Amp and preamp on same outlet?
Move to a more efficient amp like Class D and no problem ever. I have both my 500w/ch monoblocks on the same outlet and dynamics match teh best I hear anywhere and are teh best I have ever had myself. Efficiency done well is always a good thing. My circuit breaker used to go frequently with modestly high power power sucking Class a/b amps. Now the only time it might go is if I power up both 500w/ch Class D monoblocks at the same time. They never show any signs of strain or break a sweat running. Plus I can leave them on most of the time and teh impact to my power bill is negligible as quality power amps tend to go, so overall cost of ownership is lower as well. |
A well regarded equipment manufacturer told me having everything on the same line is optimum. I suspect this is related to the ground loop considerations Al posted. This has nothing to do with ground loops which are an entirely separate matter (FWIW, if your equipment is properly designed, ground loops should never be a problem). The concern with different lines is that one might be on one side of the incoming AC power into the house, the other might be on the other. Sometimes you can have leakage problems caused by the two lines being of slightly different phase (or a lot different phase if taken off of a 3-phase circuit). Sometimes this can result in hum. If the equipment is properly designed though this should be a minor concern. IOW two different lines off of the same side of the incoming AC line (which is 240 Volts in the US and then gets split into 2 halves each 120Volts...) eliminates that concern. If your equipment is prone to ground loops that can still happen though... |
Jea48, Asit turns out, my krell manual for my amp says to use 20 amp single pole breaker min, they put it in their manual, that means 20am will work, really terrible, but you can get by, the 30 amp single pole allows my amp to get the correct current, does it use all 30 amps, of course not!, however, it spikes well above 20 amps, the amp never runs hot like with the 20 amp breaker, way more dynamic, bigger sound stage, it's a fit! |
Audiolabyrinth, I am sure the Krell user manual says the amp should be connected to a 20 amp circuit. They did not a have a choice if they wanted to use a NEMA 5-15P or a NEMA 5-20P plug and cord to feed the amp. Just going from memory in another thread here on Agon you and I have discussed the code violation of using a 30 amp breaker on a 20 amp branch circuit that uses NEMA 5-15R, (two or more), or NEMA 5-20R receptacles connected to the branch circuit wiring. If I remember correctly you used #10awg for your branch circuit wiring instead of #12. I believe in that thread as well as this thread #10 wire I said why #10AWG wire does a better job of controlling VD, voltage drop, placed on the circuit caused by the Krell amp. As I said in the other thread the current carrying contacts as well as the other current carrying conductors in a 20 amp breaker are exactly the same as 30 amp breaker. Only the magnetic and thermal trip units settings are different. I may not be able to convince you otherwise but it is my hope that others reading this thread or other threads like it will not think it is ok to use a 30 amp breaker in place of a 20 amp breaker. If the current carrying components inside of a 30 amp breaker are larger than a 15 or 20 amp breaker then why would they sale for the same price? Square D QO 130 single pole breaker. Square D QO 120 single pole breaker. Square D QO 115 single pole breaker. If the 20 amp breaker felt warmer to the touch with the #10AWG wire connected to it the reason could be the breaker was defective. Again it had nothing to do with the differences in the size of current carrying metal components in the 20 amp verses the 30 amp breaker because there is no difference. . Jim |
Jim, science is not all!, I am telling you, please listen, My amp does not get hot any more, got a bigger sound stage, runs smoother, hugely more dynamic, Jim, how do you explain why a single pole 30 amp breaker did all this when a 20 amp breaker choked the crap put of my amp in every way?, also Jim, this is very incredibly noticeable of the difference between the 20 amp and 30 amp breaker on my amp,I also have a $240.00 top of the line furutech GTX-D Rhodium for an outlet with the breaker, works safly, the outlet is cold all the time, period. |
Jim, take note: Never try to teach a pig to sing.... |
Jea48, I do not understand why you would make humor of the truth, I had numerous others with the Krell 750MCX mono block's and the stereo Krell 700cx say the same thing, they encouraged me to use the 30 amp breaker as did krell them selfs,no one knows it all, we all learn from each other, I did not believe that the 30 amp breaker would do any thing either, but when I got 20hrs of break-in on the breaker, it turned out to be the best cheap tweak ever I have done in my life time, the benefit's was worth thousand's of dollar's to me! |
| Post removed |
Jim, you do not understand, Krell runs 30 amp braker on every krell 700cx, 750mcx amp there at the factory, BTW, I have 4 fuses, well with-in the current capability useing a 30 amp breaker, as I said befor, I am not useing all the 30 amps!,however, This amp in particular spikes well above 20 amps while in use, maybe you should call krell, then you will get all the theory as to why this works properly you want, remeber, this amp at full power is 6,000 watts! |
