Pre-amps with seperate power supplies .....

I have a pre-amp with a seperate power supply that is connected by an umbilical cord. I am not an electrical engineer and I do not pretend to be one nor do I play one on TV.....I am pretty sure that there is DC current going from the power supply to the main pre-amp to power that component. Does it make any sonic sense to upgrade that umbilical cord seeing how that it is ''only'' carrying DC current ????? The pre-amp in question is a Classe' CP-700. I have asked this very same question to the fine people at Classe' and they said improving that cord would not make any difference.... So, I will ask that question here and also see if anybody has actually upgraded that power cord.
I am not an electrical engineer and I do not pretend to be one nor do I play one on TV.....

But....did you stay at a Holiday Inn last night? Because apparently, that may qualify you as an EE. LOL!!

I also have a preamp with a separate power supply, and have considered the same path. I own a Cary SLP-98P F1, and I know of one company that makes an upgraded umbilical cord for the Cary. Revelation Audio Labs (RAL). I even know one guy who owns the RAL and swears by it, I have also seen a couple of SLP-98's list on Audiogon with the upgraded RAL cord.
I also have heard a rumor that Cardas also supplies and upgraded umbilical cord for the Cary, but I did not check with Cardas to verify this.

I did go so far as to buy a used RAL umbilical cord, that was used on a Supratek and according to RAL was also compatible with the Cary, but it did not fit, so I sent it back. At this point I'm just listening to the preamp with the stock umbilical, but upgraded tubes and power cord to the power supply. I have never actually heard an 'upgraded' umbilical cord.
I think a lot of people confuse the word "change" with the word "upgrade". So, you seek out some of the best equipment designed by the best engineers around, but you are not satisfied or you need a fix.

It is getting to the point that buying used equipment is very scary. Maybe it would be better to have sellers send equipment to the manufacturer. After the manufacturer has given the equipment a clean bill of health payment will be sent to the seller and the manufacturer can forward the equipment to the buyer.
Hello Rrog...thank you for your comment. I bought the Classe' CP-700 new and I am very satisfied with it and listened to some real good pre-amps prior to buying this one. The qustion that I proposed was ; ''the umbilical cord is only handling DC current ...right....and if you changed out the stock cord to another cord, would there be any sonic improvement ? '' Now, Classe' has already told me; no. There has to be somebody out there that has done this or also looked at this option who has some comments....and if someone was an actual electrical engineer said - your right, it is just DC current and the cord won't matter - there you have it ! Just looking form some input from others........

Also, nice to hear from you John!
Everything matters!

My preamp does not have an external power supply, but I used to use a Modwright Oppo 83 as my main source and it came with a separate power supply. I upgraded this umbilical cord and it was a significant improvement over the stock. I say go for it.
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Rrog makes a very good point. Different isn't necessarily better. In fact, it could be that the designer experimented with various types of wire and found the particular configuration that he settled on to provide the best results. Second-guessing the designer with some other wire may actually hinder the performance.
Usually a very slippery slope regarding resale,sounds better and any other reason you want to use to mod/change a factory item.My attempts on that merry-go-round is a 25% success ratio,good luck,Bob
Yes you can change it to a better cord and it will sound better. If you sell it then just be clear on what you have done. I have changed and in the end improved lots of stock gear with better quality parts. Yes, we need to clearly point out any mods when sold.

Goodness the level of improvement afforded by simple mods is both staggering and relatively cheap. Better caps, resistors, wire, attenuators and on an on.....high end stuff is often built with embarrassingly cheap and inappropriate parts quality for the selling price. Yes, $10,000 plus speakers with $8 caps in key positions that sound ok, but can be greatly improved.

I have seen many $3000 - $4000 preamps with a poor sounding ALPS pot when a nice stepped Attenuator would elevate the sound in a stunning manner.
It`s true different and better aren`t the same.Can many audio components be improved upon? Yes! Grannyring is right in that lots of part choices are compromises by the builder to control cost and stay within a certain price target.Certain higher quality capacitors,resistors,wire,etc. wouldn`t be cost effectively for the manufactuer but can easily be improved by the owners of these components.Look at the standard power cords components are shipped with for one example of cost cutting.Of course the range of "part quality" compromise varies from one builder/brand to another.
Unless a PC carrying DC is immune to RFI and EMR, unless the resistance of a PC is irrelevant with respect to speed and dynamics of transients, and unless the quality of the terminations is somehow also irrelevant with respect to DC, I don't know how the quality of the umbilical could not make a difference.

