Latest krell saga

[mep]

I took the advice of one our members who is free to jump in here and say who he is and sent Bill McKiegan an email last night and explained the situation and asked for his help. Bill replied back today and asked me to try the amp out in another room in my house with a different system to make sure the hum problem moves with the amp. Bill told me that if Krell finds something wrong with the amp, Krell will pay shipping charges both ways. I'm very happy with that response. Now I just have to get it out of my basement and up the stairs into another room. I wil hook it up to a pair of JBL 4312B speakers I happen to have laying around. I will use the Yamaha preamp and plug in my Oppo CD/SACD/DVD/everything but the kitchen sink player and see what happens.

 

[treitz3]

Best wishes for a quick solution, mep.

 

[mep]

Thanks Tom, I appreciate it.

 

[LL21]

Yes, good luck. That's a good solution. Alternatively, if you have a good local audio tech...have him plug it into his workbench...and if he also gets a hum, that also provides you with some protection that Krell does not say 'sorry no hum...you pay'. Hum can be an elusive thing to track down and eliminate...and it can help when there is 3rd party corroboration of the hum...at least to ensure Krell try extra hard to hunt it down and fix it for good. Good luck!!!

 

[RBFC]

Krell may not be the "preferred" brand of all our members, but they have been one of the premier audio companies for decades. Bill McKiegan is a stand-up guy who will try to make this right. I sincerely hope the amp gets squared away quickly, Mark.

Lee

 

[mep]

Thanks Lee. I really do appreciate it.

 

[mep]

I tried another experiment last night. I took an entirely different pair of speaker cables and hooked up a pair of JBL 4312B speakers to my Krell KSA-250. Ta-Da, same hum. The only surprise was how high the imaging is with the JBLs. I just plopped them on the floor and lashed them up and expected to hear images that were about as tall as the speakers. These speakers really should be on some sort of stands. What I heard was imaging that was double the height of the top of the speaker. I kept looking at my main speakers and thinking the imaging even sounded higher than what I normally achieve with them. It was quite the parlor trick. There is way too much treble energy with the JBL speakers for my taste though. They are just too hot on top for me. They are mint though and I couldn’t pass them up for $100 as they are worth more than that to the right person and I think I found that person.

Bottom line: different speakers, different cables, same result.

 

[LL21]

Is there ANY chance, you can take the Krell down to the local audio store or to a nearby audio tech to sanity check the hum before you take the trouble of shipping the thing all the way back to CT (assuming they are still based in Milford, CT)?

 

[mep]

Lloyd-There is no local audio store where I live. This amp isn't something you just tuck under your arm and schlep it wherever you want to go. It's a two man job to move it anywhere. It's not just that it weighs 140 lbs, it's also the physical size of those 140 lbs. I do get your point though.

Here is the deal: no other amp that I have ever had in my listening room has hummed. None. Zero. I can plug my little PL-400 Series 2 amps into the same 20A circuit I had run for the Krell and there is nothing but deadly silence until the music starts. I'm just having a hard time believing that every other amp I have owned has no problems with hum in my room and now the fact that the Krell hums means I have something wrong somewhere else in the system that is causing the Krell to hum. It doesn't make sense. It hums with the inputs shorted. It hums when plugged into different outlets. It hums with different speaker cables and different speakers. It hums when I disconnect my subs from the main speakers. It hums when I put a cheater plug on it. Hell, it hums when I look at it. I'm tired of looking for other culprits that might be the cause of the hum. It's getting rather ridiculous really. In fact, it has crossed the line. It is ridiculous. It sort of reminds me of a state executing a prisoner via lethal injection and then wasting money to perform an autopsy to determine the cause of death.

 

[MylesBAstor]

Lloyd-There is no local audio store where I live. This amp isn't something you just tuck under your arm and schlep it wherever you want to go. It's a two man job to move it anywhere. It's not just that it weighs 140 lbs, it's also the physical size of those 140 lbs. I do get your point though.

Here is the deal: no other amp that I have ever had in my listening room has hummed. None. Zero. I can plug my little PL-400 Series 2 amps into the same 20A circuit I had run for the Krell and there is nothing but deadly silence until the music starts. I'm just having a hard time believing that every other amp I have owned has no problems with hum in my room and now the fact that the Krell hums means I have something wrong somewhere else in the system that is causing the Krell to hum. It doesn't make sense. It hums with the inputs shorted. It hums when plugged into different outlets. It hums with different speaker cables and different speakers. It hums when I disconnect my subs from the main speakers. It hums when I put a cheater plug on it. Hell, it hums when I look at it. I'm tired of looking for other culprits that might be the cause of the hum. It's getting rather ridiculous really. In fact, it has crossed the line. It is ridiculous. It sort of reminds me of a state executing a prisoner via lethal injection and then wasting money to perform an autopsy to determine the cause of death.

Dumb question. Can't remember if you tried other ICs or speaker cables?

 

[FrantzM]

The damn Amp is faulty point final.. ! Point Krell to this thread, it will document your saga better than any speech. Have them repair correctly the DARN thing. At this level of component the thing must remain silent .. So call them Monday and prepare the thing for shipping SINCE they offered to pay for that .. Moving 140 lbs of amp is not a healthy endeavor ...
Take them to their words...

 

[mep]

Dumb question. Can't remember if you tried other ICs or speaker cables?

Yep. I just talked about using different speaker cables and different speakers. If the damn thing hums with both sets of inputs shorted, that rules out ICs.

 

[MylesBAstor]

The damn Amp is faulty point final.. ! Point Krell to this thread it will document your daga beter than any speech. Have them repair correctly the DARN thing. At this level of component the thing must remain silent .. So call them Monday and prepare the thing for shipping they offered to pay for thta .. Moving 140 lbs of amp is not a healthy endeavor ...
Take them to their words...

