Review: Cullin Circuits mods to PS Audio P1000 Power Plant Tweak

Category: Accessories


I waffle. If you wish to skip the blather, let this outline be your guide. Each item in the list below refers to headings in the body of the text, so if you've no interest in chitchat, simply click to find the salient info.HELLO & GOOD EVENING
If you're reading this, I'm guessing you already know what a Power Plant P1000 is. Let me take a further stab in the dark -- I'll bet you're also aware that the P1000 has been superseded as the flagship of the PS Audio's power line by their new Power Plant Premier (PPP). The PPP is apparently a high flier, but at $2195 it had better sound good! But what if you're like me: an impoverished Power Plant owner who's hungry for pristine sonics? What happens if you're an underdog with uber-aspirations? Break open the china pig and dig the fluffy change from the back of the sofa: Rick Cullen can modify your P300 & P1000 to exalted heights for a fraction of the price of a new PPP. At $399.95 for a P300 and $550 for a P1000, Power Plant owners can get audio performance comparable to the best anywhere!

However, there are more audio-vital reasons than simple economics for upgrading your classic Power Plant. The PPP may be more efficient and capable of passing more juice than the stock P1000, but it lacks a few indispensable features that were revolutionary in the earlier models. To my mind, the largest sin of omission is balanced power. The PPP cannot accept a balanced input or generate a balanced output. Neither can it step current up or down -- what you put in is what you get out. The P1000, on the other hand, will let you do all of the above in increments of 1V; additionally you can control the frequency output in steps of 0.0625Hz from 50Hz all the way to 120Hz. It also has considerably more Multiwave patterns than the PPP. Throw in a wattmeter and power factor measurement capabilities, and you're into Swiss Army Knife territory. Besides... the P1000 looks cool! Nothing I have ever owned has garnered more oohs and aahs than my P1000. Sure the PPP is sleek and slick, but it's also slightly smarmy. You could never call a PPP cool!?

I'm an admirer of Paul McGowan and PS Audio. I've said this before, but it bears repeating: PSA products sound just right to me. Paul's ears must come from the same mold as mine, as he voices his equipment in ways that I find pleasing and exciting. No surprise then, when -- in the Spring of last year -- I took what I thought to be the ultimate step of powering my entire system with a Power Plant P1000. I got a 30-day trial of a store demo from Music Direct for the buttock-clenchingly good price of $1500. Bargain or not, that's still a big chunk o' change, and it took much spousal mollycoddling to convince my wife that regenerated power could, should and would make a positive difference to our sound system. Luckily the Power Plant did such a good job of selling itself that the seduction was relatively straightforward, if not wholly effortless, and the P1000 was given leave to sit under our GCC-100 amplifier (which I'd convinced her was a really good idea the previous year).

Now zoom forwards six months: Paul announces the PPP. If I ask my beloved to approve funds for yet another power supply, I risk the ritual presentation of my nether regions as prairie oysters. I keep my own council. And anyway, our system sounds GOOD! Lovely rich, taut bass; sweet delicate trebles; beautifully wide, deep soundstage... and my manhood's intact. Why fight it?

Enter our protagonist, stage right.

Rick Cullen has known and worked with Paul McGowan for over 30-years. They were both partners in the original incarnation of PS Audio when Paul was the 'P' and Stan Warren was the 'S'. When PSA #1 went belly-up, Rick worked in a variety of industry positions (including aerospace) before rejoining Paul by building amplifiers for Genesis Technologies in his garage! He set himself up as an independent contract manufacturer with Cullen Circuits doing work for many clients and companies, but most importantly (for our story) with PS Audio #2.

Rick's job as a production engineer is to exorcise bugs and design problems before final production begins. Cullen Circuits built every PS Audio product until the new Power Plant Premier (which Paul chose to make in China to keep prices competitive) so if your PPP goes awry, don't blame Rick! He has modded equipment for himself and friends for years. Alarmed and outraged by what he calls the "hack jobs" of many modders who are working today, he has decided to make his years of experience and professional expertise available to the general public.