There is a reason why Tesla won out over Edison. I would think the quality of the cord might be more important for DC.
Trying a different external umbilical cord is not like switching internal parts in electronics. One could simply try the different cord and keep it if it sounds better to him. Then when selling, he could just sell the stock cord and offer the other non-stock cord for sale or simply keep it. This does not effect how original the component is at re-sale.

Upgrading caps or something else internal to the component is a different matter.

The OP question is about if a different umbilical cord would make a difference. That is an interesting question.
The external PSU on the CP-700 is two PSUs, one for each channel, with a copper shielding plate in the middle, and the DC current should be pretty darn flat, and free of EMI and RFI parasites, although I do not have an oscilloscope to test. Look at the number of pins on the thing, I am sure at least one is involved with external shielding of the DC cable.

That said I doubt that we CP-700 owners can do much more to upgrade PSUs.

As a new CP-700 owner I can attest how terrible it is, very jealous and conspiring to take me away from the family every night. The sublime neutrality and wide precise soundstaging with those SACDs is addictive for sure. Last night I tried to read while auditioning Haydn's lesser oratorio, The Seasons, half an hour later I had read only 10 lines, the VIIIth cranial nerve feed got the better part of my brain.
Yes it would make a nice improvement and yes just put the other one back in at time of sale or offer out both! A good cord in most instances makes for a nice improvement.
Hello Bob - and thank you and much appreacited. I was going to contact Classe' for a schemetic but I think you just answered it for me. By the way .... I really like this pre-amp. I have matched it with the Classe' CA 2200 and now a CA 2300.
"Granny is right in that lots of parts choices are compromises by the builder to control cost qand stay within certain price target."

I would say this is true of lower priced products, however, the peramp in question is a Classe CP 700 ($8,000).

"Look at the standard power cords components are shipped with for one example of cost cutting."

IEC sockets and stock power cords were created by reviewers, dealers and the market. Many manufacturers resisted IEC sockets for many years because the socket itself is a compromise compared to a hard wired cord. Audio Research was one company that was not willing to compromise until the pressure became too great. Why should a manufacturer provide an expensive power cord when the user is going to replace it anyway.

Rrog...thank you but it not the main power cord - it is the umbilical cord between the power supply and the main chassis pre-amp. Big difference
Garebear, I realize it is an umbilical cord. I was responding to a comment made about cost cutting and power cords were used as an example.

I would go with the engineers at Classe Audio and use the original umbilical cord. I think they know what they are doing. If you have any doubts give them a call.
"I think they know what they're doing"
They know exactly what they're doing and part of this decision making
includes economic considerations (with some companies it isn't the
engineer's call to make). Even expensive components can be built with very

average part quality to stay within a pre determined budget target. The
builders working with these cost limitations are able to produce good
sounding and competitive products. Those components can be easily
elevated to very good and excellent levels with well chosen better parts.

It you're satisfied with the choices made in choosing parts then that's fine.
As Grannyring astutely pointed out, there's is often room for improvement
(sometimes significant) as an individual isn't hampered with the same cost
constraints for their specific audio system. As I noted before the issue of
part quality varies from one builder/ company to another. This is why many
companies will offer upgrade packages (better, caps, resistors,
transformers, tubes, wiring etc.). They recognize much better quality is
available but the cost puts it outside the price target of the standard level
components (for example V cap or ultra grade resistors options).