John, yes your math is of course correct. And the 700cx does indeed have a max power consumption spec of 6000 watts, which if anything seems a bit low in relation to its specified output power rating of 2800 watts/channel into a 2 ohm load (the 8 ohm and 4 ohm ratings being 700 and 1400 watts respectively). But it seems safe to assume that it would be an unusual occurrence for the amp to be used in a manner that would require it to draw more than 20 amps x 120 volts = 2400 watts for a long enough time to cause a 20 amp breaker to trip. Best regards, -- Al |
50 amps is correct. But we should keep in mind that the amp is likely never going to produce such power, as it would only be possible if the load were one ohm. I remember the Apogee Full-Range speaker approached that value, but the speaker cables used in such an installation would add to the load impedance and limit the possibility of such power. On most 4 ohm loads the output power is about 1500 watts. In addition if I recall correctly, its the power transformer in that amp that has that rating, not the amp itself. The transformer would current-limit the amp even if the output section was capable of delivering such power. Line voltage sag can cause some amps to heat up as the bias point can shift somewhat depending on the design so I can see that reducing the sag with a higher current breaker might have an effect. But installing such a breaker without upgrading the associated wiring would be foolhardy and would not meet code in any state in the country. |
Audiolabyrinth, IF, Krell is indeed telling customers the amp was designed to be connected to a 120V 30 amp branch circuit for use in the USA or Canada. Again IF!!! You are the one that that does not understand what Krell is actually up to. If Krell is having to connect the amp to a 120V 30 amp circuit for the amp to operate properly as designed as well as to achive the amps reported specs then Krell should be using a captive power cord and a NEMA 125V 30 amp plug on the end of the cord. The user, customer, would then be required, per NEC Code, to install a 120V 30 amp branch circuit with the correct NEMA 125V 30 amp receptacle for the Krell amp plug. Per NEC Code a 30 amp branch circuit requires #10AWG minimum wire and shall be connected to a 30 amp branch circuit breaker, period. The receptacle must be a NEMA rated 125V 30 amp receptacle, period. No exceptions. Instead Krell is apparently more interested in building a product that violates NEC code safety standards for the USA by using a 20 amp max rated IEC inlet connector on the amp where by the user can use a power cord that has a NEMA 5-15P or a NEMA 5-20P plug. Then Krell has the gull to tell a customer that bought the amp to change out the breaker at the electrical panel from a 20 amp to a 30 amp, which I believe the real reason is, because the Krell amp is nuisance tripping the 20 amp breaker on startup in rush current. So because Krell was too tight to design/incorporate a soft start circuit to limit inrush current to solve the customer's problem of the 20 amp breaker nuisance tripping they tell the customer to change out the 20 amp breaker to a 30 amp breaker. What they should be telling the customer is to change out the 20 amp breaker to a 20 amp HM, High Magnetic, breaker that has a longer delay time for startup inrush current. Problem solved. I wonder how many Krell users have followed the advice of krell? How many users who changed out the 20 amp breaker to a 30 amp on a 20 amp dedicated branch circuit that has #12AWG 20 amp rated wire? As I have pointed out earlier in this thread the current carrying contacts as well as the other current carrying metal parts of a 20 amp breaker are identical to that of a 30 amp breaker. Had an EE at Krell done his/her homework he/she would know this as well. They would also know as well a typical TM, thermal magnetic, breaker will easily pass short bursts of current of 120 amps all day long. More than enough for their amp but not enough apparently for startup inrush current. A 30 amp TM breaker will pass short bursts of 300 amps. Hell you can arc weld with 120V at 30 amps. And if the branch circuit wire is of any length and #12AWG copper once I get the #12 branch circuit wire cooking I won't have to worry about tripping the 30 amp breaker. I have looked at every article in NEC Code that pertains to the code violations and nowhere in the NEC Code book is an exception given for Krell inc. Audiolabyrinth , did you know? Krell recall I would bet that no owner of the Krell amp mentioned in this thread has anything in writing from a representative of Krell inc. stating Krell recommends changing the breaker on a 20 amp branch circuit from a 20 amp to a 30 amp breaker. All a user/customer has is a verbal conversation that is worthless in a court of law. So who is in violation of State, and local governing body safety electrical codes and electrical safety standards when a 20 amp breaker is changed out to a 30 amp breaker on a 20 amp branch circuit? Â…Â…. The person/home owner that changes it out of course. I suggest you call you insurance agent and ask him/her if you are covered by your home owners insurance policy in the event of an electrical fire if it is found a 30 amp breaker is installed on a 20 amp branch circuit. Then call the governing electrical inspection department in your city and ask them about changing the 20 amp breaker to a 30 amp breaker on a 20 amp branch circuit. NEC Code 210.21 (B)(3) Receptacle Rating. Where connected to a branch circuit supplying two or more receptacles or outlets, receptacles ratings shall conform to the values listed in table 210.21(B)(3), ........... NEC Table 210.21(B)(3) Receptacle Ratings for Various Size Circuits. Circuit Rating ..... Receptacle Rating (Amperes) .............. (Amperes) 15 ............................ 15 20 ....................... 15 or 20 30 ............................ 30 Minimum wire size #10awg. Breaker size 30 amp. *No exception given for Krell Inc. Circuit Breaker Myths Siemens Breakers Electrical-forensics . |
