almost" is almost certainly person- and situation-dependent. Hence if people are using JLH regs to cut costs of a few or several hundred dollars, their systems probably don't carry a degree of quality to really discern the extent of 'almost.' This is not to deny that JLH regs are good quality.

 

Link to comment
Share on other sites

Jesus R

If you are looking for info on the JLH PSU Addon , you are unlikely to find it there . The caretaker was not even aware of this PSU Addon until I sent him a copy of the original article from ETI a couple of years ago. I can email full info if requested.

Alex

 

 

How a Digital Audio file sounds, or a Digital Video file looks, is governed to a large extent by the Power Supply area. All that Identical Checksums gives is the possibility of REGENERATING the file to close to that of the original file.

PROFILE UPDATED 13-11-2020

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share



×
×
  • Create New...