It's a personal choice and I believe options to improve/upgrade is a good
thing, your call.
I have a Cary SLP05 preamp that has a separate power supply connected by an umbilical cord. I tried the RAL replacement and found the stock cord to be far superior. In all fairness, I probably didn't give the RAL umbilical enough time to break in but to my ears, it sounded horrible
Regarding the engineers at Classé knowing what they're doing, I recall a communication I had with the company many years ago. I had just purchased a new Classé amp that came with their $180.00 "Reference AC Linecord", a modest cable with a Schurter IEC plug on the amp end, and $3.00 yellow Eagle brand male plug on the wall end. Taken aback, I sent off a letter questioning their choice of an el-cheapo plug on a so-called "reference" cord. I received back a nice letter from a vice president at Classé stating that they had carefully auditioned a variety of AC plugs available at the time, both expensive and inexpensive, and found the modest Eagle plug to be the all-around best performer.
"As Grannyring astutely pointed out, there's is often room for improvement (sometimes significant) as an individual isn't hampered with the same cost constraints for their specific audio system."

Just what cost constraints do you think Classe Audio had when building the OP's $8,000 preamp? I always find it interesting, how many people think they know more than the specialty engineers designing high end audio equipment.

Gbart's post is a good illistration of how the cost of parts is not an indication of their worthyness in a specific application.

I know of at least one company that performed mods on many high end components. Their mods consisted of changing caps from the originals to much more expensive caps. This company destroyed the sound of some of the best equipment ever made. Thankfully they are now out of business. Hopefully never to return.

Grannyring said "Yes it would make a nice improvement" This is bad advice. He has no clue if it will make any improvement at all and there is a good chance it would sound worse at the OP's expense of course.

This appears to be the era of mod happy audiophiles. I can see modifying a Sony CD player if you are not concerned about getting the mod money back, but modifying the best equipment from the best companies is ludicrous. If you don't like it you should buy something else because it will eventually end up on the used market and I don't want to end up with it.
8000.00 USD for a component is no indication it uses the best parts available(it may or may not). The point to keep in mind is the option to upgrade is strictly an individual one.If you don`t believe in this concept then you don`t change parts,it really is that simple.A number of listeners have made substantial improvement it the sound quality of their audio components by installing better parts.Some have modified and have gotten worse results no doubt.Many have done modifications/upgrades and this resulted in noticeable improvements.It depends on the particular application.The basic /standard component can sound very good, yet this baseline level can be increased in many cases.
Most manufactures of high priced equipment do not include a “named” audiophile approved power cord for the simple fact that buyers in the price bracket want the flexibility of choosing their own audiophile approved PC. It analogous to why hi-end speaker companies do not include speaker cables with their products.
I have not read all the responses but will agree that just because a product has a separate power supply does not make it better. It all comes down to the design. You can put a crappy design in a separate enclosure just as easily as a superior design.
We do it in our Purity products due to space restrictions. There is no way we are fitting a dual mono PS and all the analog circuitry into a single chassis.

I also agree that umbilical cords 'can' make a big difference but just changing one out does not guarantee better performance. You have to take into consideration wire gauges that can alter voltages if differences are too large.
"It analogous to why hi-end speaker companies do not include speaker cables with their products."

Speaker cables may not be included, but some speaker manufacturers offer their own brand of speaker cables. Naim, Dunlavy, ProAc to name a few. A little company called Hammer Dynamics also had very specific speaker cable to match their speakers and it just so happens nothing works better.

"Most manufactures of high priced equipment do not include a “named” audiophile approved power cord"

LOL, Please tell me what a "named" audiophile approved power cord is. I need to know.
Please tell me what a "named" audiophile approved power cord is. I need to know.

Insert any "name" you want i.e. Cardas, Synergistic Research, JPS, Nordost, Transparent etc..
"Insert any "name" you want i.e. Cardas, Synergistic Research, JPS, Nordost, Transparent etc.."

Can you provide documentation to back up your statement?
Overall in this hobby, I think prices skew our judgment and ears, not to say expensive stuff does not sound better but the Yellow Eagle plug example by Gbart says it perfectly.

As to the OP question, that umbilical of the CP 700 looks a lot nicer than the ordinary looking network cat5 patch cable looking umbilical of my Bryston BP-20. I often wondered too about upgrading mine but it is hardwired into the ps so I will keep on wondering :)
Years ago before we made our first preamp we began using IEC connections on our amps (which continued with our preamps) for the simple reason that audiophiles like to tinker.