+10^6

 

[Orb]

Yep. I just talked about using different speaker cables and different speakers. If the damn thing hums with both sets of inputs shorted, that rules out ICs.

Only option IMO is to test with a good quality mains conditioner, continue doing the test Micro outlined with the new Fluke or send them back to Krell.
However, the risk is that they may say it is working within parameters, so best bet is to still do the test mentioned by Micro and also borrow a quality mains conditioner such as Running Springs Audio.
Even though you have the audio on a seperate feed, is it possible you are having harmonic/noise/etc related issues incoming from outside?
Apologies do not know how it works for mains from outside a residential house in US, but this is a problem over here in the UK (and one I suffer with myself).

Cheers
Orb

 

[RogerD]

Send it back and if they can't resolve the issue get the freight prepaid so your costs aren't worse then they allready are. If they can't fix it,I would ask for a written explanation from their technical department,which could help in a future sale. I myself think it's the transformer,and if so,how would they fix that.

 

[Fred]

Picked up this thread pretty late it seems. Really sorry to read all that you've endured with this mep. It sounds to me like you have a bad power transformer. All the moving it around and trying this that and the other isn't going to fix anything becuase the problem isn't with any associated equipment, connectors, or electrical supply circuits. The problem is that the amp is broke. Plain and simple.

On a scale of this exact magnitude I had a hum with my first Jolida IA. The f'ing thing hummed out of the box. For weeks on end I had to listen to that crap and call after call to Jolida about it led to the exact "suggestions" and "recommendations" that you're getting from Krell. Finally one night I got so angry with the thing that I came within a hair of taking a .357 to it. That next day I got on the phone with Jolida and told them it's come to Jesus time.

Guess what? After a week with them I got the call that the power transformer was bad. I got a new amp sent out the next day. The new one did what it's supposed to do. Amplify my speakers quietly.

I feel for ya bud. My thinking here is simple. Don't take any BS from them. Make them fix the friggin' problem.

 

[LL21]

Lloyd-There is no local audio store where I live. This amp isn't something you just tuck under your arm and schlep it wherever you want to go. It's a two man job to move it anywhere. It's not just that it weighs 140 lbs, it's also the physical size of those 140 lbs. I do get your point though.

Here is the deal: no other amp that I have ever had in my listening room has hummed. None. Zero. I can plug my little PL-400 Series 2 amps into the same 20A circuit I had run for the Krell and there is nothing but deadly silence until the music starts. I'm just having a hard time believing that every other amp I have owned has no problems with hum in my room and now the fact that the Krell hums means I have something wrong somewhere else in the system that is causing the Krell to hum. It doesn't make sense. It hums with the inputs shorted. It hums when plugged into different outlets. It hums with different speaker cables and different speakers. It hums when I disconnect my subs from the main speakers. It hums when I put a cheater plug on it. Hell, it hums when I look at it. I'm tired of looking for other culprits that might be the cause of the hum. It's getting rather ridiculous really. In fact, it has crossed the line. It is ridiculous. It sort of reminds me of a state executing a prisoner via lethal injection and then wasting money to perform an autopsy to determine the cause of death.

Good luck...'seething' i think is the word. i am sorry for that...been there and finally got it fixed and sold it.

 

[Phelonious Ponk]

Picked up this thread pretty late it seems. Really sorry to read all that you've endured with this mep. It sounds to me like you have a bad power transformer. All the moving it around and trying this that and the other isn't going to fix anything becuase the problem isn't with any associated equipment, connectors, or electrical supply circuits. The problem is that the amp is broke. Plain and simple.

On a scale of this exact magnitude I had a hum with my first Jolida IA. The f'ing thing hummed out of the box. For weeks on end I had to listen to that crap and call after call to Jolida about it led to the exact "suggestions" and "recommendations" that you're getting from Krell. Finally one night I got so angry with the thing that I came within a hair of taking a .357 to it. That next day I got on the phone with Jolida and told them it's come to Jesus time.

Guess what? After a week with them I got the call that the power transformer was bad. I got a new amp sent out the next day. The new one did what it's supposed to do. Amplify my speakers quietly.

I feel for ya bud. My thinking here is simple. Don't take any BS from them. Make them fix the friggin' problem.

I'm sure they'll be happy to. Mark bought the Krell used. If it's a transformer, a problem Krell has not worked on in the previous servicing, I'm sure they'll charge him the full shipping and repair.

Mark, you've really been through the ringer on this one. I hope it ends up being something much simpler than this.

Tim

 

[mep]

Tim-It's been my fear all along that it's the transformer. My EE friend in WA thinks it's a lack of capacitance in the first driver stage. I know my listening room is more quiet than the average bear, but your room would have to be really noisy to not hear this. If it is the transformer, an 83 lb 4.5kv transformer can't be cheap.

 

[fas42]

Okay, Mark has run quite a few tests, eliminating a number of possibilities. My thinking now is that this Krell does have a design weakness, which is that the signal input circuitry is right on the edge of magnetically coupling with the currents flowing in the power supply side of things. In other words, there is effectively a transformer interaction between the two. This can occur if the circuitry or cabling are literally too close at some point, so seeing as many examples of this amplifier don't have an apparent problem, maybe in the refurbishing some cables were moved to a different location, or allowed to casually lie wherever movement of the amp happened to jolt them, or even deliberately tied together, when they shouldn't be.

So, it may be worthwhile seeing if there is loose cabling within, and adjusting its positioning as an experiment; or, getting internal shots of another amp without such problems, so see if the physical location of cabling, or even components vary. It may turn out that something as simple as moving something several inches in a particular direction fixes everything ...

Frank