Whats a DVM. I have a fluke true RMS meter. 600 volt. Not 1000.
I have gold 10 watt resistors.
I am sick of failing amplifiers
- Thread starter Kingrex
- Start date
I have gold 10 watt resistors.
I described what you need for bleeding the caps. 'DVM' stands for Digital VoltMeter. Your Fluke is an example.
If there is a toroid power transformer then the mu metal shield isn't doing anything. I've never seen a transformer manufacturer supply a toroid with a stainless bolt if they supply one at all. We found out about that thru the School of Hard Knocks about 35 years ago. So yours is likely just steel.
But if its a toroidal transformer, DC on the incoming AC line could be causing the core to saturate and rattle. And yes, some toroids from the same run are more susceptible than others. At any rate this problem can be solved by a DC blocker, which is a simple arrangement of a diode array and some electrolytic caps bypassing them. This circuit can be installed in the amp if there's room (we put them in our stuff) or it can be in an outlet box that feeds the amp
Amps are fed by a isolation transformer, so there should not be any DC.
There are wiring discrepancies in the power supply between the two amps. They are wired different. I could take a picture, but I don't know that that would mean much as it's on a circuit board.
There are wiring discrepancies in the power supply between the two amps. They are wired different. I could take a picture, but I don't know that that would mean much as it's on a circuit board.
Tell that to my friends with krell.Switch to SS amplification , haven't had one fail on me in 40+ yrs...
Even Ralph figured that out ......
Somebody else, I knew of had a solid state amp, and one of the output transistors went out. There was 0 chance of him getting a matching transistor so the amp was basically useless. The other option was to take both of his monoblocks and completely strip all of the output transistors and put new ones in. But that was going to change the voicing of the amp.
I believe it's disingenuous to walk around insinuating Solid State amplifiers never have issues. And from what I hear when they do, they are generally unfixable. Unless the manufacturer is still around and has spare parts. And your only recourse for repairs is the manufacturer.
Come to think of it, another friend.How to solid state?Amp that went bad. They were told to throw it out by the manufacturer. And that is what they did. It was an expensive amp too.
True, I have been using a manufacturer's certified tech in the USA for my tube amp. And i'm getting less than stellar results.
First 2 images are the noisy amp.
The second 2 are rhe quiet amp
There is a small orange wire near the front of the power supply on a post that goes all over. Thats the noisy amp.
On the quiet amp, the same wire goes directly to a cap. .
Both go to this resistor. Way above my paygrade to diognose and solve.
anyone have a deaire to work on a SET.
The second 2 are rhe quiet amp
There is a small orange wire near the front of the power supply on a post that goes all over. Thats the noisy amp.
On the quiet amp, the same wire goes directly to a cap. .
Both go to this resistor. Way above my paygrade to diognose and solve.
anyone have a deaire to work on a SET.
I did not insinuate anything , i said i have not had one fail on me in 40+ yrs ..!
Your friend operating his amplifier deficiently or having a faulty amp does not negate my comment ..
I have also owned many toobs , some failed so didn't, all had some issue Or the other and required more maintenance .
Toobs require more maintenance than their SS counterparts , this is not even debatable..
BTW never had a krell fail on me , tell your friends to monitor the temps on those high bias amps , if you can’t touch the sinks they are too hot turn it off or cool momentarily with a fan ..
Last forever really ..!
PS: If your friend is throwing out those
worthless mono Bloc’s I can arrange a PU , what are they BTW .. ?
Your back peddling.I did not insinuate anything , i said i have not had one fail on me in 40+ yrs ..!
Your friend operating his amplifier deficiently or having a faulty amp does not negate my comment ..
I have also owned many toobs , some failed so didn't, all had some issue Or the other and required more maintenance .
Toobs require more maintenance than their SS counterparts , this is not even debatable..
BTW never had a krell fail on me , tell your friends to monitor the temps on those high bias amps , if you can’t touch the sinks they are too hot turn it off or cool momentarily with a fan ..
Last forever really ..!
PS: If your friend is throwing out those
worthless mono Bloc’s I can arrange a PU , what are they BTW .. ?
All krell are kitchen appliances made to fry eggs. I have 2 friends with the KSA250 and KSA600. Both have fans under the amps. Both are untouchable when on.
When my Dartzeel went back to Herv, it needed work. Minor stuff. But left unattended, could have stopped. Not bad for a 19 year old amp.
I just bought my self two Krell amps
Ksa80b and ksa200b
both work fine but to me the ksa 200 cooks at 141 degrees at idel.
