Just how much of a no-no is this? ARC goes as far to print in their manual to say to have the amp and preamp on their own circuit. I live in an apt. and I'm forced to have both plugged into the same outlet. Cords just don't reach....How much sound quality is lost by doing this? It sounds great as is, but is there a major detriment to this? I'm curious.
Electricity scares the hell out of me so I was compelled to post the info. There is no foolery with Electricity. It needs to be done the right way. But ironically the result of this hobby, the music itself, is all about fooling ourselves ?
btw - I enjoyed your electricity video especially the power plants. Thinking about it now I find it kind of funny that the closest I came to feeling like I owned my own standlone powerplant, was with these OTL's The speakers could be disconnected and others reconnected at any time without powering off the monoblocks. They used horizontal sweep tubes. 600 watts at idle just like a 50 inch plasma tv according to the manufacturer. No TV in this room so I kind of justified things in my mind.
Almost felt like the speakers were connected directly into the wall outlets. In memory now, I no longer own them, they were like driving a 911 but you could only use first gear. They were designed around the needs of Acoustats. Issues developed with consistency and reliability.
J_stereo, I had a ARC SP3 along with a Dual 51 and Dual 75. I never even thought of using the switched or unswitched outlets on the back. I don't remember doing any experiments to discourage using them, but perhaps others advised against doing so.
But I certainly do remember little concern about power cords, vibrations, EMI or RFI much less ics and speaker wires. My first special speaker wires were from Bob Fulton and I realized that I had used identical wires on my welding rig while in undergraduate days in a material testing lab.
Just an update for Jea48 and others(?) following the Krell amp rear breaker panel value saga here. :^)
To backtrack, I tried to be of service to the thread as a messenger. I posted info from an email from Patrick of Krell advising that the breaker panel value on the back of these amps is 50 amps. I was however curious so I contacted Dan D'Agostino. He advised the breaker value for 120v service amps is 20 amps for reasons noted below. Fwiw I use a custom made 20 amp power cord, with the 20 amp dedicated circuit on my Krell amp.
I can therefore only recommend that any Krell amp owner with questions, clarify directly with Krell for their specific amp if they are curious. Patrick is a great resource for me, and I would find it awkward (as you can imagine) to approach him about Dan's info. It won't change my personal situation. The emails follow
Sent: Friday, March 06, 2015 2:36 PM To: Patrick Bresnahan Subject: RE: breaker value on back of amp ?
what is the breaker value on the back of my fpb600 or the other high power amps. FPB-700cx ? the Krell stock cord looks like a 15 amp ? and my wall is 20 amp service. is the breaker 15 amp ?
Date: Tue, 10 Mar 2015 17:14:28 -0700 You have very little protection if there was a failure with a 50 amp breaker. If the unit is set for 120 volts the most a standard 120 volt receptacle can safely have is 20 amps. There is no reason for a 50 amp breaker. It is not safe Dan
In the "old days" Preamps had switched outlets on the back where you would plug the amps into because the amps did not have a power switch. Some examples from ARC were the SP3A (still one of the best sounding Preamps I have ever heard) and the SP6 etc. So not only was the Amp and Preamp on the same circuit, but the amp was plugged into the Preamp, and I never thought that was detrimental to the sound. Of course that was back in the days before people were sold on $1,000 power cords and $5,000 speaker cables, etc.
So if the branch circuit feeding the amp is 30 amps, what if there is a ground fault event anywhere in the 120Vac power wiring inside the amp, including the hot side fed of a primary winding of one of the 4kva transformers, to the safety equipment grounded metal chassis of the amp? Will the ground contacts of the plug/wall receptacle combo be able to handle the ground fault current that will travel back to the source, the electrical panel? If the receptacle and plug are NEMA 30 amp rated and UL and or CSA Listed then yes the equipment ground contacts of the plug and receptacle will be able to handle the possibly extremely high current the 30 amp breaker can supply until it reacts to the ground fault load current placed on it and hopefully trips open and breaks the ground fault circuit.
If it's a NEMA 5-15P plug/5-20R receptacle connection who knows? Not the manufacture of the devices. Not UL or CSA. And I would be willing to bet Krell doesn't know either.
Quote "Will the ground contacts of the plug/wall receptacle combo be able to handle the ground fault current that will travel back to the source, the electrical panel?"