Rick's work first came to my attention when I heard enthusiastic reports of a mod for PSA's smaller P300 Power Plant. "This is just the beginning" I heard, "There are more mods on the way!" I knew of Paul McGowan's elastic sense of time, so I took that statement with a pinch of salt and waited. A salty and generously heaped ladleful later, I posted a plea on the PSA website for P1000 owners not to be forgotten come modtime. Rick saw this post, and asked me if I would like to be the very first recipient of a Cullen Circuits revitalized P1000. Damn! A challenge! A few quick phone calls and an flurry of email convinced me that he was the man for the job, and my (very heavy) baby was duly dispatched.

We have a 2-channel system as I much prefer to do my listening 'in the dark' as it were; unlit by large-screen TVs. It's still one speaker per ear for this Luddite! We've gone through a slimming-down of our gear in the last few years, preferring (sonically and aesthetically) single-box units for their uncluttered appeal. We still clamor for pristine sound and modifying well-built equipment is the best way to achieve this, we feel. Specifically we have:This is an extraordinarily revealing system, but also a highly musical one -- the two need not be mutually exclusive. It has a liquid, grainless sound which I put down to the tubes in Dan Wright's SACD player mods and the astonishing transparency of PS Audio's Gain Cell amplifier.

A Power Plant is an amplifier: it amplifies electricity instead of a sound signal, but it's an amplifier none-the-less. Rick approached this mod from that standpoint and consolidated all of the areas that would make a good power amp great: better and more capacitors to give greater reserves of available power; better output wiring; enhanced circuit isolation; improved quality caps in key areas etc. Specifically:
  • The original 16 filter caps were replaced with 'gold series' caps rated at 3300uf. Cullen Circuits go through a mountain of electrical parts. The 'gold series' caps they use are custom-made in Japan to Rick's high specifications by the same manufacturer who makes Blackgates, and he orders them in batches of many thousands.

  • An additional 16x3300uf 'gold series' filter caps were added, thus doubling the original filtering.

  • Two Power Cells were added to the output of the P1000, thus splitting the outlets into two isolated zones. Power Cells are potted bundles of secrecy developed by PS Audio. They function as filters come noise gates, and their inclusion in this mod was a revelation to me (no pun intended).

  • All of the original output cabling was replaced with silver wire. Rick: "It just sounds better!"

  • Numerous caps on the output boards were replaced with low ESR parts. The Equivalent Series Resistance of a capacitor measures how well that capacitor passes AC while blocking DC -- the lower the ESR the better. Yes, I had to look it up...

  • Remote control functionality was added. Yea!

The problem with a review of this kind is that it is wholly dependent on memory. No A/B comparisons are possible because (a). I don't know anyone else that has a P1000, and (b). If I did, I doubt they would risk lumbar trauma by dragging its 107lb. arse over to my place! So what was I to do? Listening to my rig with plain vanilla power while the P1000 was being upgraded would only prove that the modified behemoth's juice sounded better than ordinary line electricity... and I already knew that. Listening to nothing at all would mean that I would be running on a 3-week-old memory of the sonic characteristics of the stock P1000, and if Rick's mods produced only subtle changes I might be hard-pressed to recognize any difference. As a compromise, I chose to plug my stuff into an old Monster power strip I had lying around. Mistake. It sounded soooo bad that I bit the bullet and shut my whole system down for the duration. Problem solved.

My baby returned from California and I heaved and hauled its hefty bulk into place; plugged it in then called the chiropractor. The lights in the house dimmed as it sucked power into its capacitors. Damn! I don't remember that happening before! I connected the power to the rest of my system and switched it on...

A series of undignified squeaks and squawks spat from the lips of this over-excited and normally reserved audio-enthusiast. These premature and unbecoming outbursts were quickly recognized for what they were, and sobriety was observed for the rest of the break-in period. You can read a blow-by-blow account of this unseemliness on PS Audio's website under the title Rick Cullen's P1000 Mods Are ****ing Brilliant! but I will provide a brief summary here.