See page #5 Full Power Balanced X Series Power Amplifiers
Note the word [minimum] used for the "750Mcx, 400cx, and 450Mcx amplifiers need to be operated from a dedicated AC power line rated at a minimum of 20 amps." If the equipment is manufactured for use in the USA with the intent of using a power cord with a NEMA 5-20P 125V 20 amp plug then the max branch circuit ampacity rating is 20 amps. Period! The minimum branch circuit ampacity rating because of the NEMA 5-20P plug is 20 amps. Period! Minimum wire size #12AWG copper. Branch circuit breaker size, 20 amp. Period! Receptacle, if the Krell power cord plug is a NEMA 5-20P plug then a NEMA 5-20R 125V 20 amp receptacle for the plug to fit it is required. All the above are NEC Code minimum electrical safety standard requirements. Krell can spec #10 AWG copper wire, which I would recommend. For long branch circuit runs maybe even #8 AWG Cu. They can spec an HM, High Magnetic, 20 amp breaker must be used to help prevent nuisance breaker tripping. They should spec that only power cords that has a NEMA 5-20P plug can be used with a minimum cord conductor wire size of #10AWG. They can spec only a NEMA 5-20R 125V 20 amp heavy duty commercial/industrial rated receptacle be used. The bigger wire and heavy duty receptacle will help reduce voltage sag on the branch circuit wiring, receptacle contacts to plug blades, and power cord wire right up to that 20 amp IEC inlet connector mounted on the back of the unit caused by the Krell amp's dynamic power connected load. They cannot spec a 30 amp circuit breaker be used on a 20 amp branch though. You will notice in the owner manual a 30 amp branch circuit was not mentioned. Everybody reading this thread by now should know the reason why. . |
Edit for previous first post dated 03-03-15: Jea48 NEC Code 210.21 (B)(3) Receptacle Rating. Where connected to a branch circuit supplying two or more receptacles or outlets, receptacles ratings shall conform to the values listed in table 210.21(B)(3), ........... NEC Table 210.21(B)(3) Receptacle Ratings for Various Size Circuits. Circuit Rating ..... Receptacle Rating (Amperes) .............. (Amperes) 15 ............................ 15 20 ....................... 15 or 20 30 ............................ 30 Minimum wire size #10awg. Breaker size 30 amp. *No exception given for Krell Inc. >>>>>>>>>>>>>>>>>>>>>>> Strike, Minimum wire size #10awg. Breaker size 30 amp. and replace with, The branch circuit breaker size determines the size of the branch circuit. If the branch circuit breaker is 30 amp then the minimum wire size must be #10 AWG. It can be bigger but it cannot not smaller. The receptacle must be a NEMA 125V 30 amp rated receptacle. It cannot be bigger, it cannot be smaller, it can only be a NEMA 30 amp rated receptacle. . |
Jim (Jea48), it seems that John (Jmcgrogan2) was right. Fool Hardy has no interest in learning to sing and you are getting frustrated trying to make it happen. I remember you trying to tell him the same thing in another thread a while back. Hopefully, others reading this thread will follow your advice, which as usual, is excellent. It would be a shame for anyone to burn their house down for the sake of trying to make their system sound better. One of the things I remember from the other thread is that after all of those "upgrades", he was still tripping breakers and wasn't sure why. YIKES! |
Hi Jim, sorry, I just got back to this thread, yes, I have been listening, I do have a 10/3 romex connected to a furutech GTX-D Rhodium for my amp, yes, The Krell 700cx amp comes with a captive power cord that says 600 volts rating on it, Jim, I have said over and over, my amp is NOT useing all 30 amps, it simply spikes over 20 amps, all I am saying Jim-Jea48, My krell 700cx runs cooler, more dynamic, bigger sound stage, more or less, effortless useing a 30 amp single pole breaker versus a single pole 20 amp breaker, I was shocked after 20hrs of burn-in of the breaker at the difference this made, Damn Jim, this is the best cheap tweak ever I have done, more than cost effective, I do not know why or how Jim, But I assure you, the 20 amp breaker in my opinon, was chocking my amp!, Thankyou jim for all the post you have done, I really don't have an explaination, I am just telling you that this works, no problems, and was worth doing, and that I know many members of audiogon that did the same here with their Krell amps, I was afraid to do it Jim, Chris Vanhas of vh-audio sold me the furutech GTX-D R with the understanding that it would not heat up or damge the outlet with a 30 amp breaker because of how well it is built, as it turns out, he was correct, not even warm!, I have checked this outlet over and over, the wires going to it, if any smell was coming from it, for heat, nothing, the wpo-wall power outlet is cold all the time with NO issues, thanks jim. |
