Amp and preamp on same outlet?

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 above now said, in some homes installing a 20 amp line is either not possible, and or its install cost can be prohibitive, depending on the age of the house. I know for a fact that there are many customers out there who are successfully running systems with large Krell amplifiers using a 15 amp line. Would there be a dramatic sonic difference between using a 15 amp line and a 20 amp line? Maybe and maybe not. A good stiff 15 amp line verses a weak 20 amp line, in my opinion you would probably not hear the difference between these two.

As the expression goes, “the proof is in the end result”. If when using a 15 amp line, the amp sounds open and fast and detailed with good bass and sound staging, and it does not pull the 15 amp line breaker down during loud playback or loud musical transients, he should be good to go as is. However if he is tripping the 15 amp AC line breaker occasionally during playback, he should go up to a 20 amp line if possible.

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.

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....

Happy Listening.

03-06-15: Jea48
Edit to my last post.

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.

Enjoy it.
Happy Listening.

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

@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.

here is a pic to give the others reading an idea

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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.

Have a nice day. beautiful looking Sunday.

Happy Listening.

@Audiolabyrinth

one more thing :^)

when I asked..

BTW what speakers are you using with the amp ?

It is for purely my own selfish reasons, to determine how close your speakers amp requirements come to mine.

Cheers

03-06-15: Jea48
Edit to my last post.

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

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

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Patrick Bresnahan 09/03/2015
To:
PBresnahan@krellonline.com

These are 50 amp breakers.

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 ?

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I asked the same question to Dan D'Agostino

From: dan@dandagostino.com

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


From: dan@dandagostino.com

Date: Tue, 10 Mar 2015 16:27:03 -0700
Hello Chris that amplifier should Have a 20 amp breaker not a 50

Jea48

:^)

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.

Cheers