Fresh out of the box the soundstage was immediately wider, deeper and, strangely, taller. I fancied I was -- for the first time -- aware of the ceiling and the floor of recording venues as reflective acoustic surfaces. Obviously I've heard this effect in choral works that were recorded in highly reverberant spaces like churches for example, but I've never realized it in more intimate recordings. And that was the problem -- you could hear EVERYTHING! Even diehard data retrievalists would have called it unnatural. Sheet music shuffling, chair creaking, foot tapping, grunting and snorting. There was also a nasty high etched sound to the trebles that made me want to run from the room, so I put a CD on repeat and bit down hard on a fresh bullet.

Things improved steadily until about the 250-hour mark (or about 10-days of continuous play). After that time I knew I had a winner. The bass was full, deep, extended and rich; the highs were pleasingly detailed crisp, clear and transparent with just the tiniest pinprick of brightness left, which I put down to wall reflections. Out of deference to the stock state of my P1000, I had left my system untouched while I performed comparisons. Now that the upgraded version was clearly seen to be superior, I dismantled the whole setup and cleaned every blessed nook and cranny: every cable, tube pin, fuse and spade was Caiged and ProGilded.

I reconnect and va-va-voom! AWAY WE GO!

Musical performances now rival the best I've heard: jazz bands swing like they've never swung before; orchestras soar; rock bands rock; crescendos really peak; diminuendos fade longingly away. Little delicate sounds exist next to bellowing roars. Tonal colors are miraculously pleasing. The sound is silky smooth where needed or cuttingly abrasive if the song calls for it, but always utterly grain-free. Everything sings and swings and bops and rocks and lilts and floats and dives and swoops and soars... and always effortlessly. Even my wife's infernal techno records beep and blip almost tolerably.

Clean, balanced power refreshes the parts other tweaks cannot reach, and everything is rejuvenated simultaneously. There's a feeling of unity to the sound after Rick's mods; parts don't fight other parts. There's certainly a driving, muscle-bound brawn, but this is not simply your hi-fi on steroids. Brute force and polished grace are here in equal measure and ready for whatever's called for. This is your system as a refined and dignified bouncer. This is your setup schooled in etiquette and knuckle-duster street fighting. This is your hi-fi Master Chef with a penchant for Big Macs. This is your wine connoisseur of a rig that relishes a night swilling beer with the lads. You get it all with these upgrades! My hat's off to you Mr. Cullen: these mods are a remarkable achievement!

But there's.....................more?

The P1000 has four power regenerated duplexes and one filtered duplex to choose from. My system is a little cable-heavy because Dan Wright's SACD mod requires two power cables and my powered speakers & sub require a cable each, so that's five of only eight available regenerated sockets taken up already. The amp makes up the difference. I was arranging the plugs on the two new isolated zones that Rick's upgrades have given me, making sure that the digital stuff was connected well away from the rest, when I had this thought: Dan's mods have one power cable for the digital circuitry of the SACD and another for the outboard box that houses the rectifiers for the tubed stage that powers the op amps. I had always treated them both as digital sources, but what if -- now that I've got these two isolated zones -- I treated the op amp stage as amplification and isolated one from the other.

I try it.


Hi-fi stops -- music starts. The last few pinpricks of brightness vanish and with them go the last vestiges of the illusion of the speaker as a source for sound. This innocuous event has a profound impact. A perfectly autonomous musical performance was happening in open space before my befuddled brain. I am not being metaphorical here. The sound just was. It was seemingly independent of my rig. It was in the room just as much as furniture was in the room. You could almost walk around it and appreciate the perspective. My ears were picking up real and actually happening spatial clues for a space that my eyes could not see, and it stalled my thinking process. I was feeling stupid, confused and utterly incapable of understanding what had happened. It was as if my mind had stopped working. This couldn't happen to me! I've been involved with recorded music and hi-fi for nearly 40-years: I've heard it all and been unmoved. I once remained jaundiced before a quarter-of-a-million dollar system. Stereo is incapable of surprising me! But here I was, literally dumbstruck before a perfect little 3-dimensional ensemble, floating in free space, seemingly uncaused by any equipment that I owned. I wasn't so much listening to a recorded event: I was just listening. Just hearing. That sounds weird, I know. After all, what else are you going to do when you've parked your butt in front of a pair of speakers!?