I lowered the bias a bit to get to 130 now.
I can’t imagine how someone would leave an amp on st this high temp and who knows if the room is hot. My place is 68
it heats up my room have use a ceiling fan and leave door and widow open
Ksa80b and ksa200b
both work fine but to me the ksa 200 cooks at 141 degrees at idel.
I lowered the bias a bit to get to 130 now.
I can’t imagine how someone would leave an amp on st this high temp and who knows if the room is hot. My place is 68
it heats up my room have use a ceiling fan and leave door and widow open
If there is DC on the line, an isolation transformer will often pass it right along. DC on the line is one side of the AC waveform not being quite as high as the other side. Its caused by things like electric heaters on low that are only using half of the AC waveform.
Well, IME having been repairing older solid state amps over the last 40 years, they often are quite fixable. Maybe you can't find the original output device, but chances are good you can find a suitable replacement. In some cases you simply can't so the amp is junk but IME that's generally not the case.
You'll likely have to send both amps along to whomever works on the noisy one. Just looking at the photos there are things that don't make sense including that orange wire- at least one diode that don't appear to be hooked up...
The tec who did the work responded. Some excuse about it's basically the same, so he left it alone.
Then he agrees that if the input and driver tube are so reactive that lightly tapping on them creates a loud noise out the speakers, that they are most likely picking up vibrations from the output transformer and amplifying them. They want me to set a block of wood on it and forget about it. Or, pay a bunch more money to have it work right. I really don't want to pay this guy anymore. Its the 4th time and still he can't get it right.
And yes I would want a tech to have both. I like to ship by pallet now, so its not much more. Its about $350 each way.
Then he agrees that if the input and driver tube are so reactive that lightly tapping on them creates a loud noise out the speakers, that they are most likely picking up vibrations from the output transformer and amplifying them. They want me to set a block of wood on it and forget about it. Or, pay a bunch more money to have it work right. I really don't want to pay this guy anymore. Its the 4th time and still he can't get it right.
And yes I would want a tech to have both. I like to ship by pallet now, so its not much more. Its about $350 each way.
Your back peddling.
All krell are kitchen appliances made to fry eggs. I have 2 friends with the KSA250 and KSA600. Both have fans under the amps. Both are untouchable when on.
When my Dartzeel went back to Herv, it needed work. Minor stuff. But left unattended, could have stopped. Not bad for a 19 year old amp.
Your moon walking now.....
Neither leave them on either. Both have been rebuilt. The 600 was rebuilt by Krell. 2 months later it failed. Now Krell is closed. Hes out in the cold until they get the trust sorted if they can.
The other guy sick of the heat and hour warm up time bought Odyssey monos. At $2700 a pair. If they fail, toss them. And they play very similar to the krell. More refined and clean. Faster. Krell is havier with a little more sense of weight. He then built subs from Dayton drivers and uses the Krell to drive them. He has too much bass for my taste.
You running out of time REX pass them on and move on to a better built amp , without issues , those things have layout issues on top of everything else ..!
...I will add: based on the pics, I etched PC boards that good...when I was in 9th grade shop class. They don't look great to me.
Yeah- I didn't want to say anything... If those amps were mine I'd be spending time cleaning up the wiring.
Obviously they are not the same. Sounds like he's suggesting the input tubes are so microphonic that the vibration from the power transformer is audible in the speaker as a hum. FWIW, that is really a microphonic tube!! -if that's what's causing it; one that is simply unacceptable. IIRC this amp uses a 6DJ8 variant; 6DJ8s and their brethren (such as the 6H6) are 'frame grid' triodes. They are meant for instrumentation and high frequency work and while very linear, are not suitable as an audio tube since they are so prone to microphonics. I've seen some so bad you could yell at them and hear yourself in the speakers. Obviously when an amp is playing with such tubes in it, vibration from the speakers will color the sound, which is both measurable and audible.
If it really is hum from vibration of the toroidal power transformer, the thing to do is install a DC Blocker as I mentioned. That might kill two birds with one stone.
The Krell 600 is an fpb? I don’t know of a ksa600
I now own 2 Krell’s the KSA 80b is a friends amp I picked up for him.
I have a Krell 700cx it’s a good amp too
Last version of sliding bias
Amp is warm if left on gets hot as I play
Sounds good on my infinity IRS 5. they dip into below 2 ohms
it’s Also rebuilt by myself
Amps are done by me
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