Jea48, one of these audiogon members that has e-mailed me for months about the 30 amp breaker is MRvordo, you can consult with him, maybe bring him to this thread, he uses the 30 amp breaker on his krell 750mcx mono amps, I believe a 30 amp breaker for each?, any way, every aspect of what he said this will do for my amp was spot on correct, he is one among many others that have done this with no issues. |
Jea48, also, this captive cord is a 10/3 copper power cord,when I get the money, I will be changeing the wall plug to a furutech or oyaide for performance, It seems I really don't need it, but I can always return it if something like this wrecks my sound, I am a skeptic by nature, so we will see Jim, cheers. |
Ralph- The guy just does not get it. He's talking how he think it sounds, you and Jim are talking electrical safety codes and specifications. Audiolabryinth- Even if were true that the larger breaker is somehow making your system sound better (I'm betting the recommendation from Krell came about like Jim theorizes, but let's put that aside. What do you think might happen if there is a short or other failure downstream of the 30 amp breaker, such that there is a long term "demand" for more than 20 amps but less than 30 amps? I'm no ee, but my guess is that there is a reasonable possibility that the house wiring, or receptacle, or power cord downstream of the breaker, will overheat, unless they are ALL also rated for 30 amps. What happens after that? I'll give you a hint, you can't shout it in a crowded theater. If your insurance co. is diligent, they'll hire a forensic ee like Jim, who will tell them that you modified your electrical system in a manner that is unsafe and does not meet code. Then your insurance company will say, "thank you" to Mr. EE and "go pound sand" to Mr. Audiolabyrinth. CLAIM DENIED. Of course, there's also the possibility that the insurance co wont' be talking to you, they'll be talking to your heirs. It's your call, dude. They are looking out for you. Do you think Krell gives a rats a$$ about you? |
I would like share some info in regards to the Krell references made on this thread. I also believe the info would be of interest to the OP Audiolover. If I can ask Audiolabyrinth a couple questions first. @Audiolabyrinth Am I reading your posts here right that you are using a 30 amp circuit breaker, but not 30 amp rated line or a 30 amp outlet; and therefore a 30 amp terminated male end on your Krell power cord ? Has your 20 amp line been checked ? So I have a friend considering a Krell amp. He has a shared 15 amp line for his present set up. To offer him more insight I reached out to Patrick at Krell about a dedicated 15, 20 and even 30 amp service (in a second email) - this due to what I read in this thread. I would like to share this info from Patrick. Patrick's answer. The answer to this is somewhat dependent on the speakers being used, as well as the length of the speaker cables. We recommend 20 amp service because with rare exception it almost always works best in terms of the amplifier always having continuous current available to be able to instantly respond to whatever type of listening style a customer may have. The Key words that stood out to me in the above. Speakers used Length of Speaker Cables The proof is the end result (the amp sounds open and fast and detailed with good bass and sound staging) A good stiff 15 amp line versus a weak 20 amp line. And from some of the discussions on this thread about 30 amp service I asked. Whats the deal with 30 amp service. Is it ever needed or warranted. FWIW I take his response as normal for someone representing a company that makes high power amplifiers. Patrick's response As they say, “the more the better” and giving a powerful amp like the FPB-600/600c/700cx a dedicated 30 amp line will make a serious difference from a performance perspective that would be obvious straight across the audio frequency spectrum. Under these circumstances however you would need to re-terminate the male end of the amps AC cord with a 30 amp twist lock type male connector. Is this really needed? Not really. But you asked . . . I interpret Patrick's comments that for 30 amp service, a 30 amp breaker, 30 amp line, 30 amp outlet and a 30 amp male connector is required to go this route. Happy Listening. |
thankyou ct0517, it is patrick bresnahan that asked the technician's and R&D design team about the 30 amp breaker, this was NOT my idea at all, it was numerous other big krell amp owner's and krell that made this sugestion to me,however, Patrick is correct about the male wall plug, I have no issues at all, but I also said, I will be getting a high performance male wall plug for sound, Not any thing else, if I decide I really want one, currently, I do not, cheers. |