If the power cord is integrated into the equipment that means they might be rewiring part of the product. So we went to IEC connections so a person could try power cords to their heart's content. It turns out that certain power cords do indeed sound better than others, but not in all situations. So you can't assume that a particular power cord will be best. As a result we use a cord that is adequate, but you may get better sound with a different cord.

This is more likely with our amps than our preamp, which has tightly regulated supplies with lots of overhead. Under such circumstances the power cord has far less effect.
Atmasphere, Years ago before you made your first preamp aftermarket power cords were not popular.
06-03-13: Atmasphere
Years ago before we made our first preamp we began using IEC connections on our amps (which continued with our preamps) for the simple reason that audiophiles like to tinker.
So True. Reason why MOST companies don't supply rare NOS tubes for stock.
I had a long talk with the technical support group at Classe' concerning the upgrading of my umbilical cord on the CP-700. Actully Bobpaule, you hit the nail right on the head. Classe' had explained to me and some of it will be lost here as I do not have an engineering or electrical enginering background is that there is such a small current going through the cord and it was built with the issues that we have all addressed here in mind...RFI,EMI etc. in that by changing the cord you could also be possibly changing the current, impedence and also be changing the sound achieved / desired by this pre-amp. They also said that they have discussed this with others and the general consensus is, you will not hear that much of a change in sound for what you will pay for an increase in that cord.....also, I need a longer length and Classe' stated be careful as the cord was built in the length to handle the current needs....any longer and you could, could run into some trouble. As the origonal poster....I will leave as is and thank you for all of yuor input.
Atmasphere, Years ago before you made your first preamp aftermarket power cords were not popular.

I first became aware of after-market power cords in about 1985. Not sure how long they have actually been around, but at least since then... that is about when we started using IEC connections too.
"I first became aware of after-market power cords in about 1985."

Who was producing aftermarket power cords in 1985. Many companies were using IEC sockets and other types of detachable cords, but I do not recall the reason was to facilitate the use of aftermarket power cords back then.
Seems to me Fulton was making power cables. Its been a long time but I seem to recall Sumiko had something too.
Atmasphere, The more I think about this the more it doesn't sound right. Atma-Sphere may have been installing IEC sockets in 1985, but I doubt it was for aftermarket power cords. Even 10 years later aftermarket power cord were not very popular.
I bought my Cardas power cords at CES in 1990, about 5 years after we switched to IEC connections. By that time Cardas was already doing quite well for himself :)

I do remember thinking that I didn't want to deal with how people would cut up the wiring in our amps which I was hoping to eliminate by using IECs.

In 1990 we built the first MA-2s. That amp had (and still has) two IECs *per chassis*, and also different (larger) fuseholders, as we wanted to reduce the effects of the AC cable on the sound of the amp, and having two AC circuits was an easy way to do it.

That was also done to reduce the effect of the internal AC wiring; the special fuses were used because they sounded better- a good 18 years or so before upscale/aftermarket fuses became popular in the high end market. All I am saying here is that by 1990 we were very well aware of the effects of AC line and power cable issues- and had been aware of them for some years prior. So I am still thinking that '1985' is about right.
All parts make have a sonic impact (caps, wire, resistors, transformers, even chassis, etc.). Some more than others. Silver and copper wire will sound different. How much of an improvement can only determined when you swap them out. There are better ways to filter AC than most conventional manufacturers use that probably would improve the sound much more that the cable.

Happy Listening.
Atmasphere, Cardas may have been doing quite well in 1990, however, it was not with power cords. It was with speaker cables and interconnects. Power cords, to my recollection, did not even start to become popular until the late 1990s. The reason manufacturers were installing IEC sockets in the mid 1980s had more to do with shipping their products to other countries with different types of wall outlets. Even Tandberg had their own 2 prong socket for the purpose of being compatible in any country.

I'm not trying to beat this to death. I'm just trying to remember how it all happened.
To the OP. I previously owned a Classe CP60 and replaced the stock umbilical with one made be Revelation Audio Labs. It cost about $100 or so and made a very nice improvement in the sound. YMMV
Rrog, I appreciate that- but the reason we went to IECs in the mid-80s was because we already knew at that time that the power cords made a difference. At that time we didn't know if anyone overseas would even want our amps... It does seem to me though that when we bought our power cords from Cardas that they were a fairly new product.