Lets get this into perspective. I have taken pride in having a 'speakerless' setup for years. It has always amused me to have audio tourists in our house marvel at the 'window on the recording studio' effect my equipment generated. But this new turn of events is a long way ahead of that. I once took part in a pointless debate that centered on which audio-illusion was the more desirable: 'you are there' or 'it is here'. (I know! I know!). At the time, I'd argued that 'you are there' was the preferable deception because it transported the listener out of his/her surroundings and into the recorded venue. But maintaining an illusion takes effort. You have to mentally read, label and identify the different aspects of the music i.e. you have to work. After the Cullen mods, the sound from my system is profoundly here, and I'm finding that to be much more realistic. Eerily so, in fact. And it's much less work! It's as if the point of comprehension is reversed: before the mods, I would mentally project myself into the illusion and think: "Wow! Listen to the (check one) cymbals/bass/ambience". After Rick's tinkerings, I find the need to label and identify is removed; a musical event arises before me and I don't have to interpret it -- I jump straight into the excitement. Cymbals crash, but the brain activity that previously would have said "Wow! A cymbal!" is not needed anymore -- the wonder and immediacy of shimmering metal is enough. All things arise and fall effortlessly -- music is received. It's as if an unconscious, but tightly clenched knot in my solar plexus has suddenly released: there is a feeling of deep relaxation and I hear the music with complete ease. There is no need to go looking anymore; sonic marvels come to me and reveal themselves without any exertion on my part.

So what do you do when you run out of hyperbole? What happens when you've used all your best superlatives, then something better comes along? What can you say when think you've reached the summit and you find you've simply underachieved? If you're anything like me, you sit stupefied. Awe-inspiring would be an entirely appropriate way to describe these mods. I sat in silent awe until the CD played out, then went to bed and lay awake for hours.

In the morning I discovered an interesting fact. The digital part of my SACD player so polluted the isolated zone that it was plugged into, that nothing other that a sub (which had a high-pass filter) could share the line with it without that nasty edge coming back into the sound, and my new miraculous soundstage collapsing. I could work with this configuration, but it was a tad inflexible. And hey! My PS Audio GCC-100 also uses digital circuitry! Could it be throwing hash onto the mix too? Shouldn't it be isolated?

The short version is that I sent my P1000 back to Rick for him to add another two Power Cells and give me a full four isolated zones, and I now have a clip-a-day bullet-biting habit.

While we're waiting for my box to return, let me take a few moments to open your eyes to the perils of transporting a hefty package across country. I took my P1000 to my local UPS Shop to ship it out to Rick in California and was charged a scrotum-chilling $126. Imagine my surprise when I discovered that return shipping was 50% less at $60... including insurance!!! In my naivety, I imagined that the UPS Shop and UPS were one-and-the-same entity. Not so. The UPS Shop franchise is a front for bare-faced, smiling highwaymen whose teeth sparkle while they pick your pockets and whose voices have just the right rich timbre to make you feel warm and fleeced at the same time. Keep your poise, dignity and pubic hair by taking your packages directly to a UPS or Fed-EX depot and thus avoid a 200% mark-up. Or better yet, have their drivers pick it up for you.

I have taken this extra hit to the wallet so that you, gentle reader, may benefit from my experience and avoid this shameless larceny.

Time passes...

The Big Boy returns and I notice something interesting. Reviewing my collection of receipts, I see that at the start of his journeys he weighed 105lbs. Now -- after twice visiting his Californian training camp -- his fighting weight has risen to 109lbs! Obviously I can't vouch for the complete accuracy of UPS's weighing machines, but you have to admit it's a very sexy sales pitch which can brag: "4lbs. of parts go into our mods!"

Phase-2 of Cullen mods proved to be problematic in a very happy sort of way. Right out of the box my P1000 sounded magnificent! There was no protracted break-in and no bullets to bite. The sound did change a little over the next 24 to 48-hours, but it was never a chore to listen to. However A/B comparisons were just as thorny as with Phase-1. Perhaps more so. If I couldn't be sure of my audio-memory in Phase-1 (between stock performance and basic upgrades) how on earth could I evaluate the transformation between basic upgrades and added extras? Luckily Rick had made this easy, yet again. The performance was ratcheted up a significant few notches because of the life injected into my system!