Audiolabyrinth, Yes from day one you said the branch circuit wiring you have is #10 awg. And yes that is the minimum size needed for a 30 amp branch circuit. If you were not using a 125V 20 amp rated receptacle your branch circuit would be code compliant. So for me in your instance the problem is the 20 amp rated receptacle. Whether you like it or not because of the 125V 20 amp rated receptacle, you are insisting on using, in the eyes of NEC code the NEMA 125V 20 amp receptacle dictates the branch circuit shall be 125V 20 amp regardless whether you used #10 awg wire or larger. Therefore per NEC Code the breaker must be a 20 amp breaker. My concern with your posts to this thread and others is when you say Krell tells customers to change out a 20 amp breaker, that is protecting a branch circuit that meets NEC code which likely may have #12 awg wire with a 15 amp duplex receptacle or a 20 amp receptacle connected to the branch wiring, to a 30 amp breaker. As for the captive power cord, my bad for being lazy and not reading through the owner manual of the Link I provided for the Krell amp above. In your particular case because at least your branch circuit wiring is #10, 30 amp rated wire, and the power cord for the Krell amp is captive that eliminates you/others from using a DIY or other non UL and or CSA Listed power cord. Why do you thing Krell chose not to use a 20 amp IEC inlet connector on the back of the Amp? At $14,000 list price for the Krell 700cx amp, Krell did the consumer an injustice, imo, by installing the 125V amperage?? type plug on the end of the 10/3 power cord. Amperage??, I could not find in any searches whether the plug is a 15 amp or 20 amp NEMA rated plug. By their specs for the amp they say it should be connected to a 20 amp circuit minimum. That would suggest the plug is a NEMA 5-20P 125V 20 amp plug. What plug did Krell install on the end of the cord? 15 amp plug? 20 amp plug? Also I could not find if the Krell 700cx amp is safety tested, Listed, by any recognized independent testing laboratory like UL or CSA. Do you know if the amp is Listed? Bottom line, imo, Krell chose to use the captive 10/3 cord to stop a user from using an aftermarket power cord there by prevent the possibility of electrical fire due to the power demand the amp can place on the power cord if the amp is driven hard. And , imo, a 20 amp IEC inlet connector would never be able to handle the varying load current placed on the connector if a user was driving the amp hard. See page 22 of owner manual. Output both channels driven, 8 ohm 700 watts 4 ohms 1400 watts 2 ohms 2800 watts 8 ohms, 700W / 115Vac = 6 amps plus. 4 ohms, 1400W / 115Vac = 12.8 amps plus. 2 ohms, 2800 watts / 115Vac = 24.35 amps plus. AC mains power consumption, 6,000 watts max. @ 115V Not sure why FLA was not given. If Al is still following this thread he can do a better job of translating the info from page 22 of the owner manual than me. The plug Krell chose to use? Imo, it was chosen because the standard receptacle configuration in the USA and Canada is the NEMA 5-15R receptacle. And just guessing, imo, they used this number 4 ohms 1400 wattsfrom their specs to justify the reason they choose the plug and not a 30 amp rated plug. . |
If Al is still following this thread he can do a better job of translating the info from page 22 of the owner manual than me.Hi Jim, I can't do that with any certainty, because as I see it the specs provided in the manual are both ambiguous and inconsistent. First, output power into the various load impedances is specified as "each channel driven." I would normally expect output power ratings to be based on both channels being driven simultaneously, but as I alluded to earlier the specified maximum input power of 6000 watts seems (given that this is not a class D amp) to be too low to be consistent with the specified output into 2 ohms of 2800 watts, if the 2800 watts (or anything close to that amount) is provided by both channels simultaneously. So perhaps "each channel driven" means "one channel driven," rather than "both channels driven." Second, the specified maximum power consumption of 6000 watts is identical to the spec for the FPB 750Mc monoblock amp (for which specs are provided on the next page of the manual), with that amp having just slightly higher output power ratings. Same goes for the other two monoblock amps in the FPB series and their stereo counterparts. Yet the power consumption numbers for standby and idle conditions differ between the stereo amps and their monoblock counterparts by approximately a factor of two in most cases, as might be expected. So I don't know how to reconcile all of that, and it seems that all of these numbers have to be taken with some grains of salt. And adding to the uncertainty is the point you raised earlier about inrush current, which of course is unspecified. Best regards, -- Al |
Reading back I see that the OP Audiolover718 says his system sounds great now - that's wonderful. Glad it worked out for you. Still would be curious to know what speakers you are using if you see this. 02-23-15: Wolf_garcia I hear you Wolf_garcia. I love my Music Reference RM9 100 wpc tube amp. But here is the thing. It puts me at the 15th row of a night club's music scene which is pretty cool. The Krell however puts me in the 5th row up front. So much energy there. Now the back rows I have to admit were better in the younger days ......for checking out all the chicks. Also no lights dimming when I turn it on (20 amp circuit) - I do close my eyes when the utility bill comes in though. Still I am able to listen all day and night if I wish and not have to strip down like I had to do with the OTL 195's. Again in my younger days this could lead to good things. These days it leads to strange looks and questions. @audiolabyrinth Not sure why you had a problem with 20 amp and your Krell amp. As you know the Krell 600 is cruising with B&W Matrix 800 which were Dan D'Agostino's personal speakers in this amp era. Any thoughts of having to tweak the power panel (non-existent). The Apogees mentioned on this thread - Apples to Oranges. Much greater amp load, and load on the house power. I guess I can maybe understand why an Apogee owner would search for power tweaks with those speakers. Does make me wonder what kind of bad ass speakers you must own? Maybe on another thread we can discuss this. fwiw - I sold a classe ca300 to an Apogee owner. He used it on them with those autoformers.... Happy Listening. |