It should have been obvious but I should have included the plug/wall receptacle Hot contact connection as the Hot brach circuit conductor that is connected to the Hot contact of the receptacle is feeding the high current, caused by the ground fault event, back to the source, the electrical panel, through the safety equipment grounding conductor. "Houston, we have ignition!"
Also in case it was not clear my load calculations, in the post, were for possible FLA full load of the two 4 KVA power transformers. I have no idea what the actuals loads could be. If Al couldn't figure them out from the Krell specs given, I assure you I can't. I did try to find a wiring diagram for the amp on the net without any luck.
03-09-15: Ct0517 post reminded me again from a previous post of his the rear panel 50 amp breaker has a pair of wires for hard wire remote control of the breaker. Just a guess, and that's all it is, the 50 amp breaker has a shunt trip solenoid that when energized will mechanically trip the breaker open. The shunt trip circuit could be controlled through relay contacts of relays that are controlled from each channel of the amp. This could be part of overload protection for the two power amplifiers of the amp. A wiring diagram of the amp's overcurrent protection would be nice.
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?
@Jea48
I received info from Patrick Bresnahan at Krell that these are 50 amp breakers.
I provided some info in my previous post about how it works.
Cheers Ct0517
Ct0517,
Thank you for taking the time and finding out the rating of the breaker.
50 amp breaker.... 'IF' we are to assume the breaker handle rating of the breaker is 50 amps that could explain the power consumption max rating given in the Krell owner manual.
6000 max. watts / 115Vac = 52.17 amps.
‘IF’ , The 700CX amp has two 4kva power transformers. 4000VA, watts, / 115 = 34.8 FLA primary amps, secondary fully loaded for each transformer. (For purposes of transformer rating only).
Note, this assumes there is not any other current limiting fusing after the load side of the rear panel 50 amp main breaker of the Krell amp for each power transformer primary winding.
Secondary fuse protection could/would limit the amount of power that could be drawn from each power transformer as well.
The 50 amp rear panel breaker limits the max FLA combined total possible connected load of the two transformers by a little over 80%. 34.8 X 2 = 69.6 X 80% = 55.68.
So what else limits the mains 115Vac power for the 700CX amp? The branch circuit breaker in the electrical panel. Though remember the branch circuit is meant to protect the branch circuit wiring not what is connected to it at the wall receptacle. It is the manufacture's responsibility to select the proper NEMA plug for the FLA load for his equipment. If he say the equipment should be connected to a 20 amp circuit then his equipment must not draw more than 16 amps FLA. The plug on the end of the cord shall be a NEMA rated 125V 20 amp plug. PERIOD!
So far I have resisted giving any, "what if", happens in this thread concerning the Krell 700CX.
So if the branch circuit feeding the amp is 30 amps, what if there is a ground fault event anywhere in the 120Vac power wiring inside the amp, including the hot side fed of a primary winding of one of the 4kva transformers, to the safety equipment grounded metal chassis of the amp? Will the ground contacts of the plug/wall receptacle combo be able to handle the ground fault current that will travel back to the source, the electrical panel? If the receptacle and plug are NEMA 30 amp rated and UL and or CSA Listed then yes the equipment ground contacts of the plug and receptacle will be able to handle the possibly extremely high current the 30 amp breaker can supply until it reacts to the ground fault load current placed on it and hopefully trips open and breaks the ground fault circuit.
If it's a NEMA 5-15P plug/5-20R receptacle connection who knows? Not the manufacture of the devices. Not UL or CSA. And I would be willing to bet Krell doesn't know either. .
I have two dedicated lines, but use only one. The benefits and cost of ac filters mean that I can afford only one and seeing to isolating it from vibrations also means use of only one outlet. Years ago I tried to have each mono block on one dedicated outlet. I found the filters were of much greater benefit than separate lines.
"Far better than any penny you have ever heard Michael."
I beg to differ; the NOS stamped pennies have better imaging and micro-detail than those Far East-sourced OEM cast plugs. It's actually a gnat taking the whizz on the second chair cellist. I can clearly hear the up and down pitch characteristic. For a typical fly, with a much lower incidence of BPH, you have a single steady pitch note. And it's 18" further to the right.
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?
@Jea48
I received info from Patrick Bresnahan at Krell that these are 50 amp breakers.
I provided some info in my previous post about how it works.