Now some of you folks might want to stand back a little here and cover your faces with a towel or something, because I'm going to be talking about things you can't read with a meter. The music in our listening room is now majestically clean and utterly crystal-clear -- I don't believe there is any cacophony that couldn't be unraveled by my new wonder rig. The sound is alive! It sparkles with bubbling ebullience! It is joyful to hear! Snares crack and toms bounce with sonorous thunder. Brasses bark, basses growl and guitars snap and punch. Pianos ring with spangly overtones. Sure! There's augmented texture and dynamics, but this is no one-trick pony. Rick's mods let my setup channel the emotion of a performer's expression. There is joy and heart-wrenching sorrow aplenty if a performance calls for it.

There's an olde, oft-quoted hi-fi saw which says you'll get better performance from your gear if you improve the upstream components first. Well things don't get any further upstream than the electricity that powers your rig, and Rick Cullen's mods for PS Audio's P1000 Power Plant are simply sphincter-bracing! I have to keep reminding myself that what I'm hearing is the result of mods to a power supply! The baseline upgrades (with just 2-isolated zones) gave my system a strength, authority and visceral presence that I'd scarcely dreamed imaginable. With a full 4-isolated zones, music crackles with punchy, scintillating, effervescent life, capable of relaying every last drop of expression from a performance. At $550 for the baseline upgrades, I believe P1000 owners can scarcely go wrong with these mods -- in buck terms, they represent the biggest bang since the Big One. So my hearty thanks and congratulations go to Rick Cullen for this marvelous achievement... and hooray for us underdogs! We can now cock our legs at the same gold-plated hydrants as those snooty pooches!

Rick Cullen has no website at the moment, but his business address is:
Cullen Circuits
2323 Tuley Road
Paso Robles, CA93446
Tel: 805-237-2113

Give him a call; he's a great guy to talk to... just don't keep him chatting too long. I've got loads of stuff I want him to mod, and I don't want you to keep him off his work.

Associated gear
* Sony 999ES SACD/CD Player Modified by Dan Wright of Modwright to Platinum ‘Signature Truth’ Level.
* PS Audio GCC-100 Control Amplifier.
* Infinity Intermezzo 2.6 powered loudspeakers and Infinity Intermezzo 1.2 powered subwoofer.
* Acoustic Zen Satori Speaker Cable.
* PS Audio xStream Statement & Plus Power Cables.
* PS Audio xStream Resolution Interconnects.
* PS Audio Power Plant P1000.

Similar products
Unmodded P1000, P500, P300. Assorted passive power strips
Thanks for the review. I have a few questions if you don't mind answering:
1. Does the output remain 1000W after mod?
2. How much does 2 extra power cells cost?
3. How many phase of upgrades are available and what will an all-out assault cost?
4. Have you had a chance comparing it to Premier?

Hello Howard,

Thanks for your interest in my post. I'll address your questions numerically:

1. Yes the output remains at 1000W after mods. Rick said that he was scheming of a way to increase the load to 1500W, but he only mentioned it in passing, and I don't know if he took it any further; I suppose that it would depend on how much interest there was from other moddees (?!).

2. I'm sorry, but I don't know how much the extra powercells cost. As I mentioned in the review, Rick and I met accidentally on the PS Audio website--I was grumbling about the lack of upgrades for the P1000 and he suggested that I become the first test case for some mods he had designed. He said he could significantly boost the Power Plant's performance and he would charge no more than $500 (at the time the projected cost of the mods was $799, so this was a good deal). When I returned the P1000 to have the extra powercells installed, the price was an additional $240, I think. In the end, Rick managed to streamline the production process so much that the labor costs were greatly reduced and he was able to offer the mods much cheaper than he charged me. By way of compensation he is now upgrading my amp free of charge--I'm sweating up a lather just waiting!

3. Again, I'm not sure how Rick is structuring his mods. He can pretty much do anything you want done, so if you're craving a tailor-made job, give him a call and see what he can do for you. He's a great guy to talk to!

4. No, I haven't heard a PPP yet, but those that I know and trust that have made the comparison say that the mods are sonically indistinguishable from the new beast.

I hope this helps. Give Rick a call!