Jea48, Hi, believe it or not, I have $11,500.00 into my amp!, it is totally new out side nearly everything inside, however, I was shocked myself, I have no idea Jim as to why Krell used a inter power 15 amp wall plug on this captive power cord!, unless they were tring to save money,LOL!, the inter power I have is brass, ok sound for what it is, but you can see as to why going to a high end wall plug like the furutech FI-50 Rhodium that is overly built 20 amp would be a good idea, Jim, I talked to chris vanhause of vh-audio, he sells the 30 amp wall plug version of the FI-50, his words- why would you buy this?, the 30 amp only has a little bigger contact surface area inside, the side ways blade is for child safty or people that would try to plug this type of wall plug to a normal fitted wall outlet, their is NO difference in each one for sound or power handling., end quote, chris also told me he does not list the 30 amp wall plug version on his site, no need, the version he sales is cheaper and can handle a load that I have here for sure, that said, I believe krell also used the inter power 15 amp plug on my captive power cord because this will not make any difference useing a 30 amp circuit, I know you dont believe that Jim, however, I have no issues!, the wall plug does not in any way change temperture driving the amp hard, it stays cold all the time jim, like I said, I am only conterplating on this furutech FI-50M for sound purposses only because I have the matching wpo's-wall power outlet's, thankyou jim, I am reading into what you are posting, I do not disagree with you, but I am saying I have NO issues here with what I have set-up, I constanly check, cheers. |
Audiolabyrinth, Krell chose to use a 125V 15 amp plug on the unit because the 125V 15 amp duplex is the standard wall receptacle found in dwelling units, homes, in the US and Canada. Krell did choose to use the 15 amp plug for economic reasons. Not because of the price of the 15 amp plug verses a 20 amp or 30 amp plug, but because how many people in the US or Canada have NEMA 5-20R 125V 20 amp duplex receptacles in their living room, family room, parlors, libraries, dens, bedrooms, or recreation rooms? They have 15 amp duplex receptacles because NEC Code says the minimum wire size that can be used on a 15 amp branch supplying power to a 15 amp branch circuit is #14 awg wire connected to a 15 amp breaker. You will find in most cases, at least in the US, residential dwelling units are wired to NEC Code bare minimum standards. But wait, Krell says the minimum circuit ampacity required for the Krell 700cx amp is 20 amps. Does your Krell 700cx amp have a 20 amp plug on the end of the cord? No, not by what you have said in your last post, it has a 15 amp plug. So why didn't Krell at least install a 20 amp plug on the end of the cord? Well that's easy, any fool knows a 20 amp plug will not fit, plug, into a 15 amp receptacle. Of course if Krell had installed a 20 amp plug on the end of the cord that would have required a 20 amp receptacle with #12 awg cu wire minimum, connected to a 20 amp breaker. Only a 20 amp breaker! I asked you in my last response to you if the Krell 700cx amp is UL and or CSA Listed. My guess it is not! As for what Chris Vanhause of Vh-Audio may have told you, I only have your side of the conversation. I would hope Chris is not telling customers it is ok to connect the furutech FI-50 Rhodium plug and Furutech receptacle to a 30 amp circuit.I suggest the manufacture of the plug and receptacle should be contacted and ask them what they have to say. IF, Furutech plugs and receptacles are UL and or CSA Listed connecting them to a branch circuit voltage or amperage circuit other than what the plug and receptacle is designed and manufactured for voids the UL Listing of the device. I would bet it also voids the manufacture warranty. As for differences found between a 125V 15 or 20 amp plug and receptacle and that of a 30 amp receptacle I suggest you go to the local electrical supply house or Home Depot store in your area and compare them to one another. What you will find is the 30 amp plug and receptacle contacts are about 50% bigger. Yes more surface area as well as more meat on the bone. After all the devices are designed and manufactured to handle 50% more load than the 15 or 20 amp device. The spacing between the contacts apart from one another is greater on the 30 amp than the 15 or 20 device. Here is some more info on the Krell 700cx amp. Audio Video Revolution, review. The Stereo Times, review. I found this thread on AA. Two 4KVA toroidal transformer in the Krell 700CX? When connected to a 30 amp branch circuit breaker the only thing that holds that puppy back is the breaker on the back panel of the unit. I wonder if it is a 30 amp? I doubt it. Audiolabyrinth, is it true the amp has two 4KVA power transformer? Do you know the ampere rating of the circuit breaker mounded in the back rear panel of the amp? 15 amp? 20 amp? Do you know if it is a magnetic trip breaker only? Another Agon thread.
. . I will leave you with this.
Electrical Forensics So a 20 amp receptacle installed on a 30 amp breaker could be 135% overloaded for up to an hour before it is supposed to trip open. 30 amps X 135% = 40.5 amps Has to trip open if overloaded by 200% in 2 minute. 30 amps X 200% = 60 amps Compared to, 20 amp breaker X 135% = 27 amps. 20 amp breaker X 200% = 40 amps . Jim |
Jim, I would have to e-mail patrick at krell, he can look into your request, or you may e-mail him, patrick bresnahan, very nice guy indeed,my amp does have two huge transformers jim,this thing weighs 180 pounds out the box!, jim, I have said that this amp is NOT useing all 30 amps period, it is spiking well above 20 amps, that is all, the 30 amp breaker gives the amp room to breath so to speak of instead of being choked down!, I believe my amp does have two 4KVA transformers, the so called breaker on the back of the amp is really a power switch, turns on the amp to stand by, I took a look at it for you, it says nothing on it or around it about amps, that stereo times review is a good one, should give you some info there if I recall Jim, and my recepticle is fine, it stays cold, no heat up or some kind of trip you specified, I learn alot from you jim, but for some reason, you believe this will not work, or does not work, please listen, this works wonderfully, sounds way better than a 20 amp breaker, I do know krell has told me it is a simple thing for them to change the power to 220 on this amp instead od 120 for u.s.a., I do not know if this helps jim, I do have a owners manual on this amp here, cheers. |
Jea48, another thing I wanted to say to you, first off, you have my respect, I bought this amp and refurbished it beyound oem because it is the last of the big iron of amps, it's the biggest most powerful stereo amp in krell history!, sure their may be better, I am thrilled with what this amp does jim, it's the kind I can ride off into the sunset with, I care less about the best next thing, very good sound is never absolete to me, sometimes, one needs to think about getting off the merry go round, do you believe that?, I do, tring to build something special here, krell already has informed me I am the only they know of with an amp like this that is modded, may not be the last to do all this, I do know this amp sounds hugely better than it did, all this took me two years jim, back and fourth this amp went to krell!, I have had it all complete as of december 2014, not very long at all,mated with tube equipment, it's magical sounding,cheers. |
03-06-15: Audiolabyrinth Well, there you go Jim! You have that going for you now. ;^) |
03-06-15: Jea48 @ Jea48 I spoke with my tech today and I asked him about the breaker panel question you had. This fellow has worked on the master Krells as a Krell tech and is independent now almost retired status. This was over the phone and I caught him in a parking lot, but he did tell me the breaker on the back of the Krell amps has four wires. It will go off not only by heat, but through something being wrong in the music signal path electronically. This is done remotely and is tied into the soft start at the front of he amp. He could not say for sure being in a parking lot, but he believe this breaker is rated for 20 amp. He has had to replace only one in his time servicing these amps. Also the stock Krell cord indeed has a 15 amp male plug, and probably for the reason you mentioned here earlier, but he feels it is good for 35 amps. It is a heavy sonofabitch. One more thing. I brought up what was discussed here about putting a 30 amp breaker in the fuse panel on a 20 amp line. He laughed, called it counter productive and for what ? He does not support it, for some of reasons stated here and used some words that I can't publish here. He then rimmed me and told me to stop reading internet banter. I told him it was cabin fever but that today is a nice day so I will go out and play. Well ....I needed an excuse to call him. he is over hauling my Music Reference RM9. Good news is I should be getting it back soon. **************************** 03-06-15: Audiolabyrinth Hi Audiolabyrinth $11.500 ? A total recap (small and large caps) and refurbishing of the big Krell amps, parts and labor by a qualified tech is in the $2000 range. You spent 5 times this amount. You must have made some design changes. Hotrodded it ? Assuming you now have a one of a kind Krell amp, and this explains some of the anomalies you were hearing with the 20 amp service ? .... which I just could not understand. Enjoy it. Happy Listening. |
LOL, he feels it is good for 35 amps? The manufacture of the plug rated the plug for a continuous connected load of 12 amps as per NEC Code, NEMA standards, as well as UL testing for a NEMA 5-15P 125V 15 amp plug. In other words the 15 amp plug can only be used on equipment that has an FLA of 12 amps or less. The 15 amp plug's blades and ground pin are the same size as that found on a 20 amp plug. The difference between the 15 amp plug and the 20 amp plug is on the 20 amp plug the neutral blade is turned 90 degrees with respect to the hot blade. In the electrical trade that is called making the device idiot proof. A 20 amp plug cannot be plugged into a 15 amp receptacle that could be connected to a 15 amp branch circuit, that is protected by a 15 amp breaker, in most cases the branch circuit wiring is #14 awg rated for 15 amps max. Do you think Krell is so stupid they do not know that? Hey, but the tech says the plug is good for 35 amps. I guess he would say the #14 cu wire is good for 35 amps as well. Forget about the plug, think about the non knowing consumer that bought the amp. If the plug on the amp plugs into the wall receptacle in his living room that's all that matters. Think the guy knows the branch circuit is only a 15 amp? All the consumer knows is that Krell knows what they are doing and the plug on the end of the cord plugged into the receptacle. Then his problems start. Who does he call first? Probably the dealer that sold him the amp. Just change the 15 amp breaker to a 20 amp breaker. Problem solved. Hell, the tech said the plug is good for 35 amps. Change it out to a 30 amp breaker! WhatÂ’s a few more connected load amps among friends.
If he does not support it why is Krell telling owners of the amp to do it? He then rimmed me and told me to stop reading internet banter.Oh, I just bet he did! Maybe if he read what is posted on audio forums he might learn something. He may also learn non-qualified people are doing what he/Krell suggests and or maybe worse. . Like I said early on in this thread Krell should be ashamed of themselves. I would guess the tech is not a state licensed electrician and it is obvious he does not know what the hell he is talking about. His expertise stops where the power cord exits the equipment. IF the amp has a 20 amp breaker on the back panel then the 125V plug should be a 20 amp plug. Krell should stop telling dealers as well as consumers that a 15 amp plug is good for 35 amps. The plug is not the issue. The issue is what the plug can be plugged into. If krell thought the 15 amp plug was plenty big, there in the FLA of the equipment does not exceed 12 amps, then they should have installed a 15 amp circuit breaker on the rear panel of the amp instead of a 20. Do you know why they didn't? NEC Code Table 210.21(B)(2) Maximum Cord-and-Plug-Connected Load to Receptacle . |
| Post removed |
| Post removed |
Jea48 the stock cord female end is labeled as 16 amps. the conversation was a noisy 5 minute phone call. He was implying I assume, that the cord could handle spikes. If he actually said 20 or 30 now I can't recall. I didn't pay much attention to this as I was calling him about the status of my Music Reference Amp. What was of interest to me and the part I did pay attention to was how the breaker worked. Not just by heat but with the signal itself. Very interesting. He said he thought the internal breaker might be 20 he's not sure and has only had to replace one. I did not ask him to confirm. Myself I would assume the breaker is going to be the same rating as the cord. He was very much against installing a 30 amp breaker in the fuse panel if the line is 20 amps. This part I remember and I made that clear in the previous post. cheers |
also the female end of the Krell cord is unlike any of my other gear and has horizontal bars like this |
Ct0517, the specified $11,500.00 is also the cost of the amp I paid before all the modds and refurbishment,the modd job was with shipping back and fourth, buying two pallets 2 diferent times, krell kept the first one and sent one back half the size of the original, so I bought a new full size pallet,straps 2 different times, fork lifts damaged the first 4 straps, $4,000.00 total for me, shipping the amp was $300.00 one way, and the amp went to krell a few times!, the actual cost I paid to krell was $3,157.38!, so wih the purchase of my amp, all the shipping, all the material to ship with, you damn straight I have $11,500.00 into this amp!, also, I do NOT have a 20 amp line, I have a dedicated 30 amp line, 30 amp breaker, copper 10 awg romex 3 conductor line,and yes I did get NONE oem brand caps, tweaked power supply, alot of new transistors, new heat sensors on both sides of the amp, 6 of them, 3 for each side, etc..., I have a huge bag of the old parts!, and I got new proccesors on each side of the amp, also, I am tired of telling all of you that the 30 amp single pole breaker made a huge difference in sound and the operation of my amp, I care less what any one says, all those that have done this convinced me to use the 30 amp breaker, it works great, again, with NO issues, BTW, I also renewed the cosmetics on the out side of my amp too. |
I have come late to this party, and I didn't read every single post, so forgive me if I missed something important to the discussion. First off, Krell IS NOT recommending that you simply replace your 15A breaker with a 30A breaker. What they do recommend is that in order to get the best out of the amp, use a 30A breaker with the APPROPRIATE wiring on a DEDICATED line. Appropriate wiring would, of course, include the appropriate outlet and plug. Now that being said, IF you have a dedicated line with 10# wire and a 30A breaker, the use of a high quality outlet and high quality plug, while NOT meeting code, would still be fine as far as safety issues go. The 20A Furutech, WattGate, ect. high end outlets and high end 20A power cords (plugs) are way over built and can handle the load presented by the amp even in the event of catastrophic failure. So there would be no fire danger. The amp in normal operation does not draw enough current to cause any problem at the outlet or plug. So technical wiring issues aside, does the 30A setup help the sound? Does a dedicated line help the sound? Do Power Cords help the sound? If you have a revealing system, you probably already know that EVERYTHING matters. The only thing is how much, and is it worth the expense. My personal experience has been that all these things help improve the overall sound of my system. If you don't believe that Power Cords make a difference, I'm probably not going to change your mind, and I would think that if you do not believe PC's make a difference, you are not going to believe that a dedicated line can make a difference, so why even discuss a 30A breaker setup? If you do think PC's make a difference, you should realize that the 30A setup COULD at least make a difference, and from my experience, it does. Good listening, M |
jea48, ct0517's tech guy did not work at krell!, no one knows krell amp's like krell does them self's, and Dan D Agostino, and Steve Lacrone that use to be the service manager there at krell up to 2009, Steve Lacrone owns a company called, The service Department Home, he specializes in all Krell equipment among other brands he services too, you may do a web search and see the company, he is located in CT, not far from Krell.cheers Jim. |