Jea and Jmcgrogan, I thought you two already knew that you can't teach a pig to sing, and I'm certainly not going to try. I think my post explained everything pretty clearly. If you already know it can't make a difference, then I guess it certainly isn't worth your time to actually try it. For those who are open minded enough to try things like power cords, outlets, dedicated lines, etc., they will actually get to enjoy their systems even more. Those that don't won't. Good listening, M
FWIW, I have found that Rectangular Solid Core® SA-OF8N® copper fuse slugs offer the best sound by far, especially when used with their Isolated Floating Shield™. Far better than any penny you have ever heard Michael.
Cris, your 12 9's plug is no match for my fuse slugs, which Gauge size is 000 = an area of 85 Square mm. I can hear a fly take a wizz on the 3rd chair cellist with my fuse slugs!!
John, you have got a good start. BUT, if you are not using twelve 9s copper plugs at 150,000 square millimeters of conductor area, you can't possibly have any idea what you are missing. No more choking those poor little electrons.
BTW, I have heard what appeared to be just a bit of humming, but absolutely no singing. Couldn't carry a tune worth a damn though. Does that count?
I found that a solid copper plug beats any of those fancy audiophile fuses!
Jmcgrogan2- Because they don't draw as much current as that big ol' Krell arcweld...I mean amp...SETs often sound better with an NOS 1909 s vdB Lincoln copper penny than w the copper plug. I find that the difference between that and the 1924 Lincoln copper to be well worth the additional $1500-$2K. Of course, you've got to be very careful inserting the pennies; if you scratch them their value on the Coiniogon drops dramatically. When scratched, they're not work a " plugged" nickel!
03-08-15: Jea48 For those of you that are hell bent on using a 30 amp circuit connected to a 20 amp receptacle in violation of all electrical safety codes why are you limiting yourselves to using a 30 amp breaker? Why not stick a 60 amp breaker in the panel in place of the 30. Hell, better yet, eliminate the bottle neck breaker all together and tie the hot conductor for the branch circuit directly to the HOT bus on the panel.
And for even better performance of the Krell amp eliminate all fusing inside the amp. Talk about a bottle neck, can you imagine all the electrons being forced to get into single file to pass through that small little wire inside the fuse. Let them run free....
It's about time you came around with some quality audiophile suggestions Jim!! That's how I have things wired up in my home. Get them stupid fuses out of there altogether! I found that a solid copper plug beats any of those fancy audiophile fuses! Also ALL circuit breakers, 20A, 30A, 60A, 100A interfere with the quality of the sound....PERIOD!! I have my hot conductor soldered directly to the hot buss on the panel, just as you suggest (using high purity silver solder of course). This is the ONLY way to go! The sound is much more open, lively and engaging.
In fact, I even took it a step further, and tied the panel buss directly to my amps power supply, eliminating silly connectors and outlets!! This is heaven! The sound is so pure you would not believe it!!!
Did you tell Audiolabyrinth it was alright to install a NEMA 5-20R receptacle 125V 20 amp rated receptacle on a 30 amp branch so he could then plug in the NEMA 5-15P 125V 15 amp plug that is connected to a power cord that feeds the Krell 700W @8 ohm, 1400W @4 ohm, 2800W @ 2 ohm, with an up to 6000 Watt power consumption rating per Krell specs of the amp?
03-04-15: Audiolabyrinth 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. Audiolabyrinth
03-08-15: Mrvordo 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. Mrvordo
Really? Curious why didn't Krell just install a 30 amp plug on the power cord to begin with?
. Highlights.....
02-13-15: Audiolabyrinth Mitch2,That is funny!, my amp got way to hot on just a single pole 20 amp breaker, krell told me that my amp was designed to run on single pole 30 amp breaker, guess what, I did what krell told me to do, my amp has incredible dynamic's, bigger sound stage and transparency, and now for the kicker, the amp never run's hot and operates smoother, my krell kick's a 20 amp in the Axx! Audiolabyrinth
02-28-15: Audiolabyrinth 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! Audiolabyrinth
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03-03-15: Audiolabyrinth 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! Audiolabyrinth
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03-04-15: Audiolabyrinth 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. Audiolabyrinth
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03-05-15: Audiolabyrinth 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 (Threads | Answers | This Thread)
03-06-15: Audiolabyrinth 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
quote "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," . .
Again for the umpteenth time there is no difference in the contacts or associated current carrying circuit parts of a 20 amp breaker or a 30 amp breaker! ONLY the TM, thermal and magnetic, trip setting are different. Any differences possibly heard could only be because of the contact seating of the contacts in the breaker or possibly the tension contact of the breaker to the bus tie of the bus of the electrical panel. Note the breaker connecting mechanism is made of exactly the same material for both the 20 amp breaker and the 30 amp breaker for that manufacture, model and style number. TRY A DIFFERENT 20 AMP BREAKER! Then listen again for any difference. IF you hear a difference it is all in your head!
For those of you that are hell bent on using a 30 amp circuit connected to a 20 amp receptacle in violation of all electrical safety codes why are you limiting yourselves to using a 30 amp breaker? Why not stick a 60 amp breaker in the panel in place of the 30. Hell, better yet, eliminate the bottle neck breaker all together and tie the hot conductor for the branch circuit directly to the HOT bus on the panel.
And for even better performance of the Krell amp eliminate all fusing inside the amp. Talk about a bottle neck, can you imagine all the electrons being forced to get into single file to pass through that small little wire inside the fuse. Let them run free.... .
@Audiolabyrinth thanks for clarifying the costs - that makes sense.
jea48, ct0517's tech guy did not work at krell!
Well of course not he is Canadian. But he has worked on the Master Krell Ref's. Can everyone working in the service dept at Krell these days say the same ? Now..... I don't "really" care about the answer - just think about it.....
Ct0517, look, I do not know what krell amp you have or owned
Not sure why not. I show a virtual page. You can see what I have.
BTW what speakers are you using with the amp ?
I have a huge bag of the old parts!
Sometimes a picture is worth a thousand words. After all the public chat forms imo are for learning sharing and a little fun.
03-08-15: Mrvordo 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.
Thanks for clarifying Mrvordo.
MrV and AudioLabyrinth
My two rooms are in the basement adjacent to one another. B is closer to the Fuse panel over A the main room. I left a path - removeable ceiling - going from outside Room A, past Room B to the fuse panel for upgrades and changes. If I ever chose to add new line (30amp service), it would be very easy laying new line over the beams. The only costs being the electrician putting in the breaker.
Ct0517, look, I do not know what krell amp you have or owned, my amp is hard wired straight to the power supply!, not going to any bus bars, there is none!,I myself have seen this inside my amp, and krell also has confirmed this to me!, my amp does NOT consume 30 amps!, it simply spikes over 20 amps, what I have tried to make clear to all of you, I have a 30 amp dedicated electrical line, a 30 amp single pole breaker, and a wpo that is 20 amp's but sustains the amp spikes over 20 amps with no issues, my amp runs smoother, cooler, bigger sound stage, hugely more dynamic, my amp is no longer choked by the 20 amp breaker.
And to the OP, having your equipment on separate dedicated lines does improve the overall sound quality of your system. That is why ARC recommends it. This does not mean that your system cannot sound good on a single outlet, just that it would sound better on separate circuits. Best, 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.
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.
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.
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.
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. 03-07-15: Ct0517
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.
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.
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?
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?
@ 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.
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03-06-15: Audiolabyrinth I have $11,500.00 into my amp!
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.
thankyou p59teitel, that is what I have, two furutech GTX-D Rhodium's,and wall frame and cover plate, I have all the box's too, just have not had time to look at the box's and info, 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.
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.
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?
Should read, Do you know the ampere rating of the circuit breaker mounted in the back rear panel of the amp? .
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.
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?
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
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.
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 Interestingly (only to me perhaps), after switching to a moderately powered tube power amp (60 to 85 watts or so per side) I found that the lights no longer dimmed at loud passages like they did with my previous 100 watt pc high current SS amp.
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....
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.
Listen everyone, I have a dedicated line rated above 30 amps!, their is no issues,I have said numerous times, I have a 10/3 romex, meaning 10 awg 3 conductor dedicated line, it is the same as the captive cord on my krell 700cx, seems no one is listening to me more like it! 03-05-15: Audiolabyrinth
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?
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.
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 watts
from their specs to justify the reason they choose the plug and not a 30 amp rated plug. .
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.
Listen everyone, I have a dedicated line rated above 30 amps!, their is no issues,I have said numerous times, I have a 10/3 romex, meaning 10 awg 3 conductor dedicated line, it is the same as the captive cord on my krell 700cx, seems no one is listening to me more